The thermodynamics of -18°C solar: why self-consumption is 94-98%
The compressor loads required to maintain -18°C in a large frozen store are continuous and substantial. For a 50,000 sqft blast freeze and -18°C store: compressor load 400-600 kW running 24/7, never cycling off (unlike chilled storage). Defrost cycles (3-4/day, 20-30 minutes) temporarily increase power draw. Condenser fans, evaporator fans, pumps: additional 50-150 kW. A 500 kW solar system generates approximately 500,000 kWh/year. With 96% self-consumption: 480,000 kWh offsets grid import (worth £120,000/year at 25p/kWh). Export: 20,000 kWh at 10p/kWh = £2,000/year. Total annual value: £122,000. Simple payback (500 kW at £1,100/kW = £550,000): 4.5 years. With IETF at 40% = £220k grant: effective capex £330k. Payback: 2.7 years.
IETF for frozen food processing: eligibility by process type
IETF eligible frozen food processes: blast freeze (rapid cooling to -18°C or below — defined as energy transformation), IQF (individually quick frozen — belt freezers), tunnel freeze (for fish, poultry, baked goods), plate freeze (block fish, offal), cryo-freeze (liquid nitrogen — extremely energy intensive, highest IETF priority). IETF intervention rate: 30-50%, with blast freeze and cryo-freeze typically achieving 40-50% intervention. Maximum award: £10m. Not IETF-eligible: frozen storage-only operations without active processing (frozen 3PL warehouse without blast freeze). We confirm IETF eligibility for each frozen food client at desk feasibility.
UK frozen food solar map by location and economics
Grimsby (blast freeze — Young's, Birds Eye, Findus, DAAL): Humber Freeport ECA + IETF + east coast irradiance + Northern Powergrid fast G99. Payback: 1.9-2.5 years. The UK's strongest commercial solar economics. Lowestoft (Birds Eye — East Anglian blast freeze): UKPN fast G99 (4-5 months), IETF-eligible, east coast irradiance 1,020-1,050 kWh/kWp/yr. Payback: 2.5-3 years. Peterborough (McCain frozen potato, Greencore frozen meals): WPD DNO, IETF-eligible, Golden Triangle irradiance. Payback: 2.8-3.5 years. Warrington/Manchester (3 Sisters frozen food, Kepak Barrow): ENW DNO, IETF-eligible. Payback: 3-4 years. Bridgend/South Wales (Kepak Cardiff, ready meal manufacturers): WPD DNO, Welsh Freeport (Port Talbot adjacent for some), IETF. Payback: 2.5-3.5 years.
Common questions
What is the minimum frozen food warehouse size to make solar worthwhile?
From 20,000 sqft blast freeze: 150-200 kW PV viable. At this scale: £170,000-£220,000 installed, annual saving £38,000-£48,000. Simple payback: 4.5-5 years. With IETF at 35%: 3-3.5 years. Smallest IETF-eligible project: £100k capex minimum. Below this: no IETF, but 100% AIA still applies.
Can ambient cold store and blast freeze be on the same building?
Yes — and mixed-temperature facilities (ambient/chilled/blast freeze sections on the same roof) are common. PV sizing should be based on aggregate load profile across all temperature zones. For a mixed-temperature facility: blended self-consumption 85-93% (between the blast freeze high and ambient lower). We model HH meter data from the whole building, not individual temperature zones.