By - Michael Drost

Rooftop solar could generate 5,000 MW: Report


Energize Weekly, June 10, 2015

Mid-sized cities could install as much as 5,000 megawatts (MW) of solar on municipal property and save millions of dollars in energy costs, according to a new report by the Institute for Local Self-Reliance. That’s more than a quarter of all solar installed in the U.S. to date.

The study found that the 200 U.S. cities with populations of 100,000 people or more could easily and inexpensively install more than 5,000 MW of solar on municipal buildings if certain policy barriers, such as the fact the 30 percent federal investment tax credit is unavailable to local governments, are circumvented by embracing legal third-party ownership.

“Cities have unused building roofs that are perfectly positioned to capture solar energy,” says John Farrell, director of Democratic Energy at the Institute for Local Self-Reliance. “We knew there was an opportunity, but were surprised by how much money cities could save, how much potential solar could be installed, and how solar on municipal rooftops has spillover effects making solar easier for residents and businesses.”

The report says that cities which have embraced rooftop solar have already experienced millions of dollars in savings. The town of New Bedford, Massachusetts, for example, is saving $6 to $7 million per year on electricity through 16 MW of installed solar on municipal property, or over 2% of the city’s entire budget. Lancaster, California, a city of 159,000 people, currently saves $450,000 per year by generating 9 MW of solar to power over half its municipal operations, according to the report.

“Cities like Raleigh, NC, and Kansas City, MO, have made remarkable strides given the uphill fight against restrictive state policies,” says Farrell. “Whereas New Bedford, MA, has more solar per capita on public buildings because of two key state policies: aggregate net metering allows the city to group buildings together to offset electricity use and virtual net metering lets the city produce solar energy off-site for municipal use. Rules matter.”

Not only will installing rooftop solar save money, it will also significantly reduce carbon footprints. San Francisco, for example, emits 5.3 million metric tons of carbon dioxide per year. If the city were to maximize school rooftop potential (32 MW), for example, it could displace 14,900 metric tons of carbon dioxide, or 0.28 percent of the city’s emissions, according to the report.

The biggest obstacle to more cities installing rooftop solar is price. Without the federal tax credit, the cost of installing a solar array is 15.5 cents per kilowatt-hour. With the tax credit, the cost drops to 11.2 cents per kilowatt-hour, according to the report. As a result, it does not make financial sense for cities to invest in their own solar arrays.

A solution is to look to third parties, according to the report, however only 23 states currently allow for power purchase agreements. That is changing, according to Farrell, who cited Georgia and Florida as states which have recently moved to allow third party power purchases.

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