With increasing investment into wind and solar, companies in the US, Germany, and Australia are producing so much energy that the price is falling below zero, Bloomberg reports.
What it means: Sadly, it doesn't mean free energy for all. It's just an interesting example of how difficult it is to manage a transition in the economy - in this case, from coal and gas-powered energy systems to wind and solar.
A lot sunny days and breezy mornings has basically meant that at certain times of day, we're producing more than enough energy through renewables not to need coal and gas plants. But the plants weren't designed to just switch on and off quickly, so they keep producing as much as they used to, and we end up with way more energy than we need - which is why prices fall below zero (because no-one needs to pay for it, so it's got no value).
It's a sign that we need better energy infrastructure to allow a smooth phasing out of coal and gas - so that eventually we get to a point where we're able to just switch it on for an hour or two when we need it.