Bio fuels


Fortum uses many types of fuels in electricity and heat production, each of which has different environmental impacts.

Natural gas

Natural gas accounts for about 65% of the different energy sources used by Fortum. Natural gas is used mainly in Russia, which accounts for close to 99% of our total use of natural gas. Natural gas is used in small quantities also in Finland, the Baltic countries and Poland. The world’s natural gas reserves are big, and there is enough natural gas for energy production demand for several decades.

Natural gas is the cleanest of the fossil fuels in terms of greenhouse gases and other flue-gas emissions because it doesn’t contain sulphur and it generates minimal particle emissions. Nitrogen oxide emissions can be decreased with combustion technology. Potential leaks from gas pipelines have an impact on the climate because natural gas is almost 100% methane, which is a greenhouse gas worse than carbon dioxide.  


Coal accounts for about 10% of Fortum’s energy sources. About half of this is used in Russia and the other half in Finland and Poland. The world’s coal reserves are big. Coal’s availability and storability make it an economical source for reserve and peak-load power; in some situations, it is the only viable alternative.

Coal has big environmental impacts because of the carbon dioxide, sulphur, nitrogen and particle emissions. However, various combustion and flue-gas cleaning technologies can decrease the sulphur, nitrogen and particle emissions to levels within the regulatory requirements. Viable technology for separating carbon dioxide from flue gases is not available for the time being.

The ash generated at our power plants is utilised in the construction material industry and in earthwork, and the gypsum generated in the flue-gas cleaning process is used in the production of gypsum board. Recycling reduces landfill waste and the need to use other natural resources.

Coal mining is a large-scale operation. Safety is an important issue in underground coal mines due to the risk of methane gas explosions, for example. We are a member of the Bettercoal initiative established by international utilities to promote corporate responsibility throughout the coal supply chain. Our experts make regular visits to mines to assess the coal suppliers’ operations.

Biomass and other biofuels

Biomass and other biofuels account for about Biomass and other biofuels account for about 3% of Fortum’s energy sources. We use primarily forest residues and other wood-based fuels. Bio-based municipal waste and industrial waste are used to some extent. According to our estimate, the use of renewable biofuels will increase in the future.

When used in a sustainable manner, biofuels mitigate climate change: new biomass is cultivated to replace the incinerated biomass, which absorbs carbon dioxide from the atmosphere. Biofuels generate about the same amount of nitrogen and particle emissions as coal, but, in general, less sulphur emissions. Ash generated from biomass combustion can be utilised in the same way as coal ash.

The sustainable production and use of bioenergy is gaining more attention worldwide. We recognise the challenges related to the origin of bioenergy and have prepared a position paper on the sustainable use of bioenergy. We are continuously developing measures to improve the traceability of fuels and ensure their sustainable use. Furthermore, we participate in international organisations promoting the sustainable use of bioenergy.  


Oil is used mainly in the start-up phase of power plants and in small heat boilers. Oil accounts for about half a per cent of Fortum’s energy sources. Oil is a fossil fuel, so its environmental impacts are comparable to those of coal. 


Peat accounts for about half a per cent of Fortum’s energy sources. Peat is combusted in Finland and in Estonia, where it is a domestic energy source. 

In Finland, peat has been defined as a slowly renewing biomass fuel. Even though peat is not a fossil fuel, it is treated in the same way as fossil fuels in climate policy. Peat-based fuel generates more greenhouse gas emissions than coal.

In addition to carbon dioxide, peat combustion also releases sulphur and nitrogen oxides as well as particles. Some methane is formed during the storage of peat. The ash generated in peat combustion can be used in earthwork, for example. The recycling of the ash is limited by the heavy metals that accumulate in the ash and in some cases the radioactivity. 


Uranium fuel accounts for about 20% of the fuels acquired for Fortum’s own energy production. Uranium is a heavy and weakly radioactive element. Its symbol is U and its atomic number 92. In nature, uranium consists of three isotopes: 238U (99.28%), 235U (0.71%) and 234U (0.005%). Only nuclei of the isotope 235U have an inherent ability for fission when they are bombarded with neutrons. The energy released in this reaction is utilised in nuclear power plants.

Uranium fuel production is a multi-step process. Natural uranium is excavated from the bedrock and is concentrated like other ores. The uranium concentrate is converted into a gaseous form and enriched in special enrichment plants to increase the 235U proportion. The enriched uranium is converted into solid uranium oxide, which is then compressed into fuel pellets. The fuel pellets are loaded into fuel rods that are then grouped together into fuel assemblies for use in reactors.

The mining of uranium can be compared to any mining operation. But because of the radioactivity of uranium, special attention is paid to the processing and storage of the waste rock and tailings to minimise environmental impacts. The isotope enrichment of uranium is  carried out with centrifuges. This method uses only a small fraction (less 1%) of the electritcity required by the earlier gaseous diffusion method.

Fuel for the Loviisa power plant is acquired from the Russian TVEL as a turnkey delivery – from the acquisition of the raw uranium to the production of the fuel assemblies. We regularly assess the quality, environmental, and health and safety management systems of our nuclear fuel suppliers and the production of the fuel assemblies. Our experts also make regular visits to the uranium mine to assess the fuel supplier’s operations in Russia.

The spent fuel removed from a nuclear reactor is highly radioactive waste, which is initially stored in a controlled environment at the power plant. Loviisa power plant’s spent nuclear fuel will eventually be disposed of in Posiva’s final repository under construction in Olkiluoto.

Waste-derived fuels 

Waste-derived fuels account for a total of about one per cent of Fortum’s energy sources. We believe that waste-to-energy production is an essential part of a sustainable waste management system. Waste-derived fuels can be used to replace fossil fuels and, at the same time, reduce the amount of waste ending up in landfills. 

We burn municipal waste at the Klaipeda power plant in Lithuania. Additionally, we burn industrial wood-based waste at the Joensuu and Järvenpää power plants in Finland. Strict limits have been set for flue-gas emissions from waste incineration, and the ash must also be handled properly.  


A bio-oil production plant has been integrated with the Joensuu combined heat and power (CHP) plant. Bio-oil raw materials include forest residues and other wood-based biomass, and thus it is a renewable energy.

We use bio-oil at our own heat plants to replace heavy fuel oil. It has also been delivered to Savon Voima’s Iisalmi heat plant and E.ON’s Karlshamn power plant. In the future, bio-oil can also be used as a raw material for various biochemicals or traffic fuels.
The use of bio-oil in energy production reduces greenhouse emissions by more than 70% compared to fossil fuels.