TERRE HAUTE, Ind. - Beyond the farms of central Indiana, where the ground is so flat that driving over a bump can be exciting, the land becomes more varied as you approach Terre Haute. Endless fields give way to more trees.
Here, in the Wabash River valley, sits one solution for electricity production, a plant that takes otherwise dirty fuel and turns it into a relatively environmentally friendly source of power.
One part of a 1950s generating station run by Cinergy, whose main subsidiaries provide power in Indiana and Cincinnati, has been replaced with a gasification system fed by Global Energy, a Houston firm that has a contract with Cinergy.
The gasification process produces gas - called syngas - by breaking down coal or, in this particular case, petroleum coke. The syngas is burned in a turbine, essentially a jet engine bolted to the floor, which turns a generator. Excess heat from the gasification process is used to produce steam which turns another generator. The result is 262 megawatts of power with very few pollutants flowing into the air.
Very generally speaking, based on emissions numbers supplied by Global Energy and from a U.S. Department of Energy report on the gasification project, the Wabash River syngas plant emits slightly less than one-tenth the nitrous oxide and sulfur dioxide emitted by a standard coal-fired plant generating the same amount of power.
Gasification is one of the technologies that We Energies proposes to use in its expansion of the Oak Creek generating station, but it will build that 600-megawatt plant at the end of the expansion cycle at the end of this decade.
Wabash River is running now.
So why shouldn't We Energies start out with gasifiers instead of building two supercritical pulverized coal generators? Gasification is still an immature technology, said Margaret Stanfield, a spokeswoman for We Energies. "It still needs to evolve before it meets the three criteria that we need from a base load power plant." The plant must be low cost, must meet strict environmental regulations, and it must be reliable, she said. "And when we say reliable, we mean 24 hours a day, seven days a week."
Base load plants - meaning a generating station expected to run almost all the time and meet basic power demands - are available between 80 and 90 percent of the time, Stanfield said. The remaining 10 to 20 percent of the time the plants are out of commission either for routine maintenance or emergency repairs, she said.
Last year, Wabash River was available 79 percent of the time, said Phil Amick, vice president of commercial development for Global Energy. It would be easy to have a gasification operation with a reliability of more than 90 percent, he said; just add a couple of more gasifiers so that when one is down for maintenance, the others runs.
For Cinergy, the Wabash River syngas plant provides fuel for base load operation, said Angeline Protogere, a company spokeswoman. There were problems in the early years of the project when the gasfication plant began as a government-funded demonstration, but those have been corrected, she said.
The Wabash River gasification plant started operating in 1995 as a replacement for a coal-fired generator commissioned in 1953. In 1990, that old generator consumed 1.5 million tons of coal, according to the environmental impact statement prepared by the Department of Energy. A gasification plant uses about 20 percent less fuel to produce the same amount of power.
When it began, the gasification project was a joint venture of PSI Energy Inc. (now part of Cinergy) and Destec Energy Inc., which was once part of Dow Chemical. The Energy Department supplied grant money for a demonstration project. When that ended in 2000, Global Energy, now the owner of the plant, had to figure out how to make money.
The answer was not coal but a cheaper fuel called petroleum coke, or petcoke for short. Petroleum coke is a byproduct of oil refineries. "You take off everything you can boil off, and you're down at the bottom of the barrel; that's petroleum coke," Amick said.
The high sulfur content of petcoke, and the environmental consequences of burning it, typically makes it unsuitable as a fuel. The Wabash River syngas plant started using petcoke all the time beginning in 2000.
In its proposal, We Energies uses a gasification technology developed by Texaco. The draft environmental impact statement prepared by the state says that the proposed gasification plant would not be economical.
Amick disagrees. "We were fairly incensed about the statement that coal gas is not cost-effective in any scenario that the Wisconsin DNR made."
Global Energy supplied a comparison drawn from a 1998 conference of the Electric Power Research Institute. That comparison shows that the Texaco technology picked by We Energies had the lowest cost of existing gasification systems ($1,148 per kilowatt-hour vs. $1,171 for the technology used at Wabash River) but also the lowest efficiency.
"They sure picked a poor case to use to represent gasification," Amick said.
Stanfield, the We Energies spokeswoman, said the company has not picked the gasification technology it will use. Although Wabash River is operating, We Energies has to balance cost, reliability,and emissions, she said.