Emission factors in Brazil: MCTI, IPCC and Defra compared

What emission factors are

An emission factor is a coefficient that converts a unit of activity, litres of diesel burned, MWh of electricity consumed, tonnes of waste landfilled, into a quantity of greenhouse gases expressed in tonnes of CO2 equivalent (tCO2e).

Without emission factors, a GHG inventory would be nothing but a record of physical consumption. The factor is what turns operational data into a carbon footprint. The accuracy of the inventory depends directly on the quality and the fit of the factors used.

Each emission factor is specific to a combination of activity, fuel, technology, region and period. Using a generic global factor when a specific national or sector factor exists introduces distortions, in either direction, that undermine the usefulness of the inventory.

The SIN grid factor: how it moves and how it is updated

The emission factor of the Sistema Interligado Nacional (SIN), Brazil's interconnected grid, is probably the most consulted factor in the country. It represents the average carbon intensity of electricity delivered by the national grid and is published annually by MCTI.

The value moves with the generation mix: in years of good hydrology, with a high share of hydro, the factor falls. In dry years, with gas and coal thermal plants dispatched, it rises. The expansion of wind and solar also pushes the factor down over time.

Historically the SIN factor has ranged between 0.04 and 0.10 tCO2/MWh, depending on the year and the methodology (average or margin). The long-run trend is downwards, driven by the decarbonisation of Brazil's power mix.

For corporate inventories, the choice between the average grid factor and a margin factor (build margin or operating margin) has practical implications. The GHG Protocol Scope 2 Guidance calls for two calculations: location-based (the average grid factor) and market-based (the factor of the energy contract or renewable energy attribute).

In Brazil, companies on the free energy market that buy renewable energy certificates (I-RECs) can report market-based Scope 2 at zero or close to it. Companies on the regulated market use the average SIN factor.

MCTI vs IPCC vs Defra: when to use each

Three emission factor databases are widely used in Brazil: MCTI, IPCC and Defra (the UK Department for Environment, Food and Rural Affairs).

MCTI, Brazil's Ministry of Science, Technology and Innovation. It publishes factors specific to Brazil, covering fuels, electricity, waste, agriculture and livestock, land use and industrial processes. It is the priority source for Brazilian inventories reported under the Brazilian GHG Protocol Programme and in SIRENE. MCTI factors reflect local conditions, fuel composition, technologies in use, climate and soil, and they are more accurate than global factors for operations in Brazil.

IPCC, Intergovernmental Panel on Climate Change. It publishes default factors in its assessment reports and in the guidelines for national inventories (2006 Guidelines, 2019 Refinement). These are global average factors, useful when no national factor exists or when international comparability is needed. The IPCC also publishes the GWPs (Global Warming Potentials) used to convert different gases into CO2 equivalent.

Defra, UK Department for Environment, Food and Rural Affairs. It publishes a comprehensive UK factor database annually, with broad coverage of Scope 3 categories (air travel, accommodation, materials, logistics). It is often used to fill gaps where neither MCTI nor IPCC offers a factor for a specific category.

The general rule: use MCTI whenever it is available. Fill gaps with IPCC for categories with no national coverage. Use Defra for Scope 3 categories the other two do not cover, particularly travel and materials.

Sector-specific factors (transport, energy, waste)

Transport. Transport emission factors depend on vehicle type, fuel, load and distance. In Brazil, MCTI publishes factors for gasoline C, hydrous ethanol, diesel S10/S500, CNG and biodiesel at different blend rates (B10, B15 and so on). The mandatory biodiesel blend in diesel, currently 14%, lowers the effective factor of commercial diesel relative to pure diesel.

For air travel, ICAO and Defra publish factors by cabin class (economy, business, first) and route type (domestic, short-haul, long-haul). The difference is significant: a business class seat can carry a factor 2.5 to 3 times higher than economy, because of the space it occupies.

Electricity. Beyond the SIN factor, companies operating outside the interconnected grid (isolated systems in the Amazon, for example) use isolated-system factors, which tend to be much higher because they depend on diesel generation.

Companies with their own generation, solar PV, small hydro, biomass, can use technology-specific factors. Solar and wind have a zero operational factor (no combustion), but there are life-cycle emissions in manufacturing the panels and turbines.

Waste. Emission factors for solid waste in landfill depend on waste composition (organic fraction), landfill depth, whether methane is captured, and climate. MCTI and the IPCC publish first-order decay (FOD) methodologies to estimate methane emissions over time. Landfills that capture and flare biogas have much lower effective factors.

IPCC AR5 vs AR6: the difference in GWPs

GWPs (Global Warming Potentials) are the coefficients that convert different greenhouse gases into CO2 equivalent. A GWP of 28 for methane (CH4) over a 100-year horizon means one tonne of CH4 has the same climate impact as 28 tonnes of CO2 over a century.

The catch: GWPs change with each IPCC assessment cycle. AR5 (2013) set the 100-year GWP of CH4 at 28 and of N2O at 265. AR6 (2021) adjusted CH4 to 27.9 (essentially stable) but changed how climate feedbacks are accounted for, producing shifts in other gases.

For companies, the move from AR5 to AR6 can shift inventory figures even with no real change in physical emissions. CDP and SBTi already accept both, but consistency within a time series is essential: do not compare a 2023 inventory (calculated on AR5) directly with a 2024 one (calculated on AR6) without an adjustment.

The regulatory direction is a progressive move to AR6. The European CSRD and the ISSB already recommend it. In Brazil, the Brazilian GHG Protocol Programme still accepts AR5, but convergence is a matter of time.

How the Mangue Tech platform manages 60,000+ factors

Managing emission factors is one of the biggest operational challenges in an inventory. The Mangue Tech platform maintains a consolidated database of more than 60,000 emission factors, covering MCTI, IPCC (AR5 and AR6), Defra, Ecoinvent and specific sector sources.

The system offers full traceability: each factor is linked to its source, year of publication, GWP version used and region of application. When MCTI or the IPCC publish updates, the factors are folded into the database and inventories can be recalculated automatically.

For the user, the process is transparent. When you enter activity data, litres of diesel, MWh consumed, tonnes of waste, the system automatically suggests the most appropriate factor, prioritising national sources over global ones and more recent data over older.

That automation removes one of the most common errors in manual inventories: using factors that are out of date, from the wrong region, or with inconsistent GWPs. The result is an inventory that is more accurate, more defensible and easier to audit.