More wind and coal, less nat gas in Texas power mix

Texas’ power generation climbed 3.5 percent in 2010, according to the state’s main grid operator, with wind continuing to provide a bigger piece of the pie and natural gas power falling to its lowest point in years.

Net energy for load was 319,097 gigawatt-hours (GWh) for all of 2010, according to the Electric Reliability Council of Texas. That compares to 308,278 GWh in 2009 and 312,401 GWh in 2008.

Wind energy accounted for 7.8 percent of the total energy generated, up from 6.2 percent in 2009 and 4.9 percent in 2008.  Last year also saw a new ERCOT record for wind output when 25.8 percent of the total load (7,227 megawatts) was handled by wind at 7:16 am on Dec. 11, 2010.

Coal power generation was up nearly 8 percent to handle 39.5 percent of the load, while natural gas was down nearly 9 percent, to account for about 38.2 percent of the load. That’s the lowest it’s been since at least 2002, when 48.2 percent of Texas’ power was gas fired.

Nuclear was down about 3.6 percent. The full report is here.

Here’s a summary of usage by fuel for the past 4 years:

ERCOT ENERGY BY FUEL TYPE

Fuel Type 2010 2009 2008 2007
Percent Percent Percent Percent
Natural Gas 38.2 42.1 43.0 45.5
Coal 39.5 36.6 37.1 37.4
Nuclear 13.1 13.6 13.2 13.4
Wind 7.8 6.2 4.9 2.9
Water 0.3 0.2 0.2 0.4
Other 1.1 1.2 1.6 0.4

I can understand why wind is taking up more of the slack: There’s simply more of it being built (9,528 MW of installed wind generation in Texas – the most in the U.S. and the fifth highest in the world) and operators are getting much better at predicting when wind power will be available.

The drop in gas usage isn’t as clear, however.

The state had long bucked the national trend and has had natural gas account for the biggest piece of its power pie (until this year). There’s been a big drop in natural gas prices from 2008 highs and the national trend has been for more utilities to switch off coal plants in favor of gas.

Some possible explanations for the Texas anomaly:

  • There have been a significant number of older gas-fired plants retired since 2002 — about 12,000 MW — and another 3,400 MW put in mothball status.
  • More new coal plants have come on line at that time.
  • The lignite coal that fuels many of Texas’ largest coal plants is very cheap compared to even the low natural gas costs.
  • Gas plants are often used as “peakers,” units that can be turned on quickly should predictions for daily power use be off and more capacity needs to come on line in a hurry. Maybe ERCOT operators are just getting better at predicting demand.

Other suggestions for why natural gas has fallen from its esteemed place as Texas’ top power plant fuel? Post them in the comments.

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