Annual heat consumption expanded by 6% globally over 2017-2022. Renewable energy – excluding traditional uses of biomass – met only half of this increase, with its share in global heat consumption rising by only 2 percentage points to 13% in 2022.1 More than two-thirds of global growth in renewable heat use was in the form of bioenergy (especially in industry) and renewable electricity (mainly in buildings).

Industry sector renewable heat use increased the most in India over the last six years, owing chiefly to expansion of the sugar and ethanol industry that uses biomass residues, and – to a lesser extent – to the development of biomass briquette use in industrial boilers. The next-largest increases were in the European Union, thanks mainly to greater municipal waste and biomass use, and in the People’s Republic of China (hereafter “China”), with increasing reliance on electricity (a growing part of which is renewables-based) for process heat.

In the buildings sector, three-quarters of renewable heat developments in the past six years took place in China, the European Union and the United States.2 Heat pump deployment has played a major role in all these markets, translating into rising consumption of both electricity and ambient heat for space and water heating. Large additional contributions also came from electric heating equipment and solar thermal and geothermal developments in China, and increased biomass boiler and stove use in the European Union.

Renewable heat consumption is expected to accelerate slightly over the outlook period, rising more than 40% (+12 EJ) globally during 2023-2028 – twice the increase of the previous six-year period. Nonetheless, this growth represents just 70% of the projected global increase in total heat demand, leading to rising fossil fuel consumption for heat and associated CO₂ emissions (+5%/+0.6 Gt CO₂ in annual emissions). Over 2023-2028, cumulative heat-related CO₂ emissions are anticipated to total 86 Gt CO₂ – more than one-fifth of the carbon budget remaining for a 50% likelihood of limiting global warming to 1.5°C.3

Industrial heat demand is projected to expand 16% (+17.6 EJ) globally during 2023-2028, with China and India together accounting for more than half of the growth. Over this period, renewable heat developments are expected to represent just over one-third of additional heat demand, despite nearly 50% growth in consumption. The share of renewable energy sources in global industrial heat consumption is therefore anticipated to continue rising only slowly, from 12% in 2022 to 15% in 2028.

Renewable electricity makes by far the largest contribution to projected renewable heat developments in industry, representing 70% of the growth in annual consumption over the forecast period. This trend results from rising shares of renewables in electricity generation and, even more significantly, the tripling of electricity consumption for process heat.

This growing reliance on electricity for process heat (from 4% of global industrial heat consumption in 2022 to almost 11% in 2028) comes mostly from non-energy-intensive industries, with industrial heat pumps increasingly meeting temperature needs of up to 200°C, and from scrap metal recycling and aluminium industries, which use electric arc furnaces. China leads this trend, enlarging its use of renewable electricity for process heat more than fivefold over the outlook period, representing almost half of global growth while the European Union, the United States and Japan together account for one-third of it.

Remaining industry sector growth in renewable heat use comes essentially from rising bioenergy consumption (+1.8 EJ/+15%), which remains the largest renewable energy source globally, meeting around 10% of global industrial heat demand over the outlook period. More than 60% of this projected growth takes place in India. However, global bioenergy developments essentially reflect expanding industrial activity rather than fuel switching. 

Global heat consumption in the buildings sector is expected to remain flat during 2023-2028, as increases in sub-Saharan Africa, Europe,4 the Caspian region and most of Southeast Asia (resulting from population growth, changes in living standards and greater service sector activity) offset declines in the United States, India, China, Japan and Indonesia (owing to energy efficiency improvements).5 Modern uses of renewable energy sources for space and water heating, as well as for cooking, are projected to expand nearly 40% in the meantime, raising the share of renewables in buildings sector heat consumption from 15% in 2023 to 21% in 2028, and displacing 5.7 EJ of fossil fuel consumption in 2028.

Renewable electricity remains the fastest-growing renewable heat source in buildings during the outlook period, its use expanding by two-thirds globally (+2.2 EJ) and contributing almost 40% of the sectoral increase in renewable heat consumption. China, the European Union and the United States lead this trend, making up 70% of global growth in renewable electricity use for heat in buildings. In contrast with the industry sector, three-quarters of this growth results from a rising share of renewables in power generation, while the rest comes from the deployment of new electric heaters, boilers and heat pumps.

