Cannot say that I agree that the future is car batteries.<br>Tesla installed a massive mains battery in South Australia and it's the best thing to have happened for the South Aus and national grids.<br>The uptake time for the battery is some fractions of a second from zero load to maximum.<br>It is also solar/wind charged so costs are very small compared to coal. We don't have nuclear power in Aus....,(reply>), You have to distinguish between short-term frequency support and long-term energy storage. For the former, Li-ion batteries are absolutely great, for the latter, they are far from being cost-effective.