A new biomass-fired boiler at the Vanaja power plant moves Loimua toward carbon neutrality

The city of Hämeenlinna, an hour’s drive north of Helsinki, is famous for its Häme Castle, built during the late 13th century. Although the Vanaja power plant does not come even close to this, it is the oldest power plant still functioning in Finland, at a respectable 82 years of age. 

In a recent upgrade project, this “old lady” got a new heart – a modern biomass-fired K6 boiler – that will enable the plant to efficiently and sustainably produce district heat for many decades to come. The old K4 boiler, dating from the 1950s, had reached the end of its life and was ready for retirement.

Share of renewable fuels increases to 90 percent

On November 23, 2020, Loimua, an energy company that owns the plant and has operations at various locations in Finland, inaugurated the new biomass-fired boiler supplied by Valmet. With the investment, the share of renewable fuels used by the plant will increase to 90 percent, and the CO₂ emissions from district heat production will reduce significantly at the same time. Hämeenlinna is the only large city in Finland that provides almost entirely carbon neutral heat to its inhabitants.

The boiler plant was inaugurated by Finland’s Minister of Economic Affairs Mika Lintilä.

“The new K6 boiler and its systems represent a big step for our operations in creating a carbon neutral society. Loimua will maintain its position as a frontrunner among heat producers and is ready to take new steps toward achieving 100 percent carbon neutrality,” stated Loimua’s Managing Director Matti Tynjälä in his inauguration speech.

The boiler plant was inaugurated by Finland’s Minister of Economic Affairs Mika Lintilä. Valmet’s Sales Director Hanna Alarotu had the honor of making a speech at the ceremony.

The efficient plant has a total district heat production capacity of 45 MW_th, of which 35 MW_th comes from the boiler, and an additional 10 MW_th from the flue gas scrubber.

The new boiler runs mainly on wood-based fuels such as forest residues, sawdust and bark. In addition to the boiler and scrubber, Valmet’s delivery included an electrostatic precipitator. The boiler has been integrated with the existing fuel, ash, sand and water systems of the K5 boiler, which stands next to it.

Handover five weeks ahead of schedule

The boiler hall at Vanaja has a protected historic site status that required some extra attention from Valmet during the engineering and installation phases. Additionally, tight space in the hall and a relatively low ceiling had to be taken into account in the boiler geometry.

We were actually able to hand over the boiler plant to the customer five weeks ahead of the agreed schedule.

“Thanks to very good cooperation with the Loimua project team, the project went smoothly from beginning to end, although it was challenging to demolish the two old K2 and K3 boilers and build the new boiler while the power plant was running,” says Leo Kotliar, Project Manager, Delivery Operations, Pulp and Energy Business Line, Valmet.

With a lot happening on the premises, there was a strong focus on occupational safety – and it paid off.

The efficient plant has a total district heat production capacity of 45 MWth, of which 35 MWth comes from the boiler, and an additional 10 MWth from the flue gas scrubber.

“There were zero HSE incidents, and the commissioning phase also went very well. We were actually able to hand over the boiler plant to the customer five weeks ahead of the agreed schedule. This was a great achievement – given the challenges we had,” Kotliar concludes.

Text Marjaana Lehtinen