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The Honolulu Advertiser
Posted on: Thursday, May 22, 2003

H-Power plan would boost O'ahu's trash capacity

By Jan TenBruggencate
Advertiser Science Writer

The city is considering an increase in capacity at its H-Power trash-to-energy plant in an effort to keep up with O'ahu's refuse stream.

Trash to energy

H-Power is also called Covanta Honolulu Resource Recovery Venture.

• Site: A 28-acre lot in Campbell Industrial Park.

• History: Built in 1989.

• Owner: Honolulu city government.

• Operator: Covanta Energy, Fairfield, N.J.

• System: Two 854-ton-per-day waterwall boilers, with traveling grates feeding a condensing steam turbine generator. Maximum electrical production capacity 57 megawatts.

• Capacity: Roughly 2,000 tons of waste per day.

• Pollution control: Flue gas scrubbers that inject lime; fabric filter baghouses; electrostatic precipitators that place a charge on dust particles, which then attach themselves to a metal plate instead of going out the smokestack. Covanta says stack emissions meet all state and federal limits.

• Annual power sales: About $25 million. H-Power produces about 7 percent of O'ahu's electrical power.

H-Power operator Covanta Energy says it has been asked to prepare a proposal for the expansion. A complete proposal is not yet ready, but the company said yesterday that the expansion could cost between $60 million and $65 million. Covanta expects to present its report to the city in June.

"The main goal is to significantly reduce the city's reliance on the landfill," said Frank Doyle, director of the Department of Environmental Services. City officials and H-Power operators plan a celebration today to mark the processing of 8 million tons of waste at the plant, a volume that saved about 500 acres on O'ahu from landfill use.

The expansion proposal would add a third boiler to the two in place. The boilers feed steam to a single electricity-producing turbine. The new boiler would be about the same size as the existing ones, but with more modern pollution control equipment.

Contingency role

The expanded plant would occasionally operate all three boilers to produce power at times when O'ahu needs it the most, but the main function of the third boiler would be to allow the H-Power facility to keep burning rubbish and producing electricity at near-peak levels even when one is down for maintenance, said Rob Graham, vice president for business development at Fairfield, N.J.-based Covanta. The company is the world's largest operator of waste-to-energy plants, operating 26 such facilities in the United States.

Doyle said H-Power burns about 600,000 tons of waste each year, and a third boiler would increase that to the 725,000 tons produced annually.

"Our biggest waste flow into the landfill is when one of those boilers is down," he said.

Jeff Mikulina, director of the Sierra Club in Hawai'i, said the H-Power expansion may be an acceptable "interim solution" if the city works hard on creating less waste and finding more opportunities to reuse waste materials or to convert them into other usable materials.

"H-Power is not the ideal," he said. "The ideal is reducing the amount of waste we produce, and No. 2 is recycling."

The city owns the H-Power facility, which Covanta has operated since 1990.

As cities have faced higher costs in handling solid waste — particularly the cost of managing landfills — many have gone to waste-to-energy plants to reduce the amount of trash that has to be hauled into those landfills.

The Honolulu plant reduces the volume of waste by a factor of 9 to 1, and while the ash and cinder is now landfilled, city authorities are considering other uses — as road base material, for example.

Environmental studies are under way to determine whether heavy metals like lead and cadmium will leach out of such waste. Preliminary studies show it does not, Graham said.

102 facilities nationwide

There are 102 waste-to-energy plants in the United States. Fourteen percent of U.S. municipal waste is processed through such plants. The facilities are even more popular in Europe, where 342 are operating and 166 more are planned through 2009.

But waste-to-energy is not the only solid-waste reduction technology out there. While Covanta insists it is the best option for Honolulu, the city is studying other approaches as well.

Another leading contender is plasma arc or plasma torch technology, which takes waste to vastly higher temperatures than in the H-Power incinerator— as much as 15,000 degrees.

Waste introduced to a plasma arc is converted into two products: a glass-like waste material that can be used like aggregate in roadways and a burnable gas that can be used as fuel to produce electricity in a generator.

Most existing plasma furnaces are smaller than what would be required to handle the municipal solid waste generated by a city the size of Honolulu.

Asia Pacific Environmental Technology operates the state's first plasma arc furnace, under the name Hawai'i Medical Vitrification, at Campbell Industrial Park.

Doyle said the city is committed to alternatives to burying trash.

"It's cheaper to put everything in a landfill, but (without H-Power) we would have maxed out about four landfills by now," he said.

Reach Jan TenBruggencate at jant@honoluluadvertiser.com or (808) 245-3074.