In a world of _very_ poor options for energy storage, molten salt seems to be, from very rough calculations, something which might scale to what Tom Murphy ("Do the Math") refers to as a "nation-scale battery" -- up to two weeks of stored generation capacity.<p>My own <i>very</i> naive and rough back-of-the-napkin calculations suggest that a total thermal storage facility roughly comparable with existing US oil storage tanks in Oklahoma could provide that capacity.<p>More generally, the strength of molten salt is to even out supply to variability in either demand or incident sunlight. Note also that concentrated solar power requires _concentration_ -- you cannot focus _diffuse_ light (e.g., hazy or overcast conditions), though PV still delivers some power under such circumstances.<p>But PV is instantaneous, and other storage options -- batteries, pumped hydro, compressed air energy storage (CAES), flywheels -- are either limited by material and/or sites, or by costs or engineering challenges.<p>Salts are plentiful, as are insulating options. Thermal energy systems are well understood. The concept is inherently distributable (no need to put it all in one spot), and, modulo spills, generally environmentally benign.<p><a href="https://www.reddit.com/r/dredmorbius/comments/1viied/grid_scale_thermal_energy_storage_this_might_work/" rel="nofollow">https://www.reddit.com/r/dredmorbius/comments/1viied/grid_sc...</a>
<i>That is, unless declining battery costs make storing PV power more economical. James Nelson, a California-based energy modeler with the Union of Concerned Scientists, says this intrasolar race will be good for the environment: “I’m glad we have multiple technologies that can help the transition from gas power plants.”</i><p>I agree with his remarks in principle, but really, there is far more abundant Na/K in the earths crust than the currently touted Li. And the Li would probably go to better use in ~65C melting point salts(by weight LiNO3 5%,NaNO3 6%,KNO3 23%,CsNO3 44%, Ca(NO3)2 19%, although the Cs would be the limiting resource if the competition for Li usage wasn't there)[0].<p>[0] <a href="http://moscow.sci-hub.bz/9b519cf6102a9b10fc60ce9035594865/raade2011.pdf?download=true" rel="nofollow">http://moscow.sci-hub.bz/9b519cf6102a9b10fc60ce9035594865/ra...</a>
The most interesting part of a facility like this is that it takes up the same amount of space as a regular field of solar, but it much more efficient. The trade off though, is the huge tower, which doesn't lend itself to more populated areas.
There is a plant using molten salt storage in Spain since 2009 if interested;<p><a href="https://en.wikipedia.org/wiki/Andasol_Solar_Power_Station" rel="nofollow">https://en.wikipedia.org/wiki/Andasol_Solar_Power_Station</a>
Fantastically the UK just signed an agreement with China to let China build a fission plant in the most populous south east, with the usual capital cost and total lack of realistic decommissioning plans, and still the price planned for the next thirty years is already above all our other sources<p>Nice to know the govt. is still on the ball<p>/sarcasm