Progress in developing the next-generation gas-fired turbines could increase competition between siting new cleancoal or ultra-efficient natural gas generation plants, some industry sources believe.
While some maintain that expected natural gas supply shortages favor coal long-term, others cite the generation efficiency of natural gas turbines now being designed, which will not only provide a cleaner, more flexible energy source, but can be deployed more rapidly and at less expense than coal plants.
Calpine and GE Energy are now building an advanced gas turbine using GE’s H System, which is designed to reach a 60% efficiency rating - a measure of the amount of energy captured from the fuel. GE Energy spokesman Kenneth Darling said that in order for the H-System to reach 60% efficiency, the industry’s highest, other parts of the combined-cycle system must be enhanced as well.
Experts from the Department of Energy’s National Energy Technology Laboratory said combined cycle natural gas turbines (CCGT) have a 56% to 58% efficiency rate, while older pulverized coal (PC) plants have a 33% to 35% efficiency rate.
Tom Hewson, principle with Energy Ventures Analysis, said that efficiency factors should be carefully evaluated, as they can be manipulated by using lower or higher heating values of fuels. Advanced PC plants using super critical technology can get 40% efficiencies, the DOE said, and integrated gasification combined cycle efficiencies are 40% to 42%. Calpine plans to install the new turbine in its 775-MW Inland Empire plant, which is expected to come online in mid-2008.
The plant is located east of Los Angeles in one of the fastest-growing metropolitan areas in the US. GE will invest more than $500 million in the project that will likely ease concerns of state officials over inadequate supplies of energy in 2006 and beyond. California power demand is on the rise, with seven demand records set this past summer alone (NGW Jul. 26, p8). While generation capacity in most of the US remains overbuilt, areas that expect to see supply reserves decrease have several thousand megawatts of new generation in the pipeline, mostly natural gas.
DOE data shows plans for new gas-fired generation at 23,850 MW; 20,985 MW; and 6,797 MW for 2006, 2007 and 2008, respectively; while plans for coal-fired generation is at 2,376 MW; 4,814 MW; and 1,390 MW for 2006, 2007 and 2008, respectively. These plants have either secured financing or a financing statement; an environmental impact statement; or a signed contract for the output.
Natural gas is the only available choice for meeting growing power demand in the US, not coal, because excess gasfired generation is already in place, said Jerry Eyster, managing consultant with PA Consulting. And the nature of the new power demand to be met is a key factor in ongoing coalgas competition, he said.
“Just because gas is $6 doesn’t mean coal is a dead winner,” Eyster said. “If my growth is going to be during peak hours primarily, then I want a technology that runs during the day and turns off during the night.”
PA Consulting analysis of January through October 2004 compared to the same period in 2003 shows coal generation decreased .04% while natural gas generation increased 6.84%. Peak load growth comes from demand created by housing developments, shopping centers and office buildings, while baseload growth comes from industrial load that runs around the clock.
Peak load growth fits the cycling pattern of CCGTs much better, as they can be run as needed, unlike a coal plant, Eyster said.
