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Your first emission calculation

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An emission calculation is a quantity multiplied by an emission factor. In this tutorial you burn 1,000 kWh of butane, find ADEME's factor for it in factor search, and get 269 kg CO2e. Then you check that the factor fits your activity and copy a citation for your report.

You need a web browser and about ten minutes. You do not need an account. What is free, and what needs an account says where that changes.

The activity#

Your client heated a site in France with bottled butane in 2025. The invoices add up to 1,000 kWh of fuel. You want the emissions in kilograms of CO2e, with a source an auditor can check.

The formula is always the same:

emissions = quantity x emission factor

The quantity is yours. The factor comes from a published library, here ADEME's Base Carbone. The only rule is that the factor's unit must match your quantity's unit: a factor per kWh for a quantity in kWh.

Open factor search already filtered to butane in ADEME: /factors/?q=butane&lib=ademe.

You see a list of results with the Filters rail on the left. Because you searched, the readout above the list counts the factors the ranking holds, as "top N factors", and the columns are factor search's defaults, ending with the value, its unit and the GWP method. Read the list says what each column holds.

Note. Browsing is free. Without an account you can run 10 searches, and only a new combination of search and filters spends one: see what counts as a search. Factor pages and library pages are never counted.

Step 2: pick the right row#

Several rows mention butane. Narrow them down with three columns:

  • Activity. You want "Butane - maritime included". The row called just "Butane" sits under Category "Direct emissions" and prices a leak of the gas, not burning it.
  • Unit. The same fuel is published per kg, per litre (L) and per kwh. Your invoices are in kWh, so take the kwh row. See unit basis.
  • Region. ADEME publishes one set for Europe and one for France. This tutorial takes the Europe row, as the original worked example did; Step 5 shows what changes with France.

Open the row "Butane - maritime included", region Europe, unit kwh, boundary "Well-to-use (upstream, burn or generation, network losses)". Its Year cell reads "2019–". Click the row to open its factor page.

Step 3: read the value#

The factor page shows the value in large type: 0.269 kgCO₂e/kwh, with "GWP: AR6 (as published)" below it. That means 0.269 kilograms of CO2e for each kWh of butane you burn.

Scroll to Decomposition. The value is made of two parts, and the page says "These components sum to the parent value.":

Part Boundary kgCO₂e/kwh
Burning the fuel Combustion (tank-to-wheel) 0.23
Producing and delivering the fuel Upstream fuel (well-to-tank) 0.0392
Total Well-to-use 0.269

0.23 plus 0.0392 is 0.2692. ADEME prints its figures rounded, so the total reads 0.269. Use the total or the parts, never both: adding the parent and its parts counts the same emissions twice. Parents and parts explains the relations.

Step 4: multiply#

1,000 kWh x 0.269 kg CO2e per kWh = 269 kg CO2e

That is your result. Before you put it in a report, check that the factor really describes your activity.

Step 5: check four things#

A value is only right for your activity if its region, year, boundary and licence fit. The factor page shows all four.

Region#

The region badge next to the publisher reads EUROPE, the code for Europe. Your site is in France, and ADEME also publishes a France row for the same fuel, at 0.272 kgCO₂e/kwh. When a factor exists for your country, prefer it: that gives 272 kg CO2e. Choosing between similar factors covers this trade-off.

Year#

The line under the value says the factor was published "(2019–)": it applies from 2019 onwards, with no end year yet, so it covers 2025. The table Values by year and methodology shows that the same factor had a different value up to 2018: 0.26748 kgCO₂e/kwh, which would give 267.48 kg CO2e for an activity in 2018. Always use the value whose window covers your reporting year. See year window and reference year.

Note. Without an account, the page shows the current value and locks the older one. A free account opens every year and methodology.

Boundary#

The boundary is "Well-to-use": it counts burning the fuel and producing it. In GHG Protocol terms, burning is Scope 1 and producing the fuel is Scope 3, category 3. If you report them apart, use the two parts from Step 3 instead of the total. See system boundaries.

Licence#

The badge reads Open licence. ADEME publishes the Base Carbone under the licence etalab-2.0, which lets you reuse the value with a credit line. The ADEME library page gives the exact credit line, "Source ADEME, Base Carbone v23.6", in its Licence section. See licence tiers.

Step 6: cite it#

On the factor page, click Cite. It takes you to Cite this factor at the bottom of the page. Click Copy citation and paste it into your report. The citation names the activity, the publisher, the library edition, the dataset stamp, the date you retrieved it and the factor's address, so anyone can open the same value later.

Add ADEME's credit line next to it. Cite a factor explains both parts.

What you did#

  • You found a factor by searching, then chose the row whose activity and unit match yours.
  • You read its value and its parts, and did not add them together.
  • You multiplied: 1,000 kWh gives 269 kg CO2e for Europe, or 272 kg CO2e with the France row.
  • You checked region, year, boundary and licence, then cited the factor.

To see a factor page with the same layout right now, open anthracite burned in France.

Next#

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