District heating production units in Helsinki metropolitan area

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District heating energy production in Helsinki metropolitan area is divided by three energy companies in 2007; Fortum Power and Heat Oy, Helsingin Energia and Vantaan Energia Oy. These companies energy production units are listed in following table.[1]

. . . . . . HEAT OUTPUT HEAT OUTPUT HEAT OUTPUT . . .
DISTRICT HEATING COMPANY AND NAME OF THE PRODUCTION UNIT Type of production unit Connected to a CHP Year started up Number of boilers Type of the boiler v/h Via turbines Direct from boilers Total Power output Main fuel Capacity of heat pump
. 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 4.11
. . . . . . MW MW MW MW . MW
Fortum Power and Heat Oy, Espoo
Kivenlahti klk - 1974 2 v - - 130,0 - bio -
Suomenoja 4 klk 1 1989 1 v - - 35,0 - maka -
Tapiola klk - 2002 2 v - - 160,0 - rpö -
Suomenoja 1 klk 1 1977 1 h - - 160,0 - rpö -
Suomenoja 3 klk 1 1986 1 v - - 70,0 - kihi -
Vermo klk - 1985 2 v - - 80,0 - rpö -
Kaupunginkallio klk - 1991 2 v - - 80,0 - rpö -
Otaniemi klk - 2001 3 v - - 120,0 - rpö -
Auroranportti klk - 1998 1 v - - 15,0 - kpö -
Juvanmalmi klk - 2000 1 v - - 15,0 - maka -
Kalajärvi klk - 2000 2 v - - 5,0 - maka -
Vermo klk - 2007 2 v - - 90,0 - rpö -
Masala klk - .. 5 v - - 18,0 - maka -
Kirkkonummi (keskusta) klk - .. .. v - - 31,0 - maka -
Suomenoja 1 lvl 1 - 1977 1 - 162,0 - 162,0 75,0 kihi -
Suomenoja 2 mlvl 2 - 1989 1 - - - 80,0 49,0 maka -
Helsingin Energia
Alppila klk - 1964 4 v - - 164,0 - rpö -
Munkkisaari klk - 1969 5 v - - 235,0 - rpö -
Ruskeasuo klk - 1972 4 v - - 280,0 - rpö -
Lassila klk - 1977 4 v - - 334,0 - maka -
Patola klk - 1982 6 v - - 240,0 - rpö -
Salmisaari klk 1 1978 3 v - - 120,0 - rpö -
Salmisaari klk 1 1986 1 v - - 180,0 - kihi -
Salmisaari klk 1 1977 1 h - - 8,0 - rpö -
Jakomäki klk - 1968 2 v - - 56,0 - rpö -
Myllypuro klk - 1978 2 v - - 240,0 - rpö -
Vuosaari klk 3 1989 3 v - - 120,0 - maka -
Hanasaari klk 2 1977 1 h - - 56,0 - rpö -
Katri Vala lp - 2006 5 - - - 90,0 - muu 30,0
Salmisaari lvl 1 - 1984 1 - 300,0 - 300,0 160,0 kihi -
Hanasaari lvl 2 - 1973 2 - 420,0 - 420,0 228,0 kihi -
Vuosaari lvl 3 - 1991 4 - 580,0 - 580,0 630,0 maka -
Helsinki-Vantaan lentoasema
Lämpökeskus klk - 1976 4 v - - 32,0 - rpö -
Vantaan Energia Oy
Pähkinärinne klk - 1974 2 v - - 46,6 - rpö -
Koivukylä klk - 1972 4 v - - 145,0 - maka -
Hakunila klk - 1972 2 v - - 80,0 - maka -
Martinlaakso klk 1 1976 1 v - - 60,1 - rpö -
Metsola klk - 1977 2 v - - 17,4 - rpö -
Katriina klk - 1990 2 v - - 3,6 - bio -
Maarinkunnas klk - 2002 5 v - - 200,0 - maka -
Martinlaakso 2 lvl 1 - 1982 1 - 135,0 - 135,0 80,0 kihi -
Martinlaakso 1 lvl 2 - 1975 1 - 120,0 - 120,0 60,0 maka -
Martinlaakso Gt mlvl 3 - 1995 1 - - - 75,0 58,0 maka -
Katriina mlvl 4 - 1994 1 - - - 0,6 0,4 bio -
Col. 4.2 Col. 4.10
klk = stationary heating plant kihi = coal
lp = heating pump rpö = heavy fuel oil
lvl = steam power station kpö = light fuel oil
mlvl = other power station jtu = milled peat
ptu = sod peat
Col. 4.5 maka = natural gas
popu = forest fuel
v = water tept = industrial wood residues
h = steam pjät = black liquour
bio = biogas
kipa = recovered fuels
sek = Industrial reaction heat
säh = electricity
muu = other 
 Note! Masala and Kirkkonummi production units are located in Kirkkonummi and not in Helsinki metropolitan area.


