Helping a warming world to keep cool

Heatwaves this summer that have left many Europeans sweltering highlight the growing demand for air conditioning in a warming world. Access to cooling services is becoming a major issue, especially in developing countries where owning an air conditioner is still uncommon.  

Nearly 2.8 billion people today live in hot countries, where the average daily temperature is greater than 25°C. Less than 10% of them own an air conditioner, compared with ownership of more than 90% in countries like Japan and the United States. And while as many as 2.5 billion people in hot countries are projected to have an air conditioner by 2050, another 1.9 billion could still be going without.

Recent IEA analysis examines the amount of energy that would be needed to provide access to affordable and sustainable cooling solutions for all. We consider in our Cooling for All scenario the challenges and implications of achieving access to air conditioning for more than 90% of people living in hot climates by 2100. That comes in the context of the much bigger challenge of first providing reliable access to electricity in developing countries.

That fundamental issue informs the IEA’s Sustainable Development Scenario, which charts a path to universal electricity access by 2030 and other sustainable energy goals. In that scenario, more than one-third of the 900 million people currently living in rural areas without electricity gain access through off-grid solutions, and another 400 million gain access via mini-grids.

Our Cooling for All analysis considers two possible approaches to providing cooling services for areas in which off-grid technology solutions are likely to be used for electricity access. Under the first approach, people in hot countries gain access to cooling services using a diesel generator distributed to individual households with one small air-conditioning unit to cool around 20 square metres of space. The second approach uses a solar photovoltaic (PV) unit with battery storage in the same situation.

In both cases, access to air conditioning is assumed to increase significantly over the next 30 years, with as much as 75% of the total population living in hot countries potentially having an air conditioner by 2050. This means that an additional 720 million people, or equivalently 175 million households, beyond those already expected to purchase one would have access to an air conditioner by 2050. This grows to as much as 1.6 billion people by 2100 – giving access to cooling to the equivalent of the current populations of India and Brazil combined.

Achieving this would come with significant challenges. Providing access to an air conditioner is only one element of a Cooling for All scenario. How often households use the air conditioner and how affordable it is are also important factors to consider, particularly as cooling is only one piece of the puzzle of improving access to modern energy services in many developing countries.

Other energy needs – such as clean cooking, lighting and refrigeration – are also critical parts of the energy access story. Even the use of just a small air conditioner for a few hours every day would represent a significant share of a household’s electricity demand.

Meeting the energy demands of the 175 million households gaining access to an AC by 2050 in the Cooling for All scenario would require roughly 105 terawatt-hours (TWh) of electricity in 2050. Around 45% of that would be consumed by the AC units, piling onto the yearly diesel costs for generator operations. Given that households with limited energy access typically have low disposable incomes, this means that additional cooling services would likely represent an important opportunity cost, even if the households were given access to a generator and small AC unit.

This challenge underlines the importance of super-efficient ACs and appliances for off-grid applications in developing countries. High energy performance of ACs would drastically reduce the necessary diesel consumption for electricity generation. For instance, if the average performance of the ACs distributed to households were to improve by 50% by 2050, the yearly running cost for the diesel generator for three hours of daily cooling would drop by more than a third.

These cost estimates could vary substantially when taking into account the differences in diesel prices based on a household’s location. For example, transportation costs are higher for difficult-to-reach areas. The risk is that some households may not use the air conditioners because of operational costs, defeating the ambitions of affordable access to cooling even with energy-efficient air conditioning. Other factors, such as local air pollution created by diesel fuel consumption, could also affect the use of air conditioners.

Improvements in solar technologies, including lower costs, are offering new opportunities to make significant progress on electricity access in developing countries. Solar PV packs are a growing market for providing off-grid access. Expanding that access to include cooling services via an AC would require greater electricity generation and battery storage capacity. But it could potentially offer an affordable form of access to cooling for populations in hot countries.

Initial analysis suggests that a large single solar module with a maximum capacity of 250 W and a lithium-ion battery would not be sufficient to cover the entire electricity demand of a typical household based on an air conditioner performance of less than 3.5 EER. But on a sunny day, it could cover around 80% of the demand.

As with diesel generation, this underscores the critical need for high-performance AC equipment to reduce the net impact of electricity demand from household AC use. This case also shows the need to increase the net solar module capacity to meet overall electricity needs.

For example, a more efficient air conditioner would enable to the solar module to cover nearly 95% of the electricity demand on a good day. But the solar module would probably still have difficulty meeting the household’s energy demands over the course of the entire day, particularly during peak hours in the evening.

One solution to this challenge could be to provide greater solar and battery-storage capacity or, for example, to use more efficient cold storage, such as chilled water or ice making (which, however, could only be used for cooling services and not the additional electricity loads).

Hybrid systems that supplement the solar PV generation with some diesel capacity are already common in some developing countries today and could also be a sensible solution for meeting household electricity demands more reliably. The operational costs of a hybrid system would be much more affordable than a diesel generator.

There are numerous additional measures that should be considered when addressing access to cooling, such as basic building design.

Low-tech and generally low-cost building measures, including passive cooling solutions, can drastically improve thermal comfort in buildings and therefore reduce or eliminate the need for cooling that consumes energy. This includes commonly used solutions such as overhangs, shutters and cool- or light-coloured roofs. Additional low-tech solutions – such as rammed-earth wall construction, green roofs and urban vegetation – can also improve thermal comfort in buildings.

Alternative technologies to air conditioning – such as high-efficiency fans, evaporative coolers (in dry climates) and dehumidifiers (in humid climates) – could help to improve access to thermal comfort in the evening, when people return home, while using far less electricity than an air conditioner. These measures could also fit well with current solar PV module deployment in many countries.

At the same time, air conditioners may make a lot of sense for applications outside the home. For instance, some of the hottest parts of the day in many countries are in the mid- to late-afternoon when people are often outside their homes in places like schools, hospitals and health centres, public buildings and community centres. Access to air conditioning in those facilities may make sense in terms of energy emissions and affordability, as well as offering other potential benefits such as improved health and greater productivity.