A chart showing the US shift in source of electrical power from coal to natural gas

Today's chart, from the US Energy Information Administration Agency (via Alexis Madrigal at TheAtlantic.com) shows the increasing use of natural gas, instead of coal, to power the US electric grid. It's a historical shift, and the reasons for it are complicated, involving prices, changes in generating capacity (the capacity to generate power from natural gas has been increasing) and changes in transmission capacity. It's a big change, to move from using coal to using natural gas - according to the EIA, coal and natural gas generated equal amounts of power in April 2012 for the first time.

As shown in the chart above, there are strong seasonal trends in the overall demand for electric power. In April 2012, demand was low due to the mild spring weather. Also in April, natural gas prices as delivered to power plants were at a ten-year low. With warmer summer weather and increased electric demand for air conditioning, demand will increase, requiring increased output from both coal- and natural gas-fired generators.

I hope readers are staying cool in this new heat wave.