AC use surged in 2024 heatwaves, straining grids, fuelling fossil demand

In 2024, extreme heatwaves in India, China, and the US triggered a massive surge in the use of air-conditioning (AC) devices, doubling power demand growth in some months, according to a report by Ember, an energy think tank.

The previous year saw a substantial rise in coal-fired power production (and gas in the US) to satisfy the added demand. 2024 was the hottest year ever, with several heatwaves in highly populated regions around the globe.

Consequently, heatwave-induced use of air-conditioning substantially raised the demand for electricity during the summer months — August and September in China, June in the US, and May in India.

Air-cooling doubled the growth in electricity demand in China during August and September 2024 over the same period last year. It was responsible for all the year-on-year demand growth in the US in June and over one-third of the year-on-year demand growth in May in India.

In August and September 2024, China recorded its highest temperatures for these months in a decade. According to Ember’s assessments, increased air-cooling demand doubled year-on-year power consumption during this period under review. Overall, from April to September 2024, higher air-conditioning needs accounted for 31% of the rise in China's electricity demand compared to the same period in 2023.

In the US, the impact of heatwaves was more pronounced in June 2024 with average temperatures rising to 23.8°C — the highest for the month in the past decade. Air-cooling drove the entire year-on-year rise in electricity demand that month in the world’s largest economy.

Ember researchers also figured that demand in the country would have fallen by 1.3% in June but air-cooling needs resulted in a 9.4% rise instead. Electricity demand in the US — from April to September 2024, relative to the same period in 2023 — jumped 37% for the same reason.

May 2024 was the hottest in India, with temperatures averaging 31.7°C — a 1°C increase from May 2023. Air-conditioning drove nearly one-third of the year-on-year demand increase that month and led to 19% of the demand growth from April to September 2024.

The spike in power demand in India was less pronounced than in the US and China, likely due to unmet air-cooling needs and strong economic growth driving demand from other sectors.

As temperatures soared, straining the grid, all three countries turned to coal-fired power generation, while the US additionally relied on gas to ease the pressure.

The hottest months drove most of China's annual coal-fired power generation surge, with 59% of the 2024 increase recorded in August and September.

While clean energy met over two-thirds of the June demand growth in the US, the rest was supplied by fossil fuels, including gas and coal. In that month, coal-fired generation grew by 6.4% year-on-year and gas by 4.6% year-on-year, noticeably higher than the 2024 annual average growth.

In India, clean energy fulfilled 19% of the increase in May power demand, while coal met 70% and gas covered the rest.

As climate change progresses, driven mainly by the burning of fossil fuels, scientists expect heatwaves to become more frequent and more intense, affecting many countries.

Combined with the rising use of air conditioning — especially in the Global South, where rapid urbanisation and extreme heat are driving a surge in air-cooling device ownership — electricity demand is set to spike even further.

Encouraging the sale of more energy-efficient air-conditioners, promoting solarisation and improving retail pricing can enable households and businesses to generate cheaper, cleaner power and help reduce pressure on the grids during heatwaves.

 Allowing these demand surges to be met with coal and gas generation will increase carbon emissions.

Kostantsa Rangelova, electricity analyst at Ember said, “2024 was the hottest year on record, with heatwaves causing massive spikes in demand — and the pressure will only grow as the planet warms.

The solution is twofold: scale up efficient air-conditioning adoption to cut costs and ease peak demand, and invest in clean, flexible power to keep grids resilient as extreme weather intensifies. The crisis is accelerating — our response must, too.”

Ember is an independent energy think tank that aims to accelerate the clean energy transition with data and policy. It creates targeted data insights to advance policies that urgently shift the world to a clean, electrified energy future.