A remarkable thing happened in the US in April. For the first time ever, renewable electricity generation beat out coal-fired electricity generation on a national level, according to the Energy Information Agency (EIA). While renewable energy—including hydro, wind, solar, geothermal, and biomass—constituted 23 percent of the nation's power supply, coal-fired electricity only contributed 20 percent of our power supply.
There are seasonal reasons this happened in April. Wind power generation tends to be higher in spring and fall, hydroelectric generation usually peaks as winter snow melts, and lengthening days mean more solar power can be fed to the grid.
In addition, people use less electricity in spring, as it's not cold enough to need a lot of heating and not warm enough to require lots of air conditioner use. Coal-fired power plant owners, expecting this low demand, often use spring and fall to take their power plants offline for regularly scheduled maintenance.