Ideally you would pair these 4-hour batteries with CHEAP sources of electricity. Fill the battery when electricity is cheap, empty the battery when electricity is expensive (ie, when demand spikes or when other sources of generation drop off the grid).
The cheapest source of electricity today is noontime solar. Batteries can fill up on noontime solar and discharge into the evening peak. They could also charge on wind or traditional baseload sources overnight, and discharge into the morning peak.
The cheapest source of electricity today is noontime solar. Batteries can fill up on noontime solar and discharge into the evening peak. They could also charge on wind or traditional baseload sources overnight, and discharge into the morning peak.