How do I calculate the energy and emissions of a blast freezer per tonne?
Sub-meter the blast freezer, multiply its kWh by 0.710 kg CO2 per kWh, and divide by tonnes frozen. Add refrigerant top-ups from service records as Scope 1. Product entry temperature and loading pattern change the energy per tonne, so record both.
What drives the energy
- Product entry temperature: warm product needs more cooling.
- Target core temperature and cycle time.
- Door openings and defrost cycles.
- Condenser condition and ambient temperature.
Refrigerant leaks
Top-ups of HFC refrigerants are Scope 1 at their global warming potential. Ammonia has no direct warming effect, but its compressors still use electricity.
Per tonne
Report kWh and kg CO2 per tonne frozen each month, and compare like products, since seafood, meat and bakery items freeze differently.
Worked example: one month of blast freezing (illustrative inputs)
- Electricity: 36,000 kWh x 0.710 = 25,560 kg CO2
- Tonnes frozen: 300
- Total: 25,560 / 300 = 85.2 kg CO2 per tonne
Inputs are illustrative; use a sub-meter and the freezing log.
What Senseible does here
Senseible reads electricity bills (CEA grid factor 0.710 kg CO2 per kWh, CO2 Baseline Database version 21.0) and diesel, LPG and gas invoices (IPCC 2006 defaults) into a dated, fingerprinted Scope 1 and 2 record for each site. Intensity per unit uses the activity count you enter, and estimates are labelled as estimates.
Sources: GHG Protocol Corporate Standard, CEA CO2 Baseline Database, version 21.0, IPCC AR6 WG1, Chapter 7, Table 7.15 (GWP100)
Last reviewed 2026-10-21.