For established utilities, though, this is a disaster. Their gas plants are being shouldered aside by renewable-energy sources. They are losing money on electricity generation. They worry that the growth of solar and wind power is destabilising the grid, and may lead to blackouts or brownouts. And they point out that you cannot run a normal business, in which customers pay for services according to how much they consume, if prices go negative. In short, they argue, the growth of renewable energy is undermining established utilities and replacing them with something less reliable and much more expensive.