In 2018, the power sector in United States emitted 13.6 billion tons of carbon dioxide (CO2) into the atmosphere, 41 percent of total global emissions. To have a chance of holding global temperature rise below 1.5 degrees Celsius relative to its preindustrial level, global emissions from all economic sectors, including the power sector, must be reduced to net-zero around 2050.

One of the challenges of decarbonizing the power sector is sufficiently reducing greenhouse gas (GHG) emissions while guaranteeing reliability, security, and affordability. Solar and wind power are zero-carbon technologies, but their variability could challenge grid stability if they are not properly balanced by sufficient storage and firm power.