TransAlta SD Report 2004 : Environmental Performance : Waste : Marketing Waste By-Products

FGD unit at Centralia

Case study

TransAlta and wallboard manufacturer develop win-win situation

At our coal plant in Centralia, Washington state, our company has installed two flue gas desulphurization (FGD) units that filter out more than 94 per cent of the sulphur dioxide (SO₂), a contributor to acid deposition. This equates to about 110,000 tons each year.

The FGD units mix flue gas with a water slurry containing limestone. The mixture absorbs the sulphur and other trace amounts of impurities like mercury. The emissions coming out of chamber are nearly sulphur-free and the FGD units, along with other improvements, make the Centralia plant one of the cleanest coal plants in the United States.

As a bonus, the scrubbing process results in tons of excess commercial grade synthetic gypsum, which is highly desired by wallboard (drywall) manufacturers. Normally, manufacturers have to sort, test and crush the gypsum to a uniform sand size. However, with synthetic gypsum, the power plant does all this, producing a consistently high quality substance. The gypsum is so highly sought after that regional wallboard manufacturers compete for the TransAlta contract.

In 1999, GP Gypsum of Tacoma, Washington state was awarded a 20-year contract. With its primary source for natural gypsum in Mexico starting to run out, the company needed a more reliable source. Securing the contract, the company invested $7.5 million to handle the synthetic gypsum. Now the plant uses 35 truckloads of the synthetic product a day.

In 2004, the Association of Washington Business awarded TransAlta and GP Gypsum its Environmental Excellence Award for their combined projects.

At TransAlta, we seek innovative market opportunities where we can conserve the resources we use and benefit the company’s financial bottom line by creating new revenues and avoiding the costs of disposal in our mines.

In 2004, we continued to develop commercial markets for the major by-products of our fossil fuel generation: coal fly ash, coal bottom ash and gypsum. Fly ash is used in manufacturing cement and concrete. Bottom ash is used as granular fill in roadbeds, and gypsum from our flue gas desulphurization plant at Centralia is used for the manufacture of wallboard. At the Whitewood mine, we also mine through gravel deposits, which we collect and sell for use in road construction.

In 2004, we sold almost 1.3 million tonnes, or 51 per cent, of our by-products. Sales of fly ash and bottom ash from our coal plants to cement and concrete manufacturers in Alberta and the western United States reached 768,000 tonnes, slightly lower than our 2003 sales of 783,000 tonnes. We also achieved our most successful year yet for the sale of gypsum from our Centralia power plant. By year-end, gypsum sales totalled 416,000 tonnes, about 156,000 more tonnes, or 60 per cent, than the previous year.

In 2004, we sold 51 per cent of waste by-products, or 1.3 million tonnes, that would otherwise have been sent to landfills or stored at our mines. The percentage of waste by-products sold has increased from 27 per cent in 2000.

Luong Du (left), Ron Lehay, Tony Smith and others helped to expand TransAlta’s by-product business

Case study

New team expands by-product business

TransAlta is achieving record revenues from the sale of waste by-products from coal plant operations. And working behind the scenes to deliver this success is a cross-functional team of employees from Alberta and Centralia, Washington state, dedicated to exploring by-product markets and sales.

“Our team’s goal is to improve overall profitability by bringing increased focus to by-product sales in our business,” says Tony Smith, manager, Mine Operations. “It’s an exciting area of growth — and one that is becoming more significant to our business.”

In 2004, the team created a new reporting and management process to more clearly identify the costs, revenues and opportunities of by-product sales. The team also found new markets and developed new sales agreements for waste by-products like bottom ash.

In 2004, the team oversaw the sale of 200,000 tonnes of bottom ash from our Alberta power plants for use in construction of a large road project in Edmonton. Smith says the unique thermal qualities of bottom ash, which helps road beds withstand tough freezing and thawing cycles, makes this commodity a valuable material for road construction, especially in northern areas. “We’re anticipating a continued increase in the consumption of bottom ash,” says Smith.

The team also developed a business case to expand the sale of fly ash, another by-product of coal combustion, used to replace cement in concrete manufacturing. Based on this work, the company plans to invest $4 million in 2005 in a new classifier machine, used to process ash before it is shipped to market. Smith predicts the new equipment, to be installed at the Sundance coal plant near Wabamun, Alberta, will help TransAlta to double its fly ash sales in five years.

A key to this investment and the associated growth opportunities is the quality control associated with processing and shipping Sundance fly ash. "Sundance fly ash is recognized for its excellent properties, and the consistent, high quality control associated with processing the fly ash. It is considered a premium fly ash within North America and is in great demand by the concrete industry," says Ron Lehay, Production Area Coordinator at Sundance. "Luong Du and his team at the ash farm have made the Sundance fly ash a valuable commodity."

Looking forward, the team is anticipating the first sales of another by-product — cenospheres, which are found in large quantities in fly ash at TransAlta’s Keephills coal plant. The small hollow spherical particles can be used to improve the manufacture of drilling muds and down hole cement used in the oil and gas business. In 2004, the company signed a one-year agreement to supply the product for marketing, primarily to Alberta’s oil patch.