Avoided emissions: how do you get a calculation for investors reviewed?

The avoided emissions of a solution are the difference between the emissions of a scenario in which it is used and those of a baseline scenario in which it is not. For a start-up selling heat pumps, energy efficiency software or recycled material, this figure of "avoided tonnes" often ends up in a pitch or an impact report. It is calculated on assumptions that nobody will ever be able to observe, which is why an investor asks for it to be reviewed.

The example above, constructed for this article, shows what is at stake: the same 1,000 heat pumps display a figure almost 40 times larger depending on 4 calculation choices. The following sections take these choices one by one, then the review itself.

1What are avoided emissions, and why have them reviewed?

The WBCSD guide, published by the World Business Council for Sustainable Development, defines them as the difference in emissions over the whole life cycle between a scenario with the solution and a baseline scenario without it. The baseline describes the most likely situation without the solution. Loft insulation, software that optimises shipping routes or animal feed that reduces methane from cows can all generate them, provided this is demonstrated.

What they are not

Avoided emissions occur at other parties: at the customer heating their home, at the haulier driving fewer kilometres. They do nothing to reduce the carbon footprint of the company selling the solution, and that footprint may even rise with its sales. The published frameworks draw 3 rules from this:

• They are never subtracted from the company's emissions: ADEME (the French Agency for Ecological Transition) states that the sum of the emissions in a GHG emissions report and the avoided emissions must not be used under any circumstances.
• They are not a reduction in the company's emissions, which is measured year on year across its scopes 1, 2 and 3.
• They are not offsetting and do not support any claim of carbon neutrality or "net zero", a prohibition written into the WBCSD guide.

The rule is the same as for CO2 capture in a carbon footprint: what is not an emission of the company is reported separately, never as a deduction.

Why an investor asks for it

A fund that finances climate solutions reports on their effect to its own investors, alongside its financed emissions. The avoided tonnes of its portfolio companies are the most telling indicator, and the most fragile, since each company chooses its own baseline. To harmonise practice, Robeco, Mirova and Edmond de Rothschild AM launched in April 2025, with 2 consultancies, a shared platform of avoidance factors for 65 climate solutions.

Having the figure reviewed first protects the fund's own communication: a fund that repeats overstated tonnes faces the same accusation of greenwashing as the company. The review also shows whether the gap between the solution and its baseline remains clear under more conservative assumptions, which the WBCSD calls a significant contribution.

2Which methods are recognised for calculating avoided emissions?

No law and no ISO standard sets out how to calculate the avoided emissions of a product. One international standard has covered them since January 2026, IEC 63372, but only for electrical and electronic products. For everything else, the reviewer uses a voluntary guide as the reference grid, the WBCSD guide, together with the French frameworks around it.

The WBCSD guide, revised in July 2025

The WBCSD published its guide in March 2023, which was cited the following month in the communiqué of the G7 ministers meeting in Sapporo, then a revised version in July 2025, after a public consultation launched at COP29. It sets 3 conditions to be met before calculating anything, which it calls "gates":

• The credibility of the company: it publishes its emissions inventory and targets aligned with 1.5°C. For a start-up or an SME, a recent inventory of scopes 1, 2 and 3 is enough.
• The alignment of the solution with climate science: it is among the levers recognised by the IPCC (Intergovernmental Panel on Climate Change), the EU taxonomy or an equivalent framework, and it is not used to extract, produce, transport or sell fossil fuels.
• The legitimacy of the contribution: the emissions reduction is measurable, large enough to withstand the uncertainties, and linked to the solution by a demonstrated cause-and-effect relationship.

The calculation then follows 5 steps: choose the period, define the baseline, calculate the life cycle emissions of the 2 scenarios, take the difference, then check gate 3 again. The guide requires recalculation every 2 to 3 years, and every 5 years at the latest. It also asks companies to publish the share of turnover represented by the solutions concerned, so that a single product range is not mistaken for the whole company.

The French frameworks and the GHG Protocol

In France, ADEME's technical sheet of January 2020 accepts avoided emissions only if the organisation has first acted on its own emissions. The Pillar B Guide of the Net Zero Initiative, published in June 2022, requires every figure to be accompanied by the share of sales it represents.

In January 2019 the GHG Protocol published a working paper on the comparative impacts of products: a company that publishes such impacts must also publish its full inventory, as for a carbon footprint under the GHG Protocol. The table below sets the 4 texts side by side on the points a reviewer checks.

Investor frameworks

Venture capital investors have their own tool, the Project Frame methodology of December 2024, which estimates the climate impact of a start-up before the investment, on sales that are still to come. The WBCSD guide, limited to solutions already sold or installed, refers to it for projections. Their joint guide of June 2025 describes these as directional estimates, more credible once validated by a third party.

