Battery storage, wholesale electricity prices and the generation mix: estimated price effects and descriptive results for nine markets, 2020–2025.

Results supporting an MSc thesis at the University of Padua on the effect of grid-scale battery storage on wholesale electricity prices. Nine markets are covered across three continents over 2020-2025: the four regions of the Australian National Electricity Market, Great Britain, CAISO, ERCOT, Germany and Italy. The record contains two datasets. battery-price-effects.zip holds the estimated price effects. For each market-year a merit-order supply curve is fitted relating price to residual demand, which is load net of wind and solar, and net of interchange in markets that price it outside their own dispatch. The counterfactual asks what the price would have been at the residual demand that would have prevailed had the fleet not operated. Five outcomes are reported per market-year - mean price, peak shaving, valley filling, daily spread and volatility - giving 160 market-year-outcome cells across 32 retained market-years. Intervals are 95 per cent day-block bootstrap over 200 replications, with the curve refitted inside each replication. Seven markets produce estimates; Germany and Italy do not, and carry their screening evidence instead. All effects are observed minus counterfactual, so a negative value means the observed market settled below the constructed series in which the fleet is removed. Currency is local throughout and is never converted. battery-generation-mix.zip holds the accompanying descriptive generation-mix results: energy and operating hours by technology, shares on a denominator reconciled separately for each market, explicit coverage status for all 683 technology-year rows so a closed plant is distinguishable from a broken data feed, and a table of which technologies run during the tightest one per cent of hours by residual demand. The price estimates are model-based counterfactuals, not causal effects. The curve is fitted to prices observed while the fleet was operating, and no market in the panel supplies variation in fleet size independent of the price relationship. The generation results are descriptive and attribute no change to storage. Each zip contains a README documenting the method, the screens, the documented exceptions, every rejected market-year and every known limitation.