Methodology 2026.2
What is in the number, and what is not.
This page is the whole method. It is written for the procurement analyst who has to defend a supplier’s figure to their own auditor, so it names every factor, every source and every limitation. If something here is wrong, write to methodology@ and it will be corrected in public with a version bump.
1. The model
The declared unit is one kilogram of finished ingredient at the factory gate. The boundary is cradle-to-gate: cultivation or wild harvest, landing and inbound haul of wet biomass, drying, extraction and milling, packaging, and outbound freight to the customer gate. Use phase, consumer transport and end-of-life are excluded.
The gross footprint is the sum of three scopes, aligned with the GHG Protocol Corporate Standard as applied to a product inventory. Scope 1 is fuel burned in owned harvest vessels and equipment. Scope 2 is purchased electricity, location-based, at the national grid intensity of the processing country. Scope 3 is the fuel supply chain, cultivation and harvest inputs, process chemicals, freight and packaging.
Global warming potentials are IPCC AR6 100-year values. Yield is handled explicitly: where an extract is produced, the biomass conversion ratio multiplies every upstream line, which is why extraction yield moves an alginate or carrageenan number more than any freight decision.
Allocation, where a co-product exists, follows the common industry choice and is stated in the Report. For fish-skin collagen the default is economic allocation, and the Report says so on the same page as the number.
2. Category A, B and C
A grade is a statement about evidence, not about performance. A Category C figure is not a bad figure; it is a figure that cannot carry as much weight in front of a buyer.
- Category A
- Primary data. The supplier's own metered energy, measured extraction yield and actual logistics records, checked line by line against invoices and meter readings. Reached only through a Primary data upgrade.
- Category B
- Species-specific secondary data with named sources, applied to the production parameters the user states. Most Runs land here. It is defensible in a tender and it says what it is.
- Category C
- Representative averages, screening only. Assigned when the species evidence base is thin, when a factor carrying at least a tenth of the total is itself Category C, or when a contractual renewable claim has no instruments on file.
A Run is graded at the lowest grade any material part of it deserves. The rule is mechanical and it is printed in the Report: if a Category C factor carries ten percent or more of the total, the Run is Category C, whatever the species evidence allows.
3. Biogenic uptake
Seaweed and algae fix carbon dioxide as they grow. That uptake is real, it is measurable, and it is reported in every Report in its own row, labelled “Reported separately. Non-permanent. Not subtracted.”
It is never netted into the headline. Harvesting an annual crop that is then eaten, spread on a field or formulated into a cream does not store carbon on a climate timescale. Subtracting it would produce a negative number that no buyer’s auditor will accept and that no honest method can defend.
Bluecarbon does not issue, price, broker or reference carbon credits, and the words carbon-negative, climate-neutral and net-zero product do not appear in any Report.
4. The factor set
Every factor in the Calculator is listed below with its provenance and its own grade. All of it is published secondary data. None of it is third-party verified, and the Reports say so.
Electricity, location-based
| Factor | Value | Grade |
|---|---|---|
| FranceIEA Emission Factors 2024, national average generation intensity | 0.0573 /kWh | B |
| NorwayIEA Emission Factors 2024, national average generation intensity | 0.0290 /kWh | B |
| IcelandIEA Emission Factors 2024, national average generation intensity | 0.0280 /kWh | B |
| IrelandIEA Emission Factors 2024, national average generation intensity | 0.2790 /kWh | B |
| United KingdomUK DESNZ conversion factors 2024, generation only | 0.2070 /kWh | B |
| SpainIEA Emission Factors 2024, national average generation intensity | 0.1310 /kWh | B |
| PortugalIEA Emission Factors 2024, national average generation intensity | 0.1590 /kWh | B |
| EU 27 averageIEA Emission Factors 2024, EU aggregate | 0.2280 /kWh | C |
| CanadaIEA Emission Factors 2024, national average generation intensity | 0.1200 /kWh | B |
| United StatesIEA Emission Factors 2024, national average generation intensity | 0.3690 /kWh | C |
| ChileIEA Emission Factors 2024, national average generation intensity | 0.3230 /kWh | B |
| BrazilIEA Emission Factors 2024, national average generation intensity | 0.1060 /kWh | B |
| ChinaIEA Emission Factors 2024, national average generation intensity | 0.5810 /kWh | B |
| South KoreaIEA Emission Factors 2024, national average generation intensity | 0.4360 /kWh | B |
| JapanIEA Emission Factors 2024, national average generation intensity | 0.4620 /kWh | B |
| IndonesiaIEA Emission Factors 2024, national average generation intensity | 0.7600 /kWh | B |
