The share of natural gas and renewable sources in U.S. electricity generation widened in the first quarter compared to the prior year, primarily at the expense of coal generation.

According to the U.S. Energy Information Administration's latest "Electric Power Monthly" released May 26, utility-scale generation net of hydroelectric pumped storage declined 3.3% year over year to 963.0 million MWh in the period of January through March.

Coal supplied 17.8% of the nation's power in the first quarter, from 26.1% in the year ago. The share of natural gas grew from 34.5% to 39.7% year over year, as the share of renewables widened from 17.9% to 20.1%. Wind led renewable sources, accounting for 9.0% of total U.S. electricity generation in the first quarter.

Over the same period, coal-fired generation declined 33.8% year over year to 171.8 million MWh, while gas-fired generation climbed 11.5% to 382.6 million MWh. Renewable generation rose 8.8% to 193.6 million MWh.

In March alone, utility-scale generation net of hydroelectric pumped storage fell 5.6% year over year to 306.1 million MWh. Gas-fired generation climbed 9.4% to 123.6 million MWh, accounting for 40.4% of the net total. Coal-fired generation declined 35.6% versus the prior-year period to 50.6 million MWh, to account for 16.5% of the nation's electricity.

Renewable output climbed 0.9% year over year in March to 64.4 million MWh, as growth among renewable resources was mixed.

Power-sector coal stockpiles increased by 5.9 million tons in March, above the 10-year average build of 3.0 million tons. During the prior 10 years, March stockpile fluctuations versus the prior month have ranged from a draw of 3.8 million tons to a build of 8.5 million tons.

The EIA estimates that the March stockpile level of 145.5 million tons translates to 127 days of burn and 114 days of burn, respectively, for bituminous and sub-bituminous coal, 41.7% and 26.1% above the five-year averages for the month.