Renewable Energy and Green Heat
By EduTransfer Design Associates and Haywire Creative
May 18, 2009
Photo by REAP
Some agriculture crops are used as a feedstock to produce renewable energy products such as liquid and solid biofuels, and power. Switchgrass, an important solid biofuel, is predominantly grown on lower quality farmland, has low input requirements and yields high energy output per hectare. Switchgrass pellets are one of the main biofuels being developed as a green heat alternative.
“There are three main markets in the energy sector for switchgrass pellets,” explains Roger Samson, Executive Director of Resource Efficient Agricultural Production (REAP) - Canada in Sainte-Anne-de-Bellevue, Quebec. “The markets include residential heating, commercial heating such as for greenhouses, and industrial heating for example in coal fired power plants.” The premium market is for residential pellet applications, with revenues of $250 per tonne compared to other markets such as the livestock bedding market of $150 per tonne or less.
“The switchgrass pellet market is very dynamic right now, and a recent request by Ontario Hydro for two million tonnes of pellets has created a lot of activity,” says Samson. “Over 20 groups of farmers in Ontario are looking at the opportunity to build an agro-pellet plant to support the bidding process to supply Ontario Hydro.”
Switchgrass Pellets Offer Higher Offset Efficiency
“A good renewable fuel is one that produces a lot of energy per hectare and has a high offset efficiency, which is the amount of fossil fuel displaced by the renewable fuel,” explains Samson. “In the conversion of switchgrass to solid biofuel, the whole plant is used and the conversion process itself retains all of the energy produced. Thermal energy from switchgrass pellets has both high production per hectare and high offset efficiency of 80 to 90 %.”
Most renewable energy alternatives have lower greenhouse gas (GHG) emissions than traditional fuel sources, but not all are equal. “Solid biofuels are 570% more efficient than liquid fuels in using farmland to mitigate GHGs,” says Samson. Grass pellets reduce GHGs by 7,600-13,100 kg CO2-e /ha. By comparison soybean biodiesel and corn ethanol were found to reduce GHGs by 900 and 1,500 kg CO2-e/ha respectively. “Solid biofuels, low-tech and readily available, emerge as a cost-effective strategy for reducing greenhouse gas emissions,” says Samson.
Capital Investment For Grass Pelleting Plant
In terms of investment into processing capability, a grass pelleting plant requires a modest investment compared to an ethanol plant. “The investment for a grass pellet plant would range from 3 to $10 million as opposed to $100 million for an ethanol plant,” says Samson. “In Ontario for example, there could potentially be 60 to 100 grass pellet plants developed as opposed to five or 10 ethanol plants. This decentralized strategy means local fuel production and local fuel consumption.” There are also opportunities for potential export markets to Europe.
“Another practical option is to blend grass pellets with wood pellets in wood pelleting facilities. Therefore, instead of building a new facility for grass pellets, they could be integrated into an existing wood pellet plant,” says Samson. “This is something being looked at in Eastern Canada, where some wood pellet plants are not operating at full capacity.”
Samson sees a positive future for grass pellet processing, particularly for green heat opportunities. “Even with the current downturn in the whole energy market, there is still commercial interest in pelleting plants,” says Samson. “Research and development to optimize the pelleting process and in particular fuel quality for residential pellet applications, combined with expanded federal and provincial bioenergy policies for green heat, will result in switchgrass and green heat becoming an important option for the renewable energy sector.”
