MSU Extension Michigan Wood Energy

A note about wood vs. fossil fuels and carbon . . .

You can burn trees for fuel for a thousand years, or a million, with no increase in carbon within the carbon cycle. In fact, managed forest landscapes actually sequester more carbon than unmanaged forest landscapes. On the other hand, no matter how little fossil fuel you burn, atmospheric carbon dioxide (CO2) will be increased. It is true that, compared with wood, burning fossil fuel may produce less CO2 for the amount of energy received, but that is irrelevant when looking at the complete carbon life cycle and how the planet moves carbon from pool to pool.  

About half of the weight of wood is carbon. No matter how a tree dies, that carbon goes somewhere. With regard to atmospheric carbon dioxide, if a tree is turned into lumber or paper products, it continues to be carbon negative until it burns or rots. If it is burned for fuel, it's a wash, since the carbon came from the air as CO2 and is then returned to the air as CO2. If it is left to rot, a small portion of the carbon is converted to methane (CH4), which is 15 to 60 times worse than CO2 as a greenhouse gas. So, if you cannot store wood out of the weather or convert it to biochar (both carbon negative at least for a while), burning is the best option, especially if done well or completely. This is particularly true if the energy is used so that the amount of fossil fuel consumed is reduced.

Q: Will Michigan run out of wood?

A: There are no wood shortages, especially within the product grades likely to supply a Michigan project. Markets for lower quality forest products are needed to better enhance forest management objectives, which provide for increased forest sustainability, economic value and forest health. Additionally, wood-fired boiler systems may be more common than some people might think.

Q: With bigger installations, won’t there be smells, noise and dangerous truck traffic?

A: Newer wood boilers and District Heating boilers burn at temperatures higher than the familiar (and smoky) backyard outdoor burners. Taller stacks effectively dissipate any odors that might escape. Little, if any, "smoke smell" should be detectable with these systems. The operations run quietly. Again, little or no noise would occur. Truck delivery would be the noisiest operation. On average, about 2-3 semi loads of chips would be delivered each week. During peak times, 1-2 trucks would deliver chips per day. In the U.P., there are about five schools that use these wood chip heating systems and the Pinecrest Health Care Facility in Powers uses a wood chip system to both heat and cool their buildings. These facilities have had no issues with smoke, noise or truck traffic. The building and chip storage structure are not large, although enough room is needed for trucks to turn around.

Q: Won’t biomass harvesting damage forests?

A: Not likely. Keep in mind that these facilities will be using a small amount of wood, considering the size of the regional forest and current draw on those forests. It is remarkably difficult to remove enough biomass to affect nutrient cycles, and most of the "goodies" are in the leaves, twigs, and roots, much of which are left on-site even with a biomass harvest. Most of Michigan's forest types and forest soils will not be significantly impacted through biomass harvesting. However, there are some forest type - soil combinations where caution is warranted. Those are known. Michigan has developed an evolving set of guidelines to minimize the risk of environmental damage from woody biomass harvesting.

Q: Aren't wood energy systems more expensive?

A: Yes! Or, at least the installation is typically more expensive. Over the life of the system, including all operating costs, wood energy systems will cost less than fossil fuel systems, especially propane and electricity. This is true even for natural gas - in the right situation. Additionally, collateral benefits occur from burning wood, such as keeping energy dollars local, carbon savings, and providing/supporting local jobs. 

Q: What is the role of wood in Michigan's current renewable energy picture?

A: Wood makes-up the largest portion of Michigan's renewable energy production.  All renewable energy technologies, combined, make-up about 7% of Michigan energy production.  The "lowest-hanging fruit" for wood-based renewable energy is in the thermal sector (heating & cooling), where a substantial portion of Michigan households heat with either propane and electricity. 

Q: What is "District Energy"?

A:  District Energy is an efficient and can be a very low cost way to heat a cluster of buildings via a central heating plant with heat distributed through an underground piping grid.  Wood chips are common feedstocks for these systems (see case studies).  This technology is commonly deployed in mature renewable energy economies. 

About the Michigan Wood Energy Team

The Michigan Wood Energy Team assesses Michigan’s woody biomass supplies, energy infrastructure, and community readiness related to wood energy. We also provide educational resources related to the use of wood energy in Michigan, and provide supporting materials for the installation of demonstration systems for wood energy combined heat and power or district heating and cooling systems at the institutional or small community scale. Learn more about our mission and our members.