One of the issues with open air water storage and transport is that there are not inconsiderable losses to evaporation.
I have always wondered why someone hasn't put solar cells above the water to generate power and reduce evaporation.
Well, it turns out that California will be erecting solar panels above the canals that transport water to Southern California.
These canals are low hanging fruit, there is not much growing in them except for fecal coliform bacteria, so there will not be mass die offs if the sun does not reach the water.
If one were to do this for a reservoir or lake, which would contain a vast number of animals, you would need to make the solar cells transparent to the frequencies used for photosynthesis (400-525nm and 675-750 nm) in order not to create dead bodies of water.
It's a good start:
California is ready to try out something that could help it save water and generate electricity at the same time: solar panels over irrigation canals.
For this proof-of-concept experiment, some 8,500 feet of photovoltaic panels will be installed over waterways just north of Turlock, central California, generating electricity while preventing water from evaporating away.
This $20 million state-funded pilot program has been dubbed Project Nexus, and will by run by Turlock Irrigation District (TID), a nonprofit water and power utility, along with its partners. If it's a success, it could well be deployed across more of America's Golden State.
Once completed, Nexus is expected to generate 5 MW of renewable energy. If all of California's 4,000 miles of public waterways were so covered, 13 GW could be generated, according to a 2021 study published in Nature that was cited by TID. That latter figure would be enough to meet a sixth of the state's energy demands, we're told.
And that's not the project's only selling point for drought-stricken California, as the canal panels will help it fight evaporation. The aforementioned study found that 4,000 miles of canal panels could save more than 60 billion gallons of water per year. According to the study's authors, full canal coverage in California would be enough to irrigate 50,000 acres of farmland or supply water for more than two million people.
In addition to helping fight drought, the panels will also reduce vegetative growth in the canals, which TID said will increase the quality of the water flowing into farm fields. Because the microclimate adjacent to irrigation canals is somewhat cooler than the surrounding air, TID said the project will also keep solar panels cool, fighting heat-based efficiency losses.
Anyone want to take a bet on how long before some group of right-wing nut jobs decides to put a law on the ballot stopping this?
Also, which Silicon Valley billionaire will bankroll the effort?
2 comments :
Wouldn't it be interesting if they decided to use solar panels in the same way over (say) the Great Lakes? Or even the Earth's oceans? Of course they'd need some drains to allow rainwater to reach the oceans, I presume.
I wonder what that would do to the Earth's albedo?
They would also need solar cells that allow the frequencies for photosynthesis to pass through, because, unlike the canals, there is an ecology that would be destroyed otherwise.
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