Development of solar power in Washington state continues to grow, bolstered by 2019 Clean Energy Transformation Act (CETA) that commits Washington to have electricity free of greenhouse gas emissions by 2045. While the biggest need for electricity is in the more populous western half of the state, much of the development is on large solar farms in the sunnier eastern half. In February 2023, for example, AVANGRID announced that it had started operating its 150-Megawatt (MW) Lund Hill solar farm in Klickitat County, the state’s largest photovoltaic plant. The Washington state Department of Fish and Wildlife (WDFW) told the Seattle Times that more than 40 proposed solar projects would collectively lease more than 80,000 acres.

Solar farms are becoming increasingly difficult to site. Highly attractive locations can be home to endangered species and critical habitat, or they can be very attractive for farming, residential development or recreation. Directed by a budget proviso passed by the Washington State Legislature, the Washington State University (WSU) Energy Program carried out a Least-Conflict Solar Siting study on the Columbia Plateau as a pilot project. The Columbia Plateau region is about 14,242,020 acres, not including Tribal reservations. While over 6,777,000 acres could be considered highly suitable for solar development, just under 212,000 acres were deemed low conflict for environmental conservation, farmland, and ranchland, and ranked “very high,” “high” or “moderately high” for solar development suitability after maps were reviewed by stakeholders, including ranchers, farmers and environmentalists.

While some farmers have leased out their land, others are outraged at the prospect of seeing solar panels next door, worry about the impact on wildlife or see risks of fires.

The American Farmland Trust said solar energy policies in Washington State are part of the solution to prolonged drought, extreme temperatures, and wildfire smoke that are impacts of climate change. While the future of agriculture depends on reducing greenhouse gas emissions to prevent climate change, protecting land threatened by solar development is also critical.

Alternatives

About 51 percent of utility-scale solar facilities in the U.S. are in deserts, Yale Environment 360 reported, with 33 percent on croplands, 10 percent in grasslands or forests and just 2.5 percent in urban areas.

It turns out that there are a variety of alternatives to deserts or croplands. Although the U.S. lags behind other countries in dual-use projects, dual use offers a wide range of best and least conflicting opportunities.  Researchers at the University of California, Riverside and the University of California, Davis who studied alternatives for solar installations found at least four types of unconventional sites: the built environment, salt-affected land, contaminated land, and lakes.

While few of the alternatives are available in Washington state yet, the experience elsewhere shows what could be feasible here.

Floating Solar

One option is floating solar panels, or floatovoltaics. A solar array is fixed onto a buoyant structure that keeps it floating on the surface of a lake or dam. Countries such as Brazil, India, Singapore and Vietnam already use floating solar panels, JLL reported. Here in the U.S., Fort Liberty (formerly Fort Bragg) in North Carolina installed the largest floating solar panel in the southeast to power one of its Special Forces training sites. Placing panels on water cools them during the daytime, NPAS observed, making them more efficient. Moreover, floatovoltaics can connect to existing transmission lines and reduce evaporation.

The National Renewable Energy Laboratory (NREL) estimates that solar development on the more-than 24,000 human-made bodies of water in the US could produce 10 percent of the nation’s electricity.

Nevertheless, it’s important to note that bodies of water in Washington State support ecologically-, culturally- and economically-important aquatic species, such as salmon, and floating structures need to be well studied so they do not have a negative impact on their habitat.

Degraded Land

Land in a multitude of locations that has been degraded by mining, landfill or other could also be used for solar farms.
In Virginia, for instance, Dominion is partnering with The Nature Conservancy to develop a solar farm on a flattened mountaintop that was blasted away for coal. While former industrial sites and landfills are also available, the New York Times reported, they are often far from transmission lines and the surfaces can be unstable.

The EPA said that more than 80 Superfund sites nationwide are in planned or actual alternative energy reuse, with several sites are using renewable energy technologies as part of green remediation strategies for site cleanups.

Solar Panels on More Buildings

There are also plenty of places where solar energy could be developed in urban areas, which would reduce conflicts with cropland or nature. In Renton, WA, for example, IKEA installed solar on its rooftop. In towns and cities in southern United States, the Wall Street Journal reported, solar developers are covering the roofs of self-storage buildings.

Even though such sites can cost about twice the amount of utility-scale ones, 1–5 MW projects can be more cost-effective than large-scale utility systems when installed in certain locations. Rooftops and parking lots combined could meet nearly 80 percent of the nation’s electricity needs, according to the Department of Energy, though such sites are generally more expensive to develop than forest or farmland.

Taking it one step further, combining green roofs and rooftop solar can boost both biodiversity and power output, as green roofs moderate rooftop temperatures, which can help to increase the efficiency of solar panels, according to the World Economic Forum.

While more expensive, “distributed solar” that makes dual-use of buildings and parking lots in urban areas avoids the need for building more transmission lines and solar farms. Generating electricity close to where it is consumed on sites such as business rooftops bypasses the transmission grid.

Solar in Parking Lots and Canals

Another option is the space on top of or alongside parking lots, transportation lines or irrigation canals. Indeed, the University of California researchers noted opportunities to integrate solar technology include panels on or alongside transportation corridors such as solar road panels or photovoltaic noise barriers. They estimated that alternative surfaces totaling more than 1.5 million football fields in size could generate more than 19,000 terawatt hours of energy per year.

Another alternative in California is covering irrigation canals and aqueducts with solar panels, to save water and generate energy. A pilot project is underway in the San Joaquin Valley. In Washington State, Puget Sound Energy (PSE) and the City of Bonney Lake partnered to install a community solar site on the roof of a storage water reservoir featuring 1,368 solar panel.

Putting solar panels on top of parking lots is yet another option for using land that is developed yet underutilized. A typical Walmart supercenter, Yale Environment 360 observed, has a five-acre parking lot that could support a three-megawatt solar array. In addition to providing power to the store, the canopy would shade customers.

One company that has developed an innovative solution is Sunspan, which produces round tube technology held up by lightweight support structures that resist soiling, reducing the cost and lowering energy losses by 5-10 percent.

Agrivoltaics 

An alternative that the Department of Energy says could help ease land-use conflicts is agrivoltaics, the co-location of solar energy installations and agriculture beneath or between rows of solar panels. This includes any dual use of solar-occupied land that provides ecological or agricultural benefits.  

NREL estimates that there are more than 2.8 GW of agrivoltaic sites in the U.S., the majority of which involve sheep grazing or pollinator habitat, and more are possible.

Done well, agrivoltaics may increase the yield of certain crops, such a broccoli. Moreover, agrivoltaics can also increase production for pastures, resulting in higher quality herbage and thus better feed for livestock. It can also provide adequate shading for animals, which lessens heat stress. An added bonus is that agrivoltaics can also stimulate pollinator habitats.

It’s Time to Go Beyond Farmland

While farmland, deserts and forests seem like easy locations to put solar panels, they come with baggage. Using a multitude of alternatives available may produce more power, overcome transmission line challenges, and speed up the implementation of solar power tremendously.