Wind and solar farms are glutting networks more frequently, prompting a market signal for coal plants to shut off.
Bright and breezy days are becoming a deeper nightmare for utilities struggling to earn a return on traditional power plants.
With wind and solar farms sprouting up in more areas — and their power getting priority to feed into the grid in many places — the amount of electricity being generated is outstripping demand during certain hours of the day.
The result: power prices are slipping to zero or even below more often in more jurisdictions. That’s adding to headaches for generators from NRG Energy Inc. in California to RWE AG in Germany and Origin Energy Ltd. in Australia. Once confined to a curiosity for a few hours over windy Christmas holidays, sub-zero cost of electricity is becoming a reality for hundreds of hours in many markets, upending the economics of the business in the process.