Landfills could host more than 60 GW of solar, RMI says

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The Rocky Mountain Institute (RMI)  released a report, The Future of Landfills Is Bright, that offers a guide to considering the value of solar power installed on landfills. The report indicates that more than 63 GW of solar power plant capacity could be located at less than half of U.S. landfills, generating 83 terawatt hours of electricity each year across all 50 states.

The plants also could generate more than than $6.6 billion annually in electricity revenue.

The report offers guidance to local jurisdictions for how to take advantage of these resources, including the considerations that must be taken when building on landfills, as well as how to create a financially viable marketplace for the sale of the solar electricity. It covers several necessary bureaucratic structures, and provides guidance on collecting the data necessary for siting projects on landfill.

According to the U.S. Environmental Protection Agency, around 428 MWac of utility scale (greater than 1 MWac) landfill solar across 126 projects had been installed at the end of 2019. Notably, Connecticut, Massachusetts, New Jersey, and New York are home to 73% of all U.S. utility-scale landfill solar projects.

A solar installation on a capped landfill in New Jersey.

Roughly speaking, if the projects cost $1.50 per watt to construct, it would cost a little less than $95 billion to build out the capacity that the RMI report envisions. Municipal electricity cooperatives could sell the electricity directly, or community solar programs might buy it, for 8¢/kWh, generating the $6.6 billion in first year revenue.

If the facilities were owned and managed by third parties, and the land was leased by municipalities at $1,000 per acre, then around $217 million a year in revenue could flow to the hosting jurisdictions.

Landfill sited solar capacity would nearly double the Biden administration’s goals to grow community solar sevenfold in five years, while increasing total U.S. solar power capacity by about 58% from 108 GWdc, the capacity reached at the end of the second quarter of 2021.

GameChange Solar Racking “Pour In Place” product often used for landfills.

The report cited a lack of data: The RMI authors were able to locate public information on only 43% of the nation’s 10,000 closed landfills. Naturally, the report’s first recommendation is to broadly collect information about the remaining sites. Of course, once more information is collected, it must also be made available. 

In order to assess the total potential of landfill solar, each site must provide key data. The site’s physical characteristics needed include the state of the landfill cap (the seal to keep the material in), settlement history, site grade, existing infrastructure and operations, on-site electricity demand data, as well as community concerns.

For those jurisdictions hoping to crunch their own numbers, RMI made available the criteria it used to develop its model for all 50 states, Puerto Rico, and the U.S. Virgin Islands. RMI estimates that solar could utilize 70% of the landfill land area considered, with a solar panel capacity of 9.5 watts per square foot.

Using the U.S. Department of Energy’s PVWatts calculator, both standard and premium panels were assessed and averaged together. The system was designed to be fixed, tilted at 20 degrees, with an azimuth of 180. Inverter efficiency was a realistic 96%, system losses 14%, and the DC to AC ratio was set at 1.2.

A solar landfill project in Tennessee.

Image: C2 Energy Capital

To calculate the potential employment opportunities generated by the construction, RMI assumed 11 jobs per megawatt, a figure borrowed from NREL’s JEDI modeling and ILSR’s Equitable Community Solar report from 2020.

Of course, once these pieces of land are recognized and deemed viable for solar projects, the most important piece of the equation will be ensuring that the billions of dollars invested in landfill solar projects have a chance to earn a fair return on the investment.

The report points out that in Massachusetts, certain regions included under the state’s SMART solar program have completely sold out. The program includes bonus incentives for building solar on landfill sites that have above average expenses.

Other RMI suggestions include equitable community solar program designs that take into account the local population when defining labor requirements, as well as local electricity savings. Another technique is to allow the landowning jurisdiction to make use of the electricity via net metering and remote net metering policies. These tend to produce the most efficient financial transactions.

The U.S. will need somewhere between 1,000 to 2,000 GW of solar power to electricity our transport and clean our power grid. Making full use of the 10,000 closed landfills across the nation to generate 10% of our electricity makes good sense.

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