Tag Archives: biomass

Seattle steam turns to wood

The Seattle Steam Company, which operates two plants that produce steam for heating downtown Seattle office buildings, hotels and hospitals, has plans to replace a natural gas-fired boiler with one that uses recycled and waste wood as its fuel. For Seattle Steam, the move to biomass represents an initial step in the switch to renewable energy sources. The switch, according to the company will reduce Seattle Steam’s carbon emissions by about 55,000 tons annually. The plans for the conversion to wood fuel were already on the table in 2006, as it is now it looks like it will be this autumn when the boiler is ready for use.

Bron: Wikipedia
Bron: Wikipedia

This 115 year old privately owned company now provides steam generated from burning natural gases, diesel and oil. This supplies heat through 18 miles of steam pipeline to 200 of downtown Seattle’s largest buildings. It also uses steam for generating hot water and humidity control. Because of rising gas prices as well as Seattle Steam being the biggest single natural gas consumer in the state, the company decided to make the switch to give it a more competitive edge. Subsequently, in its effort to reduce carbon emissions, it plans to fire up a new boiler which will allow it to derive more than half of its source fuel from wood waste. The wood coming from crates, packaging material and tree trimmings will be reduced to chips 3 inches or smaller.

Some have said the choice of wood is not a particularly sensible one. It might be a lot cheaper than natural gas, but burning wood will actually release more carbon emissions than the burning of natural gas. Still, advocates of the switch say this is not entirely true. A tree absorbs as much carbon (or carbon dioxide) in its lifetime as it releases when burnt. Wood burning does not release more carbon dioxide than during it’s biodegradation (i.e. rotting). Wood burning can therefore be called “carbon neutral”. Of course, harvesting and transport operations can produce significant amounts of greenhouse gas pollution, but considering that Seattle Steam plans to use ‘urban’ wood it seems to work out in it’s favour.

Seattle Steam’s use of biomass will reduce its use of natural gas by 60% and reduce it’s carbon footprint – and subsequently the footprints of its customers – by 50% the company says. This is an enormous step in the early days of carbon recognition. Stan Gent, president of Seattle Steam explains; ‘It will move us to beyond where the State’s goal is for 2050 and we will achieve that in 2009’. The company won’t stop here in its efforts to continue the search for more alternative fuel stocks. The use of glycerol, instead of the remaining natural gas, might be a next step. Although research is still in somewhat experimental stage at this point in time, Stan Gent has high hopes for the future: ’The process of burning glycerol might be commercially available within five years, if that’s the case we have every expectation that our carbon footprint will approach zero by 2020.’