Can flushing a toilet be considered an environmental act? Sometimes yes. In Lahti, the European Green Capital 2021, excess heat from municipal wastewater will be used in district heating.
Petri Vuori from Calefa and Jarkko Kovanen from Lahti Energy at Ali-Juhakkala wastewater treatment plant
From September 2022 onwards, Lahti Energy will start to recover heat from treated wastewater at the Ali-Juhakkala wastewater treatment plant, and upgrade it for district heating.
– Although the water is not very warm, only about 9 °C on average, there is still heat energy that can be utilized. After heat recovery, the water discharged into the Porvoo river is only 1 – 2 °C warm, tells Jarkko Kovanen, Director of district heating at Lahti Energy.
With cutting-edge heat pump technology, even from such low temperatures, district heating of 90 °C can be produced. The 5-megawatt AmbiHeat heat pump plant by Calefa will replace combustion in the energy production in Lahti.
– Our primary target is to reduce the use of fossil fuels, i.e. natural gas, but we are also looking for alternatives to the use of biofuels.
The new heat pump plant will reduce annual CO2 emissions by 1700 tons, which corresponds to the emissions from driving 11 million kilometers with an average car.
A masterpiece of Finnish engineering
The heat pump plant installed in Ali-Juhakkala will be 100% result of Finnish labor, from innovation to manufacturing.
Calefa Oy specializes in recycling industrial waste heat and has developed the modular AmbiHeat heat pump plant around its high-temperature heat pump technology. AmbiHeat can utilize locally available energy sources.
The heat sources can be outdoor air, industrial waste heat, heat from waterbodies, geothermal energy, and/or solar energy. The heat pump plant can produce even high temperatures to the district heating networks or industrial needs with good efficiency.
– The main idea with AmbiHeat is, that the plant adapts to the surroundings and not the other way around, says Petri Vuori, the CEO of Calefa.
The plant is manufactured in Finland in factory conditions as modules, which are then transported to the site and installed as a complete entity.
– Short distances are a benefit to the customer but also from the environmental point of view. For us, it’s essential that we can trust in the quality, delivery time, and work efficiency. We develop our heat pumps and heat pump plants continuously. The work will remain in Finland also in the future, says Petri Vuori.
The Green Capital 2021 shows an example
A heat plant that utilizes municipal excess heat fits the future strategy of Lahti Energy well.
– We are in the process of transforming into a society based on circular economy, in which wasting resources is minimized, Jarkko Kovanen explains.
Lahti energy considered heat pumps already about five years ago to replace district heating, in those days produced with coal, but then other solutions were more feasible. Technology has in the meantime advanced with giant steps, which can also be seen in the production cost of energy.
– As a ready-made, turnkey solution AmbiHeat is the answer to our needs. Of course, the price has also been a factor here. The efficiency of the system is quite good, Jarkko Kovanen justifies the investment.
AmbiHeat power heat pump plants are used for district heating production also e.g. in Puumala and at Orion pharmaceutical factory in Turku. The latter one won recently an award from the European Heat Pump Association (EHPA) in the category DecarbIndustry.