Heat is the largest energy end-use with over 50% of global final energy consumption

Heat is a form of energy that determines the temperature, volume, and state (gas, liquid or solid) of a material. It can be transferred from one object to another, to raise or lower temperatures, and is most commonly transferred from warmer to cooler matter. It can be produced by converting other forms of energy, such as chemical energy stored in fuels or electrical energy, in boilers, furnaces, pumps or electric heaters. Heat energy allows us to warm and cool our buildings, provides us with hot water and the ability to cook our food. Heat is also required for industrial production of steel, chemicals, food and drink.

Heat accounts for a large proportion of greenhouse gas emissions; the decarbonisation of heat is thus vital to reach emission reduction targets. With various means of production and range of uses embedded in all aspects of our lives, heat constitutes a complicated system that is difficult to lead down a single desired path. As such, fewer countries currently have policies for renewable heat than have policies for renewable electricity and transport.

Unlike electricity which can be decarbonised solely by feeding renewable energy into the grid, decarbonising heat also depends on changes at the point of use and may require millions of homes to replace their gas or oil-fired boilers with a new technology. There is no one-size-fits-all solution, since the fuel mix and the means of delivery to the end-user vary greatly from one country to another. Thus, a multiple-technology approach towards low carbon heat is most likely required, resulting in a mix of pathways. These could include electrification using heat pumps, using sustainably-produced hydrogen as a fuel, and setting up district heating networks which can incorporate a range of low-carbon heat sources as well as waste heat from various industrial and urban processes. Heat energy efficiency is also key for emissions reductions and advancements can be made in thermal performance of buildings (e.g. insulation) and the efficiency of heating systems. Wider deployment of combined heat and power (CHP), as it produces electricity and useful heat at the same time, can also help to improve the efficiency of the wider energy system. However, public acceptance, high upfront capital costs, and additional infrastructure and storage requirements pose significant challenges to implementing such transformations of the heat system.

Read our Energy Insights on heat.

Find out energy professionals’ expectations for the future sources of heat in the UK.

Learn more about district heating or combined heat and power by browsing our online knowledge resources.