One big issue with renevable energies is the inconsistancy of available electric power. While - once installed - solar pannels and windparks deliver free of CO2 electricity, the amount of energy provided depends on the momentary amount of wind and sun. When there is no sun, solar pannels don't produce any energy. Same problem with wind turbines and wind. That's why - in Germany for example which has a lot of both - when the sun is shining and there is wind they have to shut down many wind turbines because there is simply too much electricity in the grid. And a lot of free energy is being wasted that could be used in times when there is not enough wind and sun. But for every problem there is at least one solution. One great solution is: Electric cars.
Electric cars have a big battery. And while we all know that an electric car needs to be plugged into the grid to be charged with a lot of electric power, that power can or could in theory also flow in the other direction.
Instead plugging the car into the house to charge the car, it is possible to use the (huge) battery of an electric car to actually power the house!
Let's make an example: Tuesday there's a lot of wind and a lot of sun in Germany. My car is charged 50%. So instead of shutting down windmills, the power provider gives the surplus electricity away for free to charge electric cars. As an electric car owner I decide to charge my car to 100% with free electricity. On Thursday there is no wind and no sun. The electricity provider therefore decides to sell its electricity at the normal price. Because I didnt use the car a lot since Tuesday, the battery still has 90%. Instead of using (buying) the electricity for the normal rate I prefer to plug my car into the house so I can use the free electricity (from Tuesday) to supply my house.
Nowadays with internet and apps it would be easy to handle the ups and downs like this. Instead of wasting energy customers could benefit from it. Everybody wins.
When an electric car also is able to provide the house with energy (instead solely the other way round) that's called bidirectional charging.
Many electric cars offer that possibility already. Technologically it is not a big deal to make an electric car bidirectional. And as described above, that simple technique could solve the problem of inconsistancy. Instead of building huge battery storage power stations it might be enough just to build enough (bidirectional) EV's.
I encountered night storage heaters the first time when I bought a house in Germany as we never had them in Swittzerland. Its technique is simple; It's from the time when Germany was using a lot of coal for production of energy. Apparently it is impossible or useless to shut down the coal plants during the night when less energy is needed and start them up again. So Germany always had a surplus of electricity at night.
Night storage heaters are simple heating devices in the house with a built in heating rod and fan. Because of the electricity surplus at night, electricity was much cheaper at night. That's why night storage heaters were meant to heat up at night. But instead of using that heat instantly, a night storage heater is packed with a lot of stones that will store that heat by heating the stones up (but not giving that heat to the room). During the day when people wish to warm up their house they press a button which starts the built in fan. That will cool the stones which are still hot from the night and give the stored heat resp. energy to the room. The stones can store the energy for up to 48 hours. So during the day when electricity is more expensive (and less available) there is no need for additional electricity. All the needed energy is stored in the stones that are still hot from the night.
It is a very easy and effective technology to deal with different amounts of available electricity over time. Since Germany aims to reduce coal generated electricity, the government originally planned to abolish night storage heaters. But later realized that those heaters coud actually be part of the solution and not part of the problem.
In wintertime electricity companies could sell electricity cheaply when there is a lot of green energy available (for example when there is a lot of wind) to charge the storage heaters. Instead of just during the night (as it was with coal plants) they could do that independently from the actual daytime. This concept could work well especially for fluctuations that appear within 48 hours. But because the weather can change fast within that time it would still make sense. Artifficial intellignece and constantly improving weather forecast could also help. Or maybe even more effective: When people have night storage heaters in addition to another green heating technology (like pellets or heat pumps). Like this customers could use their night storage heater when there is a surplus of electricity in the grid and switch to heating with wood (pellets) or heat pumps when there is less energy in the grid.