Carbon Removal (CDR) Calculator — Biochar, BECCS, DAC & Enhanced Weathering
Compute the durable net removal of a carbon-removal portfolio — gross captured CO2 minus the life-cycle emissions penalty, adjusted for a reversal buffer — across DAC, BECCS, biochar and enhanced weathering, with grid factors read live from the MasterBrain (DEFRA 2026, EPA eGRID 2023, Ember 2025).
What this engine computes — durable net removal, not gross. The hero figure is durable net removal in tCO2e: the gross MRV-certified quantity captured or stored, less the life-cycle emissions incurred to achieve it, less a user-set reversal buffer. Gross removal alone is not a removal claim — it is the top line before the two subtractions that determine whether the project removed carbon on a net basis at all.
Per-project formula. For each project the engine computes an electricity penalty (energy consumed × the location-based grid factor), adds any other reported emissions (transport, feedstock, thermal, MRV), subtracts both from gross to give net removal, and then applies the reversal buffer to net to give durable removal:
elecPenalty = electricity_kWh × gridEF ÷ 1000 (tCO2e)
penalties = elecPenalty + otherEmissions
net = gross − penalties
durable = net > 0 ? net × (1 − buffer ÷ 100) : 0
efficiency = net ÷ gross
The grid factor is read live per project. Electricity is the dominant penalty for direct air capture, so the engine reads the location-based grid emission factor from the MasterBrain by country (grid.<iso3>.electricity.location_based; the US resolves to the national row). Provenance is not uniform: GB is DEFRA 2026, the US is EPA eGRID 2023, and all other countries are Ember Yearly Electricity 2025. Each project stamps the exact grid row it read into the audit trail. If the grid row is unavailable the engine omits the electricity penalty and flags the net figure as optimistic rather than fabricating the largest single term.
The reversal buffer is the only tonne adjustment. Durable removal is net removal discounted by a user-set buffer (0–100%) representing non-permanence or reversal risk — the share of stored carbon that may return to the atmosphere. This mirrors the buffer-pool logic registries apply to nature-based and engineered credits. It is entered per project because reversal risk is project-specific, not pathway-generic.
Durability is a qualitative integrity layer, not a tonne multiplier. Each pathway carries a durability tier score (0–3) and a storage-duration label read from the MasterBrain — DAC 3 / ~1000 yr, BECCS 3 / >1000 yr, enhanced weathering 3 / >1000 yr, biochar 2 / ~100 yr+. The engine does not multiply tonnes by the durability score. Durability frames how long the stored carbon is expected to stay put; the reversal buffer is the mechanism that discounts the tonnes. Conflating the two — treating a “durability-weighted tonne” as if the score scaled the quantity — is a common accounting error this engine deliberately avoids.
Net-emitting exposure. When penalties exceed gross removal the net figure is negative, and the engine reports the negative net with a “net-emitting” flag rather than clamping it to zero. This is intentional: a grid-powered DAC unit on a high-carbon grid can consume more emissions in capture than it removes, and the tool is built to surface that rather than hide it. Durable removal floors at zero when net is negative (there is nothing durable to discount), but the negative net remains visible.
What is out of scope. This engine takes gross removal as user-entered MRV-certified activity data — it does not derive char yields, rock-weathering uptake, or biomass carbon fractions, because those ratios are not in the MasterBrain and fabricating them would corrupt the audit trail. Afforestation, soil-carbon and forestry removals follow land-sector accounting mechanics and belong in the AFOLU forestry removals calculator. Avoidance and reduction offsets are not removals at all — see the distinction below.
Location-based grid factor (MasterBrain). The electricity penalty scales with this — clean supply is decisive for engineered removal.
Gross = CO₂ captured/stored (MRV quantity). Electricity drives the grid penalty. Other = transport/feedstock/thermal/MRV as tCO₂e. Buffer = non-permanence deduction. Multiple rows = a blended portfolio.
Enter a removal project’s gross capture and energy use to calculate net durable removal
Results appear instantly. A gross → net → durable waterfall, a net-efficiency ratio, a permanence & integrity read, a per-project breakdown, and the full audit trail appear after calculation. Removals are reported as a separate line item — never netted against Scopes 1–3.