| PhilippinesIEA Emission Factors 2024, national average generation intensity | 0.6120 /kWh | B |
| VietnamIEA Emission Factors 2024, national average generation intensity | 0.4700 /kWh | B |
| IndiaIEA Emission Factors 2024, national average generation intensity | 0.7130 /kWh | B |
| TanzaniaIEA Emission Factors 2024, national average generation intensity | 0.3410 /kWh | C |
| South AfricaIEA Emission Factors 2024, national average generation intensity | 0.9010 /kWh | B |
| MoroccoIEA Emission Factors 2024, national average generation intensity | 0.6290 /kWh | C |
| MauritiusIEA Emission Factors 2024, national average generation intensity | 0.8390 /kWh | C |
| Contractual renewable supplyMarket-based method, GHG Protocol Scope 2 Guidance. Requires contractual instruments on file | 0.0000 /kWh | C |
Freight
| Factor | Value | Grade |
|---|---|---|
| Sea freight, containerGLEC Framework v3.0 default, deep-sea container | 0.0160 /t-km | B |
| Sea freight, bulkGLEC Framework v3.0 default, dry bulk | 0.0080 /t-km | B |
| Rail freightGLEC Framework v3.0 default, European rail average | 0.0280 /t-km | B |
| Inland bargeGLEC Framework v3.0 default, inland waterway | 0.0330 /t-km | B |
| Road freight, heavy goodsGLEC Framework v3.0 default, >32t diesel truck | 0.0960 /t-km | B |
| Air freightGLEC Framework v3.0 default, long-haul belly freight | 0.6020 /t-km | B |
Packaging materials
| Factor | Value | Grade |
|---|---|---|
| Kraft multiwall paper sackPublished European kraft sack paper EPD range, mid-point | 1.1000 /kg | C |
| Corrugated boardPublished European corrugated board EPD range, mid-point | 0.9000 /kg | C |
| LDPE liner or filmPlastics Europe eco-profile, LDPE film grade resin | 2.0200 /kg | B |
| HDPE drum or pailPlastics Europe eco-profile, HDPE blow moulding grade | 1.9000 /kg | B |
| PP woven sackPlastics Europe eco-profile, PP resin plus conversion | 1.9500 /kg | B |
| Steel drumworldsteel LCI, cold-rolled coil plus forming | 2.6000 /kg | C |
| Aluminium foil laminateInternational Aluminium Institute LCI, primary foil stock | 8.6000 /kg | B |
| Glass jarPublished European container glass EPD range, mid-point | 1.2000 /kg | C |
| PET jar or bottlePlastics Europe eco-profile, bottle grade PET | 2.7000 /kg | B |
Fuels
| Factor | Value | Grade |
|---|---|---|
| Marine and vehicle diesel, combustionIPCC 2006 Guidelines Vol. 2 stationary and mobile combustion, AR6 GWP100 | 2.6800 /litre | B |
| Diesel, well-to-tankUK DESNZ conversion factors 2024, WTT diesel | 0.6400 /litre | B |
Process chemicals, cradle-to-gate per kg of reagent
| Factor | Value | Grade |
|---|---|---|
| Sodium carbonate, soda ashChemical-sector cradle-to-gate LCA for Solvay-process sodium carbonate, European market average | 1.2400 /kg | B |
| Sodium hydroxide, 100% basisChlor-alkali membrane-cell cradle-to-gate LCA, European market average | 1.1200 /kg | B |
| Potassium hydroxide, 100% basisChlor-alkali potassium route cradle-to-gate LCA, European market average | 1.9400 /kg | B |
| Hydrochloric acid, 100% basisChemical-sector cradle-to-gate LCA, by-product hydrochloric acid, European market average | 0.9000 /kg | B |
| Calcium chlorideChemical-sector cradle-to-gate LCA, Solvay by-product route | 0.8500 /kg | B |
| Citric acidFermentation-route citric acid cradle-to-gate LCA, European market average | 1.4000 /kg | B |
| Sodium hypochlorite, active chlorine basisChlor-alkali derivative cradle-to-gate LCA. Dose varies widely by plant, so graded C | 1.1000 /kg | C |
| Hydrogen peroxide, 100% basisAnthraquinone-process cradle-to-gate LCA, European market average | 1.0500 /kg | C |
| Ethanol, food grade, net of recoveryFermentation ethanol cradle-to-gate LCA. Only make-up volume is charged; recovery rate is plant-specific, so graded C | 1.6000 /kg | C |
| Isopropanol, net of recoveryPropylene-hydration isopropanol cradle-to-gate LCA. Only make-up volume is charged, so graded C | 1.8500 /kg | C |
| Protease enzyme concentratePublished industrial enzyme production LCA. The range is wide and dose is small; graded C | 12.0000 /kg | C |
| Diatomite and carbon filter aidMineral filter-aid cradle-to-gate LCA, calcined diatomaceous earth | 0.4500 /kg | C |
| Food-grade CO2, make-up for supercritical extractionRecovered and liquefied food-grade CO2 cradle-to-gate LCA. Recirculation loss only | 0.8300 /kg | C |
| Vegetable carrier oil, refinedRefined rapeseed oil cradle-to-gate LCA, European market average | 2.6000 /kg | B |
Allocated raw material burden
| Factor | Value | Grade |
|---|---|---|
| Fish skin, processing co-product, economic allocationPublished cod fishery and farmed tilapia LCA, economic allocation of the landed burden to skin. Under mass allocation the value is materially higher | 0.4200 /kg | C |
Extraction chemistry is not lumped into an amortised overhead. Where an ingredient is alkali-extracted, alcohol-precipitated or enzymatically hydrolysed, the reagent dose per kilogram of finished ingredient sits in the ingredient record and each reagent appears as its own line in the inventory. For hydrocolloids and hydrolysed proteins this block is usually the largest part of Scope 3, and a run that omits it reads far below the published literature range for the same product.
