Comment by CSSer | Hacker News Reader

Comment by CSSer | Hacker News Reader

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This all seems pretty incredible and kind of like a no-brainer. What are some of the challenges in a project like this? Are there any limitations to scale?

Lastly, do you know off-hand if these bold claims (see below) are exaggerated or oversimplified in any way?

> Covering just 10 percent of the world’s hydropower reservoirs with floatovoltaics could generate as much electricity as all the world’s operating fossil fuel power plants combined

> We found that countries in the Americas and Africa could benefit most: even low coverage of reservoirs by floatovoltaics should generate all the solar energy needed to decarbonize their electricity sector. Brazil and Canada could be hotspots, each requiring only about 5% coverage of their plentiful reservoirs to satisfy their massive solar-energy needs. Last year, Brazil implemented regulatory changes to help the industry to develop (see ‘Brazil’s photovoltaic boom’).

https://www.nature.com/articles/d41586-022-01525-1#ref-CR13 (linked in the article)

There are not significant limitations to scale other than the usual economic reasons. There are competing uses of many reservoirs, however - likely recreational boaters would strongly oppose taking over large sections of reservoirs, so floating solar is more likely going to be located in practice near to the dams / in existing keep-out zones.

Yes, those claims are technically correct, in the same way that the claims we could power all of humanity's needs with a fraction of the sahara desert are also technically correct. In practice, competing needs for the water bodies and especially the cost of transmission lines / the lower cost of nearby desert land for many of the sites means that it's certainly an oversimplification.

really, the competition against cheap desert land is what makes the difference - that is why it really makes sense in places with limited land (Japan, South Korea, eastern China, coastal California, etc)

And yes! I agree it's a no-brainer. Big barriers: 1) Getting all the stakeholders to agree (US Bureau of Reclamation, the local reservoir joint-powers authority, the Santa Barbara city council, the local utility, etc) 2) Avoiding NIMBYs and those that might be worried about ecosystem effects (e.g. Audubon society). While the evidence suggests it's not an issue for wildlife, those folks tend to be very conservative (even if they are missing the forest for the trees, IMO)

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