By: Maura Keller
Closed or capped landfills dot the landscape of many states. While many of these closed landfills can’t be used for any sort of development due to the residual toxins gracing the ground, more and more states are exploring placing solar energy arrays on this barren land – putting the tainted ground to good use as renewable energy landscapes.
Developing solar systems on closed landfills is a growing trend, which really took off a few years after the EPA launched its RE-Powering America’s Lands Initiative in 2008.
The first landfill project was completed on a landfill at Nellis Airforce Base in Nevada in 2007. The following year the U.S. Army built a system on a construction landfill at Fort Carson, Colorado. Also in 2008 was the first municipal solid waste landfill built in Sarasota, Florida. This was co-located with a park, covers one-half acre and is a .25 megawatt system.
Today there are thousands of inactive or closed landfills in the U.S. and more continue to close each year, which presents plenty of opportunity for development. Nichole Coulter, vice president of development at Distributed Solar Development, has also noticed an increase in development activity on landfills in certain states, such as New York, Massachusetts and New Jersey, due in part to new incentive programs being implemented. Solar developments on closed landfills are typically most common in states that offer incentive programs for developing landfills or community solar incentive programs, which are often built on landfills.
“By far, Massachusetts leads the states with this technology,” said Dr. Anthony DePrima, executive director of Energize Delaware, a non-profit organization helping residents and businesses save money through clean energy and efficiency. Of the 144 projects listed in the RE-Powering the Land database from 2008 to 2018, 66 (45 percent) are in Massachusetts.
“Massachusetts has a history of providing incentives for municipal-owned solar projects through renewable energy credit set-asides or reservations and financial incentives in the form of add-on value tariffs,” DePrima said. “There were many municipal owned, closed landfills in Massachusetts that took advantage of these programs.”
At Its Core
The process for developing solar installations on closed landfills depends on the location as every state and local jurisdiction has varying rules and regulations for development. As Coulter explained, some states, mainly concentrated in the northeast, have incentive programs in place to drive renewable energy adoption. Developing in these states can be extremely beneficial as the incentives provide financial support for the project.
There must be a demand for renewable energy in the area being developed, so assessing that need and identifying the potential energy off takers (i.e., the entities who will buy the energy created) is an important first step.
“The developing party will also need to get buy-in from the landfill owner, perform due diligence on the site to ensure it’s suitable for development and identify any potential setbacks or site restrictions early on,” Coulter said. Obtaining the closure report for the landfill is critical as it provides information on the makeup of the landfill, what the cap is composed of and the thickness of the geomembrane layers. Once due diligence is completed, the permitting process begins at the federal, state and local levels. Upon permitting approval, construction can move forward.
DePrima said the physical processes for placing solar arrays on closed landfills is not much different from a greenfield site, with a few exceptions.
“A closed landfill generally has a physical cap. The solar installation must respect the cap and any environmental prohibitions over penetrating the cap,” DePrima said.
As Coulter explained, using closed landfills for solar development offers several benefits. First, installing a solar system on a closed landfill is a beneficial use of an otherwise undevelopable area.
“For many municipalities with a desire to implement local solar projects, closed landfills are among the best candidate sites, often offering both the largest potential project space and the greatest economic value for the municipality,” Coulter said. “Landfills make great sites for community solar installations, which provide local municipalities and residents access to renewable energy at a reduced cost, and for which municipalities can receive lease revenue for hosting the solar project.”
In addition to the environmental benefits, solar installations on landfills can also generate up to millions of dollars in economic benefits to municipalities in the form of lease revenue and/or electricity bill savings.
Also, according to Coulter, when a solar installation is developed on a close landfill, the long term owner of that solar asset often takes over the operation and maintenance responsibilities for the landfill (e.g., maintaining the grass, etc.), which can save local municipalities money and resources.
“The benefits of these projects bring new revenue to landfill owners through the sale of electric to the local electric utility or displacing electric use on site,” DePrima said. “In some states there are other cash benefits like the sale of renewable energy credits. For landfills owned by the private sector there are federal tax incentives. Some public landfill owners lease the land to third party operators, generating additional land lease income. In general, these sites help the economy by creating green construction jobs. Finally, many local governments and private operators have sustainability goals for which these projects help them fulfill their mission.”
Embracing Challenges of Closed Landfills for Solar Energy
And while there are many benefits to developing solar systems on closed landfills, there are also a few drawbacks. The main drawback is that closed landfills are typically more expensive to develop compared to open greenfield sites, due to the higher level of complexity and the specialized equipment, materials, and skills required for the installation.
For example, according to Coulter, ballasting systems are often required to anchor the installation without puncturing the landfill’s cap, or a crane may be needed to keep the landfill from caving in while the systems are being put into place.
“Additionally, the permitting process is often tougher for landfills than other greenfield sites as any changes to post-closure plans must be filed. This process can be lengthy, adding additional costs for consulting and regulatory filing,” Coulter said. “The landfill owner may also stipulate that repairs be made to the landfill, such as fixing the cap, before developing the site for solar, which can also add costs. Additionally, since many landfills are located in rural areas with outdated electrical systems, developers may need to upgrade portions of the electrical system to connect into the grid.”
In addition, the shape and the age of the landfill will also impact the ability to develop. If a landfill has too many slopes or not enough surface area, it can be difficult to design a system with a large enough capacity to make it worthwhile. The age of the landfill is very important as the settlement rate is often highest during the first 10 years after being closed or capped. Landfills which have been closed for over 10 years are often best suited for development.
Industry experts agree that landfills will continue to close and present opportunity for development. As Coulter said, these sites are particularly great for community solar installations, which continue to grow in popularity as the country increasingly prioritizes sustainability initiatives that will help slow the impacts of climate change. “I can only see this trend continuing to grow as more and more states implement community solar or similar incentives,” Coulter said.
DePrima said that as the cost of constructing solar systems continue to fall, and as electric rates continue to rise across the country, economic incentives for constructing solar systems on closed landfills will increase. “Also, the technology for placing solar arrays over closed landfills has become proven, closing the risk gaps that previously may have discouraged operators in the past,” DePrima said.
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