The costs of renewables are dropping, thanks in large part to generous state subsidies and production chains that have helped to drive down prices of solar panels and to a lesser extent wind turbines. But cheaper doesn’t yet mean cheap—renewables still rely on government support to help them fight fossil fuels for market share—and up-front costs aren’t the only thing holding us back from a 100 percent wind-and-solar-powered society. Intermittency, the notion that wind and solar can only generate power when it’s windy or sunny, sets a limit to how much we can rely on renewables. During windless nights, we need backups (read: nuclear or fossil fuel plants) ready to come online, but the Economist notes that “it is hard to get people to build gas-fired power stations that will not be used very much—which in markets with a lot of renewables is their inevitable fate.”That’s not the only way in which intermittency hamstrings renewables. The FT today highlights research by German economist Lion Hirth, who has argued that intermittency also consigns renewable power generators to “price cannibalization”. The upshot: when renewables hit peak production they effectively flood the wholesale electricity market, depressing prices and hurting their own bottom line. Intermittency, it seems, has yet another ugly side effect.It’s therefore not enough to focus solely on further depressing the price of solar panels or wind turbines. Power generation needs to be, above all, consistent, and the vagaries of weather prevent renewables from being so. Finding a way cheaply and efficiently to store wind and solar power on a commercial scale would, of course, solve most of these problems (though grids will still need updating to account for the more distributed nature of these new power sources). To that end, and as the Economist argues, we’d be better served diverting money away from the propping up of less efficient current-generation renewables and towards the research and development of technologies that will allow wind and solar to out-muscle fossil fuels on their own merits.