ECO Kutno, the heat supplier of the Polish city of Kutno in Łódź Voivodeship, has signed for more than PLN 59 million from the National Fund for Environmental Protection and Water Management (NFOŚiGW) to build a geothermal heating plant of about 6.4 MWt, ThinkGeoEnergy reported on 5 November. Once running, geothermal heat is expected to cover 45.7% of the city's total heat supply.
The figures as published:
- total net cost above PLN 109 million, of which nearly PLN 85 million are eligible costs
- the fund covers 70% of eligible costs, partly as grant and partly as loan; the company pays the rest
- two wells to a target vertical depth of about 3,010 m
- expected water temperature of 90 °C at a flow of at least 150 m³/h, according to a board member of the ECO group responsible for operations
No construction timeline has been published yet. The company's president described the project as a change in how the city makes its heat, built on a local resource.
The national fund has paid for many exploration wells in recent years, and the government has announced a further programme for building heating plants where drilling has already confirmed the resource.
Brine on one side, city water on the other
Geothermal water from 3 km down is rarely something you want in a district heating network. It carries dissolved salts and gases and tends to scale or corrode, so the standard layout keeps it in its own loop: up the production well, through a heat exchanger, and back down the injection well, with the network water heated on the other side.
At 90 °C the source can often serve a conventional network through that exchanger without a heat pump in between, depending on the supply temperature the network runs at. What decides how long the plant runs between cleanings is mostly the chemistry of the brine, which only the wells will reveal. Plate materials and gaskets are best chosen after the first water analysis, not before.
Sources: ThinkGeoEnergy
