If you want to know what it’s like to deal with some serious energy issues, try keeping nearly one million square feet of space at a comfortable room temperature when the only thing between you and the bone-chilling -30 C of a
Manitoba winter mere inches away from you is two very thin sheets of plastic separated by a layer of air.
That’s the challenge facing Kelvin Vanderveen, a greenhouse owner in Carman, Man., on a frosty March morning as workers all around him continue to plant, pot, water and transport the crops that Vanderveen’s Greenhouses will be selling throughout the spring to its retail and wholesale customers.
Kelvin’s father began Vanderveen’s Greenhouses 40 years ago with a bit of glass and some reclaimed lumber. Since then, the business has continued to grow until it now encompasses almost 20 acres under plastic. Vanderveen’s produces poinsettias for the Christmas market, lilies, mums and hydrangeas for the Mothers’ Day and Easter markets, and a full range of hanging baskets, bedding plants and vegetables for spring and early summer. That means it operates year-round, a rarity in Manitoba’s cold continental climate.
The major expansion that took Vanderveen’s to where it is today started in 1995. The decision to get bigger was based on the conviction that businesses must be able to take advantage of economies of scale.
“Prices for the products we sell haven’t been going up,” Kelvin Vanderveen explains, “so we had to find ways of being more efficient.”
Until five years ago, Vanderveen was heating his greenhouses with gas furnaces. Then the price of natural gas spiked and he began looking at alternative sources of energy. It was a question, he says, of whether he could afford to open up his greenhouses in the wintertime. He considered a whole host of alternatives, from coal to biomass products like wood chips. Geothermal wasn’t an option because of the amount of heat that was required by his facility.
In the end, he settled on flax shives. Flax shives are a byproduct of the process by which fibre is extracted from flax straw for the paper industry. It just so happens that one of Vanderveen’s neighbours on the other side of town is Schweitzer-Mauduit Canada Inc., a major player in the flax fibre industry.
“The decision to go with flax shives was based on its availability in the area,” Vanderveen says. “They were the smartest option because they were right here in Carman.”
Manitoba guidelines say that to be competitive, a biomass product has to be used within 80 kilometres of where it is produced. In the case of flax shives — a fluffy product with a consistency that brings to mind cellulose insulation — the radius is probably more like 50 kilo-metres, but the source of the flax shives was well within the prescribed limit for Vanderveen’s.
Another attraction, as anyone who has ever burned it can attest, is that flax straw packs a lot of heat.
“We feel that flax shives are pretty similar to wood chips in terms of the BTUs (British Thermal Units) they provide,” Vanderveen says. “So we find that it offers pretty good value.”
This is confirmed by a 1995 Prairie Agricultural Machinery Institute (PAMI) study that rated dry flax straw at heat values higher than other biomass fuels like wheat straw. It is the lignin content in flax that gives it its added thermal energy.
Once Vanderveen had settled on flax shives as his heat source, he had to find a system that could make it work for him and his operation. Vanderveen went with the Blue Flame Stoker, a boiler system manufactured by the Sturgeon Creek Hutterite Colony in Headingley, Man., about half an hour northeast of Carman.
Then the work of adapting the system to his particular operation began in earnest.
“There is no one else burning flax shives as a source of heat,” Vanderveen says, “so the first year was a real trial period for us. There were several major changes to the system that we had to make in order to get it to work.”
The Blue Flame Stoker is a boiler system which uses a series of augers and hoppers to feed a steady stream of combustible material into a large burning chamber. The material is deposited onto a perforated chain bed made of steel that advances as the material burns, bringing it slowly towards the opposite end of the burning chamber where any remaining ash is deposited and augured out of the boiler.
Meanwhile, a cyclone filter traps any fly ash that is present within the boiler and prevents it from escaping through the boiler’s chimney. Water is drawn in through the side of the boiler unit, where it is heated and then removed through the top of the unit. There, it is then circulated through a series of controls and pumps to where it is needed in Vanderveen’s extensive greenhouse facilities.
