The author identifies the key appeal of concentrated solar thermal generation vs. photovoltaics, but remains a bit too optimistic about how competitive this rac

The author identifies the key appeal of concentrated solar thermal generation vs. photovoltaics, but remains a bit too optimistic about how competitive this race still is: While a big boost in efficiency is great, concentrated solar is far enough behind photovoltaics on price that it's not going to make a big enough difference in a direct competition. But the real competition here isn't directly with photovoltaics; instead there are two separate competitions. One is against photovoltaics plus batteries, since only that provides the possibility of around-the-clock energy access. Here, the costs are changing fast enough that it's difficult to figure out where things stand. I would say that it is not particularly difficult to figure out where things stand; absent a surprising catch-up from solar thermal power, photovoltaics-plus-batteries is going to win. For one thing, CSP only works where there is very high direct normal irradiance. Partially cloudy conditions cause its performance to drop much faster than the actual intensity of illumination drops. PV works fine with direct and indirect illumination. For that reason CSP performance declines in wintertime in temperate regions worse than PV does. You can see the effect by looking at performance-by-month for American solar PV and solar thermal here: https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_6_07_b https://www.eia.gov/electricity/monthly/epm_table_grapher.ph... In June 2017, solar thermal plants had a capacity factor of 37.9% while PV plants reached 35.7%. But in December 2017, thermal plants reached only a 9% capacity factor while PV plants reached 17.4%. This new material might be one way for thermal to compete better with PV. But to do so it will need to enter commercial use soon. Commercial battery storage projects are ramping up around the world. For stationary battery storage applications, technical breakthroughs for higher energy density aren't necessary; "last year's chemistry, but manufactured bigger and cheaper" is just fine. Further, the whole-project cost of PV + batteries declines when either batteries or PV decline in price. Even if solar thermal power doesn't pan out, this material might be useful in future energy systems. I have been reading for many years about how Generation IV nuclear reactors could run at high temperatures with supercritical CO2 turbines for compact, more efficient heat-to-electricity production. It's nice to have some of the supporting technology developed ahead of time. Even if such reactors never become competitive for terrestrial use, there is also the rest of the solar system to consider.