BioCycle June 2011, Vol. 52, No. 6, p. 44
Produce operation in southwest Ontario installs anaerobic digester to process area crop and food processing residuals, using heat from 1.6 MW engine in 6.5 acres of greenhouses.
DENNIS Dick has marked the time precisely in his memory: 11:16 a.m., on January 27, 2011. That’s when the first kilowatt of electricity flowed from the generator on his property on the flat farmland near Lake Erie, in the southwest corner of Ontario, Canada. Dick and his cousin, Roger Tiessen, developed and built the 1.6 megawatt project, operated as Seacliff Energy.
Most anaerobic digesters in Ontario are fed mainly by livestock manure. The major input at the Seacliff facility is wastes from farms and food processing plants in the area, known as Canada’s “Sun Parlour” and famous for its tomatoes, sweet corn and other vegetable and fruit crops. Much of that material would otherwise be dumped in a landfill.
Heat from the generator motor is used to warm 6.5 acres of greenhouses where several varieties of tomatoes are grown year-round for both processing and retail sales. In fact, keeping the plants cozy was the main reason the project was launched.
And, to close what Dick describes as an environmentally sustainable circle, he recently received federal government approval to sell the residue from the digester as fertilizer for food crops.
The cousins took a roundabout route to anaerobic digestion. Both grew up in farm families close to the current operation, in a part of the province that boasts well-drained, rich, sandy soil and Canada’s warmest climate. Dick bought the farm next door to his parents’ in 1975. Initially, he grew Burley tobacco. After that crop declined, he moved through several types of vegetables and, for a time, started seedlings that other growers would buy to transplant. “I’m used to adapting,” he notes.
Dick was raising cucumbers in his greenhouses. To keep them warm, he heated water in a massive boiler fueled by natural gas. But the price of the gas was both unpredictable and rising, so he began looking for an alternative fuel. At the same time, Tiessen, Seacliff’s president, and his wife Laura were operating a tire shop, so used tires seemed a logical choice. But technical and regulatory issues killed that idea.
The cousins then considered straw bales, wood chips, oil, coal – in fact, practically anything that would burn. “We had a great time traveling around looking for something that would work, but we weren’t making any progress,” Dick says.
Eventually, backed by a Planning and Assessment for Value-Added Enterprises, or PAVE grant from Agriculture and Agri-Food Canada, they hired a consultant to help with the search. The advisor, Martin Lensink, of PlanET Biogas Solutions, suggested an anaerobic digester.
Finally, after realizing that every other alternative raised problems – cost, environmental impacts, or simply that the greenhouse operation wasn’t big enough to support it – they decided to take a look at digestion. The cousins traveled to Europe to assess systems there. Their first stop was in the Netherlands. “Five minutes into that visit, we were sold,” Dick says. “There seemed to be no downsides. Every way you looked at it, especially environmentally, it’s a positive thing.” He particularly liked the fact that instead of simply burning materials to produce heat, digestion could lead to generating electricity for the provincial grid, in effect, “creating another profit center.”
Although they were instantly sold on the concept, they didn’t go for the system in use at the Dutch farm. Instead, after several trips to Europe, and “a lot of homework,” Dick and Tiessen chose one designed by Agrinz Technologies Gmbh, an Austrian company. A main selling point was that it’s a two-stage system in which the inputs are pretreated with heat before entering the digester vessel. The process suits an operation where the main ingredient is vegetable fiber, since pretreatment breaks down the tough material, speeding digestion and increasing biogas production. It’s like the difference between eating raw and cooked potatoes, Dick says. “Single-stage works well in applications designed for livestock manure. For our application, it’s limiting.”
It took five years to design the system, acquire the necessary permits, and complete construction. There was a setback in June 2010 when a tornado damaged the partially completed structure, as well as the greenhouses and Dick’s house. Managing Seacliff Energy became so much work that he rented out his greenhouses to another farmer and the Tiessens sold their tire business in order to focus on the digester and its spinoffs.
At the time the project was getting underway, Ontario was offering a Renewable Energy Standard Offer Program, or RESOP, which paid a premium rate for electricity generated by wind, solar, biomass, hydroelectric or other “green” sources of power. Dick and Tiessen signed a RESOP contract for their green energy. A couple of years ago, RESOP was replaced by North America’s first Feed-in Tariff (FIT) policy, which paid higher rates that were guaranteed under 20-year contracts.