What SFDR and the CSRD say

The EU Sustainable Finance Disclosure Regulation, known as SFDR, requires funds to report indicators on the emissions of their portfolio companies, but no avoided emissions indicator. On the corporate side, the climate standard of the Corporate Sustainability Reporting Directive (CSRD) requires gross reduction targets, without avoided emissions, a rule carried over into the simplified standards of July 2026. The figure remains voluntary information, hence the value of having it reviewed.

3Where does an avoided emissions calculation break down?

Avoided emissions calculations almost always break down on the same assumptions: the baseline, the period, the share claimed, the rebound effect and the emission factors. Each sector has one that is more fragile than the others, as the 5 cases below show.

The baseline scenario

The baseline is hypothetical: the WBCSD guide acknowledges that it cannot be proven, and ADEME describes it as a fictitious scenario that is bound to be a combination of assumptions. The WBCSD gives a rule for choosing it according to the situation:

• For new demand, a new building for example, the baseline is the average solution sold in the same year, in the same region, for the same function.
• For a broken-down boiler replaced by a heat pump, the baseline is the average of that year's sales, heat pumps included, not the old boiler.
• For an improvement that no regulation requires, such as insulation, the baseline is the average market solution; keeping the previous situation can be justified by proof that nothing would have been done.

ADEME goes further in its caution: it recommends taking the best available technologies as the default baseline, which reduces the tonnes displayed even further. When a regulation mandates the change, the baseline follows the regulation, and the tonnes stop being claimed on the date the text applies to everyone.

Period and volume

The guide accepts 2 ways of counting: each year, the tonnes avoided by the solutions in service, or from the year of sale, those avoided over their whole lifetime. For an air-to-water heat pump, this lifetime is 17 years according to its French energy savings certificate (CEE) sheet. A pitch that places the 17-year total next to the year's turnover mixes up the 2.

Claimed share and double counting

An installed heat pump involves a manufacturer, an installer and sometimes a platform that found the customer. If each of them publishes the same tonnes, a fund that holds 2 of these companies counts the same tonnes 2 times over. The frameworks handle this sharing differently, with ADEME going as far as rejecting it in favour of a simple "contribution". ADEME, the WBCSD and the GHG Protocol ask for the figure to be presented as the effort of the whole chain. The Net Zero Initiative, by contrast, accepts this double count, as in scope 3. A fund must therefore never add up the tonnes of 2 portfolio companies in the same chain.

The rebound effect

A house that is better heated for the same price gets heated more: this is the rebound effect. According to the report by RTE (France's electricity transmission system operator) and ADEME on heating in buildings, the theoretical gain from insulation or a heat pump is generally not observed in practice. For a shallow renovation, the report uses a rebound of 10 to 30% relative to expected consumption. The WBCSD guide asks for this direct rebound to be included, or at least for the calculation to state whether it has been identified.

4Who can review the calculation, and what does the review attest?

The WBCSD guide recommends a third-party review, especially when the figure is published, under ISO 14071, the standard for the critical review of a life cycle assessment. The French method for greenhouse gas emissions reports, which governs France's mandatory greenhouse gas emissions report, recommends a critical review for every calculation of avoided emissions.

The 3 forms of review

Depending on how the figure is used, 3 forms of review coexist, from the lightest to the most formal, and the report below shows what a review delivers:

• A reading by an independent expert, with no prescribed standard, delivers a written opinion on the method, the assumptions and the calculations, which is often sufficient for investor due diligence.
• A critical review, recommended by ADEME within the meaning of ISO 14044 and by the WBCSD under ISO 14071, in which an expert or a panel delivers a review report attached to the calculation.
• Verification of a greenhouse gas statement under ISO 14064-3, by an independent body, is suited to a project-type calculation within the meaning of ISO 14064-2.

A comparison with a competing product disclosed to the public also requires, under ISO 14044, a panel of at least 3 members: our guide on a single expert or a review panel covers this case. The verification of a product footprint and that of a climate commitment follow similar logic.

What a review does not attest

A review attests that the calculation follows a published method, that its assumptions are reasonable and documented, and that its figures are correct. It does not attest that the tonnes were avoided: since the baseline remains hypothetical, no reviewer can certify what would have happened without the solution. Nor does it deliver a carbon credit, a label or a right to claim neutrality.

Choosing the reviewer

Independence comes before everything else: the consultancy or software vendor that built the calculation cannot review it. Next come experience of life cycle assessment, knowledge of the sector, which ADEME also asks of the panel, and knowledge of the WBCSD guide. Before signing, 4 questions help sort the offers:

• Has the reviewer already carried out reviews under ISO 14071 or verifications under ISO 14064-3, and can they describe their scope?
• Have they worked recently for the company, for its fund or for a direct competitor, and how is that relationship declared?
• Does their deliverable distinguish blocking issues from recommendations, and does it provide for a round 2 after the corrections?
• Do they accept that their opinion may be cited in an impact report or an investor file, and in what form?

