Energy storage
Very important to the energy transition, and often ignored, is the need to store energy to smooth out energy generation (which with wind and solar doesn’t happen continuously) and energy demand (which is not constant either).
We have always needed to balance generation and demand, but with fossil fuel this doesn’t need to be a separate thing: for example an energy store at a coal fired power station is just the big heap of coal next to it. There was a need to spread energy usage to periods of low demand, which was achieved with off-peak tariffs, and technology such as domestic storage heaters.
Energy storage does not need to be in batteries, with their use of rare and sometimes dangerous metals. Gravity, pressure and heat can all be used, even flywheels. Some of these technologies can involve losses, but they don’t have to be very large. One company using heat in Salt, air and bricks quoted only 1% loss per day of energy from a molten salt system at 500°C.