July 1, 2009

Advanced Wood Combustion: Rekindling Wood Energy in America

Opened in February 2009, the new biomass power plant at Vermont's Middlebury College is expected to burn 20,000 tons of wood chips each year to provide heat and electricity for the campus.

The plant uses an "advanced wood combustion" system. Such plants hold great potential to save energy, cut costs, and even fight global warming, a March 2009 study says.

Photograph by Brett Simison, courtesy Middlebury College

Daniel Richter is professor of soils and forest ecology at Duke University and Director of Graduate Studies for Duke’s interdepartmental University Program in Ecology. His research investigates forest sustainability, biogeochemistry, interactions of soil and forests with the wider environment, and global soil change.

Below are excerpts from an article he wrote recently for Renewable Energy World.com about advanced wood combustion (AWC) and its promise for helping understand the intertwining of the carbon cycle and combustion - and how we can efficiently tap that energy for fuels, power, steam, and heat.

Rekindling Wood Energy in America - Renewable Energy World

One of the largest sources of renewable energy available today is one of the oldest, that is direct combustion of wood. Recent European developments in advanced wood combustion (AWC, defined as automated, high-efficiency wood-fired energy systems with strict air pollution control) have wood supplying thermal and electrical energy cleanly and reliably to thousands of communities in Europe and increasingly in North America. AWC minimizes air pollutants including fossil greenhouse gases.

AWC is so clean and safe that AWC systems are commonly deployed in the midst of picture-perfect European towns and villages. Because AWC systems can be developed in community-sized increments of 0.1 to 20 MWth, they can be managed to meet community needs and not overwhelm the productivity of local woodsheds.

Wood in the United States is several-fold less expensive per unit of energy compared with natural gas or heating oil ($2 to 5 per GJ vs $7 to 10 per GJ for recent USA prices of natural gas and heating oil). If properly deployed, AWC systems can not only affordably supply clean and renewable energy, AWC can add value to the forest itself, promote community development, and support local employment and rural and municipal economies. AWC can complement other renewable energy resources as well.

It is now time for AWC and renewable thermal energy sources to take center stage in North American energy deliberations. Not only can wood safely and affordably supply energy, but wood can teach us much about energy in general, energy-use efficiency, and sustainability itself.

No one renewable will solve our energy crisis, not solar, not wind, not wood. But recent multi-agency estimates indicate that AWC can sustainably supply at least 5% of the nation’s currently inefficient energy consumption without impacting forests that are protected for environmental, social, or economic reasons. This is more energy that that stored in our Strategic Petroleum Reserve, more than what all American hydro-power plants produce in a year, and slightly more than half of the electric energy produced annually by the entire nuclear industry.

Wood is abundant but is far too valuable to inefficiently burn. Resource policy questions should turn on how to encourage wood-energy efficiency, community development and sustainability, and how to avoid extracting wood from the forest like coal from a mine.

1 comment:

Anonymous said...

What is wrong with the loony left (again). They embrace wood feedstock for heat, for power - yet in the same breath the loony left disdain the very same waste wood being used as a feedstock for cellulose ethanol production. Hello, McFly. Is there anybody in there?

The beauty of using the wastewood as a feedstock for cellulose ethanol production is that its bioproduct, clean lignin (the structural composition of plants), is then used for combined heat-power generation. So why skip a step? The lignin (which is wood with most of the C5 & C6 sugars removed to be fermented to make ethanol) burns at a higher Btu and emits less ash than does burning straight wood.

No one advocates cutting down forests for fuel - but the USDA/DOE Billion Ton Study show that large volume sustainable yields from waste wood are viable. In the meantime it all goes up in smoke.