Tapping Into Warehouse Roof Solar Potential Could Power Entire US Cities

Installing solar panels on the roofs of warehouses and distribution centers around the United States could generate enough clean electricity to power every household in every state's most populous city, according to a report published Thursday by Environment America Research & Policy Center and Frontier Group.

"What the world needs now is rooftop solar, which produces inexpensive clean energy, averts harmful pollution, and preserves open space," Susan Rakov, chair of Environment America Research & Policy Center's clean energy program and managing director of Frontier Group, said in a statement.

"If we want to create a clean energy future, we should look first to the already-built environment that could host the tools we need," Rakov continued. "Warehouse rooftops provide a perfect opportunity—they're big, they're flat, and they're begging to be put to this crucial use."

"What the world needs now is rooftop solar, which produces inexpensive clean energy, averts harmful pollution, and preserves open space."

The U.S. is home to more than 450,000 warehouses and distribution centers, and more are under construction. Collectively, these buildings provide almost 16.4 billion square feet of rooftop space—roughly twice the area of Memphis, Tennessee, one of the nation's 30 largest cities.

Covering that rooftop space with solar panels could generate 185.6 terawatt-hours of clean electricity annually, enough to power nearly 19.4 million households for an entire year.

Fully tapping into the nation's warehouse rooftop solar potential would slash planet-heating emissions by 112.7 million metric tons of carbon dioxide equivalent annually. That's comparable to taking 24 million gasoline-powered cars off the road for a year or shutting down 30 coal-fired power plants.

"The big, flat, and sun-kissed rooftops of America's warehouses are perfect places to put solar panels," said report co-author Johanna Neumann, senior director of Environment America Research & Policy Center's Campaign for 100% Renewable Energy. "It's time to eliminate the barriers that prevent us from maximizing the benefits of rooftop solar for businesses, electricity customers, the grid, and the environment."

(Photo: Solect)

Last year, the same groups published a similar investigation into the unrealized solar potential of the country's "big box" superstores. According to that analysis, there are more than 100,000 superstores in the U.S., and putting solar panels on the combined 7.2 billion square feet of rooftop space could generate enough clean electricity to power almost 8 million homes.

As the new report on warehouse rooftop solar points out: "Producing electricity on rooftops, close to where the electricity will be used, reduces energy losses that happen during electricity transmission and distribution—losses that made up 5.2% of gross electricity generation in 2020. It also reduces the need for new utility-scale generation and transmission infrastructure and the damage to fragile ecosystems those can cause. Solar power also makes the grid more resilient to outages and disruptions."

The research comes less than a month after the International Renewable Energy Agency (IRENA) said the ongoing clean energy transition must accelerate if the world is to meet the Paris agreement's goal of limiting global warming to 1.5°C—beyond which the deadly effects of climate change will intensify, especially for people in poor nations who have done the least to cause the crisis.

According to IRENA, global investment in clean energy technologies reached a record-high of $1.3 trillion in 2022, enabling worldwide renewable capacity to grow by 9.6%. But to avert the climate emergency's worst consequences, investment must increase to about $5 trillion annually and capacity must grow at three times the current rate.

To "take advantage of untapped solar energy opportunities," Environment America Research & Policy Center and Frontier Group recommend that:

• Businesses invest in solar generation capacity on their facilities;
• All levels of government support solar energy adoption with policies such as net metering, feed-in tariffs, and/or value-of-solar payments; and
• All levels of government streamline the process for and reduce the costs of solar permitting and interconnection.

"The key to realizing the solar potential of warehouse rooftops is for warehouse owners to connect with solar developers and for utility companies to quickly connect rooftop solar systems to the grid," said Alex Keally, senior vice president for Solect Energy, a Massachusetts-based company that has completed numerous solar installations on warehouse rooftops.

According to the report, California, Florida, Illinois, Texas, and Georgia are the five U.S. states with the greatest potential for warehouse solar generation.

Whether that potential is realized will depend in part on state policymakers, as recent reporting on the Texas GOP by Inside Climate News makes clear.

"For several years in a row, the Lone Star State has generated the most electricity, by far, from wind and solar, producing nearly three times as much power from renewable sources last year as California," the outlet noted last week. "But last month, Republicans introduced a package of bills to the state Legislature intended to punish renewable energy and boost fossil fuels, including a measure that would increase the amount of gas-fired electricity generated by the state by upwards of 10 gigawatts and one that would limit the development of renewable energy in the state based on how much natural gas generation is also being built."