Future heat plant in Påttis, Vaasa, converts waste water heat into district heating

The advanced technology of the Påttis heat pump plant produces heat from treated wastewater for up to two thousand detached houses. The plant is a prime example of industrial waste heat utilization, opening up vast opportunities for the industry. Elomatic and AINS Group were responsible for implementation using the EPCM model.

A heat pump plant has been completed next to the Påttis wastewater treatment plant located near the center of Vaasa, where the waste heat contained in treated wastewater is recovered using two heat pumps and transferred to the district heating network.

The wastewater treatment plant purifies all the wastewater from the city of Vaasa and part of the wastewater from the neighboring municipalities of Mustasaari and Maalahti. The wastewater entering the plant is about 10 degrees, and with the help of two heat pumps, it can produce up to 95-degree district heat.

The waste heat recovered corresponds to the annual heating energy amount of all detached houses in the Vaasan Sähkö's district heating network, i.e., about 2000 detached houses now get their heat from wastewater.

– The Påttis plant produces renewable, carbon-free heat and is a step in our goal towards carbon-neutral heat production by the end of this decade, says Project Manager Juha-Matti Karvala from Vaasan Sähkö.

The plant was completed at the end of 2023 and heat production began last December. At the moment, final optimizations are being made at the plant. So far, the experiences have been better than expected.

– It seems that in the future we will reach greater production power than we thought. Currently, the nominal power is 12 megawatts and it has been exceeded every day, Karvala says.

Waste heat recovery a growing trend

The design and implementation of the plant using the EPCM model (Engineering, Procurement, and Construction Management) were handled by engineering and consulting firm Elomatic and built environment consultant AINS Group.

Vaasa is the fourth city in Finland to have a large-scale heat pump plant. Other similar plants are in Helsinki, Espoo, and Turku. The Påttis heat plant is the largest overall implementation to date for the experienced industrial heat plant designer Elomatic.

– Heat pump technology has developed by leaps and bounds in recent years and such wastewater treatment plant solutions are a clear rising trend. There is a lot of waste heat in industrial flue gases, waters, condensates, and processes that we can recover instead of always producing new heat. Heat recovery is a concrete example of a green transition and definitely a thing of the future, says Project Manager Anne Kujanpää from Elomatic.

Elomatic was responsible for the overall project management and the design of the technical process. AINS Group was responsible for construction and construction tasks, geo and structural design, and supervision.

– The plant is equipped with lots of technology, including extensive automation, electrical systems, and sensors. There are thousands of individual automation points, and many operators participated in the implementations. The delivery model, where construction project and design expertise were closely combined with technical process design, proved to be very functional and cost-effective, says Construction Manager Timo Juolevi from AINS Group.

The partnership between AINS Group and Elomatic was initiated last year. Together, the companies offer comprehensive solutions for industrial investment project design and implementation.

Further information:

Juha-Matti Karvala, Project Manager
Vaasan Sähkö
t. 050 547 3727 

Markku S. Lehtinen, Senior Vice President
t. 040 833 8959


Timo Juolevi, Construction Manager
AINS Group
t. 050 358 1249

"The Påttis plant is a step in our goal towards carbon-neutral heat production by the end of this decade."

Juha-Matti Karvala
Project Manager
Vaasan Sähkö