What is grid carbon intensity?

Grid carbon intensity measures the carbon dioxide associated with each kilowatt-hour of electricity, expressed as gCO2/kWh. NESO's Carbon Intensity API provides regional forecasts at 30-minute resolution [S1]. Your site can use the signal to plan flexible charging, while retaining the appropriate reporting factors for its annual electricity emissions calculation [S2], [S3]. Checked October 2026.

Last checked 19 October 2026

What does grid carbon intensity measure?

Grid carbon intensity is the carbon dioxide associated with electricity, expressed in grams of carbon dioxide per kilowatt-hour, or gCO2/kWh. A kilowatt-hour (kWh) measures energy, whereas a kilowatt (kW) measures power [S1].

Why it matters for your site: shifting flexible charging can change the electricity-generation emissions associated with its timing. NESO publishes national and regional signals so devices can schedule demand [S1]. Your vehicles still need enough energy before departure.

Why does the figure change during the day?

Demand, renewable output and the mix of operating generators change over time. NESO’s Carbon Intensity API, a data service software can read, models the Great Britain system at 30-minute resolution. Its forecast estimates future conditions; its actual series estimates intensity from metered generation [S1].

For an illustration, assume a charging session consumes 100 kWh. At assumed intensities of 100 and 200 gCO2/kWh, the calculations are 100 × 100 ÷ 1,000 = 10 kg CO2 and 100 × 200 ÷ 1,000 = 20 kg CO2. These are arithmetic examples, not current grid readings or a prediction of avoided emissions.

Is this the same as your Scope 2 reporting factor?

Location-based Scope 2 accounting uses average electricity emissions for the relevant geography. Market-based accounting concerns qualifying contractual evidence [S2]. Use the emissions scopes glossary for those categories.

An operational forecast is not automatically the factor required for your annual inventory. DESNZ publishes conversion-factor sets for company reporting [S3]. Record the year, units, category and method you use, then follow the Scope 2 reporting guide.

For charging budgets, use the charging cost tool. Carbon intensity and your contracted electricity price are separate inputs.

Next step

Bring departure times and electricity records to your energy cost plan, then get matched with an installer that covers your area.

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