Scope 1 & 2 Calculators — Energy, Fuel & Electricity Emissions
The fuel you burn and the power you buy are the foundation of almost every greenhouse-gas inventory — usually the first numbers you calculate and often the largest. Yet the two sit in different scopes, and the Scope 2 side carries a reporting split that trips up more inventories than any other single question.
Pick the source you are measuring, get a location- and market-based figure, and settle the questions that RECs, PPAs and residual mixes raise.
Fuel burned on-site is Scope 1; electricity, heat and steam you purchase are Scope 2. Both are activity data multiplied by an emission factor — but Scope 2 must be reported two ways, location-based and market-based, because instruments like RECs change one and not the other.
Scope 1 combustion runs on published fuel factors; Scope 2 converts purchased energy on grid emission factors and the DEFRA factor set, under the GHG Protocol Scope 2 Guidance. Every value is versioned in the MasterBrain data layer, and how the numbers are built explains the fuel-factor basis and why it matters.
Scope 1 or Scope 2? Start here
Energy emissions split by who owns the combustion. If you burn the fuel, it is Scope 1. If someone else burns it to supply you with power, heat or steam, it is Scope 2. And the fuel a supplier burned before it reached you — plus the losses in the grid — is Scope 3. Getting this boundary right is the first decision, because it determines the calculator and the reporting rule.
Sub-topic hubs group these by scope: Scope 1 fuel combustion (stationary, mobile, biomass, CHP) and Scope 2 purchased energy (electricity, heat, steam, RECs and PPAs).
You burn the fuel (Scope 1)
Boilers, turbines, gensets, CHP units and own-operation marine or aviation fuel. Start with the stationary combustion calculator.
You buy the electricity (Scope 2)
Purchased grid power, reported both location- and market-based. Start with the purchased electricity calculator.
You buy heat or steam (Scope 2)
District heating and cooling, or purchased steam and hot water. Use the district energy and purchased steam calculators.
You procure renewables
RECs, PPAs or a residual mix change your market-based number. See the renewable procurement and residual mix calculators.
Counting upstream losses (Scope 3)
The energy lost getting fuel and power to you — well-to-tank and transmission losses. See the well-to-tank and grid-loss calculators.
Weighing an energy switch
Comparing options rather than reporting a total. Try the heat pump vs boiler and renewable payback tools.
Provider directory
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See who does this work. Every listing names the standards it works to, and paid placements are labelled. Including KERAMIDA and The Carbon Trust.
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Pick your energy calculator
Know the source? Go straight to the calculator.
Stationary combustion
Boilers, turbines, gensets — Scope 1.
Purchased electricity
Grid power, location & market-based.
CHP / cogeneration
Combined heat and power allocation.
Biomass & biofuel
Bioenergy combustion and biogenic split.
Marine & aviation fuel
Own-operation ships and aircraft.
Renewable procurement
RECs, PPAs and VPPAs, market-based.
Residual mix
What’s left after certificates are claimed.
District heating & cooling
Purchased network heat and cooling.
Purchased steam
Bought steam and hot water.
Well-to-tank
Upstream fuel extraction and supply.
Grid T&D losses
Transmission and distribution losses.
Heat pump vs boiler
Compare a heating switch.
Renewable payback
Carbon payback of on-site generation.
Which energy calculator do I need?
The source decides the scope, the unit and the method. This table maps each tool to what it measures and when to reach for it.
