U.S. Energy Information Administration - EIA - Independent Statistics and Analysis
Electricity Monthly Update
With Data for August 2015 | Release Date: Oct. 27, 2015 | Next Release Date: Nov. 30, 2015
Resource Use: August 2015
Supply and fuel consumption
In this section, we look at the resources used to produce electricity. Generating units are chosen to run primarily on their operating costs, of which fuel costs account for the lion's share. Therefore, we present below, electricity generation output by fuel type and generator type. Since the generator/fuel mix of utilities varies significantly by region, we also present generation output by region.
Generation output by region
In August 2015, net generation in the United States increased 2.1% compared to the previous August. At the regional level, all regions of the country except for the Central region and Florida saw an increase in electricity generation compared to August 2014. Florida saw electricity generation decrease compared to last August because in August 2014, Florida experienced significantly high temperatures during the month whereas in August 2015, Florida only experienced slightly above average temperatures. The Central region also saw a decrease in electricity generation, but this was a result of cooler than normal temperatures experienced during this August, which decreased the demand for residential cooling in the region and thus, decreased the need for electricity generation compared to the previous year.
For the second consecutive month, electricity generation from coal decreased in all regions of the country. Subsequently, all regions of the country saw an increase in electricity generation from natural gas, except for Florida, which saw a very slight decrease in natural gas generation compared to August 2014. Total electricity generation from nuclear was up, increasing 1.8% compared to the previous August. The Western region continues to see a decline in conventional hydroelectric generation compared to the previous year, with electricity generation from hydroelectric generators decreasing 8% from last August 2014.
Fossil fuel consumption by region
The chart above compares coal consumption in August 2014 and August 2015 by region and shows that, like electricity generation from coal, coal consumption decreased in all regions of the country for the second consecutive month.
The second tab compares natural gas consumption by region and shows that changes in natural gas consumption from the previous August were very similar to the changes in electricity generation from natural gas over the same period.
The third tab presents the change in the relative share of fossil fuel consumption by fuel type on a percentage basis, calculated using equivalent energy content (Btu). This highlights changes in the relative market shares of coal, natural gas, and petroleum. In August 2015, the share of natural gas consumption increased in all regions of the country at the expense of coal consumption compared to the previous year.
The fourth tab presents the change in coal and natural gas consumption on an energy content basis by region. The changes in total coal and natural gas consumption were similar to the changes seen in total coal and natural gas net generation in each region.
Fossil fuel prices
To gain some insight into the changing pattern of consumption of fossil fuels over the past year, we look at relative monthly average fuel prices. A common way to compare fuel prices is on an equivalent $/MMBtu basis as shown in the chart above. The average price of natural gas at Henry Hub decreased slightly from the previous month, going from $2.91/MMBtu in July 2015 to $2.85/MMBtu in August 2015. However, the natural gas price for New York City (Transco Zone 6 NY) saw an increase from the previous month, going from $2.06/MMBtu in July 2015 to $2.48/MMBtu in August 2015.
For the second consecutive month, the New York Harbor residual oil price saw a significant decrease from the previous month, going from $8.69/MMBtu in July 2015 to $7.34/MMBtu in August 2015. Regardless, oil used as a fuel for electricity generation is almost always priced out of the market.
A fuel price comparison based on equivalent energy content ($/MMBtu) does not reflect differences in energy conversion efficiency (heat rate) among different types of generators. Gas-fired combined-cycle units tend to be more efficient than coal-fired steam units. The second tab shows coal and natural gas prices on an equivalent energy content and efficiency basis. For the eighth consecutive month, the price of natural gas at Henry Hub was below the price of Central Appalachian coal on a $/MWh basis. However, the spread between the two prices narrowed considerably due to the month-to-month decrease in the price of Central Appalachian coal. The spread between the New York City gas price and the price of Central Appalachian coal also decreased compared to the previous month, a result of the increase in the natural gas price of New York City coupled with the decrease in the Central Appalachian coal price.
The conversion shown in this chart is done for illustrative purposes only. The competition between coal and natural gas to produce electricity is more complex. It involves delivered prices and emission costs, the terms of fuel supply contracts, and the workings of fuel markets.