Press release

Altia’s geothermal fluid keeps Porvoo Cathedral warm

A significant investment in geothermal heating has been made at Porvoo Cathedral. This culturally and historically important site will from now on use geothermal heating. Altia Industrial’s Naturet was selected as the geothermal fluid for the system. Produced at the company’s Rajamäki plant, Naturet is Finland’s leading ethanol-based geothermal fluid.

The cathedral, which was previously heated with fuel oil, will from now on use geothermal heating. The fluid that flows in the ground pipes is Naturet geothermal fluid, manufactured by Altia Industrial. Naturet products are produced at Altia’s plant in Rajamäki and the main raw material comes from Altia’s Koskenkorva plant, where domestic barley is turned not only into beverage-grade grain spirit, but also into technical ethanol for industrial needs.

Porvoo cathedral is located very close to a groundwater area that is an important source of drinking water, which is why Naturet GeoSafe geothermal fluids were selected for this system.

Investing in the environment and the economy

The Evangelical Lutheran Church of Finland invested EUR 340,000 in this geothermal heating project. Before the investment, 30,000 litres of oil were used annually for heating the cathedral. The system was installed by drilling eight 340-metre deep wells into the bedrock to house the pipelines.  The drilling was carried out by Talman Energiaporaus. The geothermal energy is distributed into the church buildings using an underfloor water circulation system. The hot tap water is also heated by geothermal energy.

According to technical facility manager Timo Kraufvelin from the joint parishes of Porvoo, the motivation for the investment included both economic and environmental concerns:

“Environmental values are very important for the Church, and the transfer from oil to ecologically sound geothermal heat constitutes major action for the environment. Cost savings are also achieved at the same time. The transfer required a large investment, but will pay for itself.”

Porvoo cathedral, which was built at the turn of the 14th century and received its current shape in the 15th century, has lived through many trials and tribulations. It suffered damage in the bombing during the Continuation War and has survived several arson attacks, the latest in 2006. The church has, however, always been maintained well. Thorough renovations and repairs have been carried out on several occasions, the geothermal heating investment being the latest.

The project was challenging, as the location of the cathedral made drilling very demanding. Not only was there a groundwater area close by, but the limited space, the location in the middle of an old town centre, and the fact that the project partially overlapped the tourist season also meant that careful planning was needed.

More information and contact:
Group Communications
Petra Gräsbeck
Director, Corporate Relations and Communications
petra.grasbeck [at]