How much land does it take to produce 1 gigawatt-hour (GWh) of power a year – enough for 1,000 homes?
Answer: About 32 acres of solar PV.
That’s one of many nifty facts in a National Renewable Energy Lab (NREL) analysis of how much land is required for various kinds of solar technologies.
Until now, lots of numbers have been thrown around about how much land is needed for solar, but now there are enough plants in operation to know for sure.
Based on data from 72% of operating US solar plants, NREL researchers find that developers have been pretty accurate in their estimations.
"The numbers aren’t good news or bad news," says Paul Denholm, one of the report’s authors. "It’s just that there was not an understanding of actual land-use requirements before this work. However, we were happy to find out that many of the solar land use ranges and estimates used in the literature are very close to actual solar land use requirements that we found."
"Now people will actually have numbers to cite when they conduct analyses and publish reports," "says Sean Ong, another one of the report’s authors.
To supply 1000 homes with solar (1 GWh of electricity a year), NREL finds that about 2.8 acres are needed for solar panels, whether they be concentrating or solar PV.
Here’s how NREL describes it:
- A large fixed tilt solar PV plant that generates 1 gigawatt-hour (GWh) per year requires, on average, 2.8 acres for solar panels. This means that a solar plant that provides all the electricity for 1,000 homes would require 32 acres of land.
- Small single-axis PV systems require on average 2.9 acres per annual GWh – or 3.8 acres when considering all unused area that falls inside the project boundary.
- Concentrating solar power plants require on average 2.7 acres for solar collectors and other equipment per annual GWh; 3.5 acres for all land enclosed within the project boundary.
It’s also a starting point to compare solar land use with that of other energy sources, such as wind.
These land-use estimates can also be compared with other energy sources. A 2009 Columbia University study concluded that utility-scale solar PV in the US Southwest requires less land than the average power plant that uses surface-mined coal.
"Modelers and analysts, people looking 10 or 20 years into the future can use this report to evaluate the impacts solar energy may have," notes Denholm.
The US has more than 8.5 GW of cumulative installed solar capacity, enough to power 1.3 million homes.
This year, projections call for another 4.4 GW of solar PV and 938 megawatts (MW) of concentrating solar to come online, according to the Solar Energy Industries Association (SEIA) and GTM Research.
Read "Land-use Requirements for Solar Plans in the United States":