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1、NREL is a national laboratory of the U.S.Department of Energy Office of Energy Efficiency&Renewable Energy Operated by the Alliance for Sustainable Energy,LLC This report is available at no cost from the National Renewable Energy Laboratory(NREL)at www.nrel.gov/publications.Contract No.DE-AC36-08GO2

2、8308 Technical Report NREL/TP-6A20-88556 April 2024 County Land-Use Regulations for Solar Energy Development in Colorado Allison Jackson,1 Kate Doubleday,2 Brittany Staie,2 Allison Perna,2 Mariel Sabraw,1 Liz Voss,1 Apolonia Alvarez,2 Byron Kominek,1 and Jordan Macknick2 1 Colorado Agrivoltaics Lear

3、ning Center 2 National Renewable Energy Laboratory NREL is a national laboratory of the U.S.Department of Energy Office of Energy Efficiency&Renewable Energy Operated by the Alliance for Sustainable Energy,LLC This report is available at no cost from the National Renewable Energy Laboratory(NREL)at

4、www.nrel.gov/publications.Contract No.DE-AC36-08GO28308 National Renewable Energy Laboratory 15013 Denver West Parkway Golden,CO 80401 303-275-3000 www.nrel.gov Technical Report NREL/TP-6A20-88556 April 2024 County Land-Use Regulations for Solar Energy Development in Colorado Allison Jackson,1 Kate

5、Doubleday,2 Brittany Staie,2 Allison Perna,2 Mariel Sabraw,1 Liz Voss,1 Apolonia Alvarez,2 Byron Kominek,1 and Jordan Macknick2 1 Colorado Agrivoltaics Learning Center 2 National Renewable Energy Laboratory Suggested Citation Jackson,Allison,Kate Doubleday,Brittany Staie,Allison Perna,Mariel Sabraw,

6、Liz Voss,Apolonia Alvarez,Byron Kominek,and Jordan Macknick.2024.County Land-Use Regulations for Solar Energy Development in Colorado.Golden,CO:National Renewable Energy Laboratory.NREL/TP-6A20-88556.https:/www.nrel.gov/docs/fy24osti/88556.pdf.NOTICE This work was authored in part by the National Re

7、newable Energy Laboratory,operated by Alliance for Sustainable Energy,LLC,for the U.S.Department of Energy(DOE)under Contract No.DE-AC36-08GO28308.Funding at NREL provided by the InSPIRE project through U.S.Department of Energy Office of Energy Efficiency and Renewable Energy Solar Energy Technologi

8、es Office award DE-EE00038642.The views expressed herein do not necessarily represent the views of the DOE or the U.S.Government.This report is available at no cost from the National Renewable Energy Laboratory(NREL)at www.nrel.gov/publications.U.S.Department of Energy(DOE)reports produced after 199

9、1 and a growing number of pre-1991 documents are available free via www.OSTI.gov.Cover Photo by Werner Slocum:NREL 64503.NREL prints on paper that contains recycled content.iii This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.Acknowledgme

10、nts The Colorado Agrivoltaic Learning Center would like to thank the National Center for Appropriate Technology(NCAT)and the NCAT AgriSolar Clearinghouse for their financial support of this report.The authors wish to thank Megan Day,Anthony Lopez,Aaron Levine,Amy Brice,Mark Ruth,Caitlin Murphy,Dan B

11、ilello,David Glickson,Jeff Cook,James McCall,Martha Symko-Davies,Mary Werner,William Livingood,Doug Arent,Juan Torres,Gian Porro,Kristen Boysen,and Wil Mannes for their insightful reviews and comments,and National Renewable Energy Laboratory team members Billy Roberts and Emily Horvath for their val

12、uable contributions.iv This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.List of Acronyms CALC Colorado Agrivoltaic Learning Center CRS Colorado Revised Statutes CSG community solar garden EIA U.S.Energy Information Administration ft foot

13、GWac gigawatts alternating current GWdc gigawatts direct current kW kilowatt kWh kilowatt-hour MWac megawatts alternating current MWdc megawatts direct current NREL National Renewable Energy Laboratory PV photovoltaic SEIA Solar Energy Industries Association USDA U.S.Department of Agriculture v This

14、 report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.Executive Summary The United States is experiencing rapid growth in ground-mounted solar,including in Colorado where utility-scale(1 MW nameplate capacity)solar photovoltaic(PV)plants have been

15、 deployed in 28 of 64 counties(U.S.Energy Information Administration EIA 2023a).Ground-mounted or free-standing solar uses an array of PV modules mounted on a racking system on the ground.It includes both large,utility-scale plants as well as smaller applications,such as customer-sited arrays at com

16、mercial or industrial facilities and community solar gardens.As solar deployment has increased,so have community concerns about impacts to the visual landscape,property values,community character,and the development of agricultural land(Nilson,Hoen,and Rand 2024).Agrivoltaics,a dual land use combini

17、ng agriculture and ground-mounted PV on the same land,is one possible solution to some of these challenges(Macknick et al.2022).Agrivoltaics can include cultivating crops,beekeeping,and grazing livestock underneath and/or in between solar panels and can provide diversified income,water savings,and o

18、ther synergistic benefits(Hernandez et al.2019;Macknick et al.2022;Nilson,Hoen,and Rand 2024).There is recent interest in agrivoltaics in Colorado,including successful commercial deployments as well as state-level grants and tax incentives for more demonstration sites(Jaffe 2022b;Colorado General As

19、sembly 2023a).Additionally,Colorado has a goal of achieving a 100%reduction in economy-wide greenhouse gas pollution by 2050,and the states largest electricity provider,Xcel Energy,is targeting 100%carbon-free electricity by 2050(Colorado General Assembly 2023b;Xcel Energy 2023).Since permitting aut

20、hority for solar plants in Colorado lies with local governments,county land use codes and permitting processes play an important role in solar deployment(Lerner 2022;Lopez et al.2023;Pascaris 2021).Counties commonly define zoning districts with different allowable uses and permitting processes for l

21、and-use changes,varying in their oversight and requirement complexity.Requirements can include maximum structure height;setbacks from property lines,roads,and structures;fencing or screening for safety or visual appeal;and other visual impact and vegetation management requirements,which can impact t

22、he design and viability of solar arrays(Daniels and Wagner 2022).In addition,agrivoltaic systems are a dual land use that might not fit neatly within existing zoning definitions or solar regulations that assume single land use.Each county generally adopts unique land use codes,causing high variabili

23、ty in solar regulations,which is a challenge for interested stakeholders,such as policymakers,solar developers,and researchers.In addition,county-level codes may be publicly available online in a document form such as a pdf,or they may not be available at all.In this report,we present a comprehensiv

24、e review of county-level policies across Colorado that regulate ground-mounted or free-standing solar,as opposed to rooftop or building-integrated solar,for both utility-scale and distributed applications.This review includes both solar-specific ordinances as well as general land-use code that might

25、 be applicable in counties without solar-specific policies.This report provides an accessible reference for stakeholders interested in identifying counties with particular regulations or in analyzing the diversity of regulations across Colorado.We defined a set of search criteria to find information

26、 on solar definitions and classifications,permitting processes,and use-specific requirements in each of Colorados 64 counties.We reviewed relevant ordinances,land-use code,and comprehensive and master plans conforming to those criteria from March to November 2023.If any uncertainties were identified

27、,we contacted county officials for clarification.The findings were categorized and mapped to vi This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.illustrate the distribution of key policies adopted across Colorados counties on the followin

28、g topics:solar definitions,solar siting policy documentation,categorization of PV systems for permitting,1041 permitting,solar on agricultural land,panel height restrictions,fencing requirements,vegetation management,visual impacts,and plans and financial assurance for decommissioning.Additional top

29、ics relevant to solar permitting,such as wildlife impact mitigation,road impact fees,lot coverage restrictions,and setbacks are left for future work or are addressed elsewhere(e.g.,Lopez et al.2023).Appendix A lists the documents reviewed for each county,and other county-level results are available

30、in the appendices.As of November 2023,39 of Colorados 64 counties had documented solar land-use regulations that contain some or all of the information in the search criteria(Figure ES-1).Nineteen counties have no land-use code specific to ground-mounted solar.However,this landscape is continually e

31、volvingthe remaining six counties had moratoriums on large-scale solar applications in effect during the review and report preparation periods.Five of these moratoriums were instituted to provide sufficient time for land-use code revisions soon after large solar power plants were permitted or announ

32、ced to the public,and county officials determined that existing regulations did not sufficiently address solar as a land use or sought to proactively address other community concerns(Witowski 2022;Bunton 2023;Turner 2023a;McDermott 2023;Sida 2023).Figure ES-1.Status of solar land use regulations in

33、Colorado counties(2023).Counties with“Detailed Solar Land Use Regulations”have documentation on all the policies listed in the reviews search criteria,and counties with“Some Solar Land Use Regulations”have documentation on some but not all.While a few counties have adopted language similar to that o

34、f their neighbors,most counties have adopted their own definitions of solar energy systems and their own land-use requirements.The cumulative effect is a wide variety of potential regulations for utility-scale solar in Colorado,as summarized in Figure ES-2.When considering both solar-specific ordina

35、nces and general vii This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.land-use codes,the most common requirements regulate fencing and visual impacts,closely followed by required plans and financial assurance for decommissioning after the

36、 systems useful life.Particularly relevant for agrivoltaic installations,several counties have specific restrictions regarding solar or general development on irrigated land,and many counties have restrictions on the maximum panel height,although most restrictions are currently high enough for commo

37、n agrivoltaic configurations.Unique to Colorado,many counties also have“1041”permit requirements that might apply to solar;1041 powers refer to delegated powers from the state to local jurisdictions to regulate certain matters of statewide concern,and 1041 permits are generally more expensive,rigoro

38、us,and have a higher level of scrutiny than other permit types.Figure ES-2.Summary of land-use policies and requirements that might apply to utility-scale solar across Colorados counties From the review results,we found the following key takeaways:Solar plant permitting requirements across Colorado

39、are county-specific and highly variable.Counties often varied permitting requirements for PV systems based on their installed capacity,land area,and/or electricity end use.These groupings might not be applied as intended for new and emerging solar configurations due to gaps or ambiguity in definitio

