ORIGINAL REPORTING: Cheapest is not always best in CSP v. PV comparison

Cheapest is not always best: Concentrated solar power could beat lower price PV with new market rules; CSP can deliver greater grid stability than photovoltaics, but needs better recognition of its value to be competitive.

Herman K. Trabish, March 26, 2020 (Utility Dive)

Editor’s note: CSP is under-appreciated but the coming need for longer duration storage could be a game-changer.

Concentrated solar power's failure to gain momentum in U.S. markets is a signal that traditional resource valuations may be slowing the energy transition, a February CSP conference made clear.

CSP, which converts the sun's heat to electricity, was once dominant, then faded when photovoltaic (PV) solar, which turns the sun's light into electricity, plummeted in price. But unlike CSP, PV, even with batteries, cannot provide the long-duration, dispatchable generation that high-renewables power systems will need, conference participants said.

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"Renewables are now mainstream and fossil fuels are the alternative," California Energy Commission (CEC) Chair David Hochschild told regulators, utility executives and analysts at the conference. With new zero-emissions mandates, "we will need a diversity of renewable resources to keep the system reliable, and we will need CSP, particularly, because of its long duration storage [potential]."

Ambitious 100% renewables mandates drive indiscriminate procurement of the lowest-cost renewable kWh, utility executives and regulators said. But the transitioning power system requires broader value, even if the per-kWh price is higher. Restructuring markets, policies and utility planning to compensate investments in resources with a higher overall grid value, despite higher capital expenditures, will be necessary to deliver a reliable, low carbon power system, they added.

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CSP uses mirrors to concentrate the sun's heat within a single point containing a heat-retaining fluid. The captured heat creates steam that, like conventional generators, drives an electricity-generating turbine. CSP tower technologies focus the sun's heat on fluid flowing through a tower's apex. Trough technologies’ liquids flow through the focal points of trough-shaped mirrors. Heat-absorbing fluids include water or a molten liquid that more efficiently holds heat and can be stored for on-demand dispatch of electricity.

Utility-scale PV panels release electrons when exposed to the sun's light. The electricity flows to the grid or can be stored in batteries. Cost and regulatory barriers have largely limited cost-effective battery storage to four-hour durations, although battery stacks and alternative battery chemistries that deliver longer duration storage have been piloted. In 2010, the U.S. had 0.4 GW of CSP and only 0.1 GW of utility-scale PV. But cumulative CSP installations reached only 1.7 GW by 2020, while falling panel costs led to the installation of 35.4 GW of utility-scale PV by 2020, Wood Mackenzie Senior Analyst for U.S. utility-scale solar Colin Smith emailed Utility Dive… click here for more

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