Do I have to report well-to-tank emissions?

Not for SECR or a PPN 006 Carbon Reduction Plan, which don't include category 3 in their minimum. They are part of a complete Scope 3 inventory under the GHG Protocol, and many firms include them because the data is the same fuel and energy figures they already have.

How do I calculate them?

Multiply the same quantity you used for Scope 1 or 2 by the well-to-tank factor from the government set. In 2026, each kWh of gas adds 0.03021 kg CO2e and each litre of diesel 0.61101 kg CO2e.

Is well-to-tank the same as well-to-wheel?

No. Well-to-tank stops when the fuel reaches your tank. Well-to-wheel adds the emissions from burning it, so well-to-wheel is your Scope 1 figure plus the well-to-tank figure.

Why haven't the well-to-tank factors changed?

DESNZ updates them less often than the main factors. The 2026 methodology paper says the well-to-tank factors for fuels have been held constant since the 2023 release, so the gas and diesel figures are the same as in 2023.

Well-to-tank emissions explained

Well-to-tank emissions are the carbon released producing and delivering your fuel before you burn it, and they go in Scope 3 category 3. With the 2026 government factors they add about 17% on top of your gas emissions, 24% on top of diesel and 31% on top of grid electricity. They are optional for SECR and PPN 006 but easy to include.

Updated 19 October 2026 by the Carbon Recycling team. Figures use the official UK government conversion factors and are checked against the current gov.uk guidance.

What "well-to-tank" covers

The gas in your boiler and the diesel in your vans had a carbon cost before they reached you. Oil and gas were extracted, processed or refined, and transported to you. The government's methodology paper calls these the emissions "upstream from the point of use of the fuel": extraction, transport, refining, purification or conversion, and distribution. The name comes from transport: from the oil well to the fuel tank.

Elektrik juga mempunyai pelepasan hulu (well-to-tank). Gas dan bahan api lain yang dibakar di stesen janakuasa perlu dihasilkan dan dihantar, jadi setiap kWh yang anda gunakan membawa sebahagian daripada rantaian bekalan itu.

Which scope?

Pembakaran bahan api ialah Skop 1 (atau Skop 2 bagi elektrik). Pengeluarannya ialah pelepasan langsung pihak lain, jadi bagi anda ia Skop 3. GHG Protocol meletakkannya dalam kategori 3, aktiviti berkaitan bahan api dan tenaga, yang meliputi pelepasan huluan bahan api yang anda beli, pelepasan huluan bahan api di sebalik elektrik anda, dan elektrik yang hilang dalam grid. Hantaran kami tentang kehilangan penghantaran dan pengagihan menerangkan bahagian terakhir itu.

Senarai minimum Skop 3 PPN 006 ialah kategori 4, 5, 6, 7 dan 9, dan SECR dibina sekitar Skop 1 dan 2, jadi kedua-duanya tidak memerlukan hulu (well-to-tank). Inventori Skop 3 GHG Protocol yang penuh memasukkannya.

The 2026 factors

Fuel	Pembakaran (Skop 1 atau 2), kg CO2e	Well-to-tank (Scope 3), kg CO2e	Uplift
Gas asli, bagi setiap kWh	0.18231	0.03021	17%
Elektrik grid, setiap kWh	0.13096	0.04041	31%
Diesel (stesen minyak), setiap liter	2.58354	0.61101	24%
Petrol (stesen minyak), seliter	2.075	0.58094	28%
Minyak pemanas (kerosin), setiap liter	2.54016	0.53078	21%

The electricity row includes the well-to-tank share of grid losses as well as of generation. Its uplift looks large because the grid factor itself is now low; see why the UK grid gets cleaner every year.

Contoh yang dikira

Sebuah firma kecil menggunakan 40,000 kWh gas, 30,000 kWh elektrik dan 6,000 liter diesel dalam vannya pada 2026:

Activity	Skop 1 atau 2, tCO2e	Well-to-tank, tCO2e
40,000 kWh gas	7.29	1.21
30,000 kWh elektrik	3.93	1.21
6,000 liter diesel	15.50	3.67
Total	26.72	6.09

Well-to-tank adds 6.09 tonnes, about 23% on top of the Scope 1 and 2 total. No new data was needed: it is the same kWh and litres multiplied by a second factor.

