A biodigestester set to break ground near High River, Alta., has some local residents worried about the plant’s environmental impacts.
Last June, developer Rimrock Renewables Ltd. — established through a partnership between Tidewater Renewables and Rimrock Cattle Company Ltd. — received Foothills County’s approval last year to begin construction of a biodigester.
Once up and running, the biodigester will break down organic waste, including manure, to produce renewable energy.
Tidewater Renewables sold its shares to BioCirc Canada Holdings Inc., a self-proclaimed “world-class developer” that aims to reduce greenhouse gas emissions contributing to climate change by producing green energy in all forms.
With the parent companies’ joint expertise in agriculture and energy, the $70 million plant is set to produce renewable gas directly from the waste at Rimrock’s farm, located just off Coal Trail East.
What led to the development of this plant?
According to Dr. Kee Jim, a veterinarian specializing in cow health and partial owner of Rimrock Renewables, the idea for the plant was sparked by Canada’s desire to develop its renewable gas sector.
“Biodigesters, although new to Canada, per se, are not new in terms of a technology,” he said in an interview with the Calgary Journal. “What Canada was really doing was just catching up to the rest of the world in terms of getting this technology utilized to make renewable gas.”
Since Rimrock is, at its core, a cattle company, Jim explained that it just made sense as another way to make a profit, since they had the manure.
The biodigester’s application to Foothills County highlights the renewable gas plant producer as a safe, odourless, and environmentally friendly addition to the community, explained Garnet Dawes, who submitted the land use bylaw amendment and development permit on behalf of Rimrock.
“The facility…is designed as a series of integrated processes that work together to ensure efficient facility operations,” he wrote in the application. “While minimizing potential environmental impacts such as odorous emissions, noise and contamination.”
The proposal stresses the biodigester “has been carefully designed to meet and exceed municipal, provincial, and federal standards, with an emphasis on protecting the environment, minimizing impacts to the local community, and contributing positively to the county’s agricultural and energy sectors.”
Furthermore, it suggested that the biodigester will “minimize any negative environmental impacts it may have, and that it will continue to meet the government standards set for it to protect the environment.”
Biodigester’s green power pledge
According to the Saskatchewan Research Council, a biodigester is a “mechanical machine” that breaks down organic waste to produce biogas and fertilizer. The Rimrock biodigester will eat cow manure from the neighbouring feedlot, but any organic material can be used.
Once fed, the biodigester uses bacteria in an oxygen-free environment to decompose the material and produce methane gas. The leftover material can be used as fertilizer.
This process takes around 27 days, but that depends on how much organic matter is put into the machine.
The Simpson Center for Food and Agricultural Policy at the University of Calgary contends that “biodigesters offer decentralized renewable energy production, beneficial particularly in rural or off-grid communities.”
The plants also “support local energy autonomy and reduce reliance on non-renewable sources.”
But the researchers also point out that the plants come with risks, including odour, water contamination, and the fact that some biodigesters are inefficient, consuming more energy than they produce.
If fossil fuels are used in the process, such as transporting raw materials, this can also reduce the climate benefits.
Stressing local water sources is another factor, as is damage from improper fertilizer storage and application.
If fertilizer is overapplied or applied at the wrong time, it can cause nutrient runoff, harm aquatic ecosystems, and lead to nitrate leaching into groundwater.
For the Rimrock biodigester, plans call for a 20-acre digestate pond — a water basin used to store and manage fertilizer for land use — between two wetlands, according to documents from an appeal to the Alberta Environmental Appeals Board.
But the same document also states that they plan to operate the pond at or below the maximum level to prevent overflow.
The biodigesters triggered a local opposition movement called Stop That Smell, spearheaded by residents concerned that the plant might negatively affect the area’s environment.
Community members voice concerns over possible environmental impact
Carrie Derish, a member of the Stop That Smell movement, says the pond is one of her biggest concerns.
“ They’re gonna have this 21-acre open lagoon filled with waste. And, we have hawks, eagles, ducks, everything out here — they’re gonna land on it. So we worry about wildlife as well,” said Derish.
Water contamination is a significant risk with biodigesters, not just from fertilizer but also from leachate.
Leachate, a contaminated liquid formed when water filters through waste, can damage surface and groundwater if containment systems are not properly designed.
