Biodigesters

Monday, June 26, 2023

Sustainable? Yes. Attainable? Not to the masses. With a focus on carbon neutrality, digesters are the ideal fit, if the market allowed for increased access.

By Colleen Halpenny

Weather volatility and climate change are an increasing focal point when making decisions on-farm, as are the external pressures from boards, governments, and consumers for more sustainable operations.

Jennifer Green, executive director of the Canadian Biogas Association, explains that farms across the Prairies are well suited as biogas operations, as they can utilize the feedstocks and other organic matter that they readily have available such as livestock manure or crop residues.

"There are many biogas and renewable natural gas (RNG) opportunities across Canada, and currently there are about 45 operational digesters across the country on farms. Whether they are producing energy from the digester for use on-farm, or upgrading the gas to be fed into the natural gas pipeline as a source of secondary income, it's great to see these previous waste materials be integrated as resources in their farm systems," says Green.

Current applications for the biogas are renewable heat, electricity, and pipeline-quality gas that can be stored in the pipeline and used for transportation, household heating, or industrial, commercial and institutional processes.

For Green, the opportunities for the use of biogas and RNG are very versatile and multifaceted, and highlight the enriched end-product – the digestate – which is delivered after the anaerobic process is complete.

"When you take the digestate to the field, you're actually applying a product with much higher available nitrogen, which delivers improved yields. Through the digestion process, you're also minimizing pathogens and weed seeds that don't benefit your operation," she says.

Missing pieces

"We really were captivated by the idea that we could capture and make use of the energy we could generate with our on-farm organic materials and were lucky to enter during the micro-fit project put on by the Ontario government, which allowed us to be able to market the electricity through net metering," shares Rob McKinlay, a mechanical engineer and dairy farmer in Beachville, Ont.

"But when the government subsidizes electricity, this impacts the viability of your project. As a dairy farm your revenue is a slow build with the quota system, so if you're going to invest in innovation you need it to not only cut costs, such as buying electricity, but it should also generate income."

McKinlay notes that their farm-scale digester is a European model, as the herd sizes are similar to Canadian farms – contrary to the current direction of the digester industry. With much influence from the U.S., he feels the goals do not align with the size or practices of the majority of Canadian operations.

"With digesters you can be belt-driven like ours, and produce electricity, or you can upgrade the gas to produce RNG – but to do that you need to be a much larger farm for capacity.

And now, there isn't even a way to market the electricity a unit such as ours can generate.

"There's a real disconnect between the provincial government and the federal agriculture departments. And a lack of will to put digesters on farms, in a way that allows access for the masses and not just the large-scale producers," he says.

Green agrees that barriers do exist, which impede the sector flourishing as it could.

"The capital cost of these projects in not for the faint of heart. And you need to ensure you have a way to connect in with either the electricity or RNG markets to ensure you have revenue returning.

"We've been working hard to address these barriers, and work with many stakeholders within the ag sector to ensure more resources, answers to questions, and see the growth we envision to come true," she says.

Optimum outputs & connectivity

Justin Egan, an RNG specialist in business development with Enbridge, shares that a fair number of farmers do reach out, but that size of the operation doesn't always allow for a feasible project.

"A lot of factors are involved when deciding whether a project is sustainable, and many farms aren't able to sustain the desired system on just their animal waste.

"We usually see supplementation with off-farm organics, which pairs well if close to a nearby city, to access matter from grocery stores and restaurants," he says.

Egan suggests producers in the early stages of exploring a project should reach out to the end-market as soon as possible to explore any hurdles, such as location, that they may encounter.

If access to an existing pipeline is near your operation, that can speed the process through. But for those farther-away farms, Egan says there are workarounds.

"One of the things that farmers have on their side, usually, is land. Whether their own land or access to other's.

"We've worked on projects where connection to the main farm wasn't feasible, but moving the waste to another piece of land closer to the line made it work.

"Sometimes it can even be a group effort of multiple farms to come together to supply a digester and produce the gas," he explains.

For McKinlay, the single source of marketing potential still stings.

"The frustrating piece is that we finally have the electrical system projects fine-tuned to a point where a large number of smaller-scale farms could participate.

"But the market has shifted and there isn't a way to market that electricity.

"They want all projects to be RNG. Which, if we're looking to truly make a difference, we need to provide opportunities for all farms, not just those large operations," he says.

Just west of High River, Alta., Rimrock Renewables has been formed as a partnership between Tidewater Renewables and Korova Feeders, with the goal to build a biodigester facility adjacent to the feedlot.

Capturing both manure and organic food resources, the project has the goal to heat approximately 6,000 homes per year with the RNG produced, and offset the carbon footprint of 34,000 head of cattle per year.

With $5 million in funding from Emissions Reduction Alberta, this pilot project would serve as a model for other feedlots in Alberta, and across the Prairies, changing the way in which various production systems can participate in reducing GHG emissions.

Looking ahead

"The sector has the potential to contribute up to 26 Mt of GHG reductions by 2030, which is huge compared to our current volume of eight. Studies have shown that Canada is only tapping into 13 per cent of its biogas and RNG potential. Working to build those long-term agreements for energy, in many forms, will assist in (addressing) some of those underlying economic viability hurdles of projects going forward," says Green.

McKinlay feels that the lack of appetite from regulators to engage with more average-sized farms means we need to explore other opportunities, like the carbon market.

"We always need to think about how a project can not only offset costs, but generate revenue.

"If we can figure out how many carbon credits you could accumulate by destroying the methane and limiting GHG emissions, it might be enough to generate the revenue needed to push these projects forward.

"But again, we're stumped on ‘how do we then sell these carbon credits?' It's hard for any farmer to find those answers," he says.

Looking to national boards and organizations which set the target neutrality goals, McKinlay wonders if they should be playing a bigger role in helping to standardize how carbon is calculated, as hiring consultants on each farm could be costly.

"We're all doing the same thing, albeit a bit differently, but the base is enough that there could be some facilitation to monetize carbon credits. Seeing them stand with us – championing carbon neutrality – would give you a sense of not being alone.

"For me, at the end of the day, I can champion the electricity grid and the fact that it's a proven technology, and everyone is already connected, until I'm blue in the face. But the market will go where it wants, and I would just like more clarity from the governing bodies on how they see the increase in digesters they speak of happening. Because they aren't making it viable for the masses." BF