> A battery back up of solar and wind deployments on the scale of a nation's economy, would need to provide enough storage for WEEKS of energy - there is NO bat

> A battery back up of solar and wind deployments on the scale of a nation's economy, would need to provide enough storage for WEEKS of energy - there is NO battery technology today or upcoming that can do that. With a sufficiently broad definition of battery to include pumped hydro, grid scale batteries do exist and are cost effective. This does require rather specific geography.