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Power-producing plant keeps it simple with wood chips

August 20, 2001|By RUDY YNIGUEZ, Staff Writer

A Michigan-based company is operating a 15-megawatt power plant in the Imperial Valley that not only hired most of its workers from such places as Labor Ready and the state unemployment office, but by using wood chips as fuel prevents the addition of 140,000 tons of wood waste yearly from going into landfills.

The company is Primary Power International's Imperial Valley Resource Recovery LLP, and its power plant is on Highway 111 near Keystone Road south of Brawley.

Wickem Large, the plant manager and Primary Power regional manager, said the facility produces electrical power like any other power producer except for the source of fuel: ground-up wood waste.

"As complicated at the plant is, it's really simple," Large said.

The waste wood includes tree branches, clippings and trimmings. The material is supplied by a sole source and ground up in Riverside. The material is then piled on the 80-acre site and allowed to dry. It is then loaded onto a series of conveyor belts and screw mechanisms and dumped into five hoppers. From the hoppers, the material enters a 2,000-degree boiler, where it is blown across the boiler onto what's called a Detroit Stoker Graveling Grate, where it is burned. Initial ignition is provided using natural gas. The site holds about 20,000 tons of fuel, for about 40 generation days, on-site.


The boiler provides steam at 900 pounds per square inch and 790 degrees. The steam is superheated by adding energy, and then admitted into the 18 megawatt steam turbine, to which is attached an electrical generator.

The plant uses 500-600 tons of fuel per day.

"There's a lot of material out there," Large said. "Were it not for us, it would go to a landfill."

Samples of the wood waste are sent off to an independent and certified laboratory in Illinois to check for chlorides, sulfur dioxide and moisture.

"We like to know that we're getting somewhat quality fuel here," Large said.

The 18 megawatts produced — at 13,800 volts — is stepped up through transformers to 92,000 volts and transmitted to the Imperial Irrigation District's system via a tie-breaker that can be operated by IVRR and IID. The power goes to a local IID substation and is sold to the state of California.

The ash from the combustion process is being used locally for road construction.

The plant's emissions are cleaned of particulate matter in what's called a reverse air impulse baghouse. The plant has a system that continuously monitors stack gasses for carbon monoxide, carbon dioxide, nitrogen oxides and sulfur dioxide.

Large said plant personnel willingly follow all air pollution guidelines and promptly notify local Air Pollution Control District personnel of any potential problems.

The facility's control room personnel operate the whole process remotely, including combustion, electrical generation and electrical distribution.

Large said the turbine-generator has more than two dozen automatic trips, including excessive vibration.

The $60 million plant was built in 1988. It was purchased by Primary Power three and a half years ago and began producing power again in April.

The facility is Primary Power's first U.S. acquisition outside Michigan. The 140,000 tons of wood waste is equivalent to the energy needed for 13,000 homes. The waste wood comes from surrounding metropolitan areas of Southern California and Arizona, according to the company's Internet site, The plant was formerly powered by agricultural waste before being recommissioned by Primary as a wood-fueled power plant.

The company owns seven or eight power plants fueled by wood chips.

Large said there was no staff when he arrived in February, so he turned to Labor Ready and the state Employment Development Department for workers.

"One of our goals here was to hire as many people as possible in the Valley," he said, adding the plant employs 24 people. "We have two people here who are not from the Valley."

From 10 to 12 employees are from Labor Ready, Large said.

"I am extremely impressed with the work ethic here in the Valley," he said. "They are extremely hard-working folks."

Large said his days as plant manager are numbered, as are those of the environmental specialist.

"Ultimately, the entire plant will be people from the Valley," he said, adding the plant does as much business as possible with local vendors.

"We think it's the right thing to do," Large said. "We want to be an important part of the community and not cause problems. We work very hard at that."

Staff Writer Rudy Yniguez can be reached at 337-3440.

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