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Craboverket Thermal Power Plant

Craboverket
Craboverket Thermal Power Plant is located in Fagersta Municipality. The plant largely uses biomass fuel and provides nearly all the heat production required for Fagersta’s district heating network. Craboverket is owned by VB Energi, which is jointly owned by Vattenfall and the municipalities of Ludvika and Fagersta.

History of VB Energi

VB Energi started its operations in 1893 when the power station Hellsjöns Kraftstation and the power line to the Grängesberg mine were commissioned. The power station and power line were based on Jonas Wenström’s patent for three-phase alternating current. The new technology proved to be excellent, and more than 50 three-phase systems were constructed in Sweden before the end of the century.

When electrification started in Sweden, each power station originally ran its own electricity grid. It was not until the end of the 1920s that these grids were connected to the growing national grid.

Västerbergslagens Energi AB (VB Energi) was established in 1983 through a merger of the municipally owned company Ludvika Elverk AB and Gränges Kraft (a subsidiary of Vattenfall).

VB Energi is now owned by Vattenfall (51%), Ludvika Municipality and Fagersta Municipality.
The company’s main task today is to produce and deliver district heating with good environmental credentials to customers in Fagersta, Ludvika and Grängesberg. The majority of the district heating produced in the facilities at Craboverket in Fagersta, Lyviksverket in Ludvika and Skakelbacken Thermal Power Plant in Grängesberg takes place with environmentally adapted biomass fuels.

Recovered heat

VB Energi and the company Fagersta Stainless AB have entered into an agreement for jointly recovering (recycling) heat from the LPG furnaces at Fagersta Stainless AB. VB Energi has invested SEK 10 million in the two waste heat boilers that harness the heat from the flue gases formed when the steel furnaces are heated to the 1,250 degrees Celsius required to anneal the iron.

The new waste heat boilers act as heat exchangers and heat up cold water that can then be channelled into the district heating network along with the hot water from the Craboverket plant.

VB Energi and the Swedish company Seco Tools , based in Fagersta, have signed a collaborative agreement. VB Energi has installed a refrigerating machine with heat recovery capability at the Seco Tools factory. The cold air is supplied to Seco’s manufacturing process, and the recovered heat energy is fed into VB Energi’s district heating system.

Combustion

Craboverket is designed to be able to burn wet fuels. This takes place in a solid fuel boiler with fluidized bed combustion. The bed consists of a mixture of sand, ash and fuel. The technology is based on blowing air through the bed so that the mixture is suspended in the air when combustion takes place. The combustion temperature is about 850 degrees. The boiler is very flexible in terms of fuel types and is highly suitable for fuels such as wood chips, sawdust, bark and peat.

Flue gas cleaning and ash management

To clean the flue gases, the facility is equipped with a flue gas condenser and an electric filter that cleans the flue gases and collects the fly ash. A mixture of bottom ash and sand are removed from the bottom of the boiler each day.

Craboverket is Reko-certified

The Swedish trade organisation Svensk Fjärrvärme has developed a quality assurance system called Reko for suppliers of district heating. Vattenfall’s district heating has met the requirements of this quality system since 2006. The purpose of the Reko certification is to strengthen the position of customers and to improve the relationship between customers and suppliers. The focus is on openness, comparability and trust.

District heating is an efficient choice

In densely populated areas, district heating constitutes an efficient use of resources and helps to minimise emissions during production. District heating can be produced from several fuel types – fuels that might otherwise not be utilised. District heating thus contributes to lowering emissions and using resources (that may be difficult to use in other ways besides as fuel) more efficiently.

District heating is used in 270 of Sweden’s 290 municipalities and accounts for half of all heating in households and commercial properties. District heating is the most significant reason why Sweden has been able to reduce its carbon dioxide emissions.