Derish shared that much of the water in High River and the surrounding areas comes from groundwater and wells.
When asked about these environmental concerns, Rimrock Renewables shared that the company is considering covering the pond to allow it to harvest more gas.
As for the other environmental concerns, Jim believes there is little to worry about. He stresses that the process the company currently follow has the same effects as the biodigester will.
“I don’t quite understand the nature of the concern, because the practice of applying, whether the manure or the digestate, to the land has not changed,” said Jim.
One of the major marketing advantages of biodigesters is that they can reduce odours from unmanaged waste. However, improper handling can cause offensive odours and air pollution. Furthermore, if leaks occur in the gas collection system, it will result in improper methane emissions.
Biodigesters in the United States regularly flare — or burn off — excess methane into the atmosphere.
A 2024 study in the Journal of Safety Science reported 75 biodigester incidents worldwide, most of which occurred in France and Germany, with 16 each. The United States, Denmark, and the United Kingdom trailed behind with less than 10, respectively.
Millions of biodigesters operate around the world. China alone has more than 100,000 bidigesters.
Of the 75 reported cases, the most common incidents were explosions, followed by toxic releases, biohazard spills, and malfunctioning machinery.
Local residents, such as Derish, worry about the possibility of an explosion.
“ If there was an explosion, our town is affected as well as all the acreages surrounding it,” said Derish.
One of those properties belongs to Benita Estes, a recently elected Foothills County councillor and founder of the Stop That Smell Facebook group.
“ When this has a problem, my house will not have a window left in it, and they do explode,” said Estes.
Jim doesn’t see any reason for concern about the potential plant explosion.
“We don’t see it as a significant risk in the project. And if it were, then the government should, wouldn’t have issued the permit,” said Jim, “Obviously, they would have looked at all of the incidents and the engineering and so on. So if they thought it was a sufficient risk, then I don’t imagine they would have approved the project.”
He stressed his company aims to design the High River plant after those that haven’t exploded.
“I’m certainly not aware of any biodigester explosions that have occurred with modern technology in plants in North America… which is what we’re patterning our plants off of,” said Jim.
Estes is also concerned about the project’s size.
“ It is hideously large compared to most of the other ones in the world, including Germany, that they seem to like to keep quoting,” she said. “In Alberta, we’re not in desperate need of natural gas.”
Her concern is that it is being placed in an area she considers unsuited to its industry.
“ This is an agricultural area, and this is an industrial project, and industrial projects belong in industrial corridors and or industrial designated land,” she said. “It’s a gas plant, and it certainly doesn’t belong 200 meters from my home,”
The use of fossil fuels for transporting materials and disposing of wastewater could affect the plant’s climate benefits, which Estes noted might be the case with this biodigester.
“ Why would we waste the amount of water that this thing’s gonna need to operate just to make 6,000 homes’ worth of natural gas?” she said. “If people were really to take into account what it’s gonna take, construction-wise, concrete, and everything else, this thing will never be net zero.”
Jim said that concerns surrounding trucks or emissions concerns are just natural parts of the construction process.
“There are some inconveniences in the short term associated with construction. It’s not going to be the same for this project as any other. It won’t be it won’t be any worse, and it won’t be any better for a project of a similar size,” said Jim.
Full steam ahead, Rimrock expects
Construction on the plant is to begin next year and to be completed in the fall of 2029. Jim says Rimrock Renewables is excited to move past all of the hearings and get the construction underway.
“People had all kinds of unbelievable concerns that were just not, you know, they weren’t…they weren’t anchored in any fact. And it just takes a long time to get through all of that. It’s a pretty exhaustive process. And we’re, you know, we’re through it now, and we’re looking forward to getting under construction and getting going,” said Jim.
Once the plant is up and running, the plant’s gas will be fed directly into the ATCO pipeline.
As for upholding any environmental promises of the plant, Jim doesn’t believe they made any, but rather that they are just complying with the rules of their permit.
“We didn’t make any promises. We have to comply with the legislation. And in the detailed approval of the plan, so it gets regulatory approval, they have the conditions under which you have to comply and operate. So, in our operating pro forma and how we’re going to do it is so that we’re in compliance with all of the conditions of the permit,” said Jim.