A climate project baseline is a justified scenario of the emissions that would occur without the project. The emission reduction is calculated as baseline emissions minus project emissions, so the quality of the baseline directly determines how many tonnes of CO₂e the verifier will confirm.
A project baseline is not the same as a base year
In corporate accounting, the base year is the reference point for the whole organization. A project baseline is a scenario for a specific measure within the project boundary. It may draw on the facility's historical data, but it also reflects how emissions would have changed without the project: growing load, equipment wear, legal requirements.
How the baseline scenario is chosen
The GHG Project Protocol (2005) and ISO 14064-2:2019 require you to consider alternative scenarios and choose the most likely one. Typical options:
- continuation of current practice — the equipment keeps running as before;
- an upgrade that would have happened anyway — for example, one required by law;
- common practice in the industry or region.
If the project activity is itself the most likely scenario, the project is not additional and its reductions are not credited.
What data you need
- Activity data for the historical period: electricity (kWh), heat (kWh), gas (m³), by month.
- Factors that affect consumption: degree-days, production volume, operating hours.
- Emission factors, with their source and version.
- Primary documents: invoices, certificates of completion, meter readings.
The more complete the historical series, the more confidently the model separates the project's effect from weather and load fluctuations.
Normalization: a worked example
A building was heated by a gas-fired boiler house. In the base year it used 100,000 m³ of gas at 3,000 degree-days. In the reporting year after the project (insulation and automation) it used 75,000 m³, but the winter was colder — 3,300 degree-days.
- Baseline specific consumption: 100,000 / 3,000 ≈ 33.33 m³ per degree-day.
- Baseline adjusted to reporting-year conditions: 33.33 × 3,300 ≈ 110,000 m³.
- Baseline emissions (for this example, a factor of 2.04 kg CO₂e/m³): 110,000 × 2.04 = 224,400 kg = 224.4 t CO₂e.
- Project emissions: 75,000 × 2.04 = 153,000 kg = 153.0 t CO₂e.
- Reduction: 224.4 − 153.0 = 71.4 t CO₂e.
Without normalization, the reduction would have been (100,000 − 75,000) × 2.04 = 51.0 t — an understated value. Had the winter been warmer, the error would have gone the other way, and the verifier would have required an adjustment.
Locking and revising the baseline
The baseline is locked before the crediting period begins and is described in the PDD. It is revised only under the program rules (for example, when the crediting period is renewed). Any “silent” retroactive edit invites findings from the verifier, so it is important to keep every version of the baseline and know who created it and when.
How it works in the platform
- The MRV contour is still in development and is marked “Soon” in the platform: you cannot yet record a project baseline in it or calculate reductions against one.
- You can already build the historical series for a baseline. In Data entry, electricity, heat and gas are entered month by month for each facility, and invoices, certificates of completion and photos of meter readings are attached to the records.
- Each record shows the methodology applied, emission factors come from the platform's reference catalog (IPCC 2006, DESNZ and others), and the year's “Change history” shows who changed what and when — making it easier to answer a verifier's questions about retroactive edits.
- A closed facility year is read-only, and only the administrator can reopen it. Read more in the article on closing the year and the annual report.
Frequently asked questions
How many years of history does a baseline need?
The requirement is set by the methodology of the chosen program. The general principle: the series should cover complete seasonal cycles and be long enough to separate the project's effect from weather and load.
Can the baseline be changed after the project is registered?
Only in the cases and in the manner provided for by the program rules. A new version of the baseline is documented separately and earlier versions are kept: the verifier needs to see who created each of them and when.
Which grid emission factor should be used for the baseline?
The one the methodology requires: for the Article 6.4 mechanism, Gold Standard Tool 10 v1.0 (August 27, 2026) sets out how to calculate the grid factor using annual data, a 10% discount and a 24-month lag. Worked examples can use the estimated value of 0.726 kg CO₂e/kWh.