40、ns.For example,there might be fewer requirements for large off-grid PV arrays for commercial uses than grid-tied systems in counties that differentiate based on electricity end use.There can also be overlap with legacy 1041 regulations,in some instances requiring developers to complete both a 1041 p

41、ermit and a conditional use or special use permit(County of Elbert 2018).Relatedly,two counties require 1041 permits at a lower installed nameplate capacity threshold for solar and wind compared to fossil fuel,biofuel,or similar power generating facilities.75%of Colorados existing utility-scale sola

42、r power plants and 89%of its installed solar capacity are located in 45%of its counties,each of which has documentation for all of the policies in the review.Once a county starts receiving applications for solar power plant permits,there appear to be two common drivers motivating the adoption of 0%2

43、0%40%60%80%100%Percentage of Colorado Countiesviii This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.solar-specific regulations:community response and clear gaps in the existing land-use code.The public processes required for land use code

44、 and zoning changes can help address community needs and concerns,and clearly documented policies lower risks for solar development.Some county policies existing at the time of the review could limit agrivoltaic deployment,including four counties restricting solar in some or all agricultural zones,s

45、everal others considering agricultural impacts in the review process,four counties with 1015-foot panel height limits,and six counties with higher permitting stringency for any development on irrigated land.ix This report is available at no cost from the National Renewable Energy Laboratory at www.n

46、rel.gov/publications.Table of Contents Executive Summary.v 1 Introduction.1 2 Background.4 3 Methods.7 3.1 Search Criteria.7 3.2 Document Search.8 3.3 Contact With Planning Departments or County Commissioners.9 3.4 Categorization and Mapping of the Data.9 4 Results.10 4.1 Solar Definitions.10 4.2 So

47、lar Siting Policy Documentation and Solar Deployment.11 4.3 Categorization of PV Systems.13 4.4 1041 Permitting(Areas and Activities of State Interest).14 4.5 Solar on Agricultural Land.16 4.6 Panel Height Restrictions.18 4.7 Fencing Requirements.19 4.8 Vegetation Management.20 4.9 Visual Impacts.22

48、 4.10 Decommissioning Plans.23 4.11 Financial Assurance for Decommissioning.24 5 Discussion.26 5.1 Solar-Specific Ordinances,Deployment,and Community Response.26 5.2 Variability in Solar Permitting Across Colorados Counties.29 5.3 Agrivoltaics and Solar Land-Use Code.31 5.4 Future Research.33 6 Conc

49、lusion.35 Glossary.37 References.38 Appendix A.County Land-Use and Permitting References.48 Appendix B.Solar Definitions by County.55 Appendix C.1041 Permit Thresholds by County.66 Appendix D.Panel Height Restrictions by County.68 Appendix E.Fencing.70 x This report is available at no cost from the

50、National Renewable Energy Laboratory at www.nrel.gov/publications.List of Figures Figure ES-1.Status of solar land use regulations in Colorado counties(2023).vi Figure ES-2.Summary of land-use policies and requirements that might apply to utility-scale solar across Colorados counties.vii Figure 1.Av

51、erage solar resource and utility-scale(1 megawatt MW)solar deployed by county as of October 2023(EIA 2023b).5 Figure 2.Policies and definitions reviewed for each Colorado county.8 Figure 3.Solar power or solar power zoning definitions in Colorado counties.11 Figure 4.Identification of which Colorado

52、 counties have implemented land-use policies regulating solar installations.12 Figure 5.Colorado counties methods for categorizing solar power installations to determine which requirements to apply during the permitting process.14 Figure 6.Solar power plants might trigger a 1041 permit requirement i

53、n some Colorado counties.15 Figure 7.Regulation of solar power plants on agricultural land in Colorado counties.17 Figure 8.Maximum allowable height of solar panels in each Colorado county.18 Figure 9.Fencing requirements for solar power installations in Colorado counties.20 Figure 10.Vegetation man

54、agement requirements for solar power installations in Colorado counties.21 Figure 11.Visual impact requirements applicable to solar power installations in Colorado counties.22 Figure 12.Decommissioning and reclamation requirements for solar power installations in Colorado counties.23 Figure 13.Finan

55、cial assurance requirements for decommissioning solar power installations for Colorado counties.25 Figure 14.Timelines of solar deployment,adoption of solar-specific ordinances or definitions,and amendments to those ordinances for Colorado counties with high solar deployment to date.27 Figure 15.Tim

56、elines of current county-level solar moratoriums in Colorado,including public announcement or permit approval of key solar power plants planned in each county.The planned capacity and/or acreage of each solar plant is indicated.28 xi This report is available at no cost from the National Renewable En

57、ergy Laboratory at www.nrel.gov/publications.List of Tables Table 1.Number and Installed Capacity of Solar Power Plants Located in Counties With Different Levels of Solar Siting Policy Documentation.13 Table 2.County Policies Specifically Protecting Agricultural Lands From Solar Development.17 Table

58、 A-1.County Documents Referenced in the Review Results.48 Table B-1.Solar Siting Definitions by County.55 Table C-1.Colorado County Thresholds Potentially Triggering a 1041 Permitting Process for Solar Power Plants in Those Counties.66 Table D-1.Height Restrictions on Solar Panel Heights by County.6

59、8 Table E-1.Fencing Requirements by County.70 1 This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.1 Introduction The United States is currently undergoing a large-scale build-out of rooftop and ground-mounted solar photovoltaic(PV)projects

60、,with total installed capacity projected to nearly double from 189 gigawatts alternating current(GWac)in 2024 to 352 GWac in 20301(Gagnon et al.2023).For utility-scale solar power plants and community solar gardens(CSGs)as well as for large commercial and industrial customers consuming their own sol

61、ar-generated electricity on-site,these installations are typically ground-mounted and can cover tens or up to thousands of acres(Ong et al.2013).When trying to identify locations for large ground-mounted solar plants,the most promising sites for solar developers are often on large,cleared parcels cl

62、ose to existing transmission lines with strong solar resource,stable soil,and minimal slope(Arn Carrin et al.2008).Much of the land that meets these needs is current or former agricultural land(Adeh et al.2019).While solar development is generally supported in the United States(Carlisle et al.2015),

63、there can be opposition to projects,particularly with projects developed on farm or forest lands(Gaur et al.2022).Community resistance to solar development has occurred in rural areas,as communities attempt to balance prime farmland conservation,support new economic opportunities,maintain local rura

64、l character,and achieve renewable energy targets(Jaffe 2022b;Richardson,Kirk Hall,and Morgan 2022;Sungu 2011).One possible opportunity to address these challenges is agrivoltaics,a dual land use that combines agriculture and ground-mounted PV on the same land(Bessette et al.2024;Dinesh and Pearce 20

65、16;Kumpanalaisatit et al 2022;Macknick et al.2022;Mamun et al.2022).These dual land uses can include cultivating crops,beekeeping,and grazing livestock underneath and around solar panels(Macknick et al.2022;Kolbeck-Urlacher 2023).In the right conditions and with the right hybrid design,agrivoltaics

66、can provide an additional income stream for landowners,maintain farmland or pastureland in production,and provide other synergistic benefits(Hernandez et al.2019;Jaffe 2022b;Macknick et al.2022).These benefits have the potential to address some of the major sources of community opposition,although s

67、ome of the impacts are still unclear or mixed.The potential visual and aesthetic impacts of solar on the landscape is a common reason for community opposition(Carlisle et al.2015;Nilson,Hoen,and Rand 2024),and current literature does not find clear community preferences for the aesthetics of agrivol

68、taic systems(Pascaris et al.2022;Schrter,Pttschneide,and Mergenthaler 2023).However,other studies have also found that solar projects would be more likely to be supported with the addition of agrivoltaics,and solar developers have reported sometimes adding agrivoltaics in response to community feedb

69、ack(Pascaris et al.2022;Nilson,Hoen,and Rand 2024).Pascaris et al.(2022)found that 82%of survey respondents stated they would be more likely to accept solar projects in their community if agrivoltaics were integrated,even more so if they provided fair economic opportunities to farmers and the surrou

70、nding community.While proposing an agrivoltaic rather than a single-use PV system can impact a communitys response to a permit application,it can also change how the application is handled during the permitting process.Based on the selected dual-use activities,an agrivoltaic PV array might be config

71、ured differently from a single-use utility-scale system(Macknick et al.2022).For example,the PV panels might be mounted higher above the ground or with wider spacing 1 Based on NRELs Mid-case Standard Scenario with current policies(Gagnon et al.2023).2 This report is available at no cost from the Na

72、tional Renewable Energy Laboratory at www.nrel.gov/publications.between rows of panels to accommodate larger livestock,such as cattle,or agricultural equipment(Macknick et al.2022).Due to these differences in use and configuration,agrivoltaic and single-use PV systems might also differ in where and

73、how they can be successfully permitted for installation.While national renewable energy policies focus on financial incentives,and state policies generally include a mix of incentives,land-use laws,and renewable portfolio standards,the final authority on whether solar is permitted for installation t

74、ypically lies at the county or municipal level(Daniels and Wagner 2022;Kolbeck-Urlacher 2023;Pascaris 2021).Therefore,county zoning codes and permitting processes can have a significant impact on where and how ground-mounted solar and/or agrivoltaic installations could be built(Lerner 2022;Lopez et

75、al.2023;Pascaris 2021).Counties commonly define zoning districts,such as industrial or agricultural,with different allowable uses(Daniels and Wagner 2022).Further,some uses might be allowed as the primary land use,whereas other uses might only be permitted as an accessory that is incidental to the p

76、rimary use(Dillemuth and White 2013).Agrivoltaic installations are a dual land use that might not clearly fit within the existing zoning definitions(Pascaris 2021).Each zone can have its own requirements,such as maximum structure height,fencing or screening for safety or visual appeal,and minimum di

77、stance that structures are set back from the road(Dillemuth and White 2013).These requirements can impact the design and economic viability of ground-mounted solar and agrivoltaic installations.There are other siting considerations as well,such as minimizing impacts on wildlife,scenic vistas,and sen

78、sitive historical,cultural,or archeological resources.For each zoning district within a county,counties specify the type of permit required for each allowable use in that district,such as an accessory or use-by-right permit,conditional use permit,or special use permit.Use-by-right permits have minim

79、al if any requirements,conditional use permits have requirements that must be reviewed by the county administrator or land-use department,and special use permits require extensive documentation and are reviewed by the Board of County Commissioners in a public hearing(Daniels and Wagner 2022).Zoning

80、codes often allow large-scale ground-mounted solar plants within certain zones subject to a special use permit process(Daniels and Wagner 2022).Information on county-level regulations is not centrally located and can be time-consuming to review,presenting a challenge for stakeholders such as policym

81、akers,solar developers,and researchers interested in accessing and analyzing that information.Guarino and Swanson(2023)conducted a review of local-level agrivoltaic regulations in Illinois,which to the best of our knowledge is the only such resource for agrivoltaics in the United States.Lopez et al.