Things that trip people up

Memasukkannya ke dalam Skop 1. Kekalkannya dalam Skop 3. Mencampurkannya menjadikan Skop 1 anda kelihatan lebih besar daripada firma lain dan merosakkan perbandingan.
Memasukkannya pada satu tahun tetapi tidak pada tahun berikutnya. Putuskan sekali, nyatakannya dalam nota kaedah anda, dan kekalkannya, atau jumlah anda akan melonjak tanpa sebab sebenar.
Terlupa perjalanan dan pengangkutan barang. Perjalanan perniagaan, perjalanan ulang-alik pekerja dan pengangkutan barang juga mempunyai faktor hulu (well-to-tank). Bahan api dibeli oleh pihak lain, jadi pelepasannya adalah Skop 3 dalam apa jua keadaan.
Menganggap biobahan api tiada pelepasan. Biobahan api mempunyai faktor langsung yang rendah tetapi pelepasan rantaian bekalan yang sebenar. Artikel kami tentang HVO menunjukkan betapa besarnya ia boleh jadi.

Maksudnya dalam dunia sebenar

Well-to-tank is a reminder that every litre or kWh you save cuts emissions twice: once where it is burned and again in the supply chain behind it. In the example above, each litre of diesel saved avoids 3.19455 kg CO2e in total, not just the 2.58354 kg in Scope 1.

How Carbon Recycling helps

Well-to-tank is a single setting in Carbon Recycling. Switch it on and every gas, fuel, electricity, travel and freight entry gets its matching well-to-tank line from the same year's government set, filed in Scope 3, with category 3 for the fuel and energy you buy and travel and freight lines kept in their own categories. Changing the setting recalculates every existing entry, so all your years stay on the same basis. To see the uplift for your own bills first, tick the Scope 3 box in the free kWh to CO2e calculator, and see the guide to the 15 Scope 3 categories for where category 3 sits.

Frequently asked questions

Apakah pelepasan hulu (well-to-tank)?

The emissions from producing fuel before you use it: extracting it, refining or processing it, and transporting it to you. For electricity, it is the same for the fuels burned in power stations. They are Scope 3, category 3.

Adakah saya perlu melaporkan pelepasan hulu (well-to-tank)?

Tidak bagi SECR atau Pelan Pengurangan Karbon PPN 006, yang tidak memasukkan kategori 3 dalam keperluan minimumnya. Ia sebahagian daripada inventori Skop 3 yang lengkap di bawah GHG Protocol, dan banyak firma memasukkannya kerana datanya ialah angka bahan api dan tenaga yang sama yang sudah mereka miliki.

Bagaimanakah saya mengiranya?

Darab kuantiti yang sama yang anda gunakan untuk Skop 1 atau 2 dengan faktor hulu (well-to-tank) daripada set kerajaan. Pada 2026, setiap kWh gas menambah 0.03021 kg CO2e dan setiap liter diesel 0.61101 kg CO2e.

Adakah hulu (well-to-tank) sama dengan well-to-wheel?

Tidak. Hulu (well-to-tank) berhenti apabila bahan api sampai ke tangki anda. Well-to-wheel menambah pelepasan daripada pembakarannya, jadi well-to-wheel ialah angka Skop 1 anda ditambah angka hulu.

Mengapakah faktor hulu (well-to-tank) tidak berubah?

DESNZ mengemas kininya lebih jarang berbanding faktor utama. Kertas metodologi 2026 menyatakan faktor hulu (well-to-tank) bagi bahan api telah dikekalkan sejak keluaran 2023, jadi angka gas dan diesel adalah sama seperti pada 2023.

Bolehkah anda menggunakan faktor penukaran kerajaan UK dalam perisian anda? Lesennya diterangkan
What the Open Government Licence v3.0 allows for the DESNZ factors, the attribution statement to use, no endorsement and no warranty.
Data CBAM dan Skop 3 anda: satu angka, dua kegunaan
Bagaimana pelepasan setiap tan yang disahkan oleh pembekal menentukan caj CBAM anda dan menggantikan anggaran Skop 3 berasaskan perbelanjaan, dengan contoh pengiraan keluli.
Cara meminta data pelepasan CBAM daripada pembekal luar negara, dengan templat e-mel
What a UK importer needs from each producer to use actual data on a CBAM return, and an email you can copy and send.

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