Energy
We produce electricity and heat at the Kymijärvi power plants in Lahti. For industrial customers, we produce, for example, process steam in production facilities customised to their needs.
Heat and electricity from renewable and recycled fuels
We favour renewable and recycled fuels in our production, such as biofuel produced from the side streams of the sawmill and wood industries. Our small-scale plants use biogas and natural gas. We also recover waste heat from, for example, the wastewater treatment process.
As shareholders of EPV Energy Ltd and Suomen Hyötytuuli Oy, we are provided with their electricity produced with wind power, nuclear power and hydropower in an amount corresponding to our shareholding. For industrial customers, we produce, for example, process steam in production facilities customised to their needs.
Kymijärvi II gasification power plant
Kymijärvi II, the world’s first power plant utilising only recycled fuels, was completed in 2012. The gasification power plant produces electricity and district heat in a combined process using the back pressure principle.
The plant’s overall process includes recycled fuel receiving and storage silos, two gasifier and product gas purification lines, a gas boiler, a steam turbine, flue gas cleaning equipment and a chimney. The power plant’s fuel consists of non-recyclable but highly combustible waste, i.e. plastic, paper, cardboard and wood.
The plant’s fuel power is 160 megawatts, with an output of 50 megawatts as electricity and 90 megawatts as district heating. The power plant produces about half of the electric and district heating energy we supply.
Kymijärvi III bioenergy heating plant
The Kymijärvi III bioenergy heating plant completed in 2019 replaced a coal-fired power plant (Kymijärvi I) commissioned in the 1970s. The heating plant reduced carbon dioxide emissions by 600,000 tonnes per year.
Kymijärvi III is responsible for heating the Lahti region together with the Kymijärvi II plant. The district heat output of the bioenergy heating plant is approximately 190 megawatts, with biomass as its main fuel. The sustainable wood fuel is made up of, for example, logging residue chips and sawmill by-products, but it can also include more substantial wood materials unsuitable for further processing. This has been the case as the geopolitical environment has changed. During the coldest time of the year, about 55 truckloads of fuel are consumed per day.
The plant’s circulating fluidised bed boiler makes it possible to use other solid fuels as well, if necessary. At Kymijärvi III, the efficiency of heat production has been maximised with an efficient heat recovery plant. The resulting condensate is treated and the fly ash is recycled for reuse, where applicable.
Unique condensate treatment
A power plant needs water to function. Together with our technology suppliers, we developed a new type of condensate treatment process for the Kymijärvi III heating plant. The system makes the plant nearly self-sufficient in terms of water consumption. The plant needs raw water only for cooling. Process water is obtained from the moisture contained in the fuel, i.e. biomass. Condensate is recycled in the process, which means that the amount of excess condensate generated is very low. The water is discharged into Lake Vesijärvi cleaner than drinking water.
The condensate treatment process developed by Lahti Energy is unique in Finland. The process has been selected as one of the key energy projects of the Ministry of Economic Affairs and Employment (MEAE), and it received key project aid from the Ministry.
Kymijärvi IV
In March 2023, we made an investment decision on a 60 megawatt electric boiler. The electric boiler investment will strengthen the Lahti region’s security of supply and diversify emission-free heat production. The electric boiler will be used all year round as needed. We will place the electric boiler and its ancillary equipment in the gasifier building of the old, decommissioned Kymijärvi I power plant. The old gasifier, commissioned in 1998, has been dismantled.
The electric boiler will produce heat directly with electricity. The heat production system will be built as an independent production unit. The water in the electric boiler will not need to be replaced frequently, and the unit will not cause emissions into the air or environment. The Kymijärvi IV heat production unit is estimated to be commissioned by the end of 2024.
Ali-Juhakkala heating and cooling plant
An industrial-scale heating and cooling plant has been put into production at Lahti Aqua’s Ali-Juhakkala wastewater treatment plant in 2023. The idea behind the heating and cooling plant is to utilise the waste heat from wastewater for the Lahti district heating network and the needs of the Lahti Aqua wastewater treatment plant. The heat output of the Ali-Juhakkala heating and cooling plant is five megawatts, and approximately 17 gigawatt-hours of heat can be recovered from wastewater every year. The amount of heat corresponds to the annual energy demand of 1,000 detached houses.
The plant consists of seven heat pump units are used to raise the water temperature in phases. The heating and cooling plant is located near the existing discharge pipe for treated wastewater. Wastewater is pumped along a new wastewater line from the wastewater basin to the wastewater heat exchangers. The heat exchangers are used to transfer the energy from the wastewater to the collector circuit of the heat pump, and the cooled wastewater is returned to the Porvoonjoki river. The energy produced by the heating and cooling plant can be fed as it is into the new district heating line.
Hartwall’s Lahti biogas plant – energy and fertiliser through circular economy
The Hartwall biogas plant was commissioned in summer 2023. The biogas plant built in cooperation between Lahti Energy and Hartwall enables carbon-neutral production at the brewery. The mash left over from brewing beer is passed to the plant’s three reactors. The reactors can contain a total of 6,400 m3 of biogas. The plant’s annual production would cover the heating of 600–700 detached houses.
The purified biogas passed through the biogas plant goes to Lahti Energy’s boilers, where it is turned into energy as steam for use in Hartwall’s production. The reject generated in the process, i.e. recycled fertiliser containing nutrients, is returned to the barley fields of a local farm to fertilise future malt barley crops. All the nutrient-rich surplus material (reject) from the biogas plant is utilised and the nutrients make a full cycle from the field to the field. We spread the first fertiliser loads on the farm’s fields in autumn 2023.