82、(2023)reviewed county-level ordinances in the United States and analyzed the impacts of wind and solar setbacks on land available for renewable development.Owusu-Obeng,Mills,and Craig(2024)developed a database of local zoning ordinances for the Great Lakes region and quantified the expected impacts

83、of these ordinances on solar deployment.This report expands that knowledge pool by reviewing and reporting county-level land-use codes impacting ground-mounted solar and agrivoltaic development across all counties in Colorado.While both Guarino and Swanson(2023)and Lopez et al.(2023)only reviewed so

84、lar-specific ordinances,this review includes both solar-specific ordinances and generally applicable zoning standards for those counties that have not adopted solar-specific ordinances,offering a more comprehensive review of solar siting requirements in Colorado.3 This report is available at no cost

85、 from the National Renewable Energy Laboratory at www.nrel.gov/publications.This report reviews the state of ground-mounted solar regulations in each Colorado countys land-use code by reviewing relevant documents and directly contacting county land-use departments,administrators,or commissioners.We

86、also discuss how these regulations might impact the deployment of agrivoltaic systems;impacts to large,utility-scale solar deployment are outside of the scope of this report.Note that land-use policies are rapidly evolving due to the high demand for solar power.Six of Colorados 64 counties have temp

87、orary moratoriums on solar or all land-use applications while they develop their regulations and permitting processes.Most of these moratoriums are planned to last for 6 to 18 months,but there is potential for early resolution or extension.In the remainder of this report,Section 2 reviews background

88、 information on current developments impacting solar power deployment in Colorado.Section 3 presents the review method and key search topics.Section 4 reports the review results,which are discussed in Section 5,including variability in requirements found across Colorado counties and discussion of po

89、tential impacts on agrivoltaic deployment.Section 6 concludes.For more information on individual counties,detailed tables of the review results are available in the appendices.4 This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.2 Backgroun

90、d Colorado has multiple state,municipal,and corporate goals supporting the deployment of renewable resources to reduce greenhouse gas emissions and air pollution.Colorado previously established a renewable portfolio standard for 30%of electricity sold by investor-owned utilities to be produced from

91、renewable resources by 2020(U.S.Energy Information Administration EIA 2023a).Colorado has set a requirement for an 80%reduction in greenhouse gas emissions from electricity by 2030 and a goal of achieving a 100%reduction in statewide greenhouse gas emissions by 2050(Colorado General Assembly 2019,Co

92、lorado General Assembly 2023b).The governors office published a faster roadmap targeting 100%renewable energy by 2040(Colorado Energy Office 2019).Colorados two largest investor-owned utilities are on track to meet the 2030 target,and Xcel Energy has also set a corporate target of 100%carbon-free el

93、ectricity by 2050(Black Hills Energy 2023;Xcel Energy 2023).As of 2019,fourteen counties and towns2 have also committed to their own 100%renewable goals(Colorado Energy Office 2019).As Colorado moves toward these renewable energy targets,solar PV installation in the state is rapidly increasing.Color

94、ado has strong solar resource,particularly in the southcentral San Luis Valley and the southeastern plains(Figure 1).While there is limited electrical transmission from some of these high-resource areas to Colorados Front Range urban load centers,a new set of transmission lines are currently in deve

95、lopment to alleviate this limitation in the eastern plains(Xcel Energy 2021).Regions with available transmission capacity and sufficient land availability,particularly on the eastern plains,have a growing utility-scale solar market.2 Denver,Pueblo,Boulder,Fort Collins,Summit County,Frisco,Aspen,Glen

96、wood Springs,Breckenridge,Longmont,Lafayette,Nederland,and Golden 5 This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.Figure 1.Average solar resource and utility-scale(1 megawatt MW)solar deployed by county as of October 2023(EIA 2023b).In

97、stalled capacity bubbles are centered in each county and are not indicative of actual distances from the solar power plants to the transmission lines.Illustration by NREL As of October 2023,143 utility-scale(1 megawatt alternating current MWac)solar projects have been deployed in 28 of Colorados 64

98、counties(EIA 2023b).These plants have a combined capacity of almost 1.9 gigawatts alternating current(GWac),with another 1.3 GWac under construction or planned for installation by 2025(EIA 2023b).Most of the existing capacity is concentrated in a few counties with very large solar power plants of te

99、ns to hundreds of MWac,with over half of the states total solar capacity in Pueblo County alone(EIA 2023b,Figure 1).However,43%of the total number of utility-scale plants are smaller CSGs with installed capacities of 14.8 MWac.Agrivoltaic applications are being explored across this range of scales i

100、n Colorado,including both large,utility-scale solar plants and CSGs.One of the first agrivoltaic installations in Colorado was Jacks Solar Garden,a 5-acre,1.2-megawatt direct current(MWdc)CSG in Boulder County that includes crop production,grazing,and pollinator habitat within the solar array(InSPIR

101、E 2023;Jacks Solar Garden 2023).On the other end of the spectrum,Garnet Mesa Solar,a 383-acre,80-MW utility-scale plant in Delta County,is in preconstruction and plans to support grazing of 1,000 head of sheep within its array(Jaffe 2022b;Garnet Mesa Solar 2023).Other current and planned deployments

102、 include three sheep-grazed CSGs,several small-scale agrivoltaic crop research sites operated by the National Renewable Energy Laboratory(NREL)and Colorado State University,and a community-supported agriculture program planned for a solar array at the Denver Botanic Gardens Chatfield Farm(InSPIRE 20

103、23;Vickerman 2022).6 This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.On the policy front,Colorado passed Senate Bill 21-235 in 2021 allocating$150,000 to the“research,guidance,technical assistance,feasibility studies,and projects related

104、 to agrivoltaics”(Colorado General Assembly 2021).In 2023,Colorado passed another bill providing$500,000 in grants for more agrivoltaic demonstrations in the state and offering a personal property tax exemption for equipment used in agrivoltaic systems with novel designs(Colorado General Assembly 20

105、23).Within this context,this report offers additional information for solar developers and policymakers interested in understanding how county-level land-use codes in Colorado might impact future agrivoltaic project development and ground-mounted solar project development in general.In addition to t

106、he commonly used accessory,conditional use,and special use permit categories,counties in Colorado also regulate solar power by a“1041 permit”unique to the state(Colorado Department of Local Affairs n.d.).Passed in 1974,the Areas and Activities of State Interest Act in the Colorado Revised Statutes(C

107、RS 24-65.1)created“1041”powers,named after the original legislation,Colorado House Bill 74-1041.These 1041 powers give local governments control over certain development projects in their jurisdictions that have statewide impacts(FindLaw Staff 2022).The bill includes 13 different areas and activitie

108、s of statewide interest that communities can opt to regulate by identifying the areas and activities of interest that apply to their locality and adopting guidelines for their administration.One of these 13 areas and activities is the site selection and construction of major facilities of a public u

109、tility,which can include solar power plants.Therefore,this report also identifies which counties are opting to use this permitting process for solar power development.7 This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.3 Methods To underst

110、and Colorados county-level solar siting ordinances and land-use policies,we conducted a review of relevant publicly available data for each of the 64 counties.We first defined the review search criteria,then carried out a review for each Colorado county through document searches and by contacting pl

111、anning departments and county commissioners,and finally categorized and mapped the data.The following subsections outline details for each step.Maps of these results are shown in Section 4.County-level findings are available in the appendices,and each countys land-use codes and other documents are l

112、isted in Appendix A.The document search occurred between April 5 and Nov.1,2023.Land-use code changes and moratoriums on solar developments passed or lifted after Nov.1,2023,are not included in this report,with the exception of Mesa County,which implemented a moratorium on solar applications startin

113、g Jan.9,2024,between the review completion and report publication.3.1 Search Criteria We selected pertinent information to include in the Colorado county-based solar siting policy review through first reviewing available information from counties with recently enacted solar siting regulations.The fi

114、rst two counties selected were Boulder County,which revised its Land Use Code in 2018,and Weld County,which added new solar siting regulations in 2021.After reviewing each countys regulations,we drafted a list of relevant policies and policy categories.The list was iteratively revised throughout the

115、 data collection process based on other counties regulations.Through this iteration,some counties were revisited to ensure all criteria in the final review list had been reviewed for all counties.The final list of policy review criteria is outlined in Figure 2 and includes categories regarding count

116、y-specific definitions and classifications,permitting processes,zone-specific requirements,and decommissioning requirements.Several of these criteria,including permitting,height,setback,decommissioning,and financial assurance requirements,were similarly reviewed in Guarino and Swansons(2023)analysis

117、 of Illinoiss county-level solar requirements.8 This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.Colorado County Solar Policy Review Scope Solar Policy and Deployment Solar Siting Policy Documentation Solar Deployment Definitions and Clas

118、sifications Solar Definitions Categorization of PV Systems Permitting Processes 1041 Permitting Permitted Zones for Solar Development Permitting Requirements Application Requirement Zone-Specific Requirements Panel Height Restrictions Fencing Requirements Vegetation Management Visual Impacts Setback

119、 Requirements Nuisance(Noise,Dust,Glare)Decommissioning Requirements Decommissioning Plans Financial Assurance for Decommissioning Figure 2.Policies and definitions reviewed for each Colorado county 3.2 Document Search With the list of solar siting policies selected,we conducted Google searches for

120、publicly available information for each Colorado county.We reviewed documents like zoning ordinances,land-use codes,and comprehensive and master plans.In some cases,building codes were also reviewed,but because this report focuses on ground-mounted rather than rooftop solar,they were only relevant f

