I think there is a place of both - and that is the beauty of a free market. In general, larger batteries run by the power company should be more efficient. Howe

I think there is a place of both - and that is the beauty of a free market. In general, larger batteries run by the power company should be more efficient. However there are a few reasons why you also want your own home battery. - you become less vulnerable to short power outages - the power companies can't ask much more for electricity than solar plus battery would cost you - the grid might become more stable, as the battery can smoothe of sudden power demands, also grid fluctuations shouldn't affect you any more - on the one side, you probably can shave off a few dollars of your energy costs by not storing surplus solar vs. sending it to the grid - on the other side, home battery companies can't sell at prices higher than what the grid offers So I think there will be a combination for both, working together to get the costs down and supply more reliable. The number and the size of batteries installed at home in a region depends on the parameters of that region.