| What you’re measuring | Calculator | Scope | Method / basis | When to use it | Methodology |
|---|---|---|---|---|---|
| Fuel burned on-site | Stationary combustion | Scope 1 | Fuel use × fuel factor | Boilers, furnaces, turbines, gensets | Fuel combustion methodology |
| Combined heat & power | CHP / cogeneration | Scope 1 | Energy or efficiency allocation | Splitting a CHP unit’s fuel between heat and power | CHP allocation methodology |
| Bioenergy | Biomass & biofuel | Scope 1 | Biogenic vs fossil split | Wood, biogas, biofuels — reporting biogenic CO₂ separately | Biomass & biofuel methodology |
| Own ships & aircraft | Marine & aviation fuel | Scope 1 | Fuel use × fuel factor | Fuel burned in owned/controlled vessels or aircraft | Marine & aviation fuel methodology |
| Purchased electricity | Purchased electricity | Scope 2 | Location- & market-based (dual) | Grid power — the core Scope 2 number | Purchased electricity methodology |
| Renewable procurement | Renewable procurement | Scope 2 | Market-based instruments | RECs, PPAs, VPPAs against your market-based total | Renewable procurement methodology |
| Residual mix | Residual mix | Scope 2 | Untracked-attribute factor | The market-based factor when you hold no certificates | Residual mix methodology |
| District heat & cooling | District heating & cooling | Scope 2 | Network energy × supply factor | Purchased heat or cooling from a network | District heat & cooling methodology |
| Purchased steam | Purchased steam & hot water | Scope 2 | Steam energy × supply factor | Bought steam or hot water | Purchased steam & hot water methodology |
| Upstream fuel | Well-to-tank | Scope 3 Cat 3 | WTT upstream factor | Extraction, refining & delivery of the fuel you burn | Well-to-tank methodology |
| Grid losses | Grid T&D losses | Scope 3 Cat 3 | T&D loss factor | Electricity lost in transmission before it reaches you | T&D losses methodology |
| A heating switch | Heat pump vs boiler | Comparison | Grid factor vs fuel factor | Deciding between electrified and gas heating | Heat pump vs boiler methodology |
| On-site generation | Renewable payback | Comparison | Embodied vs avoided carbon | Carbon payback period of solar or wind | Renewable payback methodology |
What each calculator covers
Energy emissions divide cleanly by scope, and within Scope 2 by what you buy. Each calculator carries the factor set and reporting rule for one source — a burned fuel needs a fuel factor and a biogenic split; purchased power needs a grid factor and a dual location/market treatment.
Stationary combustion & on-site fuel (Scope 1)
The stationary combustion calculator is the workhorse: fuel burned in boilers, furnaces, turbines and generators, converted on per-fuel factors — the individual fuel methodologies for natural gas, diesel, LPG and coal each set out the calorific and factor basis. The CHP cogeneration calculator handles the harder case of a unit producing heat and power together, where the fuel must be allocated between the two outputs (allocation methodology). The biomass and biofuel calculator separates biogenic from fossil CO₂ — a reporting distinction, not a claim that bioenergy is carbon-free (methodology) — and the marine and aviation fuel calculator covers fuel burned in your own vessels and aircraft (methodology).
Purchased electricity (Scope 2)
The purchased electricity calculator is the core Scope 2 tool and the reason this cluster needs care: grid power must be reported two ways — location-based on the physical grid mix and market-based on the instruments you hold — using the electricity methodology and the market-based methodology. Two companion tools handle procurement: the renewable procurement calculator applies RECs, PPAs and VPPAs to the market-based figure (methodology), and the residual mix calculator supplies the factor for the power you did not cover with certificates — the residual mix exists precisely because others have claimed the clean attributes (methodology).
Heat, steam & district energy (Scope 2)
Purchased thermal energy is Scope 2 just like electricity. The district heating and cooling calculator covers heat or cooling bought from a shared network (methodology), and the purchased steam and hot water calculator covers bought steam and hot water (methodology). The factor depends on how the supplier generates the energy, which is why these are reported separately from the electricity line rather than folded into it.
Upstream fuel & grid losses (Scope 3 Category 3)
Two sources sit just outside Scope 1 and 2 but belong to the same energy story. The well-to-tank calculator covers the upstream emissions of extracting, refining and delivering the fuel you burn, before it reaches your meter (methodology). The grid transmission and distribution loss calculator covers the electricity lost in the network on its way to you (methodology). Both fall under Scope 3 Category 3, fuel- and energy-related activities, and are frequently omitted — including them is what separates a screening inventory from a complete one.
