How much storage does a grid need? Too little leads to blackouts. Too much means money wasted. Getting the predictions wrong will skew policy priorities and investments, and slow the transition to a clean electric grid. Effective Load Carrying Capability (ELCC) measures a resource’s ability to produce energy when the grid is most likely to experience electricity shortfalls. Mark Specht at the Union of Concerned Scientists explains how it works. Typical 4-hour utility-scale batteries have a high ELCC when first added to a grid. But their ELCC score decreases as more are added to cover longer periods of peak demand, because their 4-hour lifetime is too short to cover it. Specht notes that as innovations bring about longer storage durations (week-long, month-long, seasonal?) the ELCC scores will be much higher and decline more slowly. The calculations can be complex as every relevant energy source has an ELCC, and the amount of other sources on the grid will affect each other’s scores. But to get the right mix, grid operators should be using ELCC instead of the crude ways of quantifying capacity contributions currently being used, says Specht. Grid reliability and investment choices depend on it.
Energy Post 18th June 2021 read more »