Today in Energy

November 25, 2013

Coal-fired electric generators continue to dominate electric supply in the central region

graph of southeast electricity generation, as explained in the article text
Source: U.S. Energy Information Administration, Electricity Monthly Update

More than 60% of electricity in the central region of the United States comes from coal-fired electric generators, down from 80% in the early part of the 2000s.

The central region is made up of the two regional transmission organizations in the central portion of the United States: MISO, the Midcontinent Independent System Operator, and the Southwest Power Pool (SPP). Coal-fired units generate most of the electricity in this region, primarily burning relatively inexpensive Powder River Basin (PRB) coal.

The decline of coal's share of total generation has been mitigated by the attractive pricing of this PRB coal and the limited stock of efficient combined-cycle gas-fired capacity in the region. However, in the spring of 2012, a period of very low natural gas prices resulted in a large increase in natural gas use, primarily from the region's available natural gas combined-cycle fleet, as well as some natural gas-fired combustion turbines, which are traditionally used to meet peak electric demand. The other big shift in this region is the increase in renewable generation, mostly from wind generators in the Plains states.

Graph of power prices in the central region, as described in the article text

Source: U.S. Energy Information Administration, based on SNL Energy
Note: Prices are for day-ahead, on-peak wholesale power. Chicago electric price in the MISO Northern Illinois Hub. Michigan electric price is the MISO Michigan Hub. Minnesota electric price is the MISO Minnesota Hub.

Lower or stagnant electricity demand and low natural gas prices combined with increasing output from low-cost renewable sources have pushed wholesale power prices (and revenue to electric generators) down in recent years in the central region. Wholesale power prices that ranged between $20 to $60 per megawatthour before 2011 ranged between $20 and $40 per megawatthour for most of 2012, before rebounding a bit in recent months.

Graph of dark spreads to coal-fired units in minnesota, as described in the article text

Source: U.S. Energy Information Administration based on SNL Energy
Note: Minnesota electric price is the MISO Minnesota Hub. Coal price is the Wyoming 8,800 Btu/lb using a 10,000 Btu/kWh heat rate assumption and a $17/ton transportation cost.

At times over the past few years, lower power prices have squeezed the dark spreads available to coal-fired generators in the region. Dark spreads are a rough measure of the gross margins available to units that run on coal. Coal-fired units could consistently expect dark spreads of $10 to $20 per megawatthour between 2009 and 2011. During the lower power price period in spring 2012, dark spreads dropped below $10 per megawatthour for several months.

Principal contributor: M. Tyson Brown