A warning sign: a review that promises a "certification of avoided tonnes" or a guaranteed figure. What you are buying is a reasoned opinion on a calculation, like the report presented above, not a ready-made comparative claim.

5What should you prepare before the calculation is reviewed?

A complete file shortens the review and avoids most of the back-and-forth. For each solution reviewed, it brings together:

• A methodology note that states the framework followed, the function compared, the period used and the counting method, annual or over the lifetime.
• The baseline scenario and its justification, which specifies whether it is new demand or a replacement, and cites the statistics and regulations used.
• Actual usage data where it exists, such as bills before and after or meter readings, rather than flat-rate estimates.
• The emission factors with their source and date, and the calculation model in a file that the reviewer can rerun.
• The sensitivity analyses and the range they produce, together with the company's own carbon footprint assessment required by gate 1.

What drives the price

No public price list sets the price of an avoided emissions review. It depends on the number of solutions, the quality of the file and the form chosen: an expert reading takes less time than a panel review, which involves bringing several experts together. For a critical review, our article on the cost of an LCA critical review gives orders of magnitude that serve as a benchmark.

Recurring findings

Reviews most often stall on a baseline that flatters the result, a lifetime total presented as annual, and tonnes claimed in full when a partner also publishes them. Add to these forgotten manufacturing and end-of-life stages, unjustified emission factors and the absence of a carbon footprint for the company itself, all points that a file can address before the review.

At Projet Celsius, we believe the best service we can render an investor is to present an honest range rather than a spectacular figure. That means a market baseline, a stated period, the rebound counted and tonnes that are not claimed alone. A smaller figure that survives the review carries more weight in a fundraising file than a large figure that an analyst takes apart in 10 minutes. We recommend having the calculation reviewed before the first impact report, at the same time as the company's carbon footprint assessment required by gate 1.

6Key takeaways

• Avoided emissions are the difference between a scenario with the solution and a baseline scenario; they are never deducted from the carbon footprint of the company.
• The WBCSD guide, revised in July 2025, is the reference: 3 preconditions, 5 steps, and a third-party review under ISO 14071.
• The figure hinges on the baseline, the period counted, the share claimed, the rebound effect and the emission factors.
• A review attests the method and the calculations, never that the tonnes were avoided, and the reviewer must not have built the calculation.

For the investor side, our guide on a fund's financed emissions explains what the fund itself must publish.

Further resources

Frequently asked questions

1What are avoided emissions?

They are the emissions that a solution makes it possible to avoid at other parties, calculated as the difference between a scenario in which it is used and a baseline scenario in which it is not. Insulation, a heat pump or recycled material can generate them. They occur outside the boundary of the company selling the solution, and are published separately from its carbon footprint.

2How do you calculate avoided emissions?

The WBCSD guide, revised in July 2025, first requires 3 conditions to be met, including publication of an inventory of scopes 1, 2 and 3. The calculation then follows 5 steps: choose the period, define the most likely baseline, calculate the life cycle emissions of the solution and of the baseline, take the difference, then check that the contribution is significant and demonstrated.

3Can avoided emissions be deducted from a company's carbon footprint?

No. ADEME states that the sum of the emissions in the carbon footprint and the avoided emissions must not be used under any circumstances, and both the WBCSD guide and the GHG Protocol ask for them to be published separately. Nor do they allow a company to call itself carbon neutral, and the CSRD prohibits counting them towards meeting a reduction target.

4What is Scope 4?

It is the name that some software vendors and suppliers give to avoided emissions, by analogy with scopes 1, 2 and 3 of a carbon footprint. Neither the WBCSD guide, nor ADEME, nor the Net Zero Initiative treats it as a scope 4 within the carbon footprint: avoided emissions remain a separate calculation, compared with a baseline scenario.

5Who can verify an avoided emissions calculation?

An independent third party that did not build the calculation. The WBCSD guide recommends a critical review under ISO 14071, carried out by a life cycle assessment expert. A body may also verify the statement under ISO 14064-3. A comparison with a competing product disclosed to the public requires a panel of at least 3 members, under ISO 14044.

6Is reporting avoided emissions mandatory under SFDR or the CSRD?

No. The climate indicators that SFDR imposes on funds cover the emissions of portfolio companies, scopes 1, 2 and 3, with no avoided emissions indicator. The CSRD climate standard requires gross reduction targets, without avoided emissions, a rule carried over into the simplified standards of July 2026. The figure remains voluntary information.

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