On sunny days, solar panels can generate more energy than is needed in the home. Where’s that flow going?
If there are solar panels on the roof, the toaster toast and the washing machine runs on sunlight. However, these solar panels sometimes generate more electricity than is needed in the home. That power goes back into the grid, so it comes out of the wall a few doors down.
If all households with solar panels in a neighbourhood or neighbourhood together generate more energy than is needed in that neighbourhood at that moment? Then what happens to that excess energy?
To begin with, does this happen? Yes, indeed. On very sunny days, an entire neighbourhood sometimes generates more energy from solar panels than is consumed. Last year this happened a little more often than the year before, because more solar panels are added each year.
Grid operators are responsible for the power from your wall socket. If a household generates more solar energy than needed, it is returned to the grid via the network operator.
If no one can use that energy, it can happen that in one or a few households the inverter is switched off. An inverter converts the energy of solar panels into electricity. The panels may generate electricity, but that is not converted into electricity. So it’s over.
To prevent this, grid operators could lay thicker cables nearby to transport the energy to other neighbourhoods. But that is a lot of work and therefore expensive. Consumers can store the excess electricity in a battery, for example in an electric car. There are also separate batteries for sale at home, so you can use the power at a less sunny moment. Those home batteries are quite pricey and generally aren’t a good solution.
Situations in which solar panels generate so much energy that it can’t get anywhere are not very common: it must be very sunny and then it is still a few residents of a neighbourhood to whom nothing is returned.
The excess energy that you deliver back to the grid, you can deduct from your energy bill. It’s called netting, an arrangement designed to make it more attractive to install solar panels. Grid operators and energy companies argue in favour of subsidising something else: not generating energy, but storing it.