As available land for solar projects in many U.S. markets is becoming increasingly scarce—and the price almost everywhere is escalating—solar photovoltaics floating on water could be a welcome alternative, according to National Renewable Energy Laboratory (NREL) researchers.
Indeed, roughly 10 percent of the nation’s annual electricity production could be generated with the installation of floating solar photovoltaics on the more than 24,000 man-made U.S. reservoirs, according to their research, “Floating PV: Assessing the Technical Potential of Photovoltaic Systems on Man-Made Water Bodies in the Continental U.S.,” published in the journal Environmental Science & Technology.
While the world’s first installation occurred in Napa Valley, Calif. a decade ago, widespread adoption within the United States has been slow, and as of last month, there were just seven floating PV sites in the country, according to the researchers. More are being deployed in other countries, particularly Japan, which has 56 of the 70 largest floating PV installations.
“In the United States, it’s been a niche application; where in other places, it’s really been a necessity,” writes NREL’s lead energy-water-land analyst Jordan Macknick on the laboratory’s blog. “We’re expecting it to take off in the United States, especially in areas that are land-constrained and where there is a major conflict between solar encroaching on farmland.”
Floating PV installations on water could not only save about 2.1 million hectares of land, but also reduce water evaporation and algae growth, according to the researchers. Moreover, installations that operate alongside hydroelectric facilities yield increased energy output and cost savings because of existing transmission infrastructure.
“Floating solar is a new industry enabled by the rapid drop in the price of solar PV modules,” said Adam Warren, director of NREL’s Integrated Applications Center and another author of the report. “The cost of acquiring and developing land is becoming a larger part of the cost of a solar project. In some places, like islands, the price of land is quite high, and we are seeing a rapid adoption of floating solar.”
The U.S. Energy Department is currently evaluating several NREL proposals on floating PV installations. The laboratory is also currently negotiating with an unnamed client to fund the installation of instrumentation equipment at a new 75-kilowatt floating solar facility in Walden, Colo., in partnership with the French floating PV developer Ciel & Terre International.
However, the amount of risk and costs associated with the operation and manufacturing of floating PV installations is stymieing wider adoption, NREL researchers told Utility Dive. In the spring, they plan to start collecting more data to analyze such costs—as well as the benefits of overcoming the risks. The analysis will be geared to demonstrating the long-term value of the installations to potential investors.
“There are some very basic questions that still need to be answered that many private companies don't have the infrastructure … to evaluate,” Macknick told Utility Dive.