District heating is efficient method to produce thermal energy in cities and population centrals. Base idea is to produce centrally needed thermal energy for the area. This means customers and energy production plants are connected to each other with a grid.

Single apartment need of thermal energy could be determined by a warm tap water condenser, because the amount of energy, which is needed to increase houses indoor temperature, is negligible compared to energy, which is needed to heat tap water. Thermal energy, which is needed to increase indoor temperature, fraction of needed thermal energy increases, when an apartment multiplies in numbers, for example like in an apartment house. Multiple apartments’ need of thermal energy is less than sum of single apartments. The difference is caused by desynchronized use of warm tap water.

Customer’s connection to a district heating network can be done two ways: 1) open cycle and 2) closed cycle systems. In open cycle system fraction or all the water, which flows in district heating network, flow in thermal energy transferring system and it will be consumed in the destination. This means that needed warm tap water will be taken directly from district heating network and dumped to the sewers after use.

In closed circle system different water flows in thermal energy transferring system than in district heating network and the networks water won’t be consumed in destination and will return to the network. This means there’s condenser between the customer and district heating network, which will transfer needed energy to customer. Closed circle connections are mainly used in Finland.

Need of thermal energy in district heating network has to be specified in the building phase. Need of thermal energy can be calculated or estimated. Usually it is based on estimations, because often there is no accurate information about number of incoming apartments or how much energy will customers consume.

Transferred thermal energy is controlled mainly by controlling outgoing water temperature in thermal energy production units. This outgoing water temperature is often set to be dependent of outdoors temperature. Pipes heat durability defines limit-value for outgoing water temperature. Also pressure differences and static pressure have to be in control in district heating network. These adjustments and their execution methods are dependent of each others.

The main district heating network adjustment factor is consumer’s need of thermal energy. Thermal energy provider has to guarantee specific pressure difference and thermal energy output in the network that customer can get needed thermal energy from the network. Unnecessary high pressure difference or thermal energy output in the network will cause higher energy losses in the network and thus have to be avoided. Pressure difference in whole network has to be adjusted also, so machines break downs won’t happen. This way flowing water temperature will not go under the boiling temperature and vaporization will not occur in the network. Static pressure in the network has to be adjusted so it won’t go under vaporization pressure.

Temperature of outgoing water adjusting is done by mixing hot water from a boiler with flowing water in the network until the wanted water temperature is reached in heat-only boiler station. Adjustments of pressure differences and static pressure are mainly done by pumps. These pumps are controlled two ways: by throttles or by adjusting pumps tacks. Regulators are not needed if throttles are used in the heat-only boiling stations, because consumers just need to adjust the warm water flow to get needed thermal energy. By throttling most of the thermal energy is committed to the water. Adjusting pump tacks is significantly cheaper than throttling.

Thermal energy production plants connection to the district heating network can be done simplified in two ways; direct and indirect. Direct connection means, that the same water flows in district heating network as in boiler. This method is mostly used in small scale energy production plants. It is quite cheap to make, but in other hand it will put some restrictions to fuels and boiler temperatures for example.

Indirect connection means that in thermal energy production plant boiler flows different water than in district heating network. The plant and district heating network are connected by a condenser. There’s many kind of condensers, but the main idea is that the two water flows doesn’t physically mix together. Indirect connection is mostly used in larger steam turbine plants, but it can be used in small scale plants too.