This is a net carbon-removal accounting aid, not an MRV certification, a credit rating, or purchasing advice. It computes durable net removal = gross CO₂ captured or stored, minus the project’s own electricity and lifecycle emissions, minus a reversal / non-permanence buffer. Gross removal is the quantity you enter (ideally MRV-certified); GreenCalculus does not measure, verify, or certify removal. The electricity penalty uses live MasterBrain location-based grid factors; durability and integrity framing is drawn from the Oxford Offsetting Principles taxonomy and is directional, not a quality score. The optional DAC cost line is an indicative reference band (USD, DAC only), not a transacted price — no reference band exists for biochar, BECCS or enhanced weathering, and none is fabricated. Removals are reported as a separate line item outside Scopes 1–3 and must never be netted against a gross emissions inventory; they neutralise the residual only after in-value-chain reductions (SBTi / GHG Protocol). Verify durable tonnes against a recognised removal protocol (e.g. Puro.earth, Isometric, the EU Carbon Removal Certification Framework, or ICVCM Core Carbon Principles) before making any claim.
Carbon removal is the part of climate accounting where the headline number lies most easily. A project can capture a thousand tonnes of CO2 and still be net-emitting once you count the electricity it burned to do it — and most removal marketing quotes the gross tonne, not the net one. The gap between those two numbers is where credibility is won or lost.
This calculator computes the number that survives an audit: durable net removal, gross minus the life-cycle penalty minus reversal risk.
Durable net removal = gross CO2 captured − life-cycle emissions (electricity + other) − reversal buffer. A grid-powered DAC unit removing 1,000 tCO2 on the UK grid nets ~593 t and ~533 t durable after a 10% buffer; on a high-carbon grid the same unit is net-emitting.
What this calculator computes — durable net removal
Three numbers matter in carbon removal, and only the third is a defensible claim: gross removal (what was captured), net removal (what was captured minus the emissions incurred to capture it), and durable removal (net, discounted for the risk that stored carbon reverses). This engine surfaces all three and leads with the last.
Gross vs net vs durable — the three numbers
Gross removal
The MRV-certified quantity of CO2 captured or stored, in tonnes. This is the top line and the one most removal marketing quotes. On its own it says nothing about whether the project removed carbon on a net basis — it is the number before the two subtractions that decide that.
Net removal
Gross minus the life-cycle emissions penalty: the electricity consumed (× the grid factor) plus any other reported emissions from transport, feedstock, thermal energy, or MRV activity. Net is the honest physical figure — what the project actually took out of the atmosphere after paying for the operation.
Durable removal
Net removal discounted by a reversal buffer — the share of stored carbon at risk of returning to the atmosphere. This is the hero figure, the number that belongs on a disclosure. Where net is negative, durable floors at zero: there is nothing durable to discount.
Removal is not avoidance and not reduction. A removal takes CO2 out of the atmosphere and stores it. An avoidance credit funds an activity that prevents emissions that would otherwise have occurred (avoided deforestation, a renewable plant displacing grid power) — the CO2 never leaves the atmosphere because it was never emitted. A reduction lowers your own emissions. These are three different ledgers. Netting an avoidance credit against a residual emission is not the same as neutralising it with a removal, and most net-zero standards now treat them separately. Avoidance accounting lives in the avoided emissions (“Scope 4”) calculator, governed by the WBCSD avoided-emissions guidance; this tool is removals only.
The four pathways in scope
The engine covers four durable, engineered or engineered-adjacent removal pathways: direct air capture (DAC), bioenergy with carbon capture and storage (BECCS), biochar, and enhanced rock weathering (ERW). Each is entered as a portfolio row with its own gross removal, energy use, other emissions and buffer. Afforestation, reforestation, soil-carbon sequestration and blue-carbon pathways are out of scope here — they follow land-sector removal mechanics under the GHG Protocol Land Sector and Removals Guidance and are handled by the forestry removals calculator.
Why net removal, not gross, is the honest unit
Every removal pathway spends energy and materials to move carbon from the atmosphere into storage. Direct air capture runs fans and regeneration heat; BECCS grows, transports and combusts biomass; biochar pyrolyses feedstock and hauls it; enhanced weathering mines, mills and spreads rock. Those inputs carry emissions. If the emissions incurred exceed the CO2 removed, the project is net-emitting — it made the problem worse while selling a removal.
The life-cycle penalty
The engine splits the penalty into two parts: an electricity penalty (energy consumed × the location-based grid factor for the project’s country) and an “other emissions” line the user enters directly for non-electricity life-cycle burdens — feedstock cultivation, transport, thermal energy, sorbent production, MRV. Electricity is broken out and computed from live grid factors because it is the dominant, most grid-sensitive term, especially for DAC. Everything else is user-supplied activity data.