121、or certain items,such as panel height restrictions.In general,policies that were clearly intended to regulate rooftop solar were excluded,while policies that were ambiguous or applicable to both rooftop and ground-mounted solar were included.Policies addressing each element of the selected list of s

122、olar siting evaluation criteria by county were collected from the aforementioned documents.For counties with no solar-specific policies,we used a list of keywords to search for relevant policies that apply to solar development.Keywords included height,vegetation management,reclamation,decommissionin

123、g,setback,agriculture,glare,noise,erosion,dust,energy,utility,power plant,and 1041.For example,many counties have general nuisance regulations,such as a requirement that a“use does not create excessive or offensive noise,vibration,smoke,dust,odors,heat,glare or light noticeable or extending beyond t

124、he property.”These regulations are not specific to solar but may have implications for construction and operation of solar arrays.9 This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.3.3 Contact With Planning Departments or County Commissio

125、ners Following the review of publicly available documents,we identified a county contact,such as a county planner in the planning or land-use departments,a county administrator,or a county commissioner,based on the countys organization structure.If any uncertainties or missing information were ident

126、ified in the document search,we followed up with this contact via phone or email to confirm the information and/or ask any questions that remained.3.4 Categorization and Mapping of the Data Once all the data were compiled,we focused on the following subset of topics from Figure 2 relevant to solar p

127、olicy and development:Solar definitions Solar siting policy documentation and solar deployment Categorization of PV systems Solar on agricultural land 1041 permitting Panel height restrictions Fencing requirements Vegetation management Visual impacts Decommissioning plans Financial assurance for dec

128、ommissioning.We then mapped the data for each of these topics in QGIS(version 3.23.3)to visualize the range of solar policy across all 64 Colorado counties.10 This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.4 Results Here,we present the

129、key results of our solar siting policy review(Figure 2)to highlight common themes across Colorados 64 counties.The land-use documents referenced for each county are listed in alphabetical order in Appendix A,and additional county-level details of the review findings are reported in the other appendi

130、ces.Notably,six counties(9%)have passed temporary moratoriums on applications for solar energy systems and were revising their land-use codes at the time of the review and/or report preparation.Moratoriums are typically put in place to allow county officials time to revise statutes,usually with a ta

131、rget timeline(e.g.,6 to 18 months),although some are open-ended.For example,the moratorium in Montrose County was expected to be in place for 18 months,ending in October 2024.Chaffee County has had a moratorium on all land development applications since 2022 while they revise their land-use code.Thi

132、s includes most solar power plants with some exemptions,so for this analysis Chaffee County was classified as a moratorium.Mesa County implemented a 6-month moratorium on solar applications starting Jan.9,2024,after the review was completed;while no other land-use changes past Nov.1,2023,are reporte

133、d,an exception was made to include Mesa here as under moratorium.For these six counties,we do not report any findings based on the previously adopted land-use codes,as we expect changes in the near future.4.1 Solar Definitions Establishing clear definitions for solar energy systems,which can have a

134、variety of configurations and applications,creates a foundation for applying the appropriate permitting and planning requirements.The text of a definition determines what is and what is not regulated,or to what degree it is regulated.In some counties,land uses that are not explicitly defined are pro

135、hibited,while in others,undefined land uses are tacitly permitted,which can create uncertainty for solar developers(Pascaris 2021).The review found solar-specific definitions in 38 Colorado counties(59%)(Figure 3).Most counties have unique definitions,which typically include a description of applica

136、ble technologies and/or a specification of what infrastructure is or is not included.For example,Pitkin County defines a Solar Energy Collector as“a device for the passive collection of solar energy for use in the heating of water or the generation of electricity,together with related wires and pipe

137、s necessary for operation.”Many counties allow solar energy systems to include energy storage(e.g.,Boulder,Chaffee,Crowley,Weld),although Arapahoe County specifically excludes battery storage from its Small Solar System Facility definition.There is one county,Morgan County,with both a solar-specific

138、 definition and a definition of an agrivoltaic system:“A system designed for the simultaneous use of areas of land for both groundmounted sic solar collectors and agriculture.”In 12 counties(19%),solar power plants are defined more broadly within the category of“facilities of a public utility.”For e

139、xample,Douglas County defines a power plant,which is one type of a major facility of a public utility,as“any electrical energy generating facility with an energy generation capacity of 50 megawatts or more,and Appurtenance(s).”Eight counties(13%)had no definitions relevant to solar siting.The full l

140、ist of solar definitions is available in Appendix B.11 This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.Figure 3.Solar power or solar power zoning definitions in Colorado counties 4.2 Solar Siting Policy Documentation and Solar Deployment

141、 Comprehensive solar siting and permitting documentation sets clear expectations for all stakeholders and enables solar developers to manage risk regarding projects with substantial up-front investments and long development timelines.Additionally,higher solar deployment has been observed in localiti

142、es with documented solar siting policies(Cook et al.2016;Lopez et al.2023;Lerner 2022).Here,we present which Colorado counties have adopted policies addressing some or all of the items listed in the review criteria(Figure 2),as well as the current level of solar deployment in those counties.As shown

143、 in Figure 4,29 counties(45%)have detailed solar land-use regulations that address all the policies in Figure 2.One county,Gilpin,did not provide definitions for accessory or principal solar systems,but otherwise had detailed solar siting regulations using those terms.Another 10 counties(16%)have so

144、me solar land-use regulations,which address some but not all the policies outlined in the solar siting review.Other counties,19 in total(30%),have no land-use code specific to ground-mounted solar or renewable energy resources.However,some of these counties have more general public utility,power pla

145、nt,or general development regulations that are potentially applicable to ground-mounted solar,which are included in the findings in subsequent sections.12 This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.Figure 4.Identification of which C

146、olorado counties have implemented land-use policies regulating solar installations By cross-referencing this data with the EIA data on solar deployments(EIA 2023b)shown in Figure 1,we found that 107(75%)of Colorados 143 utility-scale solar power plants3 are located in counties with detailed solar la

147、nd-use regulations,accounting for 1,675 MWac or 89%of Colorados utility-scale installed solar capacity(Table 1).Ten projects(154 MWac)are located in counties that had some solar land-use regulations,and 16 projects(40 MWac)are located in counties with no code related to ground-mounted solar.Finally,

148、10 projects(24 MWac)were sited in counties where the solar siting policies are currently under revision or a moratorium.These data only include projects that are currently operational and not those that are in the development pipeline.3 While ground-mounted systems can also include arrays of 1 MW na

149、meplate capacity,the vast majority of ground-mounted solar is utility-scale and data on smaller systems is not readily available.13 This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.Table 1.Number and Installed Capacity of Solar Power Plan

150、ts Located in Counties With Different Levels of Solar Siting Policy Documentation County Documentation of Solar Siting Policies Project Count Project Count(%of Total)Installed Capacity(MWac)Installed Capacity(%of Total)Detailed Solar Land-Use Regulations 107 75%1,675 89%Some Solar Land-Use Regulatio

151、ns 10 7%154 8%No Code Related to Ground-Mounted Solar 16 11%40 2%Under Development,Revision,or Moratorium 10 7%24 1%Total 143 1,892 4.3 Categorization of PV Systems Within their solar ordinances,many Colorado counties implement a variation of permitting requirements,based on the expected impact of a

152、 solar array.For example,“medium”-sized arrays might require an administrative or minor impact review,while“large”arrays might require a major impact or special use review,4 including one or more public hearings and approval by the Board of County Commissioners.Many counties also have simplified per

153、mit requirements for“small”solar energy systems designated as accessory to the primary land use,which are likely targeting rooftop systems,although some counties specifically allow ground-mounted systems as accessory uses(e.g.,Eagle and Larimer counties).We found large diversity in how these permitt

154、ing categories are implemented across Colorado counties,resulting in variability of potential requirements for PV systems of similar scale and use cases.Three distinct methods for categorizing arrays were found in the review of Colorado counties:categorizing based on the installed capacity of the ar

155、ray(megawatts),based on the land area of the array footprint(acres),and/or based on the intended end use5 for the electricity produced by the array.This final method could include categories for PV arrays intended to export electricity to the power grid for profit or for on-site self-consumption.For

156、 some counties,these categories are designated by the number of end users(e.g.,one or more).Counties that regulate solar PV plants through existing public utility regulations applicable to multiple electricity generation technologies,rather than solar-specific ordinances,typically specify requiremen

157、ts based on the plants installed capacity(in megawatts).Thirty-nine percent of Colorado counties categorize their permit requirements based on one of these three methods,including ten counties(16%)categorizing solar arrays based on installed 4 The names of these permits differ by county,and include

158、Modified Administrative Land Use Permit,Minor or Major Impact Project,Land Development Agreement,Major Impact Review,or Limited Impact Special Review.5 In this case,intended end-use refers to the interconnection method,such as behind-the-meter and front-of-the-meter solar systems.14 This report is a

159、vailable at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.capacity,eight counties(13%)categorizing based on the intended end use of the electricity,and seven counties(11%)categorizing based on the land area(Figure 5).In addition,30%of counties apply two or more o

160、f these methods together.The remaining 14 counties(22%)not under moratorium do not define different categories of PV systems.This group includes counties with no PV permitting information available as well as counties implementing a single permitting process regardless of the solar energy system dim

161、ensions and use case.Figure 5.Colorado counties methods for categorizing solar power installations to determine which requirements to apply during the permitting process.Figure 5 includes some categorization methods that are ambiguous about whether they apply to both ground-mounted and rooftop solar

162、 systems.However,the figure might exclude some permit categories specifically for rooftop solar due to this reviews focus on ground-mounted systems.4.4 1041 Permitting(Areas and Activities of State Interest)Some Colorado counties require certain solar development applicants to complete a 1041 permit

163、 rather than a more standard accessory use,conditional use,or special use permit.1041 regulations are delegated powers from the state of Colorado to local jurisdictions to regulate matters of statewide concern,including utility infrastructure development.Additionally,these regulations serve as a mea

164、ns to safeguard particular geographical areas holding historical,cultural,or natural resources of statewide importance.Permitting processes per 1041 regulations are generally more expensive and rigorous and have a higher level of scrutiny than special review permitting processes,although requirement

165、s vary from county to county.Our review found two ways that Colorado counties have implemented 1041 regulations that might apply to solar power plants.First,1041 permits might be required for the site selection and 15 This report is available at no cost from the National Renewable Energy Laboratory

166、at www.nrel.gov/publications.construction of a“major facility of a public utility,”including power plants.Twenty-four counties(38%)in Colorado have adopted 1041 regulations for power plant siting that are or might be applied to ground-mounted solar power plants(Figure 6).Of these,21 counties apply t

167、heir 1041 regulations based on the power plants generation capacity,acreage,or both,where power plants that exceed a threshold go through the 1041 permit process,and power plants under the threshold go through some other permit process.The threshold for power plant generation capacity varies from 0.

