Impact of a warming climate on UK food retail refrigeration systems: recommendations for industry

Authors:  Matthew Hart, William Austin, Salvador Acha, Romain Lambert, Christos N. Markides and Nilay Shah, in partnership with Sainsbury’s Plc.

At the current rate of warming, the unusually hot summer experienced in the UK in 2018 is likely to become the norm by 2050. This makes refrigeration system performance from this period an invaluable benchmark of their ability to cope with a warming climate. This report provides an in-depth analysis, undertaken with a major UK supermarket retailer, to understand the impact that the summer of 2018 had upon refrigeration systems, and puts forward short and long-term strategies to ensure the sustainability of refrigeration systems up to 2050 and beyond.

Introduction

In 2018, the UK experienced its joint hottest summer on record, with a 15.8°C mean temperature, rising to a record 17.2°C for England. July had particularly elevated temperatures of 2.2°C above the 1981-2010 average, especially in central and southern locations. At current rates of warming, an equivalent hot summer will become the UK norm by 2050. This is of concern to the UK cold-chain food supply industry, with refrigeration accounting for half of supermarket-store energy consumption.

Increased electricity consumption under elevated ambient temperatures will inevitably increase carbon emissions, as grid carbon neutrality is not expected before 2050. Rising ambient temperatures will therefore counteract other initiatives aimed at improving environmental sustainability as cooling-related electricity demand increases. The UK’s new net-zero carbon target is expected to further increase emphasis on environmental sustainability via punitive legislation, not just relying on corporate social responsibility schemes.

A further pressing concern under prolonged high ambient temperatures is systems failing to provide adequate cooling for safe perishables storage. If an asset encounters a significant fault or is unable to maintain the set-point temperature, stock must be removed from cabinets resulting in labour costs and inhibited sales performance. Refrigeration systems must therefore be robust enough to withstand the summer 2018 temperatures into the future.

The cold-chain food supply industry is in the process of transitioning towards low carbon refrigerants following legislation aimed at curbing the greenhouse gas (GHG) emissions associated with refrigerant leakage. Previously UK retailers relied on hydrofluorocarbon (HFC) refrigerants, which are powerful GHGs. The Kigali Amendment to the UN Montreal Protocol ratified a removal timeline for all HFC refrigerants and the subsequent EU regulations impose strict phase-down deadlines, focusing on the most potent GHGs. Industry has responded by transitioning to low carbon, ‘natural’ refrigerants with R-744 (CO₂) clearly the optimal choice.

This report analyses the impact of the hot summer 2018 on refrigeration systems and puts forward short and long-term strategies to ensure the continued sustainability of those systems in a warming climate.