Suspended solar panels are revolutionising the way we use canals by saving millions of litres of water while also generating clean, green energy.

The advantages of solar plants placed on top canals extends beyond energy production. Solar power plants can be constructed faster than large coal or gas power stations saving time, and money.

Most importantly, by covering the canal it helps prevent evaporation of water, leaving more available for the crops, people and animals who depend on it.

The idea first started in India back in 2012 when canal-top solar panels were installed in along a 750m stretch in Gujarat - India’s sunniest state. Overall, Gujarat has more than 80,000km of canals. According to Gujarat State Electricity Corporation, if 30% of this were converted to solar, 18,000MW of power could be produced, saving 90,000 acres of land.

Since the first solar canal project, a number of others have been commissioned in India, including a 100MW canal-top solar power project over the canals which branch off the Narmada River, which enables electricity to be extracted at multiple points, providing support for farmers during the energy-intensive irrigation season.

Out of season the electricity is fed into the state grid, sold to distribution companies or used by the canal authority.

India's 'flying' solar canals have sparked a growing global interest in embracing this unconventional solution. For example, the recently announced Solar Over Canal initiative is a collaboration between public, private and academic organisations in California, US.

Known as Project Nexus - the concept grew out of a 2021 study conducted at the University of California, Merced and UC Santa Cruz. The study showed that covering the near 6,500km of public water delivery infrastructure in California with solar panels could generate 13GW of energy annually, equal to about one-sixth of the state’s current installed capacity and about half the projected new capacity needed to meet the state’s goal of reducing greenhouse gas emissions 40% by 2030.

“Solar canals are an example of an energy-water nexus that offer multiple sustainability benefits. Using water canals for solar infrastructure conserves water while producing renewable electricity and avoids converting large tracts of land to solar development,” said Dr Brandi McKuin, lead author of the study.

Following the study, the Turlock Irrigation District partnered with the Department of Water Resource, Solar AquaGrid, and the University of California, Merced for the US$20 million Project Nexus - which is funded by the State of California. Project Nexus is due to start in Autumn 2022 with the project expected to be complete in 2024.

“Research and common sense tell us that in an age of intensifying drought, it’s time to put a lid on evaporation,” said Jordan Harris, chief executive of Solar AquaGrid.

“Our initial study revealed mounting solar panels over open canals can result in significant water, energy, and cost savings when compared to ground-mounted solar systems, including added efficiency resulting from an exponential shading/cooling effect. Now is the chance to put that learning to the test.”