Environmental impacts

Flue gas emissions from energy production constitute our most significant environmental impact.

Environmental impacts

We aim to keep the emissions of our power plants having an impact on air quality, i.e. sulphur, nitrogen and particulate emissions, within the constantly tightening limit values specified by the authorities.

In 2016, we kept within the emission limits at all other power plants except at Salmisaari. The automation and electrification of both boilers at the Salmisaari power plant were modernised. In connection with the deployment of new automation, the emissions of the other boiler exceeded the monthly emission limit on four occasions. The exceedances did not cause any harm to the environment or human health.

Increased use of coal also had an impact on the amount of air emissions in 2016. Sulphur dioxide emissions grew by almost 70 per cent. Nitrogen oxide emissions remain unchanged as flue gas cleaning has been improved.

Acidifying emissions


 Sulphur dioxideNitrogen oxides
2012 2370 4420
2013 2240 3890
2014 1960 4140
2015 1550 3560
2016 2700 3550



 Sulphur dioxideNitrogen oxides
2010 180 390
2011 170 350
2012 180 330
2013 180 300
2014 160 320
2015 130 280
2016 220 280

Particulate emissions increased by about 55 per cent on the previous year, but they remained below the limit values specified by the authorities. The change was due to the increased use of coal.

Particulate emissions


2012 120
2013 130
2014 130
2015 72
2016 110



2012 9
2013 10
2014 10
2015 6
2016 10

We monitor the emissions of our power plants according to the monitoring plans approved by the authorities. An independent accredited tester ensures the quality of our measurements each year.


The limit values for emissions that adversely affect air quality were tightened at the beginning of 2016 when the EU Directive on Industrial Emissions entered into force. 

Our particulate emissions were already within the new emission limit values. Adjustments were also made to further improve the efficiency of the desulphurisation plants of power plants. The reduction of nitrogen oxide emissions has required significant investment in the emissions reduction technology. In order to keep within the tightening emission limit values, we have invested EUR 20 million in flue gas cleaning. 

From the beginning of 2016, the use of light fuel oil was increased at Helen’s heating plants. The change will reduce the sulphur, nitrogen and particulate emissions of the heating plants and help to meet the tightening emission levels.

The EU is currently updating the guidelines on the type of emission reduction technology that must be used after 2020. We are making preparations for the stricter emission limits. 


Our emissions with an impact on air quality have been reduced considerably over the past few decades. Reasons for the reduction include the commissioning of the Vuosaari power plant, which is operated with natural gas that has lower emissions, as well as the advancement in the flue gas cleaning technology.

The reduced emissions have for long been in evidence in the Helsinki air quality, which is excellent on the international scale. In 2016, the annual average sulphur dioxide contents at the Kallio monitoring station, describing the impacts of energy production on the air quality in Helsinki, was 1.2 µg/m3. The air quality limit value is 20 µg/m3. 

Before the district heating era and combined heat and power generation, the annual average sulphur dioxide contents in the city centre of Helsinki were 50–100 µg/m3.

Sulphur dioxide content at the Vallila (2012–2014) and Kallio (20152016) monitoring station

annual average

2012 2.1
2013 1.6
2014 1.9
2015 1.1
2016 1.2

Previously, the sulphur dioxide contents were measured at the Vallila monitoring station, but it was decommissioned at the end of 2014. Sulphur dioxide contents were measured at the Kallio monitoring station alongside the Vallila station for the entire year 2014, and the results are deemed to correspond with those of the Vallila station. In 2014, the sulphur dioxide contents at the Kallio monitoring station were 1.8 µg/m3.

The impacts of emissions from energy production on the air quality in the Helsinki metropolitan area are monitored as part of the air quality monitoring carried out by HSY. In addition to constant monitoring, the spreading and impacts of emissions on the natural environment are studied.

In the monitoring, it has been verified that the impacts on the natural environmental and the air quality of the Helsinki region caused by emissions from energy generation are very low due to the management of our combustion processes and the cleaning of flue gases. Air quality in the Helsinki region is primarily impaired by traffic emissions and especially by particulate emissions from small-scale wood burning in the winter season.


The majority of the heat we produce is utilised as district heat, which considerably diminishes the volume of heat conducted into the sea and, that way, the impacts on watercourses.

In 2016, a total of 160 GWh of waste heat and cooling energy from power plants and cooling centres was released into the sea. This is 1.3 per cent of the used fuel energy. The annual load has varied between 145 and 2,200 GWh since 2000.

The principal impacts of our energy production on watercourses are the result of conducting cooling water, i.e. warmed-up sea water, to the sea. When studying the impacts of power plants on watercourses, no eutrophication impacts have been detected. Eutrophication in the Helsinki sea areas is caused by other loading, basically by waste waters from households and by scattered loading.

In addition to cooling waters, small amounts of waste and washing waters from power plants, as well as neutralised washing waters from wastewater treatment plants and laboratories, are conducted into the sea. The flow rate, temperature, temperature rise, acidity and hydrocarbon, i.e. oil contents, of the waters conducted into the sea are monitored and reported to the authorities. The entry of oil into the waterways is prevented with oil separation pools equipped with alarm systems.


In 2016, one environmental deviation took place. We investigate all deviations and, if necessary, we will change our procedures in order to prevent them.

An oil leakage took place at the Ruskeasuo heating plant in December 2016. Oil leaked into the indoor areas of the plant due to human error, and there were no adverse effects on the environment. Oil spill response measures were launched immediately after the fault was detected, and the deviation was reported to the authorities. As a result of the incident, we altered our procedures in order to prevent a similar occurrence.


The waste from energy production mainly consists of ashes and end products produced in flue gas desulphurisation. In 2016, we produced a total of 116,000 tonnes of by-products (2015: 70 000 tonnes), 71 per cent (72 per cent) of which were utilised. The volume of by-products grew due to increased use of coal.

We aim to utilise by-products as efficiently as possible. Utilisation of by-products reduces the use of pristine mineral aggregate and soil.

The utilisation of bottom ash has been hampered by its irregular demand. The use of fly ash and the end product of desulphurisation is constrained by strict rules on their utilisation. It has been difficult to find suitable areas of utilisation especially for the end product of desulphurisation.

In 2016, 79 per cent of fly ash and 31 per cent of the end product of desulphurisation were utilised. Fly ash was used in cement manufacture and landfill structures together with the end product of desulphurisation. The rest was used in the filling of mines. Of bottom ash, 67 per cent was utilised in earth construction and the rest was placed in intermediate storage.

Utilisation of by-products, tonnes

 Intermediate storageDisposalUtilisation
2012 11100 48800 41000
2013 9600 46500 48900
2014 8400 38500 47900
2015 5000 14700 50000
2016 9400 31400 75100


Our operations produce various types of waste. Primarily, we aim to prevent the production of waste. Any waste we produce is sorted and recycled wherever possible. We maintain waste bookkeeping and hand over waste only to transport companies that are in the waste management register and to recipients entitled to receive the waste in question.

In 2016, we produced 8,300 tonnes of waste (2015: 2 600 tonnes), 82 per cent of which was utilised as material and 1 per cent as energy (2015: 36 and 7 per cent). We extended our waste bookkeeping to also include the heating and cooling network, which can be seen as an increase in reported waste volumes.

Waste produced in Helen’s properties and, from 2016, in the energy network areas, tonnes  

 Utilisation as energyHazardous wasteLandfillUtilisation as material
2012 6 100 360 1040
2013 20 340 770 780
2014 130 2310 1160 3170
2015 170 240 1270 950
2016 60 450 1030 6800