The federal agency said renewable sources — solar, wind and hydroelectric power — provided 742 million megawatt hours of electricity in 2018, nearly double the 382 million megawatt hours produced in 2008.
Almost 90 percent of the increase in U.S. renewable electricity between 2008 and 2018 came from wind and solar generation, the EIA said. Wind generation rose from 55 million megawatt hours in 2008 to 275 million megawatt hours in 2018, while solar generation increased from 2 million megawatt hours in 2008 to 96 million megawatt hours in 2018.
Conventional hydroelectric power (water) accounted for 6.9 percent of total electricity generation, followed by wind (6.5 percent) and solar (2.3 percent), the EIA said.
Solar generation is generally categorized as small-scale solar installations or utility-scale installations. In 2018, 69 percent of solar generation, or 67 million megawatt hours, was utility-scale solar, the EIA said.
The increases particularly in wind and solar generation can be attributed to growth in capacity, changes in state and federal policies, and declining costs, the EIA said.
In addition, state-level policies, such as renewable portfolio standards, which require a certain share of electricity to come from renewable sources, have increased targets over time. “As more wind and solar projects have come online, economies of scale have led to more efficient project development and financing mechanisms, which has led to continued cost declines,” the EIA said.