168、5 MW to 50 MW,6 and the threshold for land area varies from 0.25 acre to 320 acres.The remaining four counties(6%)have adopted 1041 regulations for siting of a major facility of a public utility,but do not specify what types or sizes of facilities would qualify.Some counties have explicitly integrat

169、ed 1041 requirements into solar-specific permitting processes,while others have not,so there can be ambiguity about whether,in some instances,counties might choose to apply their 1041 regulations over a parallel solar permitting process.Figure 6.Solar power plants might trigger a 1041 permit require

170、ment in some Colorado counties.While green,yellow,and red all indicate counties that have implemented 1041 regulations for siting a power plant or major facility of a public utility that might apply to solar,counties in red have not adopted capacity or acreage minimums to define the size of the faci

171、lities that qualify for the requirements.Separate from 1041 regulations on siting of a major facility of a public utility,our review found that some counties have implemented 1041 regulations that might apply to solar power plants specifically when sited on agricultural land.1041 permits can be requ

172、ired for developments of any type on historically irrigated land that plan a partial or complete“dry-up”of the land or 6 While some counties specify solar DC(or nameplate)capacity,many 1041 regulations are applied to power plants based on the“MW”capacity size,regardless of generation technology.This

173、 is a source of potential ambiguity in cases where DC vs.AC capacity has not been specified.16 This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.development of the land for any purpose other than irrigated agriculture,potentially impacting

174、 local water rights in the long term.Six counties(9%)require 1041 permits for any development on historically irrigated land,with minimum thresholds ranging from 3 acres to 10 acres of irrigated land.Five of these counties also have a power plant capacity and/or acreage threshold for 1041 permits,re

175、gardless of irrigation status.The full list of requirements for counties that have adopted specific capacity,acreage,and/or irrigated land development thresholds is available in Appendix C.Not all counties or localities have adopted 1041 regulations.There are 33 counties(52%)that have either no 1041

176、 regulations for any of the areas or activities of state interest,or no 1041 regulations specifically for site selection or the construction of major facilities of public utilities or development of irrigated land.4.5 Solar on Agricultural Land Current or former agricultural land has many of the con

177、ditions favorable to solar development,including large,cleared parcels with strong solar resource and flat,stable ground(Arn Carrin et al.2008;Adeh et al.2019).Renewable development offers many potential local benefits,including job and tax revenue growth(The Western Way 2022).However,there are also

178、 concerns about siting solar development on agricultural lands,including potential impacts on food production,irrigated prime farmland,water rights,and local community character(Hunter et al.2022).Therefore,Colorado counties are balancing these competing needs in their land-use codes,and some have i

179、nstituted specific restrictions regarding solar development on agricultural lands in addition to the 1041 requirements for development of irrigated land discussed in Section 4.4.In 40(63%)of Colorados counties,a solar energy system is allowed on agriculturally zoned or designated land(Figure 7),prov

180、ided that the appropriate permit process is completed based on the zone and categorization system in Section 4.3.In addition to the permitting process,11 counties(17%)have implemented specific policies that protect farmland in relation to solar energy development,which are detailed in Table 2.Two co

181、unties(3%),Fremont and Kiowa,do not allow solar energy systems on agriculturally zoned lands.Five counties(8%)do not have agriculturally zoned or designated lands and similarly have no related stipulations.17 This report is available at no cost from the National Renewable Energy Laboratory at www.nr

182、el.gov/publications.Figure 7.Regulation of solar power plants on agricultural land in Colorado counties Table 2.County Policies Specifically Protecting Agricultural Lands From Solar Development Counties Policy or Statement Arapahoe,Pueblo Allow solar on some agriculturally zoned districts but not ot

183、hers.Boulder Restrict total disturbed areas associated with the ground-mounted PV system to 7 acres on parcels smaller than 70 acres in size,or 14 acres on parcels larger than 70 acres in size.Any application for a ground-mounted solar energy system with disturbed area greater than 0.5 acres on land

184、s designated as Significant Agricultural Lands must include a Solar Energy System Development Report.Broomfield,Larimer Only allow solar on agricultural land as an accessory use for on-site consumption.Cheyenne,Phillips,Sedgwick,Yuma“Distributed and Utility-Scale Solar Energy Systems are encouraged

185、to locate on predominantly(more than 60%)non-prime farmland.”Kit Carson,Morgan“Protection of Agricultural Lands.The Wind or Solar Energy Facility shall not have a significant adverse impact on agricultural lands and agricultural operations above what is allowed for under landowner lease agreements.”

186、18 This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.4.6 Panel Height Restrictions Some local authorities impose height restrictions on solar panels to maintain the visual harmony and aesthetics of a community and/or to ensure the safety o

187、f solar panel installations under high wind loading or extreme weather events.Restricting the height of solar panels can help mitigate these risks.Restrictions on solar panel height vary across counties in Colorado(Figure 8).There are 33 counties(52%)that do not have specific height restrictions for

188、 solar panels.These include counties with no publicly available policies regarding height restrictions in general as well as counties where the height restriction for ground-mounted solar is determined by the general building height restriction for the underlying zoning district.For these counties,b

189、uilding and/or structure height restrictions range from 25 to 75 ft for principal use within the zone,which would typically not be a constraint for ground-mounted solar.Figure 8.Maximum allowable height of solar panels in each Colorado county.For counties with no restrictions specific to solar,the m

190、aximum allowable height typically defaults to the maximum building height in the underlying zoning district.Ten counties(16%)have solar panel height restrictions of 25 ft or greater,typically in the range of 25 to 35 ft.Eleven counties(17%)have maximum allowable heights of 15 to 25 ft,and one county

191、,Rio Grande County,restricts free-standing(i.e.,ground-mounted)solar panels to 10 ft in height.Morgan County has different height restrictions for traditional solar projects(30 ft)and agrivoltaic projects(35 ft).There is also variability across the counties as to what aspect of the solar array is us

192、ed to determined compliance with height restrictions.For example,Washington County measures the height from the equipment base to its highest point during operation,whereas Arapahoe County measures the height to the solar panel mounting point.19 This report is available at no cost from the National

193、Renewable Energy Laboratory at www.nrel.gov/publications.Three counties(Dolores,Douglas,and Huerfano)regulate panel height on a case-by-case basis.In Dolores County,the height restriction is determined during the land-use agreement process.Similarly,Douglas County determines maximum height during th

194、e use by special review process.Huerfano Countys Board of Commissioners may exempt solar projects from maximum structure height restrictions on a case-by-case basis during the review process.Panel height can also impact setback requirements in certain counties.In Boulder County,solar panels are rest

195、ricted to 15 ft in height,unless a project has a site-specific need and has been approved through the review process.If taller panels are approved,setbacks are then increased by 75 ft from all property lines unless adequate vegetative screening can mitigate visual impacts.In Kiowa county,there are n

196、o height restrictions,but setbacks must be 1.2 times the height of the solar panels.4.7 Fencing Requirements Solar arrays are typically fenced for protection,both to protect people and animals from the electrical equipment and to protect the solar array from accidental or intentional damage.However,

197、fencing can also have negative impacts on wildlife habitat and migration patterns(Lovich and Ennen 2011;Sadoti et al.2017).Fifteen counties(23%)have specific requirements for fencing around solar arrays(Figure 9).Of these,four counties(Adams,Gilpin,Las Animas,and Washington)provide specific informat

198、ion about height and type of fencing,while the other counties require a fence,but do not provide height specifications.Another 17 counties(27%)have fencing policies that might apply to ground-mounted solar arrays.The remaining 26 counties(41%)that are not under moratorium have no requirements for fe

199、ncing.20 This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.Figure 9.Fencing requirements for solar power installations in Colorado counties 4.8 Vegetation Management Vegetation management policies describe how vegetation such as trees,shru

200、bs,and other plant life should be managed and/or preserved during a change in land use or the development of a property.The specifics of vegetation management can vary widely depending on local land-use codes and zoning regulations,but the general goals are to balance the preservation of natural lan

201、dscapes and ground cover with the needs of development,while also managing stormwater runoff effectively.21 This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.Figure 10.Vegetation management requirements for solar power installations in Col

202、orado counties.About a quarter of Colorado counties(15 out of 64)have specific requirements regarding vegetation management during or after the construction of solar arrays(Figure 10).Another 8 counties(13%)have general vegetation management regulations for specific permits or general development st

203、andards that could be applied to the construction of solar arrays.The other 35 counties not undergoing a moratorium do not have specific policies relating to vegetation management.Most of these vegetation management policies(18 out of 22)relate to minimizing disturbances(like grading,soil compaction

204、,or vegetation clearing),revegetation requirements after construction to minimize erosion,and noxious weed management.Examples include Boulder Countys Solar Energy System Development Report,which has plans to maintain or improve soil quality and agricultural integrity,and Chaffee Countys Restoration

205、 and Revegetation of Disturbed Areas policy,which requires revegetation within one season using a mix of native,adaptive,and drought-tolerant grasses and groundcovers to prevent soil erosion and weeds.Five counties have specific policies relating to wildfire mitigation and fuel reduction caused by v

206、egetation.For example,Adams County requires a plan to keep vegetation to minimal levels around the facility perimeter through treatment,mowing,or other fuel reduction methods.Finally,two counties have requirements to retain existing trees and vegetation where possible.Archuleta County regulations st

207、ate,“Significant vegetation,including dominant or mature trees and shrubs and endangered species,should be retained where possible and in accordance with Community Wildfire Protection Plan requirements.”22 This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.

