Dear Editor,
In response to his recent letter, I am glad that David MacDougall is performing his own internet research regarding energy storage; however, he should filter his findings more. Pumped storage round-trip efficiency claims can range between 65% and 87%. As with claims from associations and institutes affiliated and funded by fossil fuel corporations, many online organizations can claim exaggerated pumped storage efficiency claims and feed these claims to reporters.
In a January 2020 Navigant Consulting glowing report on the proposed Ontario Pumped Storage (OPS) project that was prepared for and paid by TC Energy, the round-trip efficiency claim for the proposed OPS was 72%. However, this claim doesn’t include the 4% – 5% 2-way losses of the proposed transmission line to the Essa station.
This means that the total system efficiency of the OPS would be about 67% – 68%. Tesla Megapak battery units have a claimed round-trip efficiency of 93.7%. This means that this efficiency difference of about 26% would be lost to the pumps and generators of the OPS. Newer, emerging battery technologies promise even more safety, longer life and less cost.
It’s true that higher pumped storage elevation difference (head pressure) delivers more energy to the turbine/generators but this is mostly offset by the extra energy expended to pump the water up to the higher elevation.
Pumped storage plants are geographically dependent. As I mentioned before, some other grid energy storage technologies (such as batteries) can be located almost anywhere and don’t require long transmission lines.
Flow batteries are also infinitely scalable like Megapaks and they offer up to 30-year lifespans. TC Energy is currently building the Saddlebrook solar energy + storage facility in Alberta, utilizing flow batteries for energy storage.
Mr. McDougall complained about the cost of a heat pump installation but I guess he hasn’t priced modern furnaces and boilers lately. The idea is that over the long-term, the investment pays off.
Regards,
Mike McTaggart, Meaford