When a removal project is net-emitting
This is the calculator’s central lesson, and it is easiest to see by holding one DAC project fixed and moving it across grids. Take the default worked-example DAC unit — gross 1,000 tCO2, 2,500,000 kWh of electricity, 80 tCO2e of other emissions, a 10% reversal buffer — and read the grid factor from a different country each time. Net removal is 920 tonnes (gross minus the 80 t other) minus the electricity penalty, which is 2,500 MWh × the grid factor. The result swings from a strong removal to net-emitting depending on nothing but where the electrons come from:
| Grid | Grid factor (kg CO₂e/kWh) | Electricity penalty (tCO₂e) | Net removal (tCO₂e) | Net efficiency | Durable (10% buffer) |
|---|---|---|---|---|---|
| Iceland | 0.02782 | 69.6 | 850.4 | 85.0% | 765.4 |
| Norway | 0.02811 | 70.3 | 849.7 | 85.0% | 764.7 |
| France | 0.04144 | 103.6 | 816.4 | 81.6% | 734.8 |
| United Kingdom | 0.13096 | 327.4 | 592.6 | 59.3% | 533.3 |
| Germany | 0.32965 | 824.1 | 95.9 | 9.6% | 86.3 |
| United States (national) | 0.349667 | 874.2 | 45.8 | 4.6% | 41.2 |
| Australia | 0.52518 | 1,312.9 | −392.9 | net-emitting | 0 |
| China | 0.52649 | 1,316.2 | −396.2 | net-emitting | 0 |
| India | 0.67013 | 1,675.3 | −755.3 | net-emitting | 0 |
Grid factors read live from the MasterBrain, location-based. Provenance is per-row: United Kingdom is DEFRA 2026, United States is EPA eGRID 2023, all other countries are Ember Yearly Electricity 2025. The calculator stamps the exact grid row read into each project’s audit trail rather than attributing the whole table to one source.
The same DAC unit is a strong removal in Iceland and net-emitting in India. Nothing changed but the grid factor.
A gross-tonne removal claim is meaningless without the grid it ran on. Marketing that quotes “1,000 tonnes removed” while running direct air capture on a coal-heavy grid can be describing a net-emitting operation. Always compute net removal against the actual location-based grid factor, and disclose the grid you assumed. If the engine cannot find the grid row it omits the electricity penalty and flags the net figure as optimistic — treat any flagged figure as an upper bound, not a result.
Grid sensitivity is a DAC problem first
The table above is a DAC unit because DAC is where the electricity penalty dominates — thousands of kWh per tonne captured. Biochar, by contrast, uses relatively little grid electricity (its energy comes largely from the pyrolysis process itself), so its net efficiency is far less grid-sensitive, as the worked example shows. BECCS and enhanced weathering sit between the two depending on how much of their energy is grid-drawn versus process-derived. The general rule holds regardless of pathway: the more grid electricity a removal consumes per tonne, the more its net figure depends on decarbonising the grid it runs on.
How the calculation works
Each portfolio row reduces to one chain of arithmetic, run per project and then summed:
elecPenalty = electricity (kWh) × grid factor ÷ 1,000 → penalties = elecPenalty + other emissions → net = gross − penalties → durable = net > 0 ? net × (1 − buffer%) : 0
The ÷ 1,000 converts the kg-per-kWh grid factor to tonnes. Net efficiency is net ÷ gross, expressed as a percentage — the share of the gross tonne that survives the life-cycle penalty. At the portfolio level the engine sums gross, net and durable across all rows, and computes portfolio efficiency as total net ÷ total gross.
The reversal buffer
The buffer is a per-project percentage (0–100, clamped) that discounts net removal for non-permanence risk — the possibility that stored carbon returns to the atmosphere through combustion, decomposition, dissolution, or leakage. It is the calculator’s only mechanism for adjusting the tonne count downward for permanence, and it mirrors the buffer-pool reserves that carbon registries hold against reversal. A pure geological-storage DAC project might carry a low buffer; a biochar project applied to soil might carry a higher one to reflect the fraction expected to mineralise over a century. The buffer is entered, not derived — reversal risk is project-specific and the engine does not assume a pathway default.
Keep the buffer and the “other emissions” line conceptually separate. Other emissions are life-cycle emissions that already happened during the removal operation and reduce net. The buffer is a forward-looking risk discount on carbon that is currently stored but might reverse, and it reduces durable. Double-counting a reversal risk as an upfront emission, or vice versa, distorts both figures.
Portfolio rollup
Beyond the summed tonnes, the engine reports portfolio net efficiency and a durable-weighted mean durability score across rows, and — in the audit view — a grid-sensitivity line showing what net efficiency would be on a clean grid (gross minus other, over gross), isolating the electricity penalty’s contribution. That clean-grid line is the quickest way to see how much of a project’s inefficiency is the grid versus the rest of its life cycle.
