Skaerbaek Combined Heat and Power Plant, Fredericia, Denmark


Skaerbaek

Dong Energy is currently converting its natural gas-fired Skaerbaek Power Station in Fredericia, Denmark, into a dual-fuel combined heat and power (CHP) plant. The new facility will use wood chips as fuel to generate district heating and electricity.

On 28 August 2014, a groundbreaking ceremony for the construction of the 280MW Skaerbaek power station conversion was held. The project is expected to be completed in April and will create up to 700 jobs during the construction phase.

The plan is expected to supply green district heating to roughly 200,000 inhabitants in the Danish Triangle Region, with an estimated investment of kr1.8bn, which equates to approximately $259m. It is also expected to offset 400,000t of CO2 a year from the atmosphere.

Skaerbaek power station history and conversion

Generating electricity and heat from three units using natural gas, the historic Skaerbaek power station was established in 1951 on the northern side of Kolding Fjord.

Conversion of the plant into a dual-fuel facility will pave way for the establishment of a large, green power and heat production facility in the Danish Triangle Region.

The wood chip-fired plant will be linked to unit three at the power station, enabling the unit to use the chips as primary fuel to produce heat, while natural gas will be used as secondary fuel.

Construction on Skaerbaek CHP plant

Major works include installation of two 140MW wood chip boilers, construction of a boiler building, excavation and concrete works for the conveyor system, and installation of a wood chips storage facility.

The plan further includes renovation of the power station's 250m-long quay, expansion of the port facility, and installation of two new flue gas pipes in the existing chimney of unit two.

"The plan is expected to supply green district heating to roughly 200,000 inhabitants in the Danish Triangle Region."

Heavy-duty steel elements were imported from India for the construction of the wood chip boilers.

Wood chips supply to Skaerbaek CHP plant

Sustainable wood chips will be imported to the port near Skaerbaek power station and will be used as fuel. The