Energy-decision tools
Two calculators here answer a choice rather than report a total. The heat pump vs gas boiler calculator compares an electrified heating system against gas, where the answer turns on your grid’s carbon intensity — a heat pump wins comfortably on a clean grid and by less on a coal-heavy one (methodology). The renewable carbon payback calculator weighs the embodied carbon of installing solar or wind against the grid emissions it avoids, giving a carbon payback period (methodology).
Location-based vs market-based Scope 2
This is the question that causes the most Scope 2 errors, so it is worth stating plainly. The GHG Protocol Scope 2 Guidance requires companies to report purchased electricity two ways. The location-based figure uses the average carbon intensity of the grid you physically draw from — it reflects the electrons actually flowing, and it moves only when the grid decarbonises. The market-based figure reflects the electricity products you have contractually chosen, through energy attribute certificates, power purchase agreements or a supplier-specific tariff.
The honest point is that a REC or PPA moves your market-based number without changing a single electron on the wire. That is not a loophole — it is how the market-based method is designed to reward procurement — but it means the two numbers answer different questions, and a figure quoted without saying which basis it used is ambiguous. When you hold no certificates for some of your load, that portion is costed at the residual mix: the average of what is left after everyone else’s clean claims are stripped out, which is why the residual mix is dirtier than the grid average. The location-based vs market-based comparison works through when each applies, and most disclosure regimes now expect both.
A location- and a market-based figure are not interchangeable and must not be added together or averaged. Report each as its own total. If you claim renewable procurement in the market-based number, the load you did not cover is costed at the residual mix, not the grid average — using the grid average there quietly understates the figure.
How the numbers are built
Every calculator here follows the same chain — activity data (fuel volume, kilowatt-hours, steam energy) multiplied by an emission factor — and reads the same versioned factor set as our source-level tools. Scope 1 combustion uses published fuel factors; Scope 2 converts purchased energy on grid emission factors and the DEFRA factor set, under the GHG Protocol Scope 2 Guidance and stationary-combustion guidance. Grid factors draw on sources such as EPA eGRID in the US and the AIB European residual mix, with IEA data underpinning cross-country coverage.
Where energy emissions sit by scope is what the first question decides — the same kWh is a different scope depending on whether you burned the fuel or bought the power:
| Energy flow | Scope | What it captures | Calculators here |
|---|---|---|---|
| Fuel burned on-site | Scope 1 | Direct combustion CO₂, CH₄, N₂O | Combustion, CHP, biomass, marine & aviation |
| Purchased electricity, heat & steam | Scope 2 | Indirect emissions from generation | Electricity, residual mix, district heat, steam |
| Upstream fuel & grid losses | Scope 3 (Cat 3) | Well-to-tank extraction + transmission losses | Well-to-tank, T&D losses |
One provenance point specific to fuel factors is worth knowing: DEFRA-sourced fuel factors and UK grid factors carry AR5 global warming potentials internally by design, while corporate reporting defaults to AR6 — the two bases should never be mixed inside a single total. Each calculator states the basis it applied, and every factor is versioned and traceable in the MasterBrain data layer, so you can see which vintage produced a number and when it last changed. Each source also has a matching methodology page setting out its boundaries and assumptions.
The factors these calculators read, live from the data layer at MasterBrain v2026.193 — one Scope 1 fuel and the same UK grid kWh under three different bases, which is exactly the location-vs-market distinction above:
| Source & basis | kg CO₂e/kWh | Source |
|---|---|---|
| Natural gas — combustion (Scope 1, gross CV) | 0.182 | DEFRA 2026 |
| UK grid electricity — location-based (Scope 2) | 0.131 | DEFRA 2026 |
| UK grid electricity — residual mix (Scope 2, market) | 0.281 | AIB 2025 |
| UK grid electricity — well-to-tank (Scope 3) | 0.037 | DEFRA 2026 |
A kilowatt-hour of UK grid electricity is about 0.131 kg CO₂e location-based, but around 0.281 kg CO₂e on the residual mix that market-based accounting uses for consumers without clean-energy contracts — more than double. Which one you report is not a rounding choice; it is the location-vs-market decision, and best practice is to disclose both. The well-to-tank figure sits on top of either, in Scope 3.
