Will that be gas or grass in your furnace?
By John Spears
Put another blade of grass on the fire, dear, pellets made of switchgrass could become a new home-heating fuel.
Wild grass that once covered the open spaces of
switchgrass. The wild grass can grow anywhere in southern
Patrick Duxbury is part of the grass-heating research team at Resource Efficient Agricultural Production, or REAP-Canada. It’s a non-profit organization based in (Ste. Anne de Bellevue, QC). Duxbury says people have been heating their homes for years with wood pellets, made from sawmill waste and research so far shows that switchgrass pellets can perform better than wood. “There’s no plant species that’s more efficient at intercepting light,” he says. Light is energy, so it means that switchgrass is very good at storing energy, which is released when it is burned. The grass is harvested, then chopped up and fed into a machine that compresses it and extrudes pellets. The finished pellets are not far off the dimensions of a cigarette filter. The grass also burns clean, so it doesn’t release pollutants or high levels of greenhouse gases. And it doesn’t require as much drying as wood, so it takes less energy to produce. Don’t think of harvesting the stuff that’s growing in your backyard, though. Switchgrass is a tall plant. “I was out at the end of last season harvesting switchgrass growing over my head,” Duxbury says.
Mark Drisdelle of Quebec-based Dell-Point Technologies has been working on how to make switchgrass-pellet technology a commercial proposition. Since wood-pellet stove technology is well-developed, it’s mostly a matter of fine-tuning existing equipment to handle grass. Grass pellets, for example, have a higher ash content than wood. The economics work something like this: Drisdelle says heating a 2,000-square-foot home for the cold months would take about 150 bags of pellets weighing 22.7 kilograms each, or 3.4 tonnes in total. How big is that? One tonne of pellets would be contained in a 1.2-metre cube. REAP figures the pellets can be manufactured for about $90 to $125 a tonne - less than $470 a season, not including delivery.
Because the grass can be grown all over the place and pellet plants can be fairly small scale, the researchers envision a number of plants scattered across southern
For Duxbury, the goal is to provide a clean, low-carbon heating technology that can replace less environmentally friendly forms of energy. One target is
Obviously, switchgrass isn’t going to run wheat and cattle off the Prairies. But Duxbury does note that each summer about 8 million hectares lie fallow across the