Boosted by strong policy support in the context of high energy prices, global heat pump sales rose 11% in 2022. The European market experienced record 39% growth with 3 million new units installed, while in the United States heat pump purchases exceeded those of gas furnaces. The Chinese market – the world’s largest heat pump market – remained stable, however, due to the global economic slowdown.

Heat pumps typically use three to five times less electricity than conventional resistive electric heaters and boilers for a given heat output. While heat pumps consumed less than 15% of the electricity used for heat in buildings globally in 2022, their deployment accounts for one-third of the global increase in electricity use over 2023-2028, and nearly one-quarter of the growth in renewable electricity use.

Furthermore, heat pumps participate in renewable heat uptake not only by using electricity but by harnessing ambient heat, which represents one-quarter of global growth in renewable heat consumption in buildings during 2023-2028 – the second-largest increase (+1.4 EJ) after renewable electricity. This expanding ambient heat contribution comes primarily from China, followed by the European Union and the United States, owing to strong policy support (investment grants, fiscal incentives and loans) introduced in 2021.

Bioenergy remains the largest renewable heat source in buildings globally by 2028, accounting for one-fifth (1.1 EJ) of modern renewable heat developments in the sector over the outlook period. Modern bioenergy use in buildings expands most notably in sub-Saharan Africa, China and India, where improved biomass cookstoves and heating stoves are replacing traditional uses of biomass.

Solar thermal heat consumption in buildings is projected to increase nearly 40% (+0.7 EJ) during 2023-2028. Despite domestic market contraction since 2020 due to Covid-19 lockdowns, China continues to dominate global solar thermal developments, being responsible for one-third of consumption growth during the outlook period. Meanwhile, developments in the direct use of geothermal heat represent 6% (0.35 EJ) of projected growth in renewable heat consumption in buildings globally, with China anticipated to continue leading growth.

Excluding ambient heat, the outlook for renewable heat developments for 2023-2028 has been revised up 17% from the Renewables 2022 projection, with the buildings and industry sectors contributing in similar proportions to this revision. Yet, projected renewable heat developments by 2028 are still largely insufficient to displace fossil fuel use significantly and put the world on track to meet Paris Agreement ambitions.

To align with IEA Net Zero Emissions by 2050 Scenario targets, global renewable heat consumption would have to advance 2.2 times more quickly, while wide-scale sufficiency-oriented behavioural and social change,6 and much larger energy and material efficiency improvements, would be required to reduce global heat demand by more than 2% during 2023-2028.

In the Net Zero Scenario, industrial consumption of bioenergy and renewable electricity for heat both increase 2.3 times faster than in our outlook, resulting in the largest discrepancy in absolute value between the two trajectories. Meanwhile, solar thermal and geothermal heat consumption in industry in the Net Zero Scenario expands almost 20 times faster than currently projected.

For the buildings sector, the Net Zero Scenario outlines a substantial 21% reduction in heat demand during 2023-2028 and relies on much stronger (4.4 times faster) modern bioenergy development, mostly to replace the traditional use of biomass, which is assumed to decline 70% (-17 EJ). Faster heat pump deployment in the Net Zero Scenario also prompts renewable electricity use and ambient heat consumption to increase more than 40% more quickly than in our outlook. Meeting the scenario’s trajectory would require that heat pumps make up nearly 40% of global heating equipment sales by 2028 – more than double our current outlook amount, and four times more than in 2022.

Meanwhile, annual solar thermal heat consumption expands twice as quickly in the Net Zero Scenario as in our outlook. In the scenario, these renewable energy developments in the buildings sector are partly stimulated by a global ban on sales of new fossil fuel-fired boilers in 2025.

Finally, while the amount of heat supplied by district networks is assumed to decline slightly as building stock efficiency increases, the share of renewables in district heat supplies is assumed to exceed 8% by 2028.

Overall, the share of renewables in heat consumption rises to 22% in industry and 34% in buildings by 2028 in the Net Zero Scenario, while cumulative heat-related CO₂ emissions over 2023-2028 are 8% lower than in our outlook.