Impact of Siting Ordinances on Land Availability for Wind and Solar Development

The transition to a decarbonized power sector necessitates a substantial increase in renewable energy generation. Wind and solar energy are key components of this transition, but their deployment is significantly influenced by land-use regulations, particularly siting ordinances. These ordinances, often implemented at the local level, impose restrictions on the location and design of renewable energy projects, including setbacks from roads, structures, and other features. This study addresses the crucial need to understand the cumulative impact of these geographically dispersed ordinances on the overall potential of wind and solar energy resources across the United States. The research questions focus on quantifying the impact of these ordinances on the land available for renewable energy projects and on determining if ordinances are becoming more stringent over time. The findings are crucial for policymakers, energy developers, and researchers involved in planning and implementing large-scale renewable energy projects. Accurate assessments of available resources are essential for effective energy policy and investment decisions.

While previous research has examined the effects of individual siting ordinances or specific regulatory barriers, a comprehensive national-scale analysis of the cumulative impact of diverse siting ordinances on renewable energy development is lacking. This study builds upon existing work by creating a comprehensive database of siting ordinances and employing advanced spatial modeling techniques to assess their aggregate impact. The literature review highlights the need for consistent and standardized approaches to evaluating the impacts of these diverse regulations across different geographic locations and contexts.

The research involved a multi-stage methodology. First, a comprehensive database of siting ordinances related to wind and solar energy projects was compiled from various sources, including county and municipal websites, legal codes, and other publicly available resources. The data collection process extended over several years and incorporated ordinance updates to account for changes in regulations. The database structure includes details such as the state, city/town, county, feature type (e.g., road, structure, property line), value type (e.g., meters, dBA), value, citation, and comments. A machine-readable database was created to ensure data consistency and enable efficient analysis. Second, spatial modeling techniques were utilized to assess the impact of these ordinances. A high-resolution grid covering the contiguous United States was employed to simulate wind and solar resource potential, incorporating various factors such as wind speed, solar irradiance, and terrain. The collected ordinances were overlaid onto this grid to assess their spatial effects on the available land area and generating capacity for wind and solar energy projects. Three scenarios were modeled: No Setbacks (baseline), Surveyed Setbacks (incorporating the existing database), 50th Percentile Setbacks (extrapolating the median setback distance), and 90th Percentile Setbacks (extrapolating the 90th percentile setback distance). These scenarios allowed for a comparative analysis of the impact of varying stringency levels in siting ordinances. Furthermore, the research considered various factors that affect the impact of siting ordinances, including the spatial distribution of existing infrastructure and environmental constraints. Data from sources such as the Microsoft Buildings dataset was incorporated to enhance the accuracy of the spatial analysis. The analysis involved quantifying the reductions in available land area and capacity under each scenario. Additional analyses explored potential implications such as capacity factors and gen-tie impacts (distances to transmission infrastructure).

The study identified over 1800 wind and 800 solar siting ordinances in 2022, a substantial increase from 2018. The analysis revealed that extrapolating setback ordinances across the nation could significantly reduce available wind and solar resources. Specifically, the 90th percentile scenario indicated up to an 87% reduction for wind and a 38% reduction for solar resources. Setbacks imposed the greatest impact on wind resources due to larger distances (multipliers of turbine tip height) compared to fixed meter setbacks for solar. The research further indicated that incorporating setbacks significantly reduced available land for both wind and solar generation, ranging from 13% to 62% reduction in solar resources depending on the scenario and from 13% to 74% reduction in wind resources. The largest reduction was in land area for wind power when the 90th percentile setback values were extrapolated across the U.S. The impact varied across counties, with some experiencing more substantial reductions than others. The analysis also explored the impact of setbacks on the capacity factor of remaining resources, which is the actual power output relative to the maximum potential. The study found a decreased capacity factor in the more restricted scenarios for both wind and solar energy, suggesting an effect on the efficiency of the remaining available resources. Gen-tie distances, representing the distance to transmission infrastructure, also played a role. The closest sites to the transmission infrastructure suffered the largest decreases in resource availability, highlighting the importance of efficient transmission infrastructure development to mitigate the impact of these ordinances.

The findings of this study underscore the significant influence of siting ordinances on the availability of land for renewable energy development. The substantial reductions in potential capacity across varying scenarios demonstrate the need for policymakers to carefully consider the cumulative impact of these regulations. The varying impact between wind and solar resources highlights the importance of tailored approaches to mitigating the effects of these ordinances. The analysis of gen-tie distances points to the synergistic benefit of strategically planning both renewable energy facilities and transmission infrastructure. These results have important implications for renewable energy planning, resource assessments, and policymaking. The research stresses the importance of incorporating the cumulative effects of local ordinances into national-level energy planning models to provide accurate assessments of renewable energy potential. The study provides valuable insights for improving land-use planning and regulatory frameworks to support a more sustainable energy future.

This study provides a comprehensive assessment of the impact of siting ordinances on land availability for wind and solar energy development in the United States. The findings demonstrate that these ordinances significantly reduce available resources, highlighting the critical need for a more coordinated and informed approach to land-use planning for renewable energy. Future research could explore alternative methods for evaluating the cumulative impacts of these ordinances, potentially employing machine learning techniques to enhance efficiency and scalability. Further research could focus on evaluating the effectiveness of different policy interventions aimed at streamlining the permitting process for renewable energy projects while ensuring environmental protection and addressing community concerns.

While the study incorporates a comprehensive database of siting ordinances, data collection involved challenges due to the decentralized nature of regulations and the frequent updates in ordinances. The spatial modeling relies on assumptions about the extrapolation of setback distances, which might not perfectly reflect the true variability across all localities. The study primarily focuses on setbacks and does not exhaustively consider all types of siting ordinances. Future work could address some of these limitations by incorporating advanced data collection methods and enhancing the spatial models to account for local variations.