208、gov/publications.4.9 Visual Impacts Common community concerns about solar PV arrays include visual changes in the landscape and aesthetic concerns(Carlisle et al.2015).Proper siting,design,and mitigation policies,including visual screening through fencing or vegetation,can help minimize the perceive

209、d negative visual impacts.There can also be concerns about glare from solar panels impacting neighbors,motorists,and aviation,although PV is typically coated in antireflective materials,and research addressing these concerns has demonstrated that solar PV has similar reflectivity to smooth water(Ril

210、ey and Olson 2011;Day and Mow 2018).Twenty counties(31%)across Colorado have policies regulating the visual impacts of solar arrays(Figure 11).An additional 16 counties(25%)have visual impact policies that might apply to solar arrays.Three counties may require visual impact plans and mitigation on a

211、 case-by-case basis for specific sensitive locations or the size of the solar array.Other counties have visual impact policies applicable to any development within their jurisdiction that are not specific to solar.The other 22 counties(34%)not under a moratorium did not have any requirements related

212、 to visual impacts of new developments.Figure 11.Visual impact requirements applicable to solar power installations in Colorado counties Seven counties require a visual impact plan or report as part of their permitting process.Lincoln County has the most extensive requirements,including multiple vis

213、ual simulations for developments in a sensitive viewshed or with structures taller than 30 ft,and projects may be denied if significant visual impacts cannot be sufficiently mitigated.Thirteen other counties have visual impact policies related to nearby properties or rights-of-way.For example,Yuma C

214、ountys policies state:“All Solar Energy Systems shall not have an adverse visual impact on the natural features or character of the surrounding area and shall be located to minimize glare on 23 This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publicat

215、ions.adjacent properties and roadways.”This is typical for counties that state that the solar array should not impact nearby land use but do not prescribe specifically how that should be done.4.10 Decommissioning Plans Proper planning for decommissioning from the outset of a project can help mitigat

216、e potential environmental,financial,and regulatory challenges associated with the eventual end of the arrays operations.Decommissioning plans state when and how solar array infrastructure is to be removed once it is no longer operational.Decommissioning plans can dictate how materials(steel,solar pa

217、nels,wires,concrete,gravel,etc.)are to be handled upon removal(e.g.,recycled,landfilled,or donated),expectations of the lands quality after decommissioning,and who is ultimately responsible for these costs(Curtis et al.2021).Twenty-seven counties across Colorado(42%)have policies related to solar ar

218、ray decommissioning and reclamation(Figure 12).Within this group,six counties mention decommissioning or reclamation in their solar specific policies,but do not have specific requirements and rely instead on the developer to formulate an adequate plan during application.The other 21 counties have sp

219、ecific requirements for decommissioning plans.Cheyenne,Yuma,and Sedgewick counties have the most extensive requirements for decommissioning,which include structure and cabling removal and soil and vegetation restoration.These policies also provide clear guidelines of the owner or operators financial

220、 and legal obligations and the countys power to review and approve the decommissioning plan or,if necessary,complete the decommissioning if it does not proceed in compliance with the plan.Figure 12.Decommissioning and reclamation requirements for solar power installations in Colorado counties 24 Thi

221、s report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.Nine other counties require a reclamation or decommissioning plan for any development within their jurisdiction,not just specific to solar energy systems.The other 22 counties not under morato

222、rium did not have any decommissioning requirements relevant to solar arrays.4.11 Financial Assurance for Decommissioning In addition to a decommissioning plan,a form of financial assurance is often required to ensure for the removal of the solar array infrastructure at the end of its useful life,eve

223、n if the plant operator faces financial hardship or bankruptcy in the interim.Financial assurance can take various forms like a self-bond,bond,federally insured certificate of deposit,government-backed securities,corporate guarantee,letter of credit,or cash.Financial assurance is usually a certain p

224、ercentage of the total value of the project or a valuation of the funds needed to remove the solar equipment minus its salvage value.Several counties,including Cheyenne,Lincoln,and Sedgwick counties,require this value to be reevaluated every 3 to 5 years,starting either postconstruction or toward th

225、e middle of the projects lifespan after 1015 years.Financial assurance or decommissioning bonds are required for solar energy facilities in 18 Colorado counties(28%)(Figure 13).For example,El Paso County requires a financial assurance deemed acceptable to the county equal to the cost of decommission

226、ing,as estimated by a professional engineer.Some counties require financial assurance from the outset,while other counties such as Kit Carson do not require the financial assurance until partway through the systems lifespan(e.g.,10 years),unless there is abandonment or decommissioning of the project

227、 prior to that time.An additional 19 counties(30%)have financial assurance in their land-use code that is not specific for solar energy facilities but may be applicable to them.Park Countys policies are not specific to solar,but state:“The County may require monetary deposits,bonds,and/or written ag

228、reements to provide for a sufficient financial guarantee,as determined by the County,for restoration and cleanup of site access or other County property or interests.”The remaining 21 counties(33%)not under moratorium do not have any requirements for financial assurance in their land-use codes.25 Th

229、is report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.Figure 13.Financial assurance requirements for decommissioning solar power installations for Colorado counties 26 This report is available at no cost from the National Renewable Energy Labora

230、tory at www.nrel.gov/publications.5 Discussion Our review of Colorados county-level solar ordinances and land-use codes illustrates that there is currently high variability in requirements and permitting rigor for ground-mounted solar across Colorado.Depending on the county,solar arrays of similar s

231、ize,configuration,and application might be required to complete one of various permitting requirements up to and including 1041 permits(e.g.,Prowers County)or might not require a permit at all(e.g.,Baca County,which is Prowers Countys neighbor).This regulatory landscape for ground-mounted solar is a

232、lso continuously evolving,with six county moratoriums currently in effect,many of which were motivated in part by community concerns about solar.Counties that have already adopted solar-specific ordinances commonly include requirements addressing community concerns,including visual impacts,safety,an

233、d changes to agricultural land.Dual-use agrivoltaic systems are one approach to address community concerns about converting agricultural land to solar,and agrivoltaics have been deployed in multiple Colorado counties,although only Morgan County has codified a definition for agrivoltaics thus far.Our

234、 review of regulations finds that some county-level policies might impact the feasibility of agrivoltaic deployments,while other policies protecting irrigated land might be more compatible with agrivoltaic deployments than traditional utility-scale solar arrays that include a permanent dry-up.In thi

235、s section,we discuss some of these major findings,including the interactions between solar deployments and the adoption of solar-specific ordinances and moratoriums,variability in solar ordinances across Colorado,and potential impacts of county-level regulations on agrivoltaic deployments and state-

236、level renewable energy targets.5.1 Solar-Specific Ordinances,Deployment,and Community Response We found that the majority of Colorados utility-scale7 solar power plants(75%)and installed capacity(89%)are located in counties with documentation on all of the policies we reviewed(Figure 2).This is cons

237、istent with other analyses that find correlation between localities with solar ordinances and where solar is being deployed(Day 2015;Cook et al.2016;Lopez et al.2023;Lerner 2022).Additionally,Lerner(2022)notes that counties tend to adopt renewable energy ordinances when their neighbors adopt ordinan

238、ces or begin building renewable energy projects.There are potential interactions between solar ordinances and solar deployment,where the demand for solar deployment can motivate solar ordinance adoption,which can in turn enable further solar developments.Solar projects require substantial up-front i

239、nvestments and often have long development timelines.A typical utility-scale solar PV project can take up to 45 years from planning to the completion of an operational solar energy facility(SEIA 2013).Regulation changes or revisions can disrupt project planning and execution;therefore,documented per

240、mit and planning requirements enable interested landowners and solar developers to make informed decisions and manage project risk.To investigate the interdependence of solar ordinances and adoption,we reviewed the timeline of solar ordinance adoption for the five counties with the highest number of

241、 utility-scale solar 7 While ground-mounted systems can also include arrays of 1 MW nameplate capacity,the vast majority of ground-mounted solar is utility scale,and data on smaller systems are not readily available.27 This report is available at no cost from the National Renewable Energy Laboratory

242、 at www.nrel.gov/publications.projects and the five counties with the highest installed capacity(Figure 14).8 The dates of solar ordinance adoption and amendment are compared to the year that utility-scale solar capacity became operational in that county;note that the year of operation likely lags t

243、he year each solar power plant was first proposed to the community due to permitting and construction timelines.Figure 14 illustrates that these Colorado counties typically adopted solar-specific ordinances after one or more solar power plants were planned in their jurisdictions.Garfield,Alamosa,El

244、Paso,and Arapahoe counties adopted regulations around the same time as their first few solar power plants were becoming operational and then implemented amendments a few years later as more and larger solar power plants were developed.Adams,Weld,and Pueblo counties allowed for the permitting and con

245、struction of several projects prior to the adoption of solar-specific regulations.While the regulatory certainty from documented solar siting policies might reduce permitting risk for future solar developments,this analysis does not address other factors influencing solar developers to target land i

246、n these counties,such as solar resource,available interconnection capacity,land prices and availability,or expectations about community response.Figure 14.Timelines of solar deployment,adoption of solar-specific ordinances or definitions,and amendments to those ordinances for Colorado counties with

247、high solar deployment to date.Solar ordinance and amendment dates were determined by a review of county documents and personal communication with county officials.Blue dots show when a utility-scale solar power plant became operational according to the EIA(EIA 2023b),which lags the date that the pro

248、ject applied for county permitting.The top five counties in the EIA data in terms of number of projects(Adams,Weld,Alamosa,Arapahoe,Garfield)or installed capacity(Pueblo,Alamosa,Adams,El Paso,Weld)are shown.Once a county starts receiving applications for solar power plant permits,there appear to be

249、two common drivers motivating the adoption of solar-specific regulations:community response and clear gaps in the existing land-use code.More recently,from 2022 to 2023,several counties,including Morgan,Phillips,Washington,and Logan,have enacted and resolved temporary moratoriums on solar power plan

250、t applications to provide land-use departments with sufficient 8 Three of the counties(Adams,Alamosa,and Weld)are included in top five counties for both number of projects and installed capacity,so only seven counties were reviewed.28 This report is available at no cost from the National Renewable E

