There are a lot of stories on residential rooftop solar but few if any on what cities are doing to make themselves energy self-reliant by using their own buildings and lands to generate power.

In Public Rooftop Revolution, ILSR estimates that mid-sized cities could install as much as 5,000 megawatts of solar—as much as one-quarter of all solar installed in the U.S. to date—on municipal property, with little to no upfront cash. It would allow cities to redirect millions in saved energy costs to other public purposes.

This report is being released in serial format, beginning Monday, June 1 through Thursday, June 4. CHECK BACK TOMORROW FOR UPDATES.

Read the Executive Summary

Read Part 1 of the report

Read Part 2 of the report

Listen to our podcast conversations with a few of our Featured Five municipal solar cities:

Lancaster, CA city manager Jason Caudle, listen to the podcast, read the interview summary.

Raleigh, NC renewable energy coordinator Robert Hinson, listen to the podcast, read the interview summary.

Kansas City, MO project manager Charles Harris, listen to the podcast, read the interview summary.

 

The Third Party Trump Card

Although cities face a number of challenges, economic and otherwise, to installing solar, the third party ownership option—if available—ought to trump most of them. For suitable sites that won’t need a near-term roof replacement, third party ownership removes virtually all of the financial barriers to solar, and covers maintenance and operations. While some barriers (like lack of aggregate or virtual net metering) remain, most cities have a substantial solar opportunity.

ILSR estimates that over 5,000 MW of solar could be inexpensively installed almost immediately on municipal property in states with laws allowing third party ownership. This amount is more than a quarter of the nationwide total solar capacity through September 2014, and it only includes the municipal buildings of the approximately 200 cities with 100,000 or greater population.

We arrive at this number by estimating the solar potential for cities in states where third party ownership is allowed, based on the following four estimates of rooftop solar potential ILSR obtained. The estimates are shown in the table below.

Although there’s an impressive range of potential from this small sample, ILSR estimates that each city can, on average, install 25 MW of municipal solar. For comparison, the city with the most municipal solar Watts per capita, New Bedford, MA, has 16 MW, but is also smaller than 100,000.

The result is an impressive array of municipal solar potential in 23 states (plus DC) with third party ownership and 201 cities larger than 100,000. Cumulatively, these cities could have third parties install over 5,000 MW of solar on municipal buildings, as shown in the map below. Note that two states allowing third party ownership have no cities larger than 100,000 population, Vermont and Delaware.

Though the map says it powerfully, it’s worth repeating that there’s an enormous solar opportunity waiting for cities to seize it.

As a word of warning, this estimate may not account for the wide variation in solar net metering laws. While solar-leader New Bedford can obtain over a third of its solar for municipal use off-site (using virtual net metering) and apply solar produ...