Could Hemp Straw Help Canada Produce Renewable Gas?

Hemp already supplies food, fibre, and ingredients for building materials. New Canadian research suggests another part of its economic potential may lie in the straw left after harvest: a feedstock for renewable natural gas.

A study published in Biomass and Bioenergy compared 14 biomass feedstocks, including hemp straw, canola straw, fast-growing trees, and perennial grasses.¹ Hemp straw recorded the highest estimated renewable natural gas yield among the untreated samples. That is an encouraging result for an industry seeking dependable markets for more of the plant.

The opportunity extends beyond producing fuel. An additional outlet for suitable straw could help connect hemp cultivation with local energy infrastructure. Whether that becomes profitable will depend on where the material is grown, what other buyers will pay, and how efficiently it reaches a digester.

How Hemp Straw Becomes Renewable Gas

The researchers investigated anaerobic digestion, a process in which microorganisms break down organic material without oxygen. The resulting biogas contains methane, the energy-bearing component of conventional natural gas, along with carbon dioxide and other constituents.

Biogas and renewable natural gas are related but distinct products. Producing gas inside a digester does not automatically produce fuel suitable for a pipeline. Biogas must be cleaned and upgraded to meet the requirements of its intended use.

The International Energy Agency’s 2025 outlook for biogas and biomethane places these fuels within a broader effort to turn organic resources into useful energy. Hemp would be one candidate within that system, alongside other agricultural materials and waste streams.

For plant residues, the main challenge is access. Cellulose contains carbohydrates that microorganisms can convert into methane, but lignin helps protect the plant’s structure and makes those carbohydrates harder to reach. A feedstock can therefore contain substantial energy without being especially suitable for digestion.

What The Canadian Hemp Study Found

The team tested samples sourced from Saskatchewan and Nova Scotia, using small batch reactors maintained at approximately 37 degrees Celsius over 30 days. They measured gas production, methane concentration, and characteristics such as cellulose, lignin, and solids content.

Untreated hemp straw produced an estimated 163.8 cubic metres of renewable natural gas per tonne of total solids. Total solids refers to the material remaining after moisture is removed, so this is not a yield per tonne of freshly harvested, wet straw.

The table below shows selected untreated samples. These are results for specific materials and harvests, rather than universal yields for every crop bearing the same name.

Hemp ranked first numerically, but the reported variability overlaps with several grass samples. The useful conclusion is that this hemp straw performed well under the tested conditions. The results do not establish that hemp will consistently outperform all alternatives across regions and seasons.

Cellulose generally supported methane production, while lignin constrained digestibility. This points toward a practical purchasing strategy: assess a delivery’s composition and conversion performance, rather than relying only on the crop label.

Why More Processing May Not Mean More Value

The researchers also treated biomass with sodium hydroxide, an alkaline chemical intended to improve microbial access to plant carbohydrates. Samples were soaked in a 10% solution at room temperature, washed, and dried before digestion.

The response depended strongly on the feedstock. Hemp’s measured methane yield increased by 5.7%, while canola straw improved by 163.2%. Several grass samples performed worse following treatment. A process that helps one material can therefore be unnecessary or counterproductive for another.

Measure Gas Against The Original Harvested Material

One particularly important detail is biomass recovery. The study reported a post-treatment biomass yield of 62.4% for hemp straw. Its methane improvement was measured per unit of volatile solids fed into digestion, while that recovery figure describes retained biomass. Those different measurement bases cannot simply be multiplied into a definitive commercial result.

Nevertheless, they raise a valuable question: how much usable gas remains available from the original harvested tonne after treatment losses, washing, and drying? A higher yield from the material entering the digester may not compensate for material removed upstream.

For hemp, the modest methane increase makes a simpler processing route worth investigating. Further trials could compare untreated straw with less intensive preparation, tracking total gas recovery, chemical consumption, water use, and energy demand through the whole process.

Build The Market Around Available Hemp Straw

The most plausible starting point may be straw from crops already grown for established products. That approach lets energy recovery complement an existing agricultural business rather than requiring renewable gas sales to support every cultivation cost.

Recent reporting on Canada’s hemp grain market found that grain accounted for 84% of reported planted hemp area in 2025. The figures have reporting limitations, but they indicate why grain production deserves attention when evaluating potential straw supply.

A gas developer would still need to establish how much straw farmers can actually sell. Material left in fields has agricultural functions, and collection requires labour, machinery, storage, and transport. Calling straw a residue does not make it free.

The study also does not demonstrate equivalent performance for spent cannabinoid extraction biomass or every fraction left after fibre processing. Removing valuable components changes what remains. Each proposed supply stream would need its own digestion tests.

MyCannabis coverage of hemp variety and row spacing reinforces another distinction: performance per tonne is only one part of the equation. Commercial supply also depends on harvestable tonnes per hectare and reliable production under local conditions.

Give Each Hemp Fraction Its Best Destination

Renewable gas should become another option in hemp processing, with decisions guided by the value and suitability of each material. Fibre meeting a manufacturer’s specifications may have a better destination than a digester.

Research discussed in MyCannabis coverage of stronger hempcrete and carbon storage illustrates how hemp can serve durable material applications. Energy production provides a different function, with a different carbon timeline.

Similarly, work on hemp biochar and energy recovery considers how thermal processing can balance useful energy products with carbon retention. The Canadian digestion study adds another pathway to that decision.

A processor could eventually direct suitable fibre toward materials and test lower-value fractions for energy recovery. This remains a strategy to investigate, since the study did not validate an integrated commercial facility. Its appeal is flexibility: more outlets could reduce dependence on a single buyer.

What Would Make Hemp Renewable Gas Commercially Credible?

The next step is a pilot that reproduces real operating conditions. Continuous feeding, seasonal storage, mixed feedstocks, and equipment wear can all produce outcomes that small batch experiments do not capture.

A useful pilot should answer three questions:

• How much saleable gas is recovered per delivered tonne of straw?
• Do collection, processing, and upgrading costs leave a viable margin?
• Does the complete system reduce emissions against its realistic alternative?

The environmental assessment should include cultivation inputs, transport, treatment, methane leakage, and management of the remaining digestate. Renewable origin alone does not establish a favourable emissions balance. Retaining nutrients also requires testing and appropriate handling of the material left after digestion.

Hemp straw’s strong laboratory performance gives researchers and developers a credible reason to pursue those questions. The promising outcome is an additional, locally appropriate market that rewards usable biomass without sacrificing higher-value products or field health. With careful pilot design, this research could help turn hemp’s versatility into a more resilient business model.

References:

¹ Gautam, B., Soolanayakanahally, R., Mupondwa, E., Dumonceaux, T., Li, X., Tabil, L. G., Dalai, A. K., & Acharya, B. (2027). Bioenergy potential of fast-growing trees, perennial grasses, and agricultural residues for renewable natural gas production in Canada. Biomass and Bioenergy, 217, 110190. https://doi.org/10.1016/j.biombioe.2026.110190