Feedstock Eligibility

Your biomass carbon removal project begins with one of the most fundamental ingredients: feedstock. Feedstock refers to the biomass you convert into biochar, slurry, or energy. Feedstocks are commonly agricultural residues, forestry byproducts, invasive species, mill waste, and other biogenic materials. Registries care deeply about feedstock because it determines the baseline emissions, the carbon accounting, and the environmental integrity of your project. 

To qualify, feedstocks generally must be: 

• Sustainably sourced
• Legally obtained, and 
• Represent waste or low-value streams that would otherwise decompose or be burned. 

Feedstock eligibility matters because it directly affects the carbon removal calculation, the life-cycle emissions of the project, and the credibility of the storage pathway. Getting this piece right early prevents major downstream issues in your project design document, monitoring plan, audit, and credit issuance.

‍

Glossary

Feedstock Type & Characteristics

• Feedstock: The biomass used as input for biochar production (e.g., shells, husks, prunings, wood chips, residues).
• Agricultural Residues: By-products from farming activities (e.g., corn stover, rice husk, wheat straw, cotton stalks, nut shells) that typically have low economic value and are often burned, left to decompose, or mulched.
• Forestry Residues: Low-value wood materials generated through harvesting, thinning, or sawmilling (e.g., branches, offcuts, sawdust, bark).
• Invasive Species Biomass: Biomass removed to control ecological invasives; often eligible but requires legal proof.
• Residue/Waste Stream: Material with no higher-value use that would otherwise decompose, be landfilled, or burned.
• Contamination: Presence of chemicals, plastics, metals, or other materials not allowed in eligible biomass.
• Moisture Content (%): The percentage of water present in biomass. 

Eligibility, Baselines & Competing Uses

• Counterfactual Fate: The expected use of the biomass in the absence of the project. This explains what would realistically happen to the feedstock if it were not used to produce biochar (e.g., open burning, landfill disposal, mulching, stockpiling, unmanaged decomposition). Registries use this to determine baseline emissions and additionality.
• Alternative Fate: Similar to counterfactual fate, this refers to the other potential uses or destinations for the biomass. It helps determine whether the feedstock has competing value chains (e.g., livestock bedding, composting, mulch) and whether the project is diverting material away from an existing market.
• Competing Use: Any economically valuable alternative use for biomass that may challenge eligibility.
• Higher-Value Use: A competing use that would disqualify feedstock (e.g., animal bedding, mulch, compost feedstock).
• Baseline Emissions: The emissions that would occur if the biomass were not converted to biochar (e.g., methane emissions from decomposition).

Supply Chain & Documentation

• Traceability: Documentation showing the origin, transport pathway, and custody of feedstock.
• Upstream Processing: Any handling or processing performed on biomass prior to pyrolysis (chipping, drying, debarking, etc.).
• Sourcing Agreement: A contract establishing rights to collect, process, or purchase feedstock.
• Waste Classification Letter/Certificate: A document from a supplier (e.g., mill or farm) confirming the material is a waste stream.’

Production & Yield

• Biogenic Carbon: Carbon originating from biological sources rather than fossil sources.
• Biochar Yield (Feedstock-to-Biochar Ratio): Output ratio of biochar relative to input feedstock (e.g., 4:1).

‍

Frequently Asked Questions 

How do I know if my biomass qualifies as a waste stream? 

Registries look for materials with no viable alternative market or cases where disposal is a cost or operational burden. Documentation like letters, invoices, or emails from suppliers, often confirm this. 

Are agricultural residues automatically eligible? 

Often yes, but not always. Eligibility depends on moisture content, contamination, and whether the residues have existing uses (e.g., animal bedding). Offstream helps verify and document this. 

What if my feedstock has multiple uses? 

Competing uses don’t automatically disqualify your biomass, but they increase scrutiny. You need to show your project isn’t diverting material away from an existing market.‍

Can I use invasive species as a feedstock? 

Yes, these are frequently eligible, however, registries will want proof of: 

• Legal removal 
• Environmental compliance 
• Chain-of-custody 
• Disposal practices prior to your project

Is mixed feedstock allowed? 

Typically yes, but you must document: 

• Each biomass type 
• Proportion of each type 
• Eligibility for each component 
• Changes in blend over time 

Small changes will require updated documentation across all feedstocks. 

Do I need to track where my feedstock comes from? 

Yes, traceability is mandatory. This often requires something as simple as a memo. 

What about contamination (paint, plastic, chemicals)? 

Contaminated biomass is often ineligible. Even small amounts of plastic or treated wood can jeopardize compliance. 

Do registries require formal supply agreements? 

Not always, but they strongly prefer them. At a minimum, you need: 

• Documentation of access
• Confirmation that it’s a waste stream 
• Annual or monthly volumes
• Legal permission to collect or purchase it 

What if my feedstock supply changes over time?

All changes must be documented. Major changes (e.g. new biomass type) usually require updated testing and registry notification. 

Can I use feedstock from multiple suppliers? 

Yes. Multi-supplier sourcing is allowed, but each supplier must provide its own documentation. Registries will expect:

• Confirmation that each material is a waste or residue 
• Traceability from each supplier (origin, transport, and custody)
• Any relevant waste classification letters or memos
• Estimated annual volumes from each source

You can blend material from different suppliers, but eligibility must be clear for each one, not just the combined feedstock. Clean record-keeping reduces risk during audits and avoids rework later.

Is there a quick checklist to know if my feedstock is likely eligible? 

Yes. A feedstock is generally eligible if it is biogenic, traceable, legally sourced, and truly a waste or low-value residue that would otherwise decompose or be burned. You should confirm the biomass has no higher-value competing use and is free from contamination such as plastics or treated wood. If your feedstock meets most of these criteria, there’s a strong chance it can support a biochar project. 

‍

Where Offstream Supports Your Project

As part of our core offering, Offstream helps your project ensure its feedstock is presenting cohesively to registries, credit buyers, and auditors. We map the end to end feedstock supply chain, from origin and harvesting practices to moisture levels, contamination risks, and competing uses. 

We begin by assessing whether your biomass is eligible under specific registry methodologies, evaluating evidence for waste classification and residue status, and highlighting potential risk areas that auditors or registries may flag. 

The goal is simple: to ensure your feedstock strategy is defensible, compliant, and aligned with your long-term carbon-credit goals. If you want to strengthen your feedstock documentation or confirm that your biomass will pass registry review, reach out to Offstream at hello@useoffstream.com.