This timing had an impact on the Seacliff project. Most of Ontario’s on-farm digesters are associated with 500-kilowatt generators because the FIT payment drops from 16 to 14.7 cents per kWh for systems larger than 500 kW. When the new program was introduced, Seacliff’s RESOP was transitioned to an “amended” FIT contract, avoiding much of the time and expense involved with a new application. They also were able to keep the grid connection approval they’d already received – a crucial consideration, since there was no guarantee Seacliff would get a new connection if they started over. In exchange, though, they had to accept a few cents less per kWh than they could have earned had they applied for and been awarded a regular FIT contract.
Seacliff’s financing and management partners are Toronto-based Gemini Power Corp. and Alpenglow Energy Inc. of Colorado. “They bring a wealth of experience and expertise to the project,” Dick says. He wouldn’t specify the total project cost, but says it’s in the “double-digit millions.” The first batch of feedstocks went into the digester in mid-December and the system is expected to reach its full generating capacity in August 2011.
Seacliff receives its inputs – it requires up to 130 tons/day – from local farms and food processing plants, which pay tipping fees for having it taken off their hands. Contracted waste haulers deliver most of the material. The mix might also include small quantities of livestock manure or hay; in fact, Seacliff accepts any potential feedstock except human sewage and household organic wastes. This part of the enterprise is a family affair. Dick’s brother, Greg, grows sweet corn nearby. It’s processed at a plant that produces Green Giant products, and that company, in turn, ships the wastes to Seacliff.
The input “recipe” is adjusted according to what’s available. Feedstocks are mixed in a Penta TMR mixer before going into one of the three 317,000-gallon pretreatment tanks and, finally, one of two 978,000-gallon digesters. The complete process takes 20 to 25 days. The biogas powers a 1.6-megawatt Caterpillar 3520C generator set. Heat from the generator warms the pretreatment and digester tanks as well as water in a 500,000-gallon boiler – the source for the greenhouse hot water system. Enough is produced to keep the sensitive plants warm on all but the coldest winter nights. Then, a supplementary gas-fueled source is required.
The digestate – amounting to 90 percent of the original feedstock, with its nutrients intact – is pressed through rollers in a solids separator designed by Dairy Lane Systems Ltd. Seacliff received approval from the Canadian Food Inspection Agency to market both solids and liquids as pathogen- and odor-free fertilizer.
Dick says Seacliff is set to construct a second 1.6-MW system, but that project is on hold, until the Ontario Power Authority awards it a FIT contract. This is where Dick voices the frustration common to all of Ontario’s biogas producers, and those who would like to join their ranks. According to the Agrienergy Producers’ Association of Ontario, a combination of inadequate FIT payments and regulations, and roadblocks erected by Hydro One – the agency that operates the provincial grid – and the Power Authority, fewer than 30 of potentially hundreds of digester projects are going ahead.
Dick, a member of the Association’s board, agrees caution is essential when any new sources are added to the grid. “You have to handle electricity with care. Whenever you put something into the line, it affects something further down.” Still, he says, he faced a “moving target” in seeking approval for the first generator from Hydro One. “It was a difficult process,” Dick notes. “We got through it, but I’m concerned for the digesters that could be built.”
Along with the costs and technical impediments, there’s a timing disconnect. In some cases, Hydro One awaits funding to upgrade transformer stations so it can handle the increased electricity load. But the application for a FIT contract requires a substantial outlay of cash, and the steps must be taken within a legally prescribed time limit. Permitting must also be in place before a project can proceed. The mismatch between Hydro One’s funding expectations, FIT contract approval and the permitting process has put some potential biogas operators in an impossible position. “How can you throw out huge amounts of money to something you don’t know is going to be approved?” Dick asks. To make matters more uncertain, the leader of the Conservatives, the main opposition in the provincial Legislature, vows to cease awarding FIT contracts if the party wins the general election to be held in October.
For now, though, Dick and the other biogas producers have received one good piece of news: The Power Authority has clarified that it will not take a portion of the profits from digester operators who develop new products with the residues. The agency had said it wanted an 80 percent cut. Other operators hope to develop products ranging from take-out food containers to ethanol. Dick says he and Tiessen, too, “have a lot of ideas. We’re looking into some of them.” For now, though, “our focus is on making the plant work as efficiently as possible.”
Peter Gorrie is a free-lance writer based in Toronto, Ontario.
June 16, 2011 | General
Greenhouse Grower As Digester Entrepreneur
BioCycle June 2011, Vol. 52, No. 6, p. 44