The environmental costs of business-as-usual cold chain development
Investment in cold chains is already booming in the megacities of developing countries, and this is vital to satisfy the changing diets of the emerging middle classes, reduce postharvest food losses, and mitigate the environmental impacts of agriculture. But conventional cold chain technologies impose huge environmental penalties of their own.
One particular culprit is the transport refrigeration unit (TRU) – the secondary diesel engine that powers refrigeration on trucks worldwide. Even in developed economies, TRUs are generally unregulated and highly polluting. According to a recent report from the Liquid Air Energy Network, trailer TRUs not only consume up to 20% of the truck's fuel, but also emit six times as much nitrogen dioxide (NOx) and 29 times as much particulate matter (PM) as a modern (Euro VI) propulsion engine. These are the pollutants that cause 29,000 premature deaths in Britain each year60; 400,000 in the EU61; and 600,000 in India.62 Since the local air pollution caused by diesel TRUs is so disproportionate, any of the cold chain forecasts discussed in section 6 would impose heavy environmental and health costs.
The pollution and health impacts of any such expansion of the diesel TRU fleet would be significant, but so would the greenhouse gas (GHG) emissions. Diesel TRUs can emit up to 50 tonnes of CO2 per vehicle per year from diesel consumption alone63, and the total emissions will become increasingly significant as the size of the refrigerated fleet increases. At the same time the CO2 savings that could be achieved by replacing each diesel TRU with sustainable cooling technologies will grow as the carbon intensity of grid electricity falls in many markets. Conventional TRUs also contain refrigerants known as F-gases that have extremely high Global Warming Potential (GWP), and which tend to leak. The most commonly used F-gas has a GWP almost 4,000 times higher than CO2, so even the small volumes thought to escape from each TRU system could equate to several additional tonnes of CO2 per vehicle per year.
60 R (on the application of ClientEarth) (Appellant) v The Secretary of State for the Environment, Food and Rural Affairs (Respondent),The Supreme Court, 1st May 2013, https://www.supremecourt.uk/decided-cases/docs/UKSC_2012_0179_Judgment.pdf
61 Europe's cities still suffering from harmful air pollution, European Environment Agency, http://www.eea.europa. eu/media/newsreleases/europes-cities-still-suffering-from.
62 Study of air pollution due to vehicle emission in tourist centre, 0 Subramani, T., International Journal of Engineering Research and Applications, 2:3. (2012)
63 Source Air Liquide, cited in Special Report: Cryogenic Truck Refrigeration with Nitrogen, Global Cold Chain News, February 2011.