I do not know enough about batteries to comment, but the author is wrong about wind and solar:
They are not approaching the limits of their contribution. That would be ~20% with today's distribution network. They do not require "near 100% backup for renewables in the form of mostly conventional generating sources." This is wrong for several reasons. First, I think it is more like 30% which is about the same amount of backup as conventional sources need. Coal and gas plants also need backup because they go off by accident or for scheduled maintenance. Nowadays in places like Texas, maintenance is scheduled on days when the weather forecast indicates there will be a lot of wind. In other words, it works both ways: renewables are the backup for coal. Second, in a wind farm, they seldom lose more than one turbine at a time to accident, and they never take more than one at a time off line for maintenance, so they never lose more than a megawatt or two. Third, in many places, solar generation peaks right when demand is highest, because air conditioning is one of the biggest demands. Even in Germany, where temperatures are moderate, peak demand is usually in the afternoon when solar output is highest. No source is more difficult to back up than nuclear power because the plants are huge and they tend to SCRAM and go off line completely at random times. I have not seen that factor accounted for in the cost of nuclear power. If this author says the cost of backup should be added to wind power, we should also add it to cost of nuclear power. At present nearly every Japanese nuke is down, and they are having a heck of a time backing them up with conventional sources. It is costing a fortune, and adding lots of CO2 to the world total. - Jed