Durability — the qualitative integrity layer
Durability answers a different question from net removal. Net removal asks how much carbon the project took out; durability asks how long it will stay out. A tonne stored in stable mineral form for a thousand years and a tonne stored in soil biochar for a century are both one net tonne removed — but they are not equivalent climate assets, and durability is how the difference is communicated.
The tier model
| Pathway | Durability score (0–3) | Expected storage duration | Storage mechanism |
|---|---|---|---|
| DAC (with geological storage) | 3 | ~1,000 yr | CO₂ injected into stable geological formations |
| BECCS | 3 | >1,000 yr | Biogenic CO₂ captured and geologically stored |
| Enhanced rock weathering | 3 | >1,000 yr | CO₂ mineralised as stable carbonates / bicarbonate in solution |
| Biochar | 2 | ~100 yr+ | Recalcitrant carbon in charred biomass, applied to soil |
The scores and labels are read from the MasterBrain, and the engine carries an in-code fallback mirroring these live values so the durability layer still renders if the MasterBrain row is briefly unavailable. The score is directional integrity framing — it is not a quality grade and it is not blended into a single “credit rating”.
Durability is a chip and a flag, never a tonne multiplier. The engine does not multiply net removal by the durability score — a biochar project scored 2 is not counted as two-thirds of a tonne. The only downward adjustment to the tonne count is the reversal buffer, which the user sets explicitly. This is a deliberate design choice: implying a “durability-weighted tonne” by scaling quantity with the score would fabricate a discount the accounting standards do not endorse and would double-count with the buffer. Durability tells the reader how long the carbon stays put; the buffer discounts the tonnes for the risk it does not.
The four CDR pathways compared
The four pathways differ in their storage mechanism, their durability, where their life-cycle emissions concentrate, and how mature their measurement and verification is. The comparison below is framed around the variables this calculator computes — durability tier and the dominant life-cycle penalty — rather than a cost-per-tonne league table, because cost data exists for only one pathway in the MasterBrain (see the cost section).
| Pathway | Mechanism | Durability | Dominant life-cycle penalty | MRV maturity | Cost band in MB |
|---|---|---|---|---|---|
| DAC Direct air capture |
Sorbents/solvents pull CO₂ directly from ambient air; captured CO₂ is geologically stored | Score 3 · ~1,000 yr | Electricity + regeneration heat — highly grid-sensitive | High — metered capture and injection volumes | USD 500 / 750 / 1,000 (low/central/high) |
| BECCS Bioenergy with CCS |
Biomass combusted for energy; biogenic CO₂ captured at the flue and geologically stored | Score 3 · >1,000 yr | Biomass sourcing, land use and transport — feedstock-dependent | Medium–high — capture metered; feedstock accounting contested | No band — not shown |
| Biochar Pyrolysed biomass |
Biomass pyrolysed into recalcitrant carbon and applied to soil | Score 2 · ~100 yr+ | Feedstock transport and pyrolysis energy — modest grid draw | Medium — carbon-fraction and permanence assumptions vary | No band — not shown |
| ERW Enhanced weathering |
Silicate rock milled and spread; CO₂ mineralised via natural weathering | Score 3 · >1,000 yr | Mining, milling and spreading — plus slow, hard-to-verify uptake | Emerging — uptake measurement is the open MRV problem | No band — not shown |
DAC — the grid-sensitivity case
The most durable and most measurable pathway, but the most exposed to its energy source. Every tonne captured costs thousands of kWh; on a clean grid DAC nets most of its gross, on a dirty grid it can go net-emitting (see the grid table). Site DAC where the grid is decarbonised, or pair it with dedicated renewables, and the net figure follows.
BECCS — the feedstock question
Durable and measurable at the capture point, but its integrity turns on the biomass. Sustainably-sourced residues make BECCS a strong removal; purpose-grown biomass on cleared land can erase the benefit through land-use emissions the “other emissions” line must capture. The pathway is only as good as its feedstock accounting.
Biochar — the near-term workhorse
Lower durability (~100 yr+, score 2) but the most deployable today, with modest energy penalties and high net efficiency. Its open questions are the carbon fraction that stays recalcitrant and the buffer that reflects soil-application reversal. Enter a buffer that matches the permanence evidence for the specific char and application.
