Installing solar panels over California's network of water canals could save an estimated 240 billion litres of water and produce 13 gigawatts of renewable power every year, according to a recent feasibility study. California moves more water than any other system in the world, and covering the canals with solar panels would reduce evaporation by shading them from the sun. The cooling effects of the water would also boost the solar panels’ efficiency. Another advantage is that this massive amount of solar energy would be produced without using any land. “You're taking something that's already been altered by human activity and doubling the benefits it provides.”