The law of supply and demand can have surprising impact on the energy market. For a few hours on 11 March 2017, California produced so much solar electricity – over 4 GWh – that the wholesale electricity price temporarily became negative. In other words, the available electricity supply had exceeded demand and the producers had to sell at a loss and pay to produce the electricity. This atypical situation ties in with the tricky issue of how to store renewable energy such as solar and wind power. Progress is expected and it should solve the problem of negative prices.

Find out more