Environmental Benefits of Heat Pumps
Dieter Wittwer, FWS, Seefeldstr. 5a, CH-8008 Zurich

Heat pump technologies are widely used for upgrading ambient heat from sustainable sources, such as air, water, the ground and waste heat, to heating temperatures. They can be used for residential and commercial space heating, cooling and water heating, refrigeration and in industrial processes. In producing heat , they are called heat pumps and they compete with fossil fired boilers and direct electric heating. This paper addresses the large potential contribution of heat pumps in reducing CO2 emissions. It is possible to save up to 6% of the global CO2 emissions by using heat pumps worldwide. The market share of heat pumps in new built single family houses in Switzerland shows, that this technology is also interesting with regard to economy.
The environmental impact of an electric heat pump applied in a building is compared with a conventional boiler. The single most important CO2 emission source is the local combustion of oil or gas in a boiler and the generation of electricity for driving the heat pump compressor. The emission rates of a boiler and a electric heat pump depend on the energy efficiency of the equipment, and on the fuel mix and efficiency of electricity generation. The relative CO2 emissions of conventional heating systems are compared with different types of heat pumps. Assumed is an average European CO2 emission for electricity of 0.55 kg CO2/kWhel. The result shows, that the electric driven heat pump reduces the CO2 emissions by 45% compared to an oil boiler, or 33% compared to an gas fired boiler. Gas heat pumps have reduction rates of the same amount. The impact of heat pumps in Switzerland is even greater because of the high amount of water power production of around 60%. This may be an important factor of the market success in Switzerland. In conclusion, heat pumps offer a distinct advantage over conventional heating systems in terms of CO2 emissions.
The results of installed heat pumps so far can be summarized as follows: (1997 hp stock)

This means that already installed heat pumps are saving 0.5% of the total global CO2 emissions of 22 billion tonnes.
The potential of heat pumps for reducing global CO2 emissions is naturally much higher than the current small rate of less than 1%. It is estimated, that the 30% CO2 emissions from the buildings can be reduced by 50%. This will save 1 billion tonnes. In the industrial sector 0.2 billion tonnes are saveable by industrial heat pump systems.

The key factors will be the future prices of fossil fuels, of electricity and of the equipment. In the residential sector the heat pump equipment price is around 600 $/kWthermal. Due to rising seasonal performance factors ranging between 3 and 4.5 the price per MWh heating energy is in the vicinity of 30 $. The economy of heat pump energy will get even more attractive due to the liberalisation of the electricity market and the foreseeable tax increases for fossil fuels.

In conclusion, there is a large potential for extending the present environmental advantage of heat pumps over conventional systems. This is an invitation for all countries to invest in heat pump technology and to reduce CO2 emissions in an economical way.

In Memoriam: Dieter Wittwer sadly deceased shortly after his excellent speech at the CLEAN ENERGY 2000 Conference in Geneva just after he founded the Swiss Heat Pump Association.

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