Quite a bit. In power systems of the future, it’s not just that smaller is better, smaller is essential. Big centralized systems like power stations with vast physical grids for transmission are inefficient. It was great to get started – we could take advantage of the economies of scale.
Barely a third of the primary energy content in most sources is converted to useable energy. Solar and Wind are limited by physics. But in Fossil Fuels and Nuclear, most of the loss happens because we use the energy for a single purpose, such as producing electricity or thrust, rejecting the remaining two-thirds as waste heat. Only Combined-Cycle (~60%) or Combined Heat & Power (~80%) Natural Gas technologies use more than 40% of their heat. Beyond that in electrical storage, up to 30% of all kilowatt hours stored are lost and another 5% is lost during grid transmission from the plant to the end user.