Thursday, March 31, 2005

Using Forest Waste For Electric Power Generation

According to this Texas A&M University bulletin, tree waste from forestry operations can be a possible fuel source for electricity generation. During lumber harvest, tree tops are frequently left behind to biodegrade, and sometimes shredded to accelerate that process.

According to one processor, about 12% of the volume of the trees brought to the factory is unusable, and is currently used to run the plant, though this only works out to a fraction of the energy needed to operate the facility. Presumably, the mass of the crowns amounts to a much greater volume.

Since the remains are important to the regrowth of the forest, renewing the soil is important, and the bulletin says that the key to any successful program involves leaving some crowns intact, as well as possibly returning ash to the site.

Used in combination with a gasification system, such a system could be very efficient; the gas turbine unit at the above link is estimated to be about 30% efficient, and if "waste" heat were utilized, I would be willing to bet it would be even greater (as the IGCC power plants the Engineer-Poet is so fond of). Interestingly enough, in World War II, even vehicles were propelled by gasified wood products in the UK, Germany, and Scandinavia when fuel shortages made petroleum hard to come by.