Green Energy

Linking Solar Canopies and Irrigation Canals

With an ambitious plan to cover irrigation canals with solar canopies, California adds a new twist to the new subject of agrivoltaics

Only a few years ago, the idea of combining solar panels and farming became popular. The field already has a name: agrivoltaics, and its devotees are already looking for new, more advanced variations on the theme. The Turlock Irrigation District in California, for example, recently launched a new agrivoltaics project that may provide the state with multiple gigawatts of solar power by installing solar panels in irrigation canals.

Until now, the agrivoltaics industry has focused on the advantages of lifting solar panels a few feet off the ground, giving farmers a twofer. They get fresh cash by leasing their land for electricity generation, and they can continue to farm while the solar panels are installed.

That’s a big improvement over traditional farm-to-solar methods, which put solar panels closer to the ground, on a bed of gravel or some other non-crop ground cover.

Agrivoltaics is closely related to regenerative agriculture, which is a science-based sustainable farming technique that emphasises soil conservation and improvement. Raised solar panels, in fact, give the farmer a triple benefit in terms of sustainability and profitability.

Solar panels can help to accelerate restorative aims by shading the soil and minimising excessive evaporation. That’s a fresh take on the water-energy connection. Agrivoltaics allows solar energy collecting to conserve water resources rather than exploiting water resources to generate power.

The Turlock Irrigation District project is the result of this. TID revealed earlier this week that it had been chosen to test the nation’s first water-energy nexus system, which involves building solar canopies atop canals.

The solar canopies would prevent evaporation from the canals as well as generate sustainable electricity.

In terms of scale and influence, the new TID initiative would undoubtedly create history. If everything goes according to plan, California’s 4,000 miles of public water infrastructure could support a solar energy capacity of 13 gigawatts while conserving 63 billion gallons of water annually, which is equivalent to the irrigation demands of 50,000 acres of farmland, according to a 2021 study.

That 50,000-acre figure is a drop in the bucket compared to California’s prime, irrigated agriculture, which is estimated to be around 9 million acres. Still, saving 63 billion gallons of water is a major feather in the zero-carbon energy lily.

The fact that evaporation can be reduced should draw the attention of other water agencies in California, the United States, and the rest of the world. The solar canopy concept could provide canal owners with a cost-effective alternative to offset water loss due to seepage.

The US Department of Agriculture has been attempting to get canal owners to line their canals in order to avoid water loss due to seepage. However, for obvious reasons, the concept has not taken off.

Almost 76 percent of water delivery companies cite expense as a factor for leaving conveyance infrastructure unlined, according to data collected in the USDA’s 2019 Survey of Irrigation Organizations.

Apart from the water conservation aspect, the Nexus project is another another example of how the United States has vast renewable energy supplies that can be exploited without damaging wildlife habitats or putting farmers out of production.

The US Department of Energy estimated in 2010 that 14 million acres of brownfields and other undeveloped land in the US may be used for wind or solar projects. The country has also only scratched the surface of its rooftop solar potential, and new solar window technology will allow it to collect even more clean kilowatts from structures.

Meanwhile, the National Renewable Energy Laboratory predicts that floating solar panels placed over a chosen group of human-made reservoirs and other bodies of water infrastructure could meet 10% of the country’s overall electricity consumption.

Along with the agrivoltaics angle, the TID project brings a new pool of prospective solar sites.

Arizona could be next on the list, as the 336-mile Central Arizona Project canal was the focus of a 2015 NREL study. Solar coverings have long been a demand, but things weren’t looking so good back then. NREL calculated that the over-the-canal layout would be 24 percent more expensive than alternative sites based on a similar canal-plus-solar installation in India.

“Shading the CAP canal with PV panels has the potential to reduce evaporation by reducing evaporation. However, in comparison to the expenses of installing solar over the CAP canal, this savings is minor, at 6 acre-ft per year,” NREL observed.

Location is a part of the problem. The CAP route passes through some remote and difficult terrain.