Trade-Offs Part of Power Story
A pillar of water vapor rises ghostly white from the bottoms where the Poteau and Arkansas rivers angle through southeastern Oklahoma to join at Fort Smith, Ark.
To some environmentalists, it’s a hobgoblin.
To economic development boosters, it’s more like Casper the Friendly Ghost.
The vapors rise from the AES Shady Point power plant, which began generating coal-fueled electricity for OG&E Energy Corp. 18 years ago.
Pledging to burn only high-sulfur Oklahoma coal, AES pulled the state’s mining industry from the brink of extinction, saving and creating thousands of mining, trucking, railway and other jobs, according to Lundy Kiger, AES vice president and director of government and community relations. Other power plants in the state burn mostly coal shipped from Wyoming.
By capturing and purifying part of its carbon dioxide emissions, the plant also aided food producers and, more recently, oil and gas drilling efforts in the area.
Carbon dioxide was barely on the public’s radar screen when the plant was built. And while most of the CO2 salvaged from flue gases at the plant eventually finds its way into the atmosphere, it is put to productive use along the way, Kiger said.
About 15 percent of the 320 megawatt plant’s flue gas is captured and put through a process that scrubs out sulfur, according to Howard Massie, who is in charge of the plant’s CO2 operations.
A solvent is added to absorb the CO2, which is then purified to “food grade,” Massie said.
For the past 18 years, nearly 200 tons of food grade liquid CO2 has been produced daily and sold to food giant Tyson Foods, where it is used mainly to flash freeze prepared chicken, Massie said.
High petroleum prices sparked a rebound of drilling in the region, and about 50 tons of carbon dioxide is being converted daily to dry ice pellets used in fracturing stubborn reservoirs.
Massey said he expects to supply dry ice for about 200 jobs (shipments to wells) in 2008.
He said he knows of only one other plant – also an AES venture – using the CO2 recovery process.
The plant consumes about 800,000 tons of coal a year, controlling sulfur with a limestone injection system.
At construction, it was billed as one of the cleanest solid-fueled power plants in the world, and Kiger said the facility continues to meet or exceed all state and federal pollution standards.