We’ve all heard it. That phrase trotted out with deadening familiarity by green sceptics: “Solar and wind are all very well, but what happens when the breeze doesn’t blow and the sun doesn’t shine? Have you thought of that, eh?”
For anyone who believes in the renewable energy revolution, it’s a frustrating comment, but it contains more than a grain of truth. Because, while increasingly cheap and efficient, wind and solar are undeniably intermittent. They don’t provide so-called ‘baseload’ electricity – always on, 24/7 – in the same way that conventional power plants can.
That’s a problem, as electricity is notoriously hard to store: ideally, you balance supply and demand. Hence the appeal of ‘baseload’ gas, coal or nuclear plants, which can be brought into play to match demand. Hence, also, the need to pay wind generators to turn off their turbines when excess supply is being produced: around £180,000 spent per hour in the UK alone. Large battery banks are coming onstream, but they’re expensive and have limited capacity.