Enhanced weathering — the measurement frontier
Highly durable in principle (mineralised carbonates, >1,000 yr) but the hardest to verify: the CO₂ uptake happens slowly across soils and waterways where measurement is genuinely difficult. Treat gross figures for ERW as the MRV-certified quantity only, and note that verification methodologies are still maturing.
Worked example — a DAC + biochar portfolio
This example is the calculator’s default seed — it renders identically the moment the page loads, so the figures below reconcile exactly against the live tool. The portfolio runs on the UK grid (DEFRA 2026, 0.13096 kg CO2e/kWh) with the currency set to USD. Two projects: a grid-heavy DAC unit and a low-energy biochar project.
| Project | Pathway | Gross (tCO₂) | Electricity (kWh) | Other emissions (tCO₂e) | Buffer |
|---|---|---|---|---|---|
| Project 1 | DAC | 1,000 | 2,500,000 | 80 | 10% |
| Project 2 | Biochar | 500 | 30,000 | 60 | 20% |
Project-by-project arithmetic
DAC. Electricity penalty = 2,500,000 kWh × 0.13096 ÷ 1,000 = 327.4 tCO2e. Penalties = 327.4 + 80 = 407.4. Net = 1,000 − 407.4 = 592.6 tCO2e. Durable = 592.6 × (1 − 0.10) = 533.3 tCO2e. Net efficiency = 592.6 ÷ 1,000 = 59.3%. The electricity penalty alone consumes nearly a third of the gross tonne — the signature of grid-powered DAC.
Biochar. Electricity penalty = 30,000 kWh × 0.13096 ÷ 1,000 = 3.9 tCO2e. Penalties = 3.9 + 60 = 63.9. Net = 500 − 63.9 = 436.1 tCO2e. Durable = 436.1 × (1 − 0.20) = 348.9 tCO2e. Net efficiency = 436.1 ÷ 500 = 87.2%. The electricity term is trivial; the biochar’s penalty is almost entirely its “other emissions” (feedstock and transport), and its higher 20% buffer reflects soil-application reversal risk.
| Project | Elec penalty (tCO₂e) | Net (tCO₂e) | Net efficiency | Buffer | Durable (tCO₂e) |
|---|---|---|---|---|---|
| DAC | 327.4 | 592.6 | 59.3% | 10% | 533.3 |
| Biochar | 3.9 | 436.1 | 87.2% | 20% | 348.9 |
| Portfolio | — | 1,028.7 | 68.6% | — | 882.2 |
Portfolio rollup
The portfolio removed 1,500 gross tonnes but only 882.2 durable net tonnes — 41% of the gross figure evaporated into life-cycle penalties and reversal buffers. That gap is exactly what a gross-tonne headline hides. The cost band applies only to the durable DAC tonnes and only because DAC is the sole pathway with a MasterBrain cost band; it is indicative, not a transaction price (see below).
What DAC costs today — indicative only
Cost is a minor output of this engine, not its purpose, and it is deliberately narrow. The MasterBrain carries one cost band, for direct air capture only: USD 500 (low), 750 (central), 1,000 (high) per durable tonne, vintage 2025, sourced from the CDR.fyi DAC market snapshot. The cost line appears only when the currency is set to USD and the portfolio contains durable DAC tonnes — it multiplies the durable DAC quantity by the band, nothing more.
No cost is shown for BECCS, biochar or enhanced weathering, because no cost band for them exists in the MasterBrain and the engine does not fabricate one. Do not read the absence of a biochar or BECCS price as those pathways being free or unpriced in the market — it means this tool has no verified band to display. The DAC figure itself is an indicative market reference, not a quote: real contracts vary by offtake structure, delivery year, storage geology and volume. For decision-grade cost comparison across abatement options, use the marginal abatement cost calculator, and for offset pricing more broadly the carbon offset cost calculator.
MRV, standards and credit quality
The gross removal figure this calculator consumes is only as trustworthy as the measurement, reporting and verification (MRV) behind it. A durable net removal computed from an unverified gross number is precise arithmetic on a soft input. This section covers the standards and registries that make a gross figure defensible — the layer that decides whether the tonne you entered is real.
Registries and methodologies
Engineered and hybrid removals are certified under methodologies published by carbon-crediting programmes. The Verra VCS and Gold Standard programmes carry removal methodologies alongside their larger avoidance catalogues, and specialist registries publish durable-CDR methodologies for biochar, DAC, BECCS and enhanced weathering. Each methodology defines how gross removal is quantified, how life-cycle emissions are bounded, and how permanence is treated — which is precisely the information you need to populate the gross, other-emissions and buffer fields honestly.
