Friday, August 19, 2011
District heat: A major advantage of Swedish energy system
District heat (or fjärrvärme in Swedish) is a costly investment, but with many advantages. In many countries in the world there is a network of electricity, but not district heat or chill as we have in Sweden. When you burn coal, oil, nuclear energy, biomass etc. to produce electricity, the efficiency is generally about 40%. It means just 40% of the original energy is recovered in form of electricity, while the rest of the energy (about 60%) will be lost in form of heat. Therefore, we see big cooling towers as part of the power plants.
There is similar problem in industries. When the industries consume energy (electricity, oil etc.) to run their equipment, a major part of this energy is converted to heat, and in many cases, they have to get rid of this energy (heat).
Sweden is a cold country with the average temperature of 4.8 C for the whole country through the year. Many cities in Sweden have district heat system to heat up the houses. The energy companies burn waste, biomass etc. and produce electricity and the rest of the energy is fed to this distric heat system and transported to the households. It creates a good income by:
1) getting paid via collecting the wastes,
2) selling electricity
3) selling district heat
In addition, the companies (such as refineries) with waste heat are connected to this network of district heat. It means an extra income for these companies, while their competitors in other countries have to pay to get rid of this energy.
In Sweden, 69 TWh district heat was produced in 2010, where 9 TWh was lost through the system and 60 TWh was delivered to the households. The energy source was dominated by hosehold wastes and biomass (figure below). The complete report can be found here!
(Distric heat production in Sweden in 2010 from different energy sources)
This blog is dedicated to collect some interesting news and developments on biofuels, bioenergies, biomaterials and biological treatments of residuals and wastes, as well as my personal opinions in this field.
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