251、nergy Laboratory at www.nrel.gov/publications.time to draft suitable regulations for local needs.Current moratoriums are in effect for Chaffee,Delta,Montrose,San Miguel,Rio Blanco,and Mesa counties.Chaffee County has had an ongoing moratorium for multiple land-use categories while it completes broad

252、er updates to its land-use code(Ark Valley Voice Staff 2022;Chaffee County 2022);the other five counties instituted moratoriums soon after large solar power plants were announced for development or solar permit processes were resolved,as shown in Figure 15(Chaffee County 2022;Montrose County 2022b;D

253、elta County Board of Commissioners 2022;Tuttle 2023;Mesa County 2024;Turner 2023b;SolarGen 2022;McDermott 2023;Garnet Mesa Solar 2023;Bunton 2023;NextEra Energy 2023;Sida 2023).Figure 15.Timelines of current county-level solar moratoriums in Colorado,including public announcement or permit approval

254、of key solar power plants planned in each county.The planned capacity and/or acreage of each solar plant is indicated.This timeline focuses on key developments and is not intended to be a comprehensive review of solar developments in each county.Chaffee,Montrose,Rio Blanco,and Mesa also had relative

255、ly small(18 MWac)solar power plants developed in 20122020(EIA 2023b)prior to this 18-month timeline.Several of these solar projects elicited strong community response,both positive and negative,and county officials reported feeling that their existing land-use code was insufficient to address concer

256、ns(Witowski 2022;Bunton 2023;Turner 2023a;McDermott 2023;Sida 2023).In Delta County,an 80-MW solar project that was initially rejected by county commissioners for concerns of losing farmland was approved after the addition of sprinkler and drip irrigation to support agrivoltaic sheep grazing below t

257、he panels(Jaffe 2022a;Witowski 2022).Two weeks after the approval,the county commissioners implemented a moratorium on all utility-scale solar projects to develop relevant solar policy for future projects(Delta County Board of Commissioners 2022).Similarly,a few weeks after a large-scale solar proje

258、ct was proposed in Montrose County,county commissioners enacted a 6-month moratorium on all solar projects,or“until appropriate facility standards are incorporated into the Montrose County zoning regulation,whichever comes first”(McDermott 2023;Montrose County 2022b).In San Miguel County,a solar pro

259、ject proposal caused locals to raise concerns around visual impacts and impacts on recreation,hunting,and wildlife(Bunton 2023).Amid feelings at the county that the existing code is“lagging behind,”San Miguel County commissioners approved a 6-month 29 This report is available at no cost from the Nat

260、ional Renewable Energy Laboratory at www.nrel.gov/publications.moratorium 1 week later to make the application process fair and“to respond intelligently for both our citizens(and)also for future applicants”(Bunton 2023;Tuttle 2023).In this ordinance development process,each county is balancing local

261、 needs,and many counties have implemented solar-specific policies to proactively address community concerns,such as visual impacts(31%of counties).However,a side effect of this county-by-county approach is that the solar permitting landscape across Colorado is varied,resulting in a regulatory varian

262、ce that can present a challenge to solar developers and interested landowners where there are ambiguities and gaps in local ordinances.5.2 Variability in Solar Permitting Across Colorados Counties Due to the county-by-county approach to developing ordinances,there is variability of permitting rigor

263、for solar power plants across Colorado.Counties commonly apply varying permitting requirements for different types of PV systems,categorized based on installed capacity(MWdc,MWac,or MW),land area(acres),and/or electricity end use(self-consumption vs.grid export).Additionally,some counties have adopt

264、ed 1041 regulations that are explicitly integrated into solar-specific permitting processes,while in other counties there is ambiguity about whether legacy 1041 regulations apply.For example,a few counties have adopted 1041 requirements without further definitions of what constitutes a“major facilit

265、y of a public utility,”while many other counties have defined specifications of which power plants qualify.In aggregate,this presents a variance of potential requirements across the state for landowners and solar developers interested in developing projects.At the same time,the three commonly used p

266、ermitting categorization methods have potential gaps or limitations that might inadvertently impact the types of solar deployments a county is intending to support.When considering the installed capacity,PV systems have two ratings to consider:the DC capacity(MWdc),which is the total capacity of the

267、 PV modules,and the AC capacity(MWac),which is the rating of the inverters that interface between the PV modules and the electric grid.Due to the higher relative cost of inverters,PV systems are commonly built with a DC-to-AC capacity ratio of 1.3 or more,although including energy storage can increa

268、se this ratio(Bolinger et al.2023).Some counties specifically define which capacity they are referring to in their solar permitting regulations,such as Garfield and Lincoln counties,but other counties simply refer to the“MW”capacity without clarifying their definitions.While the DC installed capacit

269、y is commonly referenced by the solar industry,this ambiguity in definitions may be more prevalent for counties that use the same permitting processes across multiple types of power plant technologies,for which the AC capacity is the default rating under consideration.When categorizing based on eith

270、er land area or installed capacity,permitting requirements and land-use restrictions might not be applied as intended for new and emerging solar configurations.Currently,utility-scale solar arrays require an average of 5.75 acres per MWdc9 of installed solar capacity,equating to a capacity density o

271、f 0.17 MWdc/acre(U.S.Department of Energy 2021).However,there is variability in this capacity density due to topography and technology choices;for example,optimized tracking systems can enable higher densities.In other cases,lower 9 Solar Futures Study reports typical land use requirements of 7.5 ac

272、res/MWac and inverter loading ratios of 1.3,which are converted here into acres per MWdc.30 This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.densities are intended and desired,such as in agrivoltaics configurations with wider row spacing

273、to prioritize use of arable land and improve access for labor and equipment(Macknick et al.2022).In very widely spaced arrays,the system might include far fewer PV module rows and have a lower impact on the land compared to a traditionally configured array on the same area,leading to smaller energy

274、generation per acre when compared to traditional utility-scale designs.Further,advances in PV technology,including module efficiency,layout,and tracking optimization,could continually impact the solar capacity density that is considered typical.Due to the variability in capacity density,establishing

275、 requirements based on either land area or installed capacity may result in situations that may or may not align with the original intention of the regulations.For example,a county that requires 1041 permits for any plant greater than 5 acres might require a 1041 permit for both a 1-MWdc(5.75 acres)

276、traditional utility-scale solar plant and a 0.5-MWdc agrivoltaic plant with twice the row spacing.When categorizing PV systems based on the expected electricity end use,such as commercial vs.noncommercial use or self-consumption vs.electricity export to the grid,counties are potentially balancing pr

277、ivate property rights and expected land impacts.While PV systems for noncommercial use or self-consumption might typically be expected to be small rooftop mounted systems,there are also emerging applications for large ground-mounted,off-grid PV systems.These include large commercial and industrial c

278、ustomers,such as data centers,mining operations,or indoor agricultural grow centers,powering their own on-site operations(Peacock 2021;Schoenberg 2020;Sandfire 2024).These applications could impact significant land areas but may or may not fall into the intended permit category based on an end-use c

279、ategorization.Finally,many counties categorize PV systems based on some combination of these three methods,which might be a source of ambiguity or confusion,particularly as new PV configurations and use cases emerge,and counties might need to update their approaches to match their intended outcomes.

280、At the state level,this variance in local permitting regulations has raised concerns within the legislature about uneven deployment and the impact on broader statewide goals for renewable energy deployment,including Colorados target to achieve 100%renewable energy by 2040(Brasch 2024;Colorado Energy

281、 Office 2019).In response to concerns about the rate of deployment,Colorado lawmakers are currently drafting legislation that would establish a standardized process for local government reviews of renewable energy proposals,including limits on the durations of moratoriums and setback restrictions(Br

282、asch 2024).With a similar approach,Illinois passed a law in 2023 mandating review procedures,timelines,and standards for county-level permitting of utility-scale wind and solar projects(Granholm,Antoniolli,and Montgomery 2023).Other states,including Connecticut,Maine,Michigan,Ohio,New Hampshire,New

283、York,Oregon,and Vermont,have opted to establish state-level siting authorities for new energy-generating facilities over a certain capacity or acreage(Ellison and Orner 2023;State of Oregon 2024;Farm and Energy Initiative 2024;Ohio Power Siting Board n.d.).For example,New York has a state-level proc

284、ess for renewable projects larger than 25 MW,while Vermonts Public Utilities Commission has authority over all solar array siting(Farm and Energy Initiative 2024).In Oregon,large PV systems are subject to siting by the state,depending on the acreage and whether the proposed location is on farmland(S

285、tate of Oregon 31 This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.2024).It is likely too early to assess the efficacy of these state approaches compared to county-based approaches in meeting state goals for renewable deployment.Separatel

286、y from the development of state-level siting boards,other efforts have focused on developing model land-use codes and educating local officials on best practices in solar permitting regulations.These programs include the U.S.Department of Energys SolSmart program,which provides no-cost technical ass

287、istance to local governments to implement best practices and offers Bronze through Platinum designations based on the localitys processes(SolSmart 2023),and International City/County Management Associations SolarScale program,which helps local governments overcome common barriers to utility-scale so

288、lar deployment(ICMA 2024).A variety of other organizations have developed model solar ordinances,which often target a particular state(Energy,Policy,and Innovation Center n.d.;Dillemuth and White 2013).While the Colorado Energy Code Board has published a Solar Ready Code package that targets rooftop

289、 solar,there is not currently a state-level model ordinance package for utility-scale solar in Colorado,although the Colorado Department of Local Affairs plans to release a Template Land Development Code in 2024 that includes some specifics on ground-mounted solar systems(personal communication).Add

290、itionally,the Colorado Solar&Storage Association has published a recommended guide of best practices from a solar developers perspective(Colorado Energy Office 2024;Colorado Solar&Storage Association 2022).While each locality has unique circumstances to consider,there are many commonalities and stan

291、dardized practices that can decrease the burden of code development for resource-limited local governments while also decreasing permitting uncertainty for solar developers.5.3 Agrivoltaics and Solar Land-Use Code Agricultural land is often well suited for solar development(Adeh et al.2019),yet 5 ou

292、t of the top 10 agricultural producing counties in Colorado currently have no deployed solar(Yuma,Kit Carson,Prowers,Washington,and Phillips counties)(Colorado Department of Agriculture n.d.;U.S.Department of Agriculture USDA NASS 2017;Figure 1).Demand for solar development in some of these counties

