A few years ago, ethanol and biodiesel from grains and oilseeds looked like a promising solution to the looming energy crisis, but the “food versus fuel” debate that followed put a damper on enthusiasm for renewable fuel sources that depended on edible feedstocks.
Lately, the focus seems to be shifting towards biomass energy sources, mainly woody materials, straw or grasses, as a means of converting sunlight into fuel.
According to Agriculture Canada Swift Current applied sciences researcher Mark Stumborg, who has been studying the potential of biomass on the Prairies for three decades, the often-overlooked resource has potential for renewable energy as well as industrial applications.
Getting such projects off the ground requires financing, however. Before an entrepreneur can convince bankers to lend money, they have to be able to prove that enough of the resource is there to make their idea viable and a good credit risk.
To get around that problem, he developed the Biomass Inventory Mapping and Analysis Tool (BIMAT). Users can access the online tool via Agriculture Canada’s website and get an instant picture of Canada’s crop and forest biomass resources, be it wood chips, sawdust, or flax straw.
“We built it so that we could put together an accurate, reasonable estimate of agriculture and forestry residual biomass that’s available for industrial purposes,” he said.
“In Canada, we’ve always said that we’re going to use grain-based ethanol and biodiesel from canola as a bridge to get the market started. Long term, we want to look at sustainable biomass conversion.”
He recently received a National Green Fuels Industry award for his efforts on the BIMAT project.
But just as ethanol and biodiesel have come under attack for diverting food from the hungry, proponents of biomass projects are wary of criticism. One of those is the charge that using crop residues to make transport fuel instead of leaving it on the field to break down into organic matter amounts to “burning topsoil in our gas tanks,” he said.
With that in mind, Stumborg and his colleagues were careful to build sustainability into the equation.
“What we wanted to do was come up the middle with a conservative estimate that reflects sustainability and is fully defensible and based on 10-year running averages of Statistics Canada data,” he said.
That means that straw would only be grown under minimum or no-till management, and only be taken off one year in four-year rotation. Also, the equation is based on tall stubble being left over, which leaves behind at least 750 kilograms of crop residue per hectare after all the straw is baled.
“Well-anchored tall stubble is the best protection against erosion. Most of the nutrients in the plant – the carbon, nitrogen and phosphorous are in the bottom foot of the plant anyway,” he said.
Fifty years of data at Indian Head shows that harvesting straw off six-inch stubble had no long-term impact on soil fertility and only a minor impact on soil carbon.
A 2002 study, he also noted, showed that the nutrient value of straw as less than $5 per acre.
“As long as the farmer is getting between $12 to $15 per tonne back in his pocket, at the end of the day, he’s way ahead of the game,” said Stumborg, adding that the cost of bunch-and-burning straw is at least $5 per acre, and heavy harrowing costs $10 to $12/acre.
“So instead of spending that money, we’re offering you an opportunity to make $30 to $40 per acre. That’s more margin than a lot of guys make off the seed.”
Many critics of biomass-to-ethanol are skeptical that a viable process will ever be developed, noting that it always seems to be five years away from being ready for prime time.
That may be true of cellulosic ethanol, which uses micro-organisms to digest the fibre and excrete sugars, much like a termite digests wood, he said. But there are also other ways of converting biomass to more concentrated forms of energy, including pyrolysis (burning) and gasification.
Besides being simpler, thermal-type or solvent-based processes also have the advantage of being viable on a smaller scale and require far less capital investment.
Unlike gasoline, a compact, highly potent source of stored, ancient sunlight that is easy to transport and store, biomass is by nature bulky and far less energy dense.
That means it only tends to be a viable source of energy for local sources or processing facilities, and a few dozen kilometres of distance from the feedstock source can make or break a project.
“Transportation is the biggest cost,” he said.
The BIMAT system can be seen at atlas. agr. gc.ca/agmaf/index_eng.html? context=bimatocib_en.