Grid Transmission & Distribution Loss Factors

What T&D losses are & where they go

Every grid loses electricity between the power station and the end user — as resistive heat in high-voltage transmission lines and in the transformers and cables of the distribution network. The loss rate is that lost share as a percentage of the electricity put onto the grid. Because the lost electricity still had to be generated, its emissions are real; the question is only which scope they fall in.

UK T&D factors

For the UK, DEFRA/DESNZ publish ready-to-use transmission & distribution emission factors in kg CO₂e per kWh consumed — for grid electricity and district heat, each with a well-to-tank (WTT) companion for the upstream fuel — alongside the World-Bank loss rate. Multiply these directly by the electricity or heat you consume to get the Scope 3 Category 3 T&D emissions.

Electricity T&D loss rates by country

The share of generated electricity lost in transmission and distribution before it reaches the meter, as a five-year average from the World Bank. Losses range from under 2% in the most efficient grids to over 50% where infrastructure is weak or theft is high — use the country matching where the electricity is consumed.

Application — formula & worked example

UK site, direct factor. An office consuming 1,000,000 kWh of UK grid electricity: T&D emissions = 1,000,000 × 0.01299 = 12,990 kg CO₂e ≈ 13.0 t CO₂e in Scope 3 Category 3, plus the well-to-tank companion of those losses, 1,000,000 × 0.00359 = 3,590 kg CO₂e. This sits alongside — not inside — the Scope 2 emissions of the 1,000,000 kWh actually delivered.

Other country, gross-up. Where no direct factor exists, use the loss rate and the grid emission factor. The same 1,000,000 kWh in a grid with an 8.79% loss rate implies losses of 1,000,000 × 0.0879/(1−0.0879) = 96,400 kWh of extra generation; multiplied by that country’s grid emission factor it gives the Scope 3 T&D emissions.

Framework requirements

T&D losses of purchased electricity are a defined upstream Scope 3 category — the emissions of energy your organisation buys that occur before it reaches you.

Common reporting errors

1. Putting T&D losses in Scope 2. Scope 2 is the electricity you received; the losses are the extra generation to deliver it and belong in Scope 3 Category 3.
2. Grossing up with the raw loss percentage. Losses are a fraction of generation, so use loss/(1−loss), not the loss rate times consumption — the two differ increasingly as the loss rate rises.
3. Applying the UK loss rate everywhere. Loss rates span from under 2% to over 50% — use the country where the electricity is consumed.
4. Confusing the T&D factor with the WTT factor. Both are Scope 3 Category 3, but the T&D factor covers the losses’ generation emissions and the WTT companion covers the upstream fuel — report both, separately.
5. Re-counting the delivered electricity. Only the losses are the Category 3 line; the kWh you actually used is already in Scope 2 — don’t double-count it.
6. Carrying a stale loss rate. The World Bank revises the series; these are a five-year average — refresh when the source updates.
7. Missing a country. Where a country is not listed, use a comparable grid or a regional average, and state the substitution.

Methodology, boundaries & uncertainty

What this dataset is. Grid transmission & distribution loss factors — the World Bank five-year-average electricity T&D loss rate (% of power output) for 149 countries, plus the DEFRA/DESNZ 2026 UK T&D emission factors (kg CO₂e/kWh consumed) for grid electricity and district heat with their well-to-tank companions — as implemented in the GreenCalculus MasterBrain. A standalone dataset with its own Zenodo DOI (concept 10.5281/zenodo.21482078).

Boundary. The losses in transmission and distribution networks only. The generation emissions of the delivered electricity are Scope 2 (see the grid emission factors dataset); the upstream fuel of both delivered and lost electricity is the well-to-tank pathway. This dataset provides the loss rate to gross up losses, and the UK’s ready-made T&D factor.

Rounding policy. Values are reproduced as published. Loss rates are a percentage of power output (World Bank five-year average); UK factors are kg CO₂e per kWh consumed (DEFRA/DESNZ 2026).

Uncertainty. Loss rates vary year to year and reflect national averages that mask sub-grid variation; some countries’ reported figures include non-technical losses (theft, unbilled use) that inflate the physical loss. Use as a national default; a grid operator’s own figure is more precise where available.

Applicability. National loss rates for the country of consumption; the UK direct factors for UK reporting. For countries not listed, substitute a comparable grid and disclose it.

Implementation & provenance chain

1. Primary sources — World Bank, Electric power transmission and distribution losses (% of output) (five-year average, 2024 data release); DEFRA / DESNZ, UK Government GHG Conversion Factors 2026: transmission & distribution (UK electricity and district-heat T&D factors, OGL v3.0).
2. MasterBrain — each factor is curated under a stable transmission_distribution.<iso3>.* key with its source reference; current version v2026.203 (2026-09-22).
3. REST & CSV — the /transmission-distribution-factors endpoint projects these rows as JSON; the CSV button below serves the identical set.
4. Calculators — GreenCalculus Scope 3 tools read the same keys, so a published inventory and this page cannot diverge.
5. Update plan — refreshed on the World Bank series update and the annual DEFRA/DESNZ release; bumps the dataset version and mints a new Zenodo version DOI.

Data access — REST API & CSV

The full 153-row dataset is available as a machine-readable REST endpoint and as a flat CSV download — the same rows shown above, versioned and citable.

Citation guidance

Cite the primary sources and, for the machine-readable compilation, the GreenCalculus dataset DOI.

World Bank (2024). Electric power transmission and distribution losses (% of output). World Development Indicators. Washington, DC: World Bank. Licensed under CC BY 4.0. — and DEFRA/DESNZ (2026), UK Government GHG Conversion Factors 2026: transmission & distribution (OGL v3.0).

World Bank & DEFRA/DESNZ primary citations

Say, Jeremiah (2026). Grid transmission & distribution loss factors by country (machine-readable). GreenCalculus. Zenodo. https://doi.org/10.5281/zenodo.21482079

GreenCalculus dataset DOI — 2026 edition (concept DOI 10.5281/zenodo.21482078 resolves to all versions)

Frequently asked questions

Version history