  • Regulations for district heating plants in Finland

Directive for protecting environment and lowering emissions, so called IPPC – directive, requires information exchange between countries and industry of best available technique (BAT). Based on this information exchange BAT-correlation documents are formed, so called BREF- documents (BAT Reference Documents), which were made for large scale energy production plants in year 2004. BREFs for small scale energy production plants are not determined yet. Finnish environmental law requires use of best technique available. Old air pollution law has implied in small scale energy production plant cases, which is from year 1987. Emissions caps do not imply to current techniques, so permission policy for small scale energy production plants have been diverse in last years.

National assessment for BAT-technique for Finnish 5-50 MW energy production plants was made for uniting the permission policy in year 2003. BAT-levels are not emission caps; they are only for help authorities to set emission caps when the local conditions are taken into account.

Finnish environmental law (86/2000) 20 § requires that action, which is or may be dangerous to environment, must have a permission for it. Actions that require permission are described more closely in the Finnish environmental regulation 1 § (169/2000), where energy production is mentioned in part three. Part three divides in two parts; to nuclear plants and to oil, mineral coal, wood, peat, gas or other flammable material using combustion plants, of which total potential fuel energy output is over 5 MW or which used total potential fuel energy output in a year is at least 54 terajoules (TJ). Energy production plant may have more than one boiler and permission will be given applying combined total potential fuel energy output of the boilers. If the total potential fuel energy output is less than mentioned above, but the plant is located in ground water area, it will require permission as well.

Environmental regulation third moment mentions also, that landfill and disposal plants such as incineration plants requires a permission also.

Authorities permit jurisdiction is regulated in environmental protection regulation second moment. It says that community council will handle permissions, if energy production plant total fuel energy output potential is over 5 MW but less than 50 MW. Over 50 and less than 300 MW plants permissions handles the aerial environmental administrations. Over 300 MW plants permissions will be handled in environmental permission agency.

In 41 § of environmental protection regulation are closer regulations for already exiting 5-50 MW plants and in 43 § for large scale energy production units statutory permission procedure. For small scale plants there is only one emission norm (Finnish government decision 157-1987), which is for particle emission and does not fulfill the BAT- requirements.

  • Small scale district heating units

Total fuel consumption of energy production plants was 580 PJ in Finland in year 2001 and 13 % of it were used in less than 50 MW energy production plants. Numerically there are energy productions plants, which fuel energy output less than 50 MW, about 1400 and larger plants roughly 200 in Finland. Significant part of these small scale energy production plants is backup and peak heating units, which are not constantly in use during a year. In table 1 is fuels used in small scale plants.

Table 1. Fuels consumption in less than 50 MW plants in year 2001.

. Mineral coal Heavy fuel oil Light fuel oil Natural gas Peat Wood other Total
TWh 0,8 5,1 0,2 4,4 2,0 4,6 3,3 20,4
% 4 25 1 22 10 23 16 100

Other fuels in table 1 are mostly fuels from industries processes, like waste- and bigas, coke, pine oil, hydrogen and solid fuels. These can be burned as main or supplementary fuel.

Small or mediocre scale energy production plants are either heat-only and vapor production stations or back pressure power plants, which produce combined electricity and heat or vapor. Among the small scale energy production plants there are technically none electricity-only production plants.

Most of the fuel consumption is done in large scale energy production plants in energy production and most of them also got efficient flue gas cleaning system, so emissions per produced energy are lower than in small scale plants. Small scale plants potential to reduce emissions are then higher, because authorities haven’t required as efficient emission reduction systems as in bigger plants.

Fine particle assessment for energy production was made and possibility to reduce fine particle (PM2.5) emissions was evaluated in year 2007. In the report is calculated that less than 5 MW plants affects almost half the fine particles emissions of energy production in Finland, even though they use only 4 % of the sectors total fuel. In that assessment PM2,5-emission of small scale plants reduction potential is estimated to be 40 % of whole energy production potential.

Most used boiler-types in small scale energy production plants are burner, grate and bubbling fluidized bed boilers. Burners can be used also in Grate boilers, which allow an additional fuel use, like natural gas or heavy/light fuel oil for example.