The GHG Protocol removals accounting frame
At the corporate-inventory level, the GHG Protocol Land Sector and Removals Guidance sets how removals are accounted and reported inside a GHG inventory — separately from gross emissions, never netted silently into a single number. That separation is the same discipline this calculator enforces at the project level: removals are their own line, and a removal does not cancel an emission without an explicit, like-for-like accounting decision.
Credit quality — ICVCM and VCMI
Two initiatives govern quality on the two sides of the market. The ICVCM Core Carbon Principles set a supply-side quality threshold — additionality, robust quantification, permanence and no double-counting — that a credit must meet to be labelled high-integrity. The VCMI Claims Code of Practice governs the demand side: what a company may credibly claim after buying credits. Together they frame whether a removal you have quantified can be used in a public claim, and how.
Permanence and reversal are a registry-level accounting problem, not just a project-level one. Registries hold buffer pools — reserves of unsold credits — to cover reversals across their portfolios, which is the collective analogue of the per-project reversal buffer this calculator applies. When you set the buffer field, you are estimating the same non-permanence risk the registry prices into its pool. A buffer of zero asserts the stored carbon cannot reverse; for anything short of stable geological or mineral storage, that assertion needs evidence.
How CDR fits a net-zero strategy
Carbon removal has a specific, bounded role in a credible net-zero plan: it neutralises the residual emissions that remain after deep reductions, not the emissions you could have cut. Buying removals in place of reducing is the failure mode every serious standard is built to prevent.
The residual-emissions-only rule
Under the SBTi Corporate Net-Zero Standard, a company reaches net zero by reducing emissions across its value chain by the science-aligned amount — typically ~90% — and then neutralising only the small residual with durable removals. Removals are the last mile, not a substitute for the reductions. A removal portfolio that grows while gross emissions stay flat is not a net-zero strategy; it is compensation dressed as one. Sequence the work with the net-zero pathway calculator before sizing a removal budget.
Neutralisation and compensation are different claims. Neutralisation counters your residual emissions with durable removals inside a net-zero framework — like-for-like, ideally matching the durability of the emission. Compensation is using any credit (including avoidance) to offset emissions outside that framework. The ISO 14068-1 carbon neutrality standard and the ISO 14068 calculator formalise the distinction; this tool produces the durable-removal quantity that a neutralisation claim requires.
Insetting versus offsetting
Where the removal happens matters for the claim. Insetting funds removals or reductions inside your own value chain; offsetting funds them outside it. Durable CDR can serve either, but the accounting treatment and the strength of the claim differ. The insetting versus offsetting calculator works through which treatment applies to a given project, and the durable net removal figure from this tool is the input either way.
Removals neutralise the residual you could not eliminate. They are the last 10%, not a licence to skip the first 90%.
Data sources, factor versioning and update transparency
The engine reads live factors from the MasterBrain and takes everything else as user-entered activity data. This section documents what comes from where, because the provenance is not uniform across the grid factors — a point that matters when you cite a net removal figure.
Grid emission factors — three sources, per row
The electricity penalty is the only term the engine computes from a live factor, read as the location-based grid emission factor for the project’s country. The source depends on the country, and the calculator stamps the exact row it read into the audit trail:
| Geography | Source | Vintage | Basis |
|---|---|---|---|
| United Kingdom | DEFRA / DESNZ conversion factors | 2026 | Location-based, kg CO₂e/kWh |
| United States (national + eGRID subregions) | EPA eGRID | 2023 | Location-based, kg CO₂e/kWh |
| All other countries | Ember Yearly Electricity | 2025 | Location-based, kg CO₂e/kWh |
Because the three sources carry different GWP conventions internally, the calculator does not blend them into a single stated basis — each project’s net figure inherits the basis of the grid row it read, and the audit trail records which. A custom grid factor field is available (entered in g CO2/kWh) for jurisdictions or dedicated-supply arrangements not covered by the country list. Full grid factor reference is on the grid electricity emission factors data page.
Durability tiers and the DAC cost band
The pathway durability scores and labels are read from the MasterBrain, with an in-engine fallback mirroring the live values for cache safety. The DAC cost band (USD 500 / 750 / 1,000, vintage 2025) is sourced from the CDR.fyi DAC market snapshot and is the only cost data the engine carries — there is no fallback for it, and the cost line simply does not render if the band is absent. Gross removal, electricity consumption, other emissions and the reversal buffer are all user-entered MRV-derived activity data; the engine holds no database of project removals and does not estimate them.
