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Land Not Needed: Why we should go big on rooftop solar

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This post was co-authored by Laura Deehan, Environment California Research & Policy Center

In 2020, a Pew Research poll found that nearly 80% of American adults think the U.S. should be prioritizing renewable energy sources like wind and solar over fossil fuels. Renewables have a number of obvious benefits, chiefly that they don’t emit greenhouse gases or air pollution. Most forms of renewables also use far less water than fossil fuel generation.

But every source of energy has impacts on the environment. Utility-scale wind and solar facilities, for instance, require large amounts of land. A recent analysis estimated that a national transition to wind and solar power could require land equivalent to the area of several Midwestern states.

Wind and solar plants don’t ruin land in the same way as fossil fuel production, and can co-exist with other land uses such as farming and ranching. But it’s important that, as we transition to a 100% clean energy economy, we reduce land impacts where we can. That means maximizing the amount of energy we save through efficiency and conservation and taking advantage of technologies that generate renewable energy without consuming land.

Solar sheep.JPG

Sheep on a solar farm at Antioch College, Ohio. Credit: GabeIglesia via Wikimedia, CC BY-SA 4.0

 

Places like California are already feeling the tension between decarbonizing the economy and protecting land and threatened species. But there’s a key technology that can help minimize that tension: rooftop solar power.

As we wrote in our recent report, The Environmental Case for Rooftop Solar Energy, there are many reasons to go big on rooftop solar, from global warming to air pollution and water conservation. Rooftop solar can even improve resilience by providing power during outages. But the fact that rooftop solar can provide these benefits without impacting the landscapes and ecosystems we want to protect is one of its most powerful assets.

That’s what makes the current fight over net metering (the policy that allows solar owners to be paid for the excess electricity they sell back to the grid) in California so important. The state’s three biggest utilities – PG&E, SoCal Edison and SDG&E – are pushing to slash net metering payments and impose large fees on owners of rooftop solar panels. If those efforts succeed, growth of rooftop solar could very well grind to a halt – forcing California to get more of its power from large-scale sources of renewable energy, many of them in ecologically sensitive areas.

Tensions are already arising between clean energy and conservation goals. A recent utility-scale solar project in California, the Blythe Solar Power Project, which came online in 2016, was built on the Palo Verde Mesa in the Sonoran Desert, an area with plant species that grow nowhere else in the state. The facility occupies more than 4,000 acres of desert that is home to sensitive species, including the threatened desert tortoise and Harwood’s woollystar, a wildflower that grows in fewer than 20 locations around the world. Another solar project, the CalSun Solar Project in Alameda County, will sit on nearly 90 acres of agricultural land.

The task of transitioning to a renewable energy system will not be possible without using land for utility-scale generation infrastructure, including in places like the California desert. We should ensure that the siting and design of those facilities minimizes conflicts with fragile ecosystems and threatened species. But we should also take every opportunity to minimize the total footprint of solar and wind power when and where we can.

Rooftop solar can make a big difference in the impact decarbonization has on natural spaces. As we calculated for The Environmental Case for Rooftop Solar Energy, 1 gigawatt of rooftop solar capacity can substitute for utility-scale solar installations that would occupy 5,200 acres of land, an area just slightly smaller than the city of Monterey, California. So building out the nearly 129 gigawatts of rooftop solar technical potential that California has would help protect a huge amount of land. And since rooftop solar doesn’t require new transmission infrastructure, rooftop solar protects even more land from being developed for transmission lines from new generation facilities. That means more desert, more forest and more farmland that can continue to flourish. Hawaii, which also has a large amount of renewable energy, has reached this exact conclusion – that rooftop solar must play a critical role in its decarbonization effort if it wishes to preserve land for nature, farming and other uses – and is working hard to incentivize and support the continued growth of rooftop solar in the state.

Preventing the worst impacts of climate change will require big shifts in the way we live and consume, huge investments at all levels, and massive build-outs of infrastructure, including and especially of renewable energy generating infrastructure. But by going all-in on rooftop solar, we can transition away from dirty fossil fuels more quickly, generate energy locally to empower communities and improve resilience, and do it all with less impact on the environment we’re working so hard to protect.

Solar on affordable, multi-family housing in Tulare County, California. Credit: Spectrum Energy Development.