Reduced emissions from heating in the buildings sector in the Net Zero Emissions by 2050 Scenario depends on high-efficiency electric heat pumps as the primary technology. This is part one of a two-part series.

Image supplied by Refrigeration Industry.

Image supplied by Refrigeration Industry.

The number of heat pumps installed globally rises from 180 million in 2020, to around 600 million in 2030. At least three times more efficient than traditional fossil fuel boilers, installation of heat pumps in individual buildings are forecast to rise from 1.5 million per month currently to around 5 million by 2030.

The fast ramp-up of heat pumps facilitates a complete phase-out of new fossil fuel boilers by 2025 – a key milestone in the NZE Scenario. Heat pumps in combination with energy storage can absorb fluctuations in variable renewable generation, which will enable around 40% of electricity to be produced by solar PV and wind power by 2030. The renovation of the existing buildings stock to the zero-carbon-ready level also enables heat pumps to operate even more efficiently in this segment.

Heat pumps are much more energy-efficient than other renewable and conventional buildings technologies, including low-emission hydrogen and biomass boilers. Once installed and operated properly, one unit of electricity used by a heat pump delivers three to five units of heat on average over the heating season. By contrast, one unit of electricity used by an electrolyser to produce hydrogen, which is then combusted, results in 0.6-0.8 units of heat.

The efficiency of a high-efficiency biomass boiler is around 0.9 units. The efficiency of heat pumps has increased steadily over the past decades due to research, competition, minimum efficiency performance standards (MEPS) and energy labelling schemes. Moreover, heat pumps are multi-service providers since they can deliver heating, cooling and dehumidification needs. Different types of heat pumps suit different applications and regions. There are air-to-air, air-to-water, hot water and ground source heat pumps (geothermal). Enhanced design can improve their efficiency even further. For instance, the seasonal energy efficiency can reach 500% to 1000% in commercial buildings for both heating and cooling demand.

Heat pumps can also contribute to meeting national targets for the share of renewable energy in the mix. When coupled with building-integrated PV or powered with off-site renewable electricity, they are a fully renewable solution, making electrification an important lever to phase out fossil fuels. Heat pumps can already be integrated at the district and urban levels. Smart thermostats and active controls can unleash their demand-side response potential and help achieve higher shares of variable renewables in the grid.

In several regions, heat pumps already have a considerable market share due to their beneficial total life-cycle cost, especially in the Nordic European countries – for example, Norway, Sweden, Denmark and Finland – but also in France. In Sweden, 29% of the heating demand in buildings is covered by heat pumps and the corresponding figure for Finland is 15%. In other regions – such as parts of the US and Japan – heat pumps already represent a large share of the heating markets since they can also fulfil demand for cooling. In Japan, a reversible air conditioner is usually the only space heating appliance due to moderate heating demand in comparison to cooling needs. In the US, about 40% of new single-family homes are heated by heat pumps. In these countries, the market and the value chains are well developed, and end-user awareness and acceptance are both high. In several other countries, the market share is significant for newly-built houses because heat pumps are often the best option to meet energy performance standards set by new building regulations.

Continued in part two…