293、 may increase with the completion of the Colorado Power Pathway,which will expand transmission capacity to the southeastern corner of Colorado(Xcel Energy 2021).Solar development restrictions or challenges often arise from local land-use policy or lack of community acceptance(Carlisle et al.2015;Kol

294、beck-Urlacher 2023;Lopez et al.2023).To address these challenges,agrivoltaics has been proposed as a potential solution to keep agricultural land in production and increase local acceptance of solar projects(Pascaris et al.2022).However,some Colorado county-level policies may unintentionally restric

295、t agrivoltaics by limiting solar development on agricultural land and/or restricting panel height.These two topics are each discussed below,including considerations and potential impacts.Solar Development on Agricultural Land Agricultural land made up 48%(31.8 million acres)of Colorados land in 2017

296、(USDA NASS 2017).Farm and ranchlands are abundant in Colorado and are often available at a lower cost than other land types.An average acre of commercial or residential land costs$11,600 in Colorado(Morris 2023)compared to$1,770/acre for agricultural land(USDA NASS 2022).This contributes to making f

297、arms and ranches attractive options for solar developers who require large 32 This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.contiguous areas for their installations.However,converting agricultural land into solar arrays can have multip

298、le trade-offs.Communities across the state have debated the use of agriculturally zoned land for solar projects,as it could compete with food production,raise rental prices for farmers and ranchers,and increase development around rural communities(Hunter et al.2022).Due to these concerns,some local

299、governments have enacted policies that restrict the development of solar arrays on agriculturally zoned land.Such policies restrict the size/output of solar arrays,add permitting requirements,or ban solar energy systems on agricultural land altogether(e.g.,Fremont and Kiowa counties).Counties that p

300、rohibit solar energy infrastructure on agricultural lands also prevent the addition of agrivoltaics.Some counties do not ban solar development of farmland but restrict or discourage solar development on“prime”10 or“significant”11 agricultural lands(Cheyenne,Phillips,Sedgewick,Yuma,and Boulder counti

301、es).In 2017,Colorado had 1.4 million acres of prime farmland(National Resource Conservation Service 2017)and in 2016,the state had 5.6 million acres of nationally significant agricultural land(American Farmland Trust n.d.).Policies that limit solar development on prime farmland might also impact the

302、 deployment of agrivoltaic systems.Further,six counties(Alamosa,Bent,Cheyenne,Otero,Prowers,and Sagauche)have irrigated land clauses in their 1041 regulations that may also impact agrivoltaic deployment.These clauses are intended to prevent the sale of water rights separately from the land and preve

303、nt the dry-up of irrigated agricultural land.However,the water redistribution and lower evaporation rates under solar panels could allow for decreased irrigation or the cessation of irrigation altogether.A recent study found that for semiarid C3 grassland growing beneath an agrivoltaic system in Col

304、orado,the aboveground net primary productivity was reduced by only 6%7%with no irrigation in the past 3 years(Kannenberg et al.2023).Permitting that allows for the dry-up of land but continued agricultural production,such as grazing and hay production,would allow agrivoltaic systems to be developed

305、on these lands.In addition,agrivoltaics has shown to provide local community and farmer benefits.Solar panels redistribute moisture to the edges of their panels that can enable deeper soil moisture retention(Sturchio et al.2023).Solar panels also provide shade to the ground,which can lower soil and

306、plant temperatures while reducing evaporation rates from the soil(Barron-Gafford et al.2019).These benefits are especially important in semiarid climates like Colorado because they can help lower irrigation requirements.The shade and lowered air temperatures may assist with lowering health-related i

307、llnesses in farmworkers(Ghosh 2023).However,solar panels may come with trade-offs,such as lowering the total amount of arable land to farming or impacting current farming practices due to the placement of the structures(Pascaris et al.2020).Early collaboration with farmers during the project design

308、phase can help mitigate these impacts(Macknick et al.2022).Policies that forego any possibility of solar development on agricultural 10 USDA designation of high-quality farmland of major importance in meeting national needs for food and fiber production,including cultivated land,pastureland,and fore

309、stland.11 Nationally significant agricultural land is the“land best-suited to long-term,intensive crop production”(American Farmland Trust n.d.).33 This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.land can inadvertently prevent landowners

310、 from accessing solar land leases for agrivoltaic systems that potentially allow for greater farm viability and more diversified income.Panel Height Agrivoltaic systems often require alternative configurations to traditional utility-scale PV designs to permit agricultural activities(Macknick et al.2

311、022).This can include various design changes,such as increasing the height of panels.In cropping systems,some agrivoltaic designs are elevated up to 1215 ft to allow for maximum crop growth height,larger agricultural equipment(Marrou et al.2013;Weselek et al.2019),and optimal diffusion of sunlight f

312、or plant growth(Faizi et al.2022).Some agrivoltaic orchards are built even higher,with panel heights up to 16.4 ft(Juillion et al.2022).In orchards,elevated solar panels may offer the additional benefit of hail protection to the crops(Willockx et al.2024).For grazing systems,most solar arrays of tra

313、ditional height will accommodate the integration of sheep,but panels often require higher elevation for the integration of cattle(Macknick et al.2022).Cattle are an important market for Colorado farmers and ranchers,valued at$2 billion in 2020(USDA NASS 2021).In 2021,Colorado had 2.7 million head of

314、 cattle but only 445,000 head of sheep(USDA NASS 2021),leading to a smaller agrivoltaic grazing market if panel height is restricted.The panels also offer potential benefits to cattle,such as access to shade,reduced radiant heat load(Maia et al.2020),and lower respiration rates and body temperatures

315、(Sharpe et al.2021).In one study,cattle preferred the shade of the panels over a shade cloth(Maia et al.2020).Some Colorado counties limit the panel height of solar panels(e.g.,a 10-ft restriction in Rio Blanco County and a 15-ft restriction in Pitkin,Arapahoe,and Larimer counties).This restriction

316、could potentially limit the types of agrivoltaic systems that could be incorporated into the PV structure,such as taller cropping systems(e.g.,fruit trees)and cattle grazing.All other county panel restriction heights are higher than 15 ft and would have a low probability of interfering with agrivolt

317、aic systems.While allowing flexibility for solar designs can be important to the success of agrivoltaic projects,it is important to note that there can be trade-offs for alternative designs,such as increased costs(Horowitz et al.2020)and increased risk in areas with high wind or snow loads(Macknick

318、et al.2022).5.4 Future Research Extensions to the Current Report on Colorados County Policy Landscape While this report focused on reviewing and summarizing the current county policies applicable to ground-mounted solar development,additional analyses quantifying the impacts of these local policies

319、on land availability for solar development would be a valuable extension,similar to those in Lopez et al.(2023)and Owusu-Obeng,Mills,and Craig(2024).This review focused on many of the key policies of interest for siting and permitting ground-mounted solar,but there are additional policies that would

320、 be valuable to add,including lot coverage restrictions,impact fees for heavy machinery use on roadways during construction,and wildlife impact mitigation requirements,which can be a significant factor in the permitting process(e.g.,Park County Board of County Commissioners 2021).Future research are

321、a could also include actual or expected impacts on zoning differentiation on deployment patterns throughout Colorado.Finally,a review of recent solar permit applications denied by counties could provide valuable lessons 34 This report is available at no cost from the National Renewable Energy Labora

322、tory at www.nrel.gov/publications.learned for other counties and solar developers to understand and prepare for key issues that are arising across the state.Comprehensive Analysis of Local Solar Regulations in the United States While analysis of local solar regulations has been completed in Illinois

323、(Guarino and Swanson 2023),the Great Lakes region(Owusu-Obeng,Mills,and Craig 2024),and now Colorado,data are limited across the United States.Comprehensive state-by-state analysis of local solar regulations could help inform developers and policymakers of local solar policies and their potential di

324、versity.Lopez et al.(2023)have performed a similar analysis that examines local setback requirements across the United States,but further variables explored in this report(e.g.,panel height restrictions,vegetation management plans,decommissioning requirements)could be relevant to add.This analysis c

325、ould also include the impact of statewide regulations that have been used to create consistency for solar regulations throughout other states(e.g.,Connecticut,Vermont,New Hampshire,Maine,New York Farm and Energy Initiative 2024)to understand the impact of statewide versus local codes on solar develo

326、pment.As evidenced by the Colorado example,the solar industry is rapidly expanding,and state and local governments are presently trying to update their codes and regulations to match this pace of development.Future analyses and overviews of local policies would be most useful in a dynamic format tha

327、t could be readily adjusted as states and counties update their policies.Socioeconomic Solar Analysis While research has been limited,several studies have reviewed the impact of solar policy or solar deployment on environmental justice or socioeconomic factors(Si and Stephens 2021;Lukanov and Kriege

328、r 2019).Si and Stephens(2021)found that while low-income households were represented in the 2020 Solar Massachusetts Renewable Target(SMART)Emergency Regulation,they had less political power and representation than other groups(e.g.,corporations).Lukanov and Krieger(2019)found that solar adoption le

329、vels were disproportionally lower in disadvantaged communities in California.High-level state and county data comparisons of renewable energy deployment and environmental justice factors have also been initiated by the Deployment Gap Model Education Fund(2023)through their found that 82%of Dashboard

330、.Using a similar but more detailed and policy-related framework,socioeconomic analysis throughout the cities and counties of Colorado could help to determine the impact of local solar regulations on inclusivity of environmental justice and disadvantaged communities in policymaking and solar deployme

331、nt.This analysis could include use of EPAs Environmental Justice Screening and Mapping Tool to evaluate local variables such as environmental justice indexes,pollution and sources,socioeconomic indicators,health disparities,climate change data,critical service gaps,and demographics(EPA 2024).35 This

332、 report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications.6 Conclusion The state of Colorado has experienced the rapid expansion of solar projects over the past few years(EIA 2023a).Solar policy across Colorado counties can impact the types,sizes,and

333、locations of solar projects approved,the complexity and cost of the permitting and construction process,and ability to incorporate agrivoltaic systems.This report presents an overview of the status of county-level solar policy across the state of Colorado as of November 2023.By reviewing county documents,such as land-use codes,zoning ordinances,and comprehensive and master plans,this report summar