Dive Brief:

Changes to the United States' power generation mix last year reflected fuel price fluctuations and the growth of renewable energy, though overall demand fell. According to the U.S. Energy Information Administration, total U.S. net generation fell by 1.5% in 2017, compared with the year before.

Natural gas generation fell most steeply by 105,443 Gwh, or 7.7%, and coal generation declined 31,248 GWh, or 2.5%. More than 11 GW of capacity retired last year, with most of that being coal.

Both wind and utility-scale solar cracked new records, according to EIA's Electric Power Monthly. Wind accounted for 6.3% of total net generation, and utility-scale solar made up 1.3%.

Dive Insight:

There are several major shifts ongoing in the United States generation sector, including the battle between coal and gas and the rise of renewables.

Neither of the fossil fuels posted inspiring generation numbers last year, but gas' decline was three times as steep as coal. Despite that, retirement figures paint a clearer image of where the market is heading.

Source: U.S. Energy Information Administration

The power sector retired 11.2 GW of generation last year, and 6.3 GW of that was coal capacity. About 4 GW was natural gas, mostly steam turbine units. Importantly, however, more gas capacity was added than retired. And for the first year in a decade, no new coal capacity came online.

Gas remained the most-utilized fuel for power generation for the third year running, a sea change from coal's decades-long run as the top fuel. EIA said 9.3 GW of new gas-fired capacity came online last year, of which 8.2 GW were combined-cycle units.

This was the first year since 2008 that both gas- and coal-fired generation declined, EIA noted. But for renewable energy it is a different story, despite the country's declining demand.

Wind made up 6.3% of total net generation, and utility-scale solar made up 1.3%, both of which were record shares. Hydroelectricity accounted for 7.5% of net generation, but the resource got a boost from record precipitation in California.

EIA said it "expects hydro to continue to exceed wind in 2018, but wind is projected to become the predominant renewable electricity generation source in 2019."

There were about 11 GW of new solar and wind added last year. EIA said wind resources grew by almost 6.3 FW, and utility-scale solar added 4.7 GW. There was also 3.5 GW of small-scale solar capacity added last year, bringing the resource to a total of 16.2 GW, EIA said.

Earlier this year, EIA said it expects gas prices will remain below $5 per million British thermal units and will continue to fuel a switch to gas-fired generation. The agency's projections have natural gas’s share of generation steadily increasing market share relative to coal through 2050.