A new study, for the first time, analyzes local ordinances and their potential effect on the development of wind and solar resources, according to the National Renewable Energy Laboratory.
The number of local ordinances is growing, which is “a sign that the renewable energy industry is maturing,” Anthony Lopez, senior researcher at NREL and lead author of the study, said in a statement.
Ordinances are often a prerequisite to development of renewable energy resources and their absence can slow the spread of those resources. In addition, local ordinances can impose restrictions that can limit the potential capacity of renewable resources.
The study, Impact of Siting Ordinances on Land Availability for Wind and Solar Development, which was published in the journal Nature Energy, found that there were 1,853 local wind ordinances in effect during 2022 compared to 286 in 2018. A companion survey of regulations related to the development of utility-scale solar found 839 ordinances in effect during 2022.
In many places, zoning ordinances at the county and township level need to be enacted before a large-scale solar or wind facility can be constructed on private land, the study noted. In those jurisdictions, decisions are typically made by elected officials following public meetings and input from local citizens and other interested parties.
The most common types of ordinances were related to setbacks from structures, roads, and property lines; noise levels; and wind turbine heights. For instance, setback distances, which can vary considerably across jurisdictions, are typically determined by a multiplier of a wind turbine’s total height. For solar power, the setback is typically a fixed distance.
The impact of setback ordinances has not traditionally been captured in large-scale resource assessments because it requires highly detailed modeling and hyperlocal data, the NREL researchers said. As a result, previous assessments have likely overestimated the amount of land available to renewables and, in turn, underestimated the cost and challenges of achieving high levels of deployment, they said.
“It’s important to understand the types of ordinances in effect, specifically setback ordinances, or the required distance from a specific feature like a house,” Lopez said. “Setback ordinances determine how much land is available for deployment and how much wind and solar resource we have to decarbonize our energy system.”
The NREL study found that wind and solar resources could be as much as 87 percent and 38 percent lower, respectively, under the strictest setback scenario compared with a baseline that does not account for setback ordinances.
Under the most permissive scenario that does not account for setbacks and only excludes legally protected areas and land that is unsuitable for development – because of wetlands, infrastructure, high elevations, or other issues – there is the technical potential of 147 terawatts of solar capacity and 14 TW of wind capacity, more than enough to decarbonize the nation’s energy system, NREL said.
If communities across the country enact setback distances in the 50th percentile, the potential would be lower: 121 TW for solar and 4 TW for wind, the NREL study found.
If communities enact the strictest setback distances, the potential for solar could decrease to 91 TW and for wind to 2 TW.
“That is still enough wind and solar potential to decarbonize the energy system, but the quality and cost of the remaining wind and solar resources will determine how much they are leveraged in the pursuit of decarbonization,” the NREL researchers said in the report.
