Make useful products part of the project from the start.
Co-products can improve the commercial value of a bioenergy project through additional sales, useful local substitution or reduced disposal costs. Each needs its own quality specification, lawful use and route to a customer. Potential production should not be counted as saleable demand. [[ US Environmental Protection Agency, How Does Anaerobic Digestion Work? ](https://www.epa.gov/agstar/how-does-anaerobic-digestion-work); C01] Nearby users, seasonal acceptance and transport costs determine whether recovery creates additional margin or simply shifts handling costs.
Build the commercial loop
Assess products alongside the main energy route. Start with what the process actually produces, then work backwards from customer specifications and forward through treatment, storage and delivery. A useful material becomes a commercial product only when that complete route works.
| Product | Where the opportunity arises | What establishes value |
|---|---|---|
| Digestate | Residual material from digestion | Nutrient quality, approved use, application and delivered value |
| Biogenic CO₂ | A suitable separated or recovered gas stream | Purity, customer qualification and logistics |
| Biochar | Additional suitable thermal conversion | Input eligibility, product performance and verified claims |
Help existing plants participate
Modular recovery and shared logistics can be assessed around established facilities. The opportunity is particularly relevant where a usable stream exists and customers can be served without excessive delivery costs. Preserve valuable existing energy uses in the comparison.
Develop local product supply and manufacturing
There may be opportunities for Australian equipment assembly, servicing, nutrient processing and industrial product supply. Establish them through supplier capability assessments and buyer development rather than promising jobs or national market values before evidence exists.
Keep the economics transparent
Show production volume, qualified volume and sold volume separately. Include rejected or unsold material, seasonal demand, treatment and transport. Use contracted or quoted revenues where available; identify illustrative assumptions. Certification can support trust but does not create a buyer or guarantee a price.
Keep environmental claims product-specific
Biogenic origin, product quality, avoided emissions and permanent carbon storage are different attributes. Selling CO₂ for short-lived use is not automatically carbon removal. Digestate and biochar also need their own evidence and accounting boundaries. [[ GreenPower, LCLF and Biogenic CO2 Certification announcement ](https://www.greenpower.gov.au/news-and-events/news/lclf-and-biogenic-co2-certification-announcement), [ Environment Agency / UK Government, Anaerobic digestate: resource framework ](https://www.gov.uk/guidance/anaerobic-digestate-resource-framework), [ European Biochar Certificate, Biochar Guidelines ](https://www.european-biochar.org/en/certificate)]
Recognise each product once, at net producer return
One process does not automatically generate every co-product. Start with the conversion route, then test recovery, specification, lawful handling and customer acceptance.
| Process origin | Potential output | Qualification and customer evidence | Costs before net return |
|---|---|---|---|
| Anaerobic digestion | Digestate | Nutrients, contaminants, lawful status and accepting farms | Separation, storage, testing, treatment and transport |
| Suitable gas upgrading | CO₂-rich separated stream; potentially recovered BioCO₂ | Recovery performance, buyer grade and contracted quantities | Purification, liquefaction, monitoring, storage and haulage |
| Thermochemical conversion | Biochar | Feedstock, char specification, permitted use and evidenced demand | Additional equipment, emissions control, testing and delivery |
Use measured or defensible recoverable quantities, not total theoretical production, and cap sales at qualified demand. A stream that costs money to manage may have a negative netback. Record avoided disposal cost separately from product sales so the same benefit is not counted twice.
Biological origin, product compliance and carbon-removal accounting are distinct. A certificate or soil-product sale does not automatically establish permanent removal. Keep speculative sales and any unverified credit scenario outside the base case.
Frequently asked questions
Are co-products extra renewable gas output?
No. Report gas and material products separately, with explicit mass and energy boundaries.
Does every project need all three products?
No. Select the combination that fits the process, customers, compliance and net economics.
Can co-product revenue support financing?
It can where volumes, quality, contracts and costs are credible. Unverified sales should remain a sensitivity case.
Sources & References
- US Environmental Protection Agency, How Does Anaerobic Digestion Work?
Publication: 2019-03-18
Observation period: United States; general technology description
Relevant page / section: Claim-level locator not yet verified
Last link / title verification: 2026-10-11
Publisher link checked; individual claims, costs and regulatory applicability still require review.
Supports process definitions. No Australian cost or project-outcome inference.
- GreenPower, LCLF and Biogenic CO2 Certification announcement
Publication: Date not verified
Observation period: Australia; scheme development
Relevant page / section: Claim-level locator not yet verified
Last link / title verification: 2026-10-11
Publisher link checked; individual claims, costs and regulatory applicability still require review.
12 August 2025 announcement. Does not prove current scheme launch, food-grade certification or automatic NGER recognition.
- Environment Agency / UK Government, Anaerobic digestate: resource framework
Publication: 2025-10-20
Observation period: England; qualifying digestate
Relevant page / section: End-of-waste criteria; England only
Last link / title verification: 2026-10-11
Publisher link checked; individual claims, costs and regulatory applicability still require review.
Published 20 October 2025. Jurisdiction- and condition-specific end-of-waste framework, not a blanket digestate exemption.
- European Biochar Certificate, Biochar Guidelines
Publication: Date not verified
Observation period: Version-specific standards and carbon-sink documents
Relevant page / section: Claim-level locator not yet verified
Last link / title verification: 2026-10-11
Publisher link checked; individual claims, costs and regulatory applicability still require review.
Medium-high for scheme requirements; not Australian law or guaranteed carbon-credit eligibility
- Shelby Bioenergy, Shelby’s National Renewable Gas Policy consultation response
Publication: 2026-10
Observation period: October 2026
Relevant page / section: Supplied company position
Last link / title verification: Not verified
Company position / supplied material, not independent evidence.
Proposals and scenarios, not adopted policy or market offers.