Versioning
Grid factors update on their source cadences — DEFRA annually, eGRID on a multi-year cycle, Ember yearly — and the calculator stamps each result with the MasterBrain version it computed against, so a figure produced today and the same inputs run after a factor refresh are distinguishable in restatement work. The worked example and grid-sensitivity table on this page are hardcoded audit records: they reflect the factor vintages named and will not move when the live MasterBrain updates, by design, so their arithmetic always reconciles.
Frequently asked questions
Gross removal is the MRV-certified quantity of CO₂ captured. Net removal is gross minus the life-cycle emissions incurred to capture it — the electricity penalty (energy × grid factor) plus other reported emissions like transport and feedstock. Durable removal is net discounted by a reversal buffer, the share of stored carbon at risk of returning to the atmosphere. Only durable net removal is a defensible disclosure figure; gross alone says nothing about whether the project removed carbon on a net basis. This calculator leads with durable net removal.
Yes, and the calculator is built to surface it. If the emissions incurred to run a removal — mainly electricity on a high-carbon grid — exceed the CO₂ captured, net removal is negative and the tool reports it with a “net-emitting” flag rather than clamping to zero. The clearest case is grid-powered direct air capture: the default DAC unit that nets 593 tonnes on the UK grid is net-emitting on the Australian, Chinese or Indian grid, because the electricity penalty alone exceeds the gross tonnes captured. A gross-tonne removal claim on a dirty grid can describe an operation that made emissions worse.
No. A removal physically takes CO₂ out of the atmosphere and stores it. Most offsets are avoidance credits — they fund an activity that prevents emissions that would otherwise have occurred, so no CO₂ ever leaves the atmosphere. The two are different ledgers, and most net-zero standards now treat them separately: a durable removal can neutralise a residual emission, whereas an avoidance credit compensates for one without removing it. This calculator handles removals only; avoidance accounting is a separate tool.
No. The durability score (0–3) and its storage-duration label are qualitative integrity framing — they tell you how long the carbon is expected to stay stored, but the engine never multiplies net removal by the score. A biochar project scored 2 is not counted as two-thirds of a tonne. The only downward adjustment to the tonne count is the reversal buffer, which you set explicitly per project. Treating a “durability-weighted tonne” as if the score scaled the quantity would double-count with the buffer and fabricate a discount the accounting standards do not endorse.
The buffer (0–100%) is the share of stored carbon at risk of returning to the atmosphere, and it is project-specific — the engine does not assume a pathway default. Stable geological or mineral storage (DAC with injection, enhanced weathering) carries low reversal risk and a low buffer. Biochar applied to soil carries a higher buffer to reflect the fraction expected to mineralise over its ~100-year storage window. Base the figure on the certifying methodology’s permanence treatment and the registry buffer-pool logic, not a guess. A buffer of zero asserts the carbon cannot reverse, which needs evidence for anything short of permanent storage.
Because electricity is the dominant life-cycle penalty for energy-intensive removals, especially direct air capture, and the engine computes the electricity penalty from the live location-based grid factor for the project’s country. The same DAC unit consuming 2,500,000 kWh incurs a 69.6-tonne penalty on the Icelandic grid and a 1,675-tonne penalty on the Indian grid — the difference between a strong removal and a net-emitting one. This is why removal claims must state the grid they assume, and why siting energy-intensive removal on a decarbonised grid (or pairing it with dedicated renewables) is decisive for the net figure.
The MasterBrain carries one indicative DAC cost band — USD 500 (low), 750 (central), 1,000 (high) per durable tonne, vintage 2025, from the CDR.fyi market snapshot. The calculator shows this only when the currency is USD and the portfolio has durable DAC tonnes, and it is an indicative market reference, not a transaction price: real contracts vary by offtake structure, delivery year, storage geology and volume. No cost band exists for BECCS, biochar or enhanced weathering, and the engine does not fabricate one — the absence of a price for those pathways reflects the tool’s data coverage, not a market judgement.
DAC with geological storage, BECCS and enhanced weathering all carry the top durability tier (score 3), with expected storage of roughly a thousand years or more — CO₂ held in stable geological formations or mineralised as carbonates. Biochar is one tier lower (score 2, ~100 years+), storing recalcitrant carbon in soil over a century-plus window. Durability is not the whole story, though: enhanced weathering is highly durable in principle but the hardest to verify, while DAC is both durable and highly measurable but the most exposed to its grid. Weigh durability against MRV maturity and net efficiency together.
