MSU Extension

Deploying wood-based heating systems may not save money in every circumstance, but there are many situations where it will. And, there are examples across the Lake States that have the numbers to prove it. However, too often, wood-based options are not considered when the time comes to replace aging fossil fuel systems.

With current low natural gas and petroleum prices, the financial argument is more difficult to make. Nevertheless, where might these fuel costs go in the next 20-30 years, over the life of a heating system? Wood fuels are traditionally much more stable with only gradually rising costs.

Michigan exports nearly 30 billion energy dollars each year. Wood fuels keep jobs and energy dollars local. Economies that have well-developed wood-based thermal energy sectors have solid numbers that demonstrate this value. It’s not rocket science.

Using wood also has important environmental benefits. Better markets for lower quality harvest products lead to more forest management options, which lead to healthier and more vibrant forests that provide a wider range of services. Rather than burning buried fossil carbon, wood heat simply recycles carbon already in the air. And, healthier forests sequester carbon at higher rates, reducing atmospheric carbon on a landscape basis.

So, what are these wood-based thermal technologies?

There are various configurations for both wood chip and pellet systems. Single buildings with individual boilers are typical. District Energy systems, with multiple buildings serviced by a shared boiler, are both efficient and reliable. Large district energy systems, such as the one in St. Paul, can heat and cool large urban areas, as well as provide power. Micro-grid district energy might heat just a handful of buildings.

Typically, wood chip systems are for larger heating demands, perhaps 100,000 square feet and larger. Capital costs can be high, depending on the existing physical layout of the site. However, operating costs are often below those for natural gas. The payback schedule is an important calculation. If air conditioning is needed, the addition of an absorption chiller may work.

Michigan has one of the nation’s top manufacturers of wood chip systems, which helps keep more dollars and jobs within the state.

In considering wood chip systems, the location must be serviceable by existing logging infrastructure – a contractor with a chipper and delivery capability. These contractors are not uniformly distributed throughout the Lake States.

Feasibility assessments should be done to help understand if all the pieces will fit together. Of course, these assessments should be done by firms familiar with wood energy systems, rather than those that only know conventional gas and oil.

Pellet systems work particularly well for completely automated home heating and small commercial applications, especially as a replacement for propane or fuel oil. Pellets are the type of uniform and consistent fuel needed to obtain the high efficiency and reliability of these modern boilers.

A homeowner can expect to burn three to six tons of pellets per year. In some areas, bulk delivery may be possible where a hopper is filled once or twice per year, similar to propane or fuel oil. However, in most locations, hoppers need to be filled by the owner from 40-pound bags of pellets. Different pellet heating designs are available to conform to a variety of applications.

There are many excellent examples of wood energy systems around the state, nation, and the world. The Lake States are just beginning to move in this direction. New England is much more advanced, largely due to their dependence upon higher-priced fuel oil, rather than low-cost natural gas. Parts of Sweden, Austria, Finland, and the United Kingdom have well-developed pellet and wood chip sectors. Larger energy facilities also produce significant amounts of electricity but the thermal component comes first. Large combined heat and power plants are located inside urban landscapes in order to provide efficient distribution of heat. There are few problems with noise, emissions, or truck traffic.

To learn more about wood-based energy systems, visit the website for the Michigan Wood Energy Team at Michigan State University Extension. Remember wood is good!