A growing share of renewable energy is pushing out conventional sources of power, reducing the “electricity system’s margin to meet peak demand in specific conditions such as cold, dark and windless days,” [Cap Gemini SA said in its European Energy Markets Observatory report]. [...]
“If we have a very cold winter, we could find ourselves in a very tense situation,” Colette Lewiner, Cap Gemini’s global energy and utilities researcher, said by phone.
Typically, fossil fuels and nuclear reactors provide what is called baseload energy, that is, a steady, dependable power output that can be counted on day in and day out. Renewables like wind and solar energy can’t replace that kind of supply, because they can only produce power when the wind is blowing and the sun is shining. These green resources instead serve to help supply peak demand, during the times of day when people are generally gluttons for electricity.