Last week’s global deal to phase out HFC refrigerant gases signed in Rwanda received a rapturous reception.
Coming just ten days after the world ratified the Paris climate treaty, this narrower technical agreement should have struggled to capture headlines, but far from it. US Secretary of State John Kerry declared the HFC deal the ‘single most important step we can take to limit the warming of the planet’, while others hailed a ‘huge win for the climate’.
Such was the fanfare you might have been forgiven for thinking that the environmental challenges of the cooling sector had all been solved, but nothing could be further from the truth. HFCs account for only a fraction of the damage.
The ‘Kigali amendment’ is of course a major achievement and wholly welcome. By extending the 1987 Montreal Protocol to include hydrofluorocarbons (HFCs), and setting a firm timetable for their withdrawal, it begins to tackle the climate emissions of a group of greenhouse gases that can be thousands of times more potent than carbon dioxide pound-for-pound. According to one estimate, the deal could save 70 billion tonnes of carbon dioxide-equivalent by 2050, avoiding almost 0.5C of warming.
This may sound enormous but the total impact of cooling is far greater. According to one estimate, greenhouse gas emissions from cooling account for 10% of global emissions, three times that of aviation and shipping combined. Within this F-gas leakage causes around 20-25% of carbon dioxide equivalent emissions and energy consumption the rest: at least 75%, or three times greater. So while Kigali is a big step forward, it doesn’t touch the bulk of the problem. Cleaning up the cooling sector means confronting its energy source and emissions.
In some applications such as building air conditioning, CO2 emissions will fall over time as electricity grids decarbonise. But in many developing countries this will not happen soon enough, and it is in these countries that cooling demand is expected to soar. In fact, the global energy demand from air conditioning is forecast to rise 33-fold by the end of the century, when it will consume around half the electricity generated for all purposes in 2010. So we must not only replace high GWP F-gases with benign alternatives, but also find ways to dramatically improve the system level energy cost of cooling.
In transport refrigeration, cooling is overwhelmingly powered by diesel, creating a whole new set of problems. In trucks and trailers cooling is usually provided by a secondary diesel engine that is scarcely regulated, even in Europe or the US, and can emit far more air pollution than the propulsion engine hauling it around.
Such transport refrigeration units (TRUs) can emit up to 6 times as much nitrogen oxides (NOx) and 29 times as much particulate matter (PM) as a Euro 6 propulsion engine. These are the toxic pollutants that cause 3.7 million premature deaths worldwide each year. Here again, we expect the number of TRUs in developing countries to soar, taking the global fleet from around 4 million today to as many as 18 million in the next 15 years. So in transport refrigeration, we must not only replace F-gases and raise efficiency, but also find a new ‘source’ of energy to displace diesel.
The good news is that clean cold technologies are beginning to be developed with the potential to dramatically reduce the environmental damage of cooling. The Dearman engine, for example, which is being commercialised first as a zero-emission TRU, is powered by the expansion of liquid nitrogen, to generate both cold and power.
This eliminates diesel and its toxic emissions of NOx and PM, and can have a positive impact on well to wheel CO2 emissions. What’s more, unlike many other zero emission technologies, it is also cost competitive.
This is only one example of a new breed of clean cold technologies recognised by the Birmingham Commission on Cold, which reported last year. None is a panacea, but they may represent the beginnings of a radically new approach to cooling that is beginning to be known as the ‘cold economy’. This applies system level thinking to cooling for the first time, to radically improve efficiency, and reduce its environmental impact and cost.
Unlike the Kigali amendment, the cold economy attempts to tackle the entire environmental impact and sustainability of cooling – not just one part of it. So of course Kigali is vital, but it is only a first step on the road to clean cold.