Helen Ltd is reducing the already low nitrogen oxide (NOx) emissions of its power plants. Due to its environmental investments of almost EUR 20 million, NOx emissions at the Salmisaari and Hanasaari power plants will fall to about a half of the current levels.
Thanks to long-standing work spanning several decades, the impacts of the power plants’ emissions on the air quality of Helsinki have been reduced to the current, extremely low level.
Entering into force in January, the Industrial Emissions Directive will tighten the power plants’ emission limits of particulates, sulphur oxides and nitrogen oxides in many respects to less than half of the current levels. Helen’s particulate matter emissions have been very low as it stands, and they are already below the new emission levels. In addition, the efficiency of the desulphurisation plants of the coal-fired power plants has been improved. However, the reduction of nitrogen oxide emissions has required significant measures.
In order to reduce NOx emissions, an SCR (Selective Catalytic Reduction) catalyst has been implemented at the Salmisaari power plant. Representing the best available technology, the catalyst cleanses nitrogen oxides of flue gases as an aftertreatment. At the Hanasaari power plant, nitrogen oxides are cleansed in a power plant boiler with the SNCR (Selective Non-Catalytic Reduction) with a urea spray system.
In both methods, harmful nitrogen oxides are converted into harmless nitrogen gas, which already constitutes the majority of the air we breathe. That way, environmental impacts that are already at a low level will be significantly reduced even further.
Equipment testing under way
– The testing of equipment is currently under way. As of 1 January 2016, we will be able to stay below the new emission levels for nitrogen oxides set for Helen, explains Helen’s project manager Reima Rynö.
Helen’s energy production has grown from the 1990s until today, but the emissions have fallen significantly during this time. The latest environmental investment will raise this already good level even further.
The Salmisaari power plant needed extensive construction work due to the SCR catalyst.