Hedensbyn bioenergy combine

Hedensbyn was Skellefteå Kraft’s first bioenergy combine when it started operations in 1996 and has been a world leader in the development of modern bioenergy technology ever since. The facility consists of a combined power and heating plant for the generation of district heating and green electricity, as well as a biopellet factory.

 

Skellefteå Kraft has been one of Sweden’s leading players in ecofriendly energy production for a number of years. The company’s development of its bioenergy combines in Hedensbyn and Storuman is unique, not just in Sweden but internationally as well, and includes an energy-efficient steam-drying technique and a method for integrating this technique with a biofuel power and heating plant. With aggressive investments in modern technology and a world-leading, in-house development team, Skellefteå Kraft plays an important role in the development of bioenergy combines.

Produces heat and electricity
The combined power and heating plant primarily consumes the by-products of natural materials harvested from the surrounding
environment. The plant’s operation is completely automated and employs fluidised bed technology – an ultra-modern, highly efficient technology which allows the process to be finely controlled and which is also eco-friendly. The generated steam is led through two turbines– one high-pressure and the other low-pressure, which operate at different speeds so as to achieve maximum output. Both turbines power a generator which produces energy in the form of electricity. The steam is then led away to a heat condenser, where it warms the water used for district heating.

World-leading pellet production
Hedensbyn’s pellet production facility employs a world-leading technique that integrates its operation with the production of heat
and electricity in the combined power and heating plant. Some of the steam produced is piped from the plant’s high-pressure
turbine over to the pellet factory, where it is used to dry raw materials. The pellet factory’s low-pressure turbine also makes it
possible to utilise waste heat from the drying process to generate electricity. The pellet factory uses raw materials in the form of byproducts from the region’s sawmills – forest raw materials of the very highest quality in terms of purity and degree of utilization.

Efficient and eco-friendly production
The Hedensbyn operation is designed to have as little impact on the environment as possible. It uses biofuels primarily harvested from near-by areas, and thanks to an electrofilter, which filters exhaust gases from the boiler before they are expelled from the chimney stack, 99.98 per cent of material contained in the gases can be removed. As a result, the chimneys emit mostly harmless water vapour. Generating district heating, green electricity and biopellets at the same plant increases the efficiency of the combined power and heating plant, which would otherwise operate at an overcapacity during the warmer months of the year.
 
Storuman bioenergy combine
The bioenergy combine in Storuman is Skellefteå Kraft’s largest project of its kind so far. The plant is the result of the company’s development work within environmentally friendly energy production and builds on state-ofthe-art technology for the production of district heating and renewable electric power. Skellefteå Kraft also produces the market’s most eco-friendly biopellets, made in a process completely free of fossil fuels.

With its vast experience within environmentally friendly energy production, Skellefteå Kraft is one of the driving forces behind the development of modern bioenergy technology. The plant in Storuman became operational in the autumn of 2008 and is considered the next generation of bioenergy combines.

The company opened its bioenergy combine Hedensbyn in Skellefteå in 1996, with market-leading solutions for efficient and eco-friendly bioenergy production. The experience from Hedensbyn formed the basis for much of the modern technology in Storuman, including the energy-efficient steam kiln technology and a method for integrating this with a combined power and heating plant powered by biofuel.

Unique energy efficiency
This process was developed for Storuman and is a world-first in terms of the efficient handling of the bioenergy raw material. The bioenergy combine consists of a combined power and heating plant for the production of district heating and renewable electric power as well as a biopellet factory. By integrating both of these facilities, an energy efficiency of 98 per cent is achieved. The plant uses mainly biofuel in the form of by-products from the
region’s sawmills, forests and farmlands.
  
 

The raw material used in pellet production has a moisture content of 50 per cent prior to being fed into the pressurized steam kiln. When the raw material has reached a suitable moisture content, it is then sent to be made into pellets. The principal components of a combined heating and power plant are a boiler, a steam turbine with a generator and a heat exchanger for district heating. Steam is produced in the boiler at a high pressure and temperature. First it is led to a turbine that drives a generator, which in turn generates electricity. The steam is then led away to a heat condenser, where it warms the water used for district heating. Steam is also extracted from the turbine to provide heat in the drying process. In total, the combined power and heating plant generates around 48 GWh of electricity and 40 GWh of heat for district heating every year.

Environmental benefits
An important reason why the company chose to establish a new energy combine in Storuman is the easy access to raw biomaterial.

The environmental benefits from exploiting the plant’s proximity to the raw material, sourced from the region’s forests and sawmills, include reduced transportation distances, thus helping to minimise overall environmental impact. Local forest owners also improve their profitability by contributing raw materials to bioenergy production when thinning out their forest stands.
 
     
 
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