By feeding electricity produced by wind turbines into the electricity networks, demand for conventional electricity reduces at certain times. This is why a fewer number of expensive coal and natural gas power stations have to be used. The trade price for a kilowatt-hour of electricity then falls on the European Electricity
Exchange. Around 5 bln euro costs were avoided in this way in 2007. But renewable energy also avoids those costs which aren‘t even shown on the bill for fossil energy sources: Their mining, drilling and combustion are responsible for climate change and health damage, for landscape destruction and the loss of biodiversity. The costs of this are borne by the general public through taxes
and health costs. Renewable energy avoided at least 8 bln euro of these external costs in Germany in 2007.

Without renewable energy our energy supply would already cost us far more than it does.