News

November 19, 2009

Some Seattle Restaurants to be Fed By Biofuel-Driven Steam Heat

A new twist on one of the nation's oldest yet least-known commercial heating methods is enabling 15 restaurants in Seattle to slash their neighborhood's carbon output.

The places are fed steam from what are in effect two communal boilers in the area. The steam is channeled through 18 miles of underground pipe beneath a one-square-mile area to heat and generate hot water for some 200 businesses in total.

The set-up has been in operation within the city's Central Business District and First Hill area for more than a century. But Seattle Steam, the private company that runs the system under a 50-year agreement with Seattle, is updating its boilers to burn waste wood supplied by local composting companies. Previously, the boilers used natural gas and oil.

The switch to so-called biofuel will require about 250 tons of clean waste wood to be recovered from Seattle's waste supply every day, according to Seattle Steam. The only by-product of the changeover should be "a small amount" of ash, which is earmarked for industrial uses like sealing landfills, the company said.

In announcing the boiler overhaul, which is scheduled to be completed this fall, Settle Steam indicated that its restaurant customers should not experience any changes in service. It did not mention any adjustments in their heating rates.

But it noted that the carbon produced by heating the places and generating their hot water should be cut in half, an ecological benefit likely to be appreciated by Seattle's green-minded residents.

It also pointed out that switching to energy from renewable sources could help the properties in securing LEED certification from the U.S. Green Building Council.

The restaurants include units of the Morton's, Ruth's Chris, Benihana, Shuckers and Elephant & Castle chains. Six are freestanding buildings. The others are housed in facilities like hotels or private clubs.

The changeover to waste wood is part of what Seattle Steam says is a multi-pronged effort to use a higher percentage of renewable energy. "We have begun the preliminary analysis of several projects to be considered for [federal] spending if such a program were to be approved," the company said in a prepared statement.

Those efforts include retrofitting some of the steam producer's existing facilities to generate electricity by burning natural gas. The waste heat would be recovered and used in the production of the company's steam.

It is also investigating the capture of waste heat from private industrial companies in the area, and setting up a new communal steam-heating network in Seattle's fast-growing South Lake Union neighborhood.

Such shared set-ups are called district heating systems and were used early in the development of some U.S. cities to support growth without the capital commitment of having each business or residence install a boiler. Although district heating is no longer in common use domestically, it is commonplace in cold-weather European counties like Sweden and Iceland.