No. This tool covers durable engineered and engineered-adjacent pathways — DAC, BECCS, biochar and enhanced weathering. Afforestation, reforestation, soil-carbon sequestration and blue-carbon pathways follow land-sector removal mechanics under the GHG Protocol Land Sector and Removals Guidance and are handled by the AFOLU forestry removals calculator. The distinction matters because nature-based removals have different permanence profiles, measurement methods and reversal risks than the geological and mineral storage this engine assumes.
Removals neutralise the residual emissions that remain after deep reductions — the last mile, not a substitute for cutting emissions. Under the SBTi Corporate Net-Zero Standard a company reduces value-chain emissions by the science-aligned amount (typically around 90%) and neutralises only the small residual with durable removals. A removal portfolio that grows while gross emissions stay flat is compensation dressed as a net-zero strategy, not the real thing. Size your reduction pathway first, then use the durable net removal figure from this tool to quantify what is needed to neutralise the residual.
On the supply side, the ICVCM Core Carbon Principles set the threshold: additionality, robust and conservative quantification, durable permanence with reversal provisions, and no double-counting. On the demand side, the VCMI Claims Code of Practice governs what a buyer can credibly claim after purchase. A defensible removal also has transparent MRV — a certifying methodology that defines how gross removal was measured, how life-cycle emissions were bounded, and how permanence is treated. The durable net removal this calculator computes is only as sound as the MRV behind the gross figure you enter.
Methodology notes and limitations
Net-removal accounting engine. The hero output is durable net removal in tCO2e — gross MRV-certified capture, less the life-cycle emissions penalty, less a user-set reversal buffer. Gross removal is entered directly as user activity data; the engine does not derive it from char yields, rock-weathering uptake ratios, or biomass carbon fractions, because those ratios are not carried in the MasterBrain and estimating them would corrupt the audit trail.
Pathways in scope. DAC, BECCS, biochar and enhanced rock weathering only. Afforestation, reforestation, soil-carbon and blue-carbon removals follow land-sector mechanics and belong in the AFOLU forestry removals calculator. Avoidance and reduction are not removals and are out of scope.
Electricity penalty and grid factors. The electricity penalty is the only term computed from a live factor: energy consumed × the location-based grid factor for the project’s country, read from the MasterBrain (grid.<iso3>.electricity.location_based; US resolves to the national row). Provenance is per-row — GB DEFRA 2026, US EPA eGRID 2023, all others Ember 2025 — and is stamped into each project’s audit trail. If the grid row is unavailable the engine omits the electricity penalty and flags the net figure as optimistic rather than fabricating the dominant term. A custom grid factor (g CO2/kWh) can be entered for uncovered jurisdictions or dedicated supply.
Other emissions taken as entered. The “other emissions” line — transport, feedstock, thermal, sorbent production, MRV — is user-supplied tCO2e activity data. The engine does not compute it from a life-cycle library; the user is responsible for sourcing it from the certifying methodology or a project LCA.
The reversal buffer is the only tonne adjustment. Durable removal is net × (1 − buffer%). The buffer is user-set per project (0–100%, clamped) and represents non-permanence risk. Where net is negative, durable floors at zero and the negative net remains visible with a net-emitting flag — a deliberate greenwashing-exposure feature, not an error state.
Durability is qualitative. The pathway durability score (0–3) and storage-duration label are read from the MasterBrain (with an in-engine fallback mirroring the live values) and are directional integrity framing only. The engine does not multiply tonnes by the durability score, and does not output a “durability-adjusted tonne”. The score describes expected storage duration; the reversal buffer discounts the tonnes.
Cost is indicative and DAC-only. The single MasterBrain cost band (USD 500 / 750 / 1,000 per durable tonne, vintage 2025, CDR.fyi) applies only to durable DAC tonnes and renders only when the currency is USD. It is an indicative market reference, not a transacted price, and no band exists or is fabricated for BECCS, biochar or enhanced weathering. The engine performs no FX conversion for the cost line.
No auto-scaling in v1. Unlike the PCAF calculators, this engine does not auto-scale to ktCO2e at ≥10,000 tonnes — all figures display in tCO2e. Worked-example and grid-table figures on this page are hardcoded audit records reflecting the named factor vintages; they will not move when the live MasterBrain updates, so their arithmetic always reconciles.
No assurance opinion. Results are estimates for screening and disclosure preparation. They do not constitute a verification opinion and should be reviewed by a qualified practitioner before use in a public claim, a net-zero disclosure, or a credit transaction. The durable net removal figure is only as sound as the MRV behind the gross figure entered — quantify the gross tonne under a recognised methodology (Verra VCS, Gold Standard, or a specialist durable-CDR registry) before relying on the net result.