After your first number
Energy is usually the largest and most certain part of an inventory, which makes it the right place to start — but it is one part. Once you have your Scope 1 combustion and Scope 2 purchased-energy figures, they fold into the wider footprint alongside the other sources. The Scope 1-2-3 inventory aggregator rolls all three scopes into one auditable number, and the ISO 14064-1 inventory calculator assembles it to a verification-ready standard. The non-combustion Scope 1 sources that do not belong here — refrigerant leakage, process emissions from cement or metals — sit in the industrial processes and fugitive emissions cluster instead.
If you are sizing a whole organization rather than working source by source, the organizational & sector footprint calculators give a fast whole-entity baseline that already includes energy as a component, and the full carbon calculator directory covers every source-level tool the inventory draws on.
Start with the two numbers most inventories lead with — the fuel you burn and the power you buy — or read how the factors and the Scope 2 dual basis work before you run them.
Location-based uses the average carbon intensity of the grid you physically draw from, so it reflects the actual electricity mix and moves only as the grid decarbonises. Market-based reflects the electricity products you have contractually chosen — RECs, PPAs or a specific tariff. The GHG Protocol requires both to be reported. They answer different questions and must never be added together or averaged into one figure.
Multiply the fuel used by its emission factor: gas by volume or energy content, diesel and other liquid fuels by litres or energy. The stationary combustion calculator applies the published factor for each fuel, and the individual fuel methodologies set out the calorific and factor basis. The one subtlety is the global warming potential basis — DEFRA fuel factors carry AR5 internally while corporate reporting defaults to AR6, so keep a single basis across a total.
They reduce your market-based Scope 2 figure, not your location-based one, and they do not change the physical electricity on the grid. That is by design — the market-based method exists to reward procurement — but it means a REC lowers one of your two required numbers, not both. The portion of your load not covered by certificates is then costed at the residual mix, which is higher than the grid average because the clean attributes have been claimed elsewhere.
The residual mix is the emission factor for electricity whose clean attributes have already been claimed by someone else through certificates. When you buy grid power without holding RECs for it, your market-based figure should use this residual factor, not the grid average — because the renewable share of that grid has been contractually allocated to other buyers. It is therefore higher than the average grid intensity, and the residual mix calculator supplies the correct value by region.
For a complete inventory, yes. Well-to-tank emissions (extracting and delivering your fuel) and transmission and distribution losses (electricity lost in the grid) both fall under Scope 3 Category 3, and both are commonly left out of a first estimate. Including them typically adds a meaningful percentage to your energy footprint and is what distinguishes a screening figure from a full inventory. The well-to-tank and grid-loss calculators handle each with the appropriate upstream factor.
Scope 2. Any energy you purchase rather than generate — electricity, heat, steam or cooling — is Scope 2, because the combustion happened at the supplier’s facility, not yours. Only fuel you burn on-site is Scope 1. The emission factor for purchased steam or district heat depends on how the supplier produces it, which is why it is reported on its own line rather than folded into the electricity figure.
Usually, but it depends on your grid. A heat pump delivers several units of heat per unit of electricity, so on a clean or average grid it beats a gas boiler comfortably. On a very coal-heavy grid the margin narrows, though electrification still tends to win as that grid decarbonises over the system’s life. The heat pump vs boiler calculator runs the comparison on your local grid factor rather than assuming a single answer.
Factors are maintained in the MasterBrain data layer and updated as their sources publish — annual DEFRA conversion factors, updated grid intensities, and revised residual-mix and IEA data. Every value is versioned, so a calculator always shows which vintage it used, and each methodology page records the basis. Because grid intensities fall over time, your Scope 2 number can drop from one year to the next even at unchanged consumption.
The rest of this topic
4 more pages in this topic that are not linked above.