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.

3 Comments

  1. Dan

    The reason coal picked up is that 3 new coal plants came on line and it is still the marginally cheaper fuel. Coal isn’t a whole lot cheaper than gas anymore, and the economics of building a new coal plant are lousy, but the decision to build new coal units was made in the 2005 time frame when people expected $10/MMBtu gas.

    #1
  2. Rice

    With so much wind on-line in Texas, ERCOT requires more spinning reserve power plants in case (and when) the wind dies and thousands of megawatts disappear. While natural gas prices are low, the heat rates (efficiency factor) at peaker plants are still higher than those at coal plants, so natural gas plants are more expensive to run on an operational basis.

    #2
  3. Energy Moron

    Howdy Neighbor:

    Three GW of coal plants came on at various times of the year in 2009 (Dan, there was a fourth in November of last year in San Antonio so “three” is the answer but that is GW).

    Let’s see… think about how coal burns… coal and nuclear take hours to turn on and off, and thus are not well suited for peaking. The wind blows when it wills. Hydro can be used in a peaking mode but is so small so as not to be relavent. So, natural gas is the reliable servant that provides the extra energy when it is needed.

    Coal use did rise about 8% last year.

    The US economy is almost completely coupled to coal.

    Let’s make a simple model to see how dependent our GDP is on an energy source

    use_2005 = use_1960 * ( ( gdp_2005 / gdp_1960 ) ^ power )

    Here we are just comparing 1960 to 2005 values… it’s slightly more complex than this but this illustrates the principle.

    For coal, the power is 0.7. While the constant dollar GDP rose by a factor of 4 our coal use roughly tripled.

    For oil the power is 0.5. Our oil use in 2005 was roughly twice that of 1960.

    For natural gas the power has been 0 since 1970. Natural gas is the poor servant that works only when others fail.

    Why 1960? Well, there were two disruptions to coal increase, the first oil after World War II (think Churchill) and the second natural gas/nuclear after WW II. But US coal use has been rising since then.

    What’s going to power the electric car?

    #3