Information on power plant emissions
Sulphur dioxide emissions
Sulphur dioxide is produced in the combustion of sulphurous fuels, such as coal and oil. The sulphur dioxide of flue gases turns into sulphuric acid when it reacts with the water vapour in the air. Together with nitric acid, it causes acidification of soil and waterways. Due to the desulphurisation plants of Hanasaari and Salmisaari and the coal qualities with low sulphur content, the sulphur emissions in Helsinki have fallen by about 76% since 1990. Introduction of centralised district heating in the mid-1950s also helped to significantly reduce sulphur dioxide emissions. The bulk of acid deposition in the Helsinki Metropolitan Area comes from outside the Finnish borders as long-range transport of pollution. Helsingin Energia accounts for about 3% of the total sulphur dioxide emissions in Finland.
Nitrogen oxide emissions
In energy generation, nitrogen oxides are derived from the nitrogen contained in fuels and the combustion air itself. Nitric acid is produced when the nitrogen oxide in the flue gases reacts with the water vapour in the air. Together with nitric acid it causes acidification of soil and waterways. The combustion technology in Helsingin Energia’s Hanasaari and Salmisaari power plants was modified in the early 1990s in order to reduce nitrogen oxide emissions. The new solutions included improved coal pulverisation, special burners and extra-air nozzles and ducts. Most of the nitrogen oxide depositions in Helsinki come from outside the Finnish borders. Finland’s own nitrogen oxide emissions in acidified nitrogen deposition accounted for 15%. Helsingin Energia’s share of the total nitrogen oxide emissions in Finland in 2001 was two per cent. Compared with 1990, Helsingin Energia’s nitrogen oxide emissions have fallen by 57%, now accounting for some 3% of Finnish emissions.
Carbon dioxide emissions
Carbon dioxide is the most significant greenhouse gas produced as a result of human activities. It accounts for about half of the total amount of gases causing climate change. Carbon dioxide emissions are produced in the combustion of fossil fuels. Energy production accounted for about 80% of the total carbon dioxide emissions in Finland. In accordance with the Kyoto Protocol, Finland aims to limit its carbon dioxide emissions to the 1990 level by 2010. Helsingin Energia has already done a great deal in order to restrict carbon dioxide emissions. We have successfully reduced our carbon dioxide emissions by raising the efficiency of fuels to more than 90% with combined heat and power (CHP) generation and by adopting natural gas as the main fuel in production. Helsingin Energia’s share in the total carbon dioxide emissions in Finland was about 5%.
Particle emissions
The fine particles floating in the Helsinki atmosphere mainly come from the city’s vehicle traffic, construction industry and as long-range transport of pollutants from outside the Finnish borders. In Helsinki, the share of energy production in the limit value of particles of the proportional concentration is less than 3%. In the power plants, particle emissions are produced in the solid fuel combustion process. Particles are also produced when sulphur and nitrogen oxides turn into acid particles. Helsingin Energia accounts for about 1% of the total particle emissions in Finland.