https://www2.deloitte.com/insights/us/en/industry/power-and-utilities/global-renewable-energy-trends.html

Wind and solar place downward pressure on electricity prices. In theory, because solar and wind have zero marginal generation costs, they displace more expensive generators and reduce electricity prices. In global practice, the deployment of solar has flattened midday price peaks, while wind has lowered nighttime prices. Three-quarters of the top 20 US solar and wind states have electricity prices below the US national average; a quarter are among the nation’s 10 states with the cheapest electricity, including the wind leader Texas. Wholesale prices in the top European solar and wind market, Germany, have more than halved over the past decade. In Denmark, which has the world’s highest share of intermittent renewables (53 percent), electricity prices exclusive of taxes and levies are among the lowest in Europe. Lawrence Berkeley National Laboratory estimates that once the United States reaches Denmark’s penetration levels of 40–50 percent renewables, some states will see the dawn of “energy too cheap to meter.”