the City of Imatra has moved into the bioenergy era | Kpa Unicon
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the City of Imatra has moved into the bioenergy era

How does 20 percent cheaper heating costs sound? What about the fact that this discount is made possible by domestic, low-emission bioenergy? In Imatra, Finland, a local heating company has invested in a new heating plant and cut both district heat customers’ emissions and money spent on heating.

As of just a few years ago, Imatran Lämpö Ltd produced all its district heat with natural gas imported from Russia. Today, the water in the boiler is heated with wood-based biomass. At the same time, the level of emissions generated by district heat production has diminished to one-tenth, and the heating costs of district heat customers have dropped from the highest quartile to the lowest in Finland.

The new heating plant in Imatra was delivered by KPA Unicon Ltd. The total delivery of the boiler plant cost Imatran Lämpö Ltd approximately 10 million euros, excluding construction and foundation work.

A lighter carbon footprint

Imatran Lämpö Ltd is a local heating company owned by the City of Imatra. The company produces and supplies district heat and distributes natural gas and biogas in Imatra. The district heating network covers most of the city’s large commercial buildings and about 50 percent of local households.

The new heating plant was built to replace natural gas as a heat source for district heating. It is used throughout the year to provide the base heat load, and nowadays natural gas is used only in the coldest temperatures to cover the peaks in energy consumption.

The heating plant, located in the Virasoja district of Imatra, has significantly increased the share of renewable energy in district heat production. Now, the carbon footprint of district heating customers is on average 25,000 tonnes lighter than before. The amount corresponds to approximately 2,400 Finnish citizens’ annual carbon dioxide emissions.

Thanks to the modern technology optimized for combustion, the plant does not produce significant particulate emissions, either.

“Ninety-five percent of the energy sources used for district heat production are by-products from forest industry and forestry – resources that would be difficult to use otherwise. With the new biomass-fired heating plant, Imatra got a more environmentally friendly, more cost-effective and cheaper heat production method” says Vesa-Pekka Vainikka, Managing Director of Imatran Lämpö Ltd.

Money stays local

The new plant is also significant to Imatra’s local economy: the employment effect ranges from the procurement, handling and transportation of the fuel to the use and maintenance of the heating plant. A significant portion of the money spent on producing district heat now stays in Finland, much of it remaining in the region of South Karelia, to which Imatra belongs. The new heating plant utilizes the by-streams of the densest forest industry hub in Europe, located in South Karelia.

According to Mayor of Imatra Kai Roslakka, cost moderation was one of the most important goals already during the preparation stage of the investment. Cooperation with the wood processing industry in the region was also an important driver in the planning phase.

“After a carefully prepared and well-executed investment, it can be said that all the goals that were set have actually been achieved. Investment has played a significant role in Imatra’s economic area and has contributed to the city’s vitality. “

Bigger than the sum of its parts

KPA Unicon supplied the Virasoja heating plant as a turn-key package. It included process equipment, buildings, installation work, commissioning and operational training.

The plant includes two 15-megawatt Unicon Biograte boilers. Unicon Biograte is a patented boiler model with a round grate and a furnace. Because of its structure, the boiler temperature is stable, and the fuel can be more humid. The boiler was originally designed for the sawmill industry, especially for burning wet bark. More than half of the mass of the biomass used at the Virasoja heating plant is water.

In addition, each boiler has its own electric filter and flue gas condenser. Electric filters remove fine particles from flue gases, and flue gas condensers recover waste heat. Because of this heat recovery, one flue gas condenser can produce up to three megawatts of power.

More power, worth one million euros

In addition to the plant delivery, KPA Unicon and Imatran Lämpö Ltd have entered into a separate service agreement whereby KPA Unicon provides support services during the heating season as well as inspections and necessary maintenance work during annual production stoppage.

Once the heating plant was established, Imatran Lämpö Ltd also commissioned plans from KPA Unicon to increase the power of the Virasoja boilers. The two initial 15-megawatt boilers now produce 17 megawatts per boiler after power take-up, which equals a total of four megawatts more power. A corresponding four-megawatt heating plant would cost approximately one million euros.

At its best, the original 30-megawatt-rated heating plant now produces heat up to 40 megawatts, allowing Imatran Lämpö Ltd to further reduce the use of natural gas.


FACT BOX 

Virasoja heating plant, Imatra, Finland

Customer: Imatran Lämpö Oy
Plant: Unicon Biograte 30
Commissioning: 12/2015
Nominal output: 30 MW (2 x 15 MW)
Output after upgrade: 34 MW (2 x 17 MW)
Flue gas processing: Electric filter and flue gas condenser
Fuels: bark 70 %, forest residues 30 %