Is the Solution to Home Heating in Our Own Backyard?

By Anita Kelman

Concern over space-heating costs, for both homes and commercial use, has been in the news lately. Rising energy prices for oil and natural gas, as well as” Peak Oil” issues, have focused attention on the need for alternatives, especially here in the Northeast with our long, cold winters. Additionally, the increasing evidence of climate change has emphasized the connection between the use of fossil fuels and greenhouse gas emissions.

Although burning cordwood, corn, or wood pellets in conventional biomass stoves works, there are numerous issues associated with these renewable energy sources. Cordwood involves the cutting of trees, handling of large quantities of firewood, emissions of particulates and other pollutants, and release of the carbon sequestered in the trees, adding to greenhouse gases. Burning corn in pellet stoves raises questions about efficiency due to the high level of energy needed to grow the corn and the secondary impacts associated with growing a row crop, including fertilizer use and soil erosion. Wood pellets are increasingly in short supply, due to efficiencies in logging operations and sharp increases in demand.

Attention is now being paid to the potential use of grass as a space-heating fuel. Historically, peasants in Europe and settlers on the Great Plains utilized grass, in primitive forms, for heating. Recent research, primarily at Cornell and McGill universities, as well as Research Efficient Agricultural Production (REAP) in Canada, has focused on the potential of grass as a fuel, utilizing new technology.

The basic scenario is as follows: Grass, either a warm-season variety such as switchgrass or a cool-season such as reed canarygrass, would be mowed as for hay once a year in the fall. The mowed grass would be left in the field for up to two weeks to allow leaching to take place, reducing the mineral content of the grass. After being baled at standard hay moisture levels the grass would be fed through a specialized processing unit called a “pelletizer.” The pellets, which resemble rabbit food pellets, would be stored out of rain or snow prior to being burned in stoves or boilers designed to burn grass pellets.

The potential benefits of grass pellet technology start with the abundance of different kinds of perennial sod crops – the grasses mentioned above plus smooth brome grass, timothy, orchard grass, or tall fescue. All require minimal fertilization, resist pest/disease problems, prevent soil erosion, and lend themselves to organic production. Most important, they adapt easily to marginal soils, providing high yields with low levels of inputs. Research has shown that the net energy yield (ratio of energy produced to energy invested) of grass pellet technology is highly positive, more than 10:1.

Allowing the grass stand to remain uncut until late summer or early fall also provides wildlife habitat, for nesting birds as an example. Grass stands maintain open space, and crop production utilizes equipment already present on many farms.

From a climate-change standpoint, it appears that grass pellets could be virtually carbon neutral, other than the energy used in production. Energy used for nitrogen fertilization could be replaced by animal manure. As a renewable resource, the carbon released through pellet burning would be sequestered again the following year in the grass crop.
The Canadian research group REAP estimates that 150 million acres could be utilized for grass pellet production in North America without significant impact on food production. REAP estimates that the U.S. could replace the equivalent of 39 percent of its yearly oil imports by growing grass for pellets on 14 percent of its farmland. As Cornell researchers point out, it takes 70 days to grow a crop of grass pellets for fuel, compared to 70 million years for a crop of fossil fuel!
Multiple issues must be addressed before this promising technology can be adopted. For starters, there are no pellet stoves, furnaces, or boilers currently designed specifically for burning grass pellets. Cornell tested a number of different style stoves and reported the results, decidedly mixed, on its website. This winter, Jim Wuertele, a retired appliance engineer and founder of the Vermont Agrifuels Institute, tested a pellet stove that had its software “tweaked” for grass pellet burning. Wuertele will be communicating his findings to its manufacturer. Stove manufacturers will need to design a variety of stoves and furnaces that can utilize grass pellets, including units that allow for operation either off-grid or with minimal power back-up during power failures.

Wuertele has signed up more than 50 Vermont farmers interested in producing pellets. He has also arranged for a pelletizer to be brought down from Canada in November for trial runs. The Quebec-manufactured, portable pelletizer carries a $500,000 price tag. The unit, therefore, could either be transported via tractor-trailer to pre-arranged sites on specified dates, or housed in a central location to receive baled hay.
The Grass Energy Collaborative, formed this past December, is focusing on promoting grass pellets as a viable heating source here in Vermont. Jock Gil, a founding member of the collaborative, states that its mission is “to create the grass energy sector and the culture to support it.” Currently, members are working on raising funds, promoting the involvement of more companies and other entities, and striving to produce pellets this year. They are hoping to produce the first-ever conference devoted solely to grass pellet technology at Shelburne Farms in October.

However, Gil cautions that there are many hurdles still to surmount, and questions to be answered, in order for grass pellet technology to become a viable fuel resource. What will grass pellets sell for? How much will stove options cost? And how will these costs compare to conventional heating costs? Will the test run of the Canadian pelletizer happen, and will enough “early adopters” be ready to test their stoves? In any case, purchase or assembly of a pelletizer that will reside in Vermont is high on Gil's list of desirable outcomes.

Grass pellet technology has obvious potential benefits for Vermont. As a virtually carbon-neutral fuel source, it grows readily in our own “back yards” and promises increased energy security, reduced greenhouse gas emissions, an additional income stream for farmers and landowners, and contributions both to open-space preservation and wildlife habitat. Sounds like a recipe for energy independence.

Web Resources

reap-canada.com
grassbionergy.org