You don’t need spinning reserve, but you do need enough reserve power that can supply grid-forming generation on demand. Batteries can react fast enough to pea

You don’t need spinning reserve, but you do need enough reserve power that can supply grid-forming generation on demand. Batteries can react fast enough to peaks and troughs in voltage load, so long as there are enough of them where needed. Grid-forming batteries can react to frequency fluctuations electronically. Flywheels are another approach for grid stabilisation without a baseload.