A 20% reduction in CO2 emissions from mobile air conditioning by 2050 is possible

A recent report from the International Energy Agency “Cooling on the Move - The future of air conditioning in vehicles” explores the current and future global energy consumption from mobile air conditioning systems, along with the resulting greenhouse gas emissions.
According to a IEA report issued in September 2019 (1), mobile air conditioning (MAC) – i.e. air conditioners in passenger cars, vans, buses and freight trucks – currently consumes over 1.8 million barrels of oil equivalent per day (Mboe/d), which represents more than 1.5% of current global oil consumption.

Around 6% of the annual global energy consumed by cars is used for MAC, varying by country between about 3% and 20% depending on climate, driving patterns and traffic congestion. It can peak at over 40% in warm climates and congested traffic.

In 2015, total carbon emissions from MAC amounted to approximately 420 million tonnes of carbon dioxide equivalent (MtCO2-eq), equivalent to more than 1% of global energy-related CO2 emissions. Of this, around 70% was due to fuel use, whilst greenhouse gas (GHG) emissions from refrigerant leakage were responsible for the other 30%.

In its Baseline scenario, the IEA foresees energy consumption almost tripling to 5.7 Mboe/d by 2050. In this scenario, there are no further improvements to MAC efficiency or changes in refrigerant use. At the same time, annual combined emissions from energy consumption and refrigerant leakage could more than triple to 1 300 million tonnes of CO2 equivalent.

This sharp rise in consumption and emissions is driven by the large increase in activity: there will be more than 2 billion cars and another 450 million other road vehicles globally – more than twice as much as currently – nearly all of which will have MAC installed. The uptake of vehicles with MAC will be greater in countries with warmer climates such as Indonesia and India, while at the same time the expected increase in global ambient temperatures will drive further MAC demand in more moderate climates.

However, the IEA identifies important potential efficiency gains for cooling in vehicles through better MAC technology, improving other components of the vehicle, such as thermal insulation, reflective windows and body paint that reduce heat load, and optimising power trains. If applied in combination, best-in-class technologies could reduce MAC energy demand by up to 67%, halving energy-related MAC emissions.

In the Efficient Cooling Scenario, where the energy efficiency of MAC systems is maximized, the energy consumption would be limited to 2.8 Mboe/d by 2050 – less than half of the Baseline Scenario. With almost universal use of refrigerants – such as HFO1234yf or CO2 – with a GWP of 1 and partial electrification of the vehicle fleet, GHG emissions by 2050 would be 20% lower than today at 320 MtCO2-eq.

The IEA concludes that governments have an essential role to play in ensuring refrigerant and energy-related GHG emissions from MAC are minimised. MAC energy consumption could be included in existing fuel economy standards, expanded vehicle testing methods and/or minimum performance standards for specific air-conditioning components.

(1) https://www.iea.org/publications/reports/coolingonthemove/