NREL Debuts Ordinance Databases for Siting Solar, Wind Energy Projects

National Renewable Energy Laboratory (NREL), has released two new databases containing state and local solar energy zoning laws, ordinances, and statutes in the United States. The data sets can easily be read by machines so geospatial researchers and geospatial analysts can easily analyze the impacts of sitting. This work is part NREL’s ongoing research on the dynamics of land use, clean energy deployment.

Previous NREL research showed that the U.S.’s total wind energy technical potential was seven times greater in less restrictive settings than under the most restrictive. State and local zoning laws and ordinances influence how and where wind and solar energy projects can be sited and deployed – which can have a measurable impact on U.S. renewable energy resource potential.

The United States has set goals to have 100% clean electricity by 2035, and a net zero carbon economy by 2050. This makes local siting issues a crucial topic. Publicly available data on local and state solar power ordinances and wind energy has not been made available.

“Our new, high-resolution data sets are tools that can help us better understand the complex interactions between siting considerations and large-scale clean energy development,” says Anthony Lopez, NREL’s senior geospatial data scientist and project lead for the new data sets. “The data can inform discussions about balancing local clean energy deployment decisions with mitigating global climate change.”

NREL released two data set: one that includes nearly 2,000 U.S. Wind Energy Zoning Ordinances and another that includes nearly 1,000 Solar Energy Ordinances at the state and county, township, city and municipal levels. Both data sets are available as downloadable spreadsheets. Interactive maps accompany the data, which illustrate wind and solar energy zoning data by location and type.

The wind energy database includes setbacks – or the required boundaries around infrastructure where wind turbines cannot be installed – for property lines, buildings, roads, railroads, electric transmission lines and bodies of water. Because setbacks are influenced by wind turbine tip heights – the taller the turbine, the larger the setback – the data set also includes height and rotor size restrictions. Other ordinances like shadow flicker limits, noise limitations, and utility-scale winds bans or Moratoriums are also included.

The solar energy database also includes setbacks for buildings, roads, property lines, and water. It also includes height restrictions, minimum lot sizes, solar power development moratoriums or bans, and many other information.

The two data sets are part of a suite of NREL developed renewable energy supply curves which characterize the quality as well as quantity of renewable resources. NREL creates and distributes the foundational data to the researchers to provide the basis for a variety analysis and modeling applications. The supply curves are useful in assessing land availability for renewable power projects, taking into account their interaction with the built and natural environments.

“Energy modelers, wind and solar energy technology engineers, land-use experts, ecologists, social scientists, and more, can use the new data to understand how other land uses may impact large-scale clean energy deployment,” states Trieu Mai, NREL’s senior energy analyst. “It can be used in modeling and analysis to assess trade-offs between emissions, costs, plant design, land use, wildlife habitat and more.”

Lopez and Mai began to think about the effects of land use restrictions on clean power deployment, particularly for wind energy, around a decade ago. Although it wasn’t a significant topic at the time, they felt it was an important question that needed to be addressed.

Lopez and his team have improved the spatial resolution of the technical potential assessments for wind and solar energy to account 124 million buildings, every road, railway and transmission line, and radar tower in the United States.

Lopez and team have conducted several studies on land use dynamics of clean energy deployment, including a recent analysis of land area requirements and land use intensity of U.S. wind energy deployments from 2000 to 2020 – finding that the total U.S. wind energy footprint is equivalent to the size of New Hampshire and Vermont combined. However, only a small fraction of that area (<1%–4%) is estimated to be directly impacted or permanently occupied by physical wind energy infrastructure.

Land use for solar power is another area of active research. The Solar Futures Study has recently produced projections of solar land usage. Results show that there is plenty of land available for solar development in every scenario. Ground-based solar technologies need a land area of 0.5% to support maximum deployment in 2050. This could be achieved with less than 10% of disturbed land. However, solar installations could have an adverse impact on local communities and ecosystems as well as agricultural areas.

“There are still a lot of questions that need to be studied,” Lopez adds. “National clean energy goals will happen at the local level. We will continue to drill down our resolution and analyze different aspects of the interactions between land use and clean energy deployment.”

The work is funded by the U.S. Department of Energy’s Solar Energy Technologies Office and Wind Energy Technologies Office.