One of the major challenges that Vanderveen faced during his first winter with the flax-shives boilers was precisely this feeding system. Shives are delivered by truck into a large wood-frame shed that is attached to the boiler room. As required, they are pushed by a loader tractor onto a moving floor that takes the shives into a pit where they are then augered into the main hopper in the boiler area. The boiler area is in a separate building made of concrete so that a fire in the shive-storage shed cannot spread to the boilers.
Unlike other materials such as coal and wood chips, flax shives have a tendency to bridge. As well, they can be very hard on any turning shafts because of their resiliency, even after the removal of fibre in the processing they undergo at Schweitzer-Mauduit. So the system of augers and hoppers had to be changed to accommodate the shives. Shafts had to be made bigger and the hoppers modified to
prevent the shives from getting hung up. As well, because the fly ash from burning flax shives is quite a bit lighter than coal ash, for example, the cyclone filters needed to be fitted with better air locks.
It took a lot of effort, Vanderveen says, to iron out the kinks in the system.
“There were times during that first winter that I honestly thought we had made a mistake. For a while, we had three people looking after the system 24/7. In fact, at one point, we even had a bed in the boiler building.”
Vanderveen also came to the realization that he had undersized the boilers. He originally put in a system that was rated the same as the gas furnaces that he was using before.
“I did start with extra capacity,” he says, “but I expanded more quickly than I originally thought. I should have added about another 25 per cent to my calculations.”
“There are a few reasons for this,” explains Eugene Gala, the mechanical engineer who is behind the original design of the Blue Flame Stoker. “You typically get a little bit more soot built up on the heat exchanger compared to what you might see with propane, for example. As well, because of the cheaper cost of alternative energy sources, producers will
often heat a bit more than they would with conventional sources of energy.”
Gala pegs the cost of alternative sources of heat like biomass (wood, straw, etc.) at $4 to $5 per kilojoule, which is around one-third of the cost of propane.
However, it’s quite clear that, unlike commodities such as electricity and natural gas, the price of alternative energy sources is really up for negotiation. In the case of a product like wheat straw, the producer needs fair compensation for the costs of baling it and getting it off the field. This usually puts the value of straw somewhere in the range of $15 to $30 per tonne at the roadside. But as far as a byproduct like flax shives is concerned, it is more difficult to establish what a fair value might be.
“We basically worked something out with our supplier that was mutually acceptable,” Kelvin Vanderveen says. “You have an idea of what the BTUs are like compared to other materials but you have to build in a “hassle factor” that accounts for the extra time and effort that are required to operate a system like this. It’s not like a gas furnace where you just flick a switch and on it comes.”
Vanderveen estimates that he has to have one full-time employee devoted to the maintenance and upkeep of the heating system year-round. In addition, there is a computerized alarm that alerts four different people in succession should anything go wrong with the boilers. He also needs to maintain a backup gas system just in case anything happens to the flax boilers that means he isn’t able to heat for any kind of an extended period of time. The gas furnaces also provide supplemental heat on nights when the mercury dips down to some really low temperatures.
“With the hundreds of thousands of dollars that we have tied up in the crops we grow here, we can’t afford to take the risk of losing everything to the cold.”
Another factor to keep in mind, according to Vanderveen, is the added electrical costs that he now faces because of all of the electrical motors that run the augers and feed the flax shives into the boilers. His hydro costs have tripled with the installation of the new system.
Then there is the capital cost. Vanderveen hopes that the boilers will last 40 years, but the cost of a Blue Flame Stoker is substantial. Eugene Gala says the largest units, which come in at 20 million BTUs, run around $25,000 per million. However, the cost per BTU increases as the boiler size decreases. The smallest boiler, rated at 1.8 million BTUs, costs $72,000 per million.
Still, now that the flax boilers are up and running and the worst of the headaches are out of the way, Kelvin Vanderveen is convinced it was the right step. Alternative energy lets him compete, even during the cold Prairie winters, with growers in much more forgiving climates.
“Shives have made me competitive with the big growers in B.C. and Ontario,” Vanderveen says.
Standing in shirt sleeves in the middle of a million square feet of plugs, seedlings and potted plants, with a temperature of -30 C hovering just on the other side of a couple sheets of poly inflated by air, he makes a pretty solid case.CG