The two renewable energy sources accounted for 17% of the country’s power mix while coal fell to a low of 15%. Natural gas remains by far the largest source of electricity, accounting for 43%.

In a first for the US, wind and solar produced more electricity than coal last year, according to a new report from energy think tank Ember. Coal fell to a historic low, generating 15 percent of the country’s electricity compared to 17 percent from solar and wind combined.