Scope 1, 2 and 3 as the GHG Protocol defines them, with all fifteen Scope 3 categories. It also covers the grey zones, where the same gas, fuel or vehicle can sit in a different scope depending on who owns it, where it leaks and which gases count.
Scopes are about who controls the source, not where the gas ends up. Your organisational boundary decides what is "yours". Most firms use operational control: if you run it, it's in. Scope 2 is the only scope defined by what you buy rather than where the emissions happen.
The questions clients actually ask. In each case the same thing can sit in a different scope depending on ownership, where it leaks, or whether the gas counts at all.
Burning gas in your boiler is Scope 1. Methane that leaks before your meter, at the gas field, in transmission or in the local network, belongs to the network operators. It reaches your report only through the well-to-tank factor in category 3. Methane leaking from your pipework after the meter is your Scope 1 fugitive emission, but it's rarely measured.
Test: which side of the meter, and who owns the pipe?
Butane and propane aren't among the seven greenhouse gases the GHG Protocol counts, so a leaking LPG cylinder isn't a reportable emission. It is a safety and air-quality issue. The CO₂ from burning LPG is Scope 1. Propane used as a refrigerant (R290) has a tiny listed GWP of 0.06, so leaks are effectively nil.
Test: is the gas on the counted list? If not, only its combustion counts.
Water itself isn't an emission. Mains water carries the water company's pumping and treatment emissions (category 1), and sewage carries the treatment works' emissions (category 5). Water from your own borehole, rainwater tank or river has no supplier emissions; the energy to pump it is already in your Scope 1 or 2. An on-site treatment plant that releases methane or nitrous oxide is Scope 1.
Water vapour from evaporation or steam isn't counted, because it isn't on the counted list.
The power station's emissions for the electricity you use are Scope 2. The share lost on the grid on the way to you is category 3. Solar or wind you generate and use yourself is reported as zero-emission energy in Scope 1, per DESNZ guidance. If you sell the renewable certificates from it, you can't also claim that electricity as zero-carbon in your market-based figure.
Test: did you buy it, lose it, or make it?
Owned vans, and leased vans you run, are Scope 1 under operational control. Staff driving their own cars on business ("grey fleet") are category 6, and so are short-term hire cars. Under a financial-control or equity approach, leased vehicles can move to category 8.
Test: who controls how the vehicle is run?
Charging at your premises puts the electricity in your Scope 2. Charging at the employee's home, with a mileage refund, has no settled treatment. Most firms report it as business travel (category 6), or as commuting (category 7) when the journey is a commute.
Pick one method, write it down and apply it every year.
Leaks from air conditioning or chillers you run are Scope 1, whoever owns them under operational control. Leaks from a landlord-run system serving several tenants can fall into category 8. Refrigerant in products you sell leaks in use (category 11) and at end of life (category 12). Older HCFC gases such as R22 are Montreal Protocol gases, not Kyoto gases, so they're reported separately.
Test: who services it, who sold it, and is the gas on the counted list?
Your own trucks burn fuel in Scope 1. A carrier you pay counts as category 4, even for outbound deliveries. Category 9 is only for transport after the sale that you don't pay for. For NI firms shipping to GB or the EU, the ferry leg sits wherever the haulage contract sits.
Test: who pays the carrier?
CO₂ from burning wood, charcoal or the bio-share of diesel and petrol blends is biogenic. It's reported "outside of scopes", not in the totals. The methane and nitrous oxide from the same burning still count in Scope 1, and DESNZ's average biofuel-blend factors already split this out.
Biogenic isn't the same as zero. Disclose it separately.
Methane from cattle digestion, slurry and fertiliser nitrous oxide are process and fugitive Scope 1 emissions for the farm. For a dairy or meat processor buying from that farm, the same tonnes are category 1, and usually the largest part of the footprint. This is why NI agri-food carbon numbers vary so much depending on who reports them.
One tonne, two reports, two different scopes, and that's correct.
Under operational control, a unit you lease and run is inside your boundary. Its gas is your Scope 1 and its electricity your Scope 2, even when the landlord pays the bill and recharges you. Shared services you have no control over, such as a landlord's central heating, can go in category 8.
Who pays the bill doesn't decide the scope. Control does.
Bought-in CO₂ released on site, such as CO₂/argon shielding gas, carbonation, dry ice or a discharged CO₂ extinguisher, is commonly reported as a Scope 1 fugitive or process emission. Practice varies when the CO₂ was captured from another process. SF₆ leaking from your own high-voltage switchgear is Scope 1, and it has a very high warming potential.
Small volumes, often missed. Check the gas supplier's invoices.
All the fuel burned in your combined heat and power unit is Scope 1, including the share that makes electricity you export or sell to a neighbour. You can't subtract the exported electricity from your scopes; report it separately as information.
Gross in, information out.
The GHG Protocol follows your accounts. If you capitalise it, it goes in category 2, with all its emissions counted in the year you buy it. If you expense it, it goes in category 1. A £4,000 tool can land in either, depending on your accounting policy.
Ask your accountant, not your engineer.
A flight's CO₂ is category 6. Contrails and high-altitude nitrogen oxides add warming that isn't counted as a greenhouse gas. DESNZ publishes flight factors "with radiative forcing" to include them. Using them is good practice, and the checker does.
State whether you included radiative forcing.
A greenhouse gas inventory counts seven gases, the Kyoto basket. Each is converted to CO₂ equivalent using its global warming potential. A gas that warms the climate but isn't on this list is reported separately, or not at all.
| CO₂ | Carbon dioxide: combustion and processes |
| CH₄ | Methane: gas leaks, landfill, livestock, slurry |
| N₂O | Nitrous oxide: fertiliser, combustion, wastewater |
| HFCs | Hydrofluorocarbons: most modern refrigerants (R404A, R410A, R134a, R32) |
| PFCs | Perfluorocarbons: aluminium smelting, electronics |
| SF₆ | Sulphur hexafluoride: high-voltage switchgear |
| NF₃ | Nitrogen trifluoride: semiconductor and panel manufacture |
| Water vapour | A real greenhouse gas, but emissions from human activity don't drive its concentration, so it's excluded. Evaporation and steam from your site don't count. |
| Butane, propane | Not Kyoto gases, so leaks aren't reported. Burning them produces CO₂, which is counted. |
| HCFCs, CFCs | For example R22. They are controlled under the Montreal Protocol and reported separately if at all. |
| Biogenic CO₂ | From biomass and biofuels. Reported "outside of scopes". |
| Contrail effects | Not a gas. Included only through the optional radiative-forcing uplift on flights. |