Land-based comparison set
| Whey protein concentratePublished dairy protein LCA range, mid-point. Category C. | 6.40 kgCO2e/kg |
| Pork protein mealPublished livestock LCA range, mid-point. Category C. | 7.20 kgCO2e/kg |
| Bovine collagen peptidePublished bovine hide and bone processing LCA range, mid-point. Category C. | 16.00 kgCO2e/kg |
The comparison set is a screening reference, Category C, and it is labelled as such wherever it appears. It exists because buyers ask the question, not because a marine ingredient and a land protein are the same product.
5. Ingredient records
12 ingredients carry a full factor set in Methodology 2026.2. Each record holds the biomass conversion ratio, the harvest fuel intensity, the cultivation input burden, the drying share of processing energy, the extraction reagent dose where the process uses one, and the biogenic uptake, with the literature range that bounds it. Every record’s default run now falls inside its own published range; where it did not, the model was wrong and was corrected, not the range.
| Species | Wet per kg | Range | Base grade |
|---|---|---|---|
| Laminaria digitataPublished European kelp LCA literature, mechanically dried powder, gross cradle-to-gate. | 8.5 kg | 0.55–3.10 | B |
| Saccharina latissimaPublished Northern European cultivated kelp LCA literature, gross cradle-to-gate. | 9.2 kg | 0.60–4.20 | B |
| Ascophyllum nodosumPublished Atlantic wrack LCA literature, hand-harvested dried meal, gross cradle-to-gate. | 4.4 kg | 0.40–2.60 | B |
| Fucus vesiculosusPublished intertidal brown algae LCA literature, thin evidence base, gross cradle-to-gate. | 4.8 kg | 0.42–2.90 | C |
| Undaria pinnatifidaPublished East Asian cultivated brown algae LCA literature, gross cradle-to-gate. | 8.8 kg | 1.10–5.40 | B |
| Kappaphycus alvareziiPublished tropical eucheumatoid LCA literature, sun-dried raw dried seaweed, gross cradle-to-gate. | 6.5 kg | 0.12–0.90 | B |
| Kappaphycus alvarezii and Eucheuma denticulatumPublished carrageenan process LCA literature, refined route, gross cradle-to-gate. | 22.0 kg | 4.20–13.50 | B |
| Laminaria hyperborea and Laminaria digitataPublished alginate extraction LCA literature, gross cradle-to-gate. | 28.0 kg | 4.80–15.20 | B |
| Chondrus crispusPublished red algae LCA literature, limited species-specific data, gross cradle-to-gate. | 5.6 kg | 0.45–3.40 | C |
| Arthrospira platensisPublished open-pond microalgae LCA literature, gross cradle-to-gate. | 55.0 kg | 5.50–22.00 | B |
| Haematococcus pluvialisPublished photobioreactor astaxanthin LCA literature, gross cradle-to-gate. | 480.0 kg | 55.00–220.00 | B |
| Gadus morhua and farmed Oreochromis niloticusPublished fish processing co-product LCA literature, economic allocation, gross cradle-to-gate. | 6.4 kg | 3.10–11.40 | C |
6. Changelog
Methodology 2026.2 — 27 August 2026
Extraction chemistry added as an explicit inventory block: 14 reagent factors, dosed per kilogram of finished ingredient and itemised one line per reagent, replacing the amortised lump that previously carried them. Allocated raw material burden added for fishery and aquaculture co-products, with the allocation rule stated on the line. Correction: sodium alginate, refined carrageenan, astaxanthin oleoresin and marine collagen peptide read below their own published literature ranges under 2026.1 because reagent manufacture was understated; the photobioreactor electricity default for astaxanthin and the raw skin conversion ratio for marine collagen were corrected in the same pass. No factors retired. No Reports were affected.
Methodology 2026.1 — 25 August 2026
First published version. 12 ingredient records, 24 grid factors, 6 freight factors, 9 packaging factors. Biogenic uptake reported separately from the first release. No factors retired.
When a factor changes, every affected Report is reissued with a version bump at no charge and every buyer of an affected Report is emailed the revised figure. The previous version stays available.
Author
Yoven Comorandy, founder, Bluecarbon Analytics, Mauritius. Corrections and disputes are answered by email, in person, and a dispute that turns out to be right becomes a version bump and a free reissue.
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