Heat-only or vapor production stations does not produce electricity and their operation efficiency in these plants are high, even 85-93 %. Flue gas losses cause the biggest efficiency loss in these stations. These are the most common small scale energy production plant types in Finland and in Helsinki Metropolitan area.

Back pressure power plants are traditionally industry- and district heating plants, which produce heat and electricity. These power plants are adjusted so they produce needed thermal energy and electricity is produced on a side. Operation efficiency is typically 80-85 % in industry and 85-90 % in district heating plants. Ratio between produced thermal energy and electricity is about 0,2-0,3 for industry and 0,45-0,55 for district heating plants

Gas turbine-/gas motor-/ diesel motor boilers are also a solution for a small scale plant. These plants produce thermal energy, vapor for a process or both. Ratio between produced thermal energy and electricity often is 0,5-0,6 and total operation efficiency 80-85 % for gas turbine boiler, if it is linked with incineration plant. For similar motor boiler plant the ratio is 0,9 and total operation efficiency is 90 %.

Wood chip and peat are the most used main fuels in small scale energy production plants in Finland. Many plants use mineral coal, refined municipal waste, heavy fuel oil or different waste- and production gases. Boilers type defines fuels which can be used in the plant.

Solid fuels consist roughly three different part; water, flammable and inflammable inorganic material. Flammable material is most important part and the two others parts are weakening factors for combustion vise. Flammable material components are carbon, hydrogen, nitrogen, sulfur and oxygen. Energy, which is released in the combustion, depends of carbon and hydrogen fractions in fuel. Sulfur and nitrogen, which the fuel contains, are significant origin of greenhouse emissions. Fuel contain trace elements also, which fractions are less than 0,1 % of the fuel in mass. Typical thermal values for fuels are listed in table 2.


Table 2. Typical thermal values for different fuels.

Fuel Thermal value Unit Dampness % Ash content
Heavy oil 41,1 MJ/kg 0,5 0,04
Light oil 42,7 MJ/kg 0,02 0,01
Mineral coal 24,8 MJ/kg 10 14
Shred peat 9,66 MJ/kg 48,5 5,1
Industrial wood ship 8 MJ/kg 55 2
Saw dust 8 MJ/kg 53 0,5
Bark of softwood 7 MJ/kg 58 2
Natural gas 35,6 MJ/kg - -
Biogas 15,8 MJ/kg 2
Recycling fuel 16 MJ/kg 25 5

Plants, which use solid fuels, often use supplementary fuels, because accessibility or/and price of the supplementary fuel. Most commonly used supplementary fuels are mineral coal, recycling fuels and heavy fuel oil.

Mineral coal is not used as a main fuel in small scale energy production plants in Finland usually, but often it is used as a supplementary fuel, because coal use would require efficient flue gas cleaning system. Sulfur content of coal varies by the origin. In Finland is specified that sulfur content cap of coal is 1 % (96/61/EY). Because of high ash content, about 10 % of the coal mass, coal burning creates high particle emissions. Because ash contains heavy metals also, heavy metal emissions are high too.

Municipal waste and fuels made of the municipal waste in recycling process are also used mainly as a supplementary fuel in small scale energy production plants in Finland. REF (REcovered Fuel) and RDF (Refuse-Derived Fuel) are the main fuels made out of municipal waste. Use of REF or RDF sets curtain demands for the flue gas cleaning system. Incineration directive came into effect end of year 2005, which restricts incineration plant emission caps to the same low level. This has restricted exclusively use of municipal waste fuels in small scale energy production plants, where flue gas measurement and cleaning commitments would increase expenses too high.

Heavy fuel oil is most suitable for solid fuel boilers as a backup or a supplementary fuel, because it got good accessibility and high thermal value. Oil burning in grate boiler plant requires separate burner. Oil has quite low ash content, so particle emissions are mainly from unburned carbon hydrogen compounds and coke. Emissions are mainly fine particles.

In tables 3 and 4 are listed fuel characteristic and typical emission factors for less than 50 MW plants in Finland. Some of the factors have emission reduction technique like Electro-static precipitator (ESP), cyclones or Low-NOx-burners.

Table 3. Typical carbon dioxide factors for fuels

Fuel Carbon dioxide factor
[g CO2/MJfuel]
Mineral coal 94
Natural gas 45
Heavy fuel oil 77
Light fuel oil 74
Shred peat 106
Woodchip 114

Table 4. Typical emission factors for small scale energy production plants in Finland

Boiler type / Fuel Fuels thermal energy output in the plant NOx SO2 Dust
[MW] [mg/MJ] [mg/MJ] [mg/MJ]
Burner
Heavy fuel oil <5 150-250 350-500 20-90
(some of the plants have Low-Nox burners 5-15 150-250 350-500 10-70
15-50 120-200 350-500 5-40
Light fuel Oil <5 100-150 50-70 <10
(some of the plants have Low-Nox burners 5-15 100-150 50-70 <10
15-50 60-120 50-70 <10
Natural gas <5 60-100 0 0
(some of the plants have Low-Nox burners 5-15 60-100 0 0
15-50 40-80 0 0
Fluidized bed boiler (ESP)
Peat 5-10 150-200 150-250 10-50
10-50 130-200 150-250 5-20
Wood 5-0 80-150 <30 10-70
10-50 80-150 <30 5-30
Circulation fluidized bed boiler (ESP)
Peat 20-50 80-150 150-250 5-20
Wood 20-40 70-120 <30 5-30
Grate (ESP + Cyclone)
Peat <5 150-250 150-250 20-150
5-10 150-250 150-250 5-120
10-50 140-220 150-250 5-100
Wood <5 80-200 <30 20-150
5-10 80-200 <30 20-150
10-50 70-150 <30 10-150
Coal 5-10 70-150 400-600 400-600
25-40 80-200 5-50 5-50

Small scale district heating plants In Helsinki metropolitan area are mainly burner type heat-only stations, which use heavy fuel oil or natural gas. Some of them have cyclones and emulators, but some does not have flue gas cleaning system at all, because particle emissions are low in natural gas burn.

  • Large scale district heating units

In this study district heating units, which thermal output of fuel is over 50 MW, are estimated to be large scale district heating units. District heating produced 31,9 TWh thermal energy in 2008, of which 74 % was produced in combined power and heat (CHP) plants. Larger thermal energy production plants are usually CHP-plants, because they are more efficient than separate energy production plants. 95 % of Finnish CHP-plants are listed in District Heating statistics. In Helsinki Metropolitan area large scale district heating units power and thermal energy production potential is presented in table 5.

Table 5 Capacity of large scale energy production units in Helsinki Metropolitan area.

Capacity of large scale energy production units in Helsinki Metropolitan area CHP-plants Separate heat production units
Thermal energy output via turbines Thermal energy output Total thermal energy output Power output
[MW] [MW] [MW] [MW]
District heating companies 1 717,0 3 645,1 5 362,1 1 340,0

CHP-production is mainly done in a large coal or peat using steam turbine and combined cycle gas turbine power (CCGT) plant now days in Finland. About half of power capacity and two thirds of thermal capacity is based on counter pressure steam turbine technology by division of EU CHP directive. Combined cycle gas turbines are used in electricity production and their electricity output is higher than extracting steam turbines capacity. In thermal energy production extracting steam turbines are second-highest production technology by capacity. CHP-technologies and production in Finland 2005 are listed in table 6.


Table 6. Capacity and production of CHP-technologies in Finland 2005[Vehviläinen et all 2007].

Capacity and production of CHP-technologies in 2005 Capacity Production
[MW] [TWh]
Thermal energy Electricity Thermal energy Electricity
Combined cycle gas turbines 1 857 1 538 10,5 9,5
Back pressure turbines 10 593 2 830 46,6 11,9
Extracting turbines 2 572 1 102 11,2 5,3
Combined cycle gas turbines with modifications 537 292 1 0,6
Combustion motors 91 70 0,1 0,1
Total 15 650 5 832 69 27


In Helsinki Metropolitan area there are two natural gas and four coal using CHP-units. Used turbine types in these plants are back pressure turbines in coal units and combined cycle gas turbine turbines in natural gas units.

CHP-plants produced 93 % of district heating in Helsinki, 60-70 % in Espoo and 87,7 % in Vantaa. Large scale energy production plants produced over 99 % of district heating in Helsinki, 97 % in Espoo and 93,1 % in Vantaa.

[2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18]

  1. ↑ Adato Energia Oy, 2008. District heating in Finland 2007. Kaukolämpötilastot 2007
  2. ↑ Vantaan Energia 2008. Social responsibility report (in Finnish). Available at http://www.vantaanenergia.fi/tietoa_konsernista/vuosiraportit/fi_FI/vuosiraportit/. Last visit 11.5.2009.
  3. ↑ Helsingin energia 2008. Vuosikertomus 2007 (In Finnish). Edita Prima Oy. 2008. Available at http://www.helen.fi/vuosi2007/Helsingin_Energia_vuosikertomus_PDF.pdf. Last visit 11.5.2009.
  4. ↑ Fortum Heat and Power oy 2008. Heat production. Available at http://www.fortum.com/dropdown_document.asp?path=14022;14024;14026;14043;14070;14071;41962;41967. Last visit 11.5.2009.
  5. ↑ Statistics of Finland 2009. Rakennukset (lkm, m2) käyttötarkoituksen ja lämmitysaineen mukaan 31.12.2007 (in Finnish). Available in http://pxweb2.stat.fi/Dialog/Saveshow.asp. Last visit made in 13.3.2009.
  6. ↑ Huovilainen, R. T.; Koskelainen L. Kaukolämmitys (in Finnish). Lappeenranta’s university of technology. Lappeenranta 1982. ISBN 951-763-209-6
  7. ↑ Jalovaara J., Aho J., Hietamäki E. & Hyytiä H,. 2003. Paras käytettävissä oleva tekniikka (BAT) 50 MW:n polttolaitoksissa Suomessa (in Finnish). Suomen ympäristö 649. 126s
  8. ↑ Raiko R., Saastamoinen J., Hupa M. & KurkiSuonio I. 2002. Poltto ja palaminen. Toinen täydennetty painos (in Finnish). International Flame Research Foundation – Suomen kansallinen osasto. 750s.
  9. ↑ Kara M. 1999. Energia Suomessa (in Finnish). VTT Energia. Edita. 367s.
  10. ↑ Korkia-Aho S., Koski O., Meriläinen T. & Nurmio M. 1995. VAHTI – Käsiteanalyysi. Länsi-Suomen ympäristökeskus 29.9.1995. 35s.
  11. ↑ Karvosenoja N. 2001. Primary particulate emissions from stationary combustion processes in Finland. Suomen ympäristökeskuksen moniste 232, 34 s.
  12. ↑ Lammi K., Lehtonen E. & Timonen T. 1992. Energiantuotannon hiukkaspäästöjen teknistaloudelliset vähentämismahdollisuudet. Ympäristöministeriö, selvitys 120. 63s
  13. ↑ Strand M. 2004. Particle formation and emission in moving grate boilers operating on woody biofuels. Växjö University. Ph.D Thesis
  14. ↑ Ohlström M. 1998. Energiantuotannon pienhiukkaspäästöt Suomessa. VTT tiedotteita 1934. 114s.
  15. ↑ Adato Energia Oy. 2009. District Heating in Finland 2007 (S).
  16. ↑ Karvosenoja N., Zbigniew K., Tohka A. & Johansson M. 2007. Costeffective reduction of fine primary particulate matter emissions in Finland. IOP Publishing. Environmental Research Letters. 8s.
  17. ↑ Statistics Finland 2005. Energy Statistics 2004. Energy 2005:2. Helsinki, Finland.
  18. ↑ Tissari J., Raunemaa T., Jokiniemi J., Sippula O., Hytönen K., Linna V., Oravainen H., Vesterinen R., Taipale R., Pyykönen J., Tuomi S., Kouki J. and Vuorio K. 2005. Fine particle concentrations in small scale wood combustion. Final report 31.8.2005. The report series of the Department of Environmental Sciences, University of Kuopio 2/2005, Kuopio, Finland. 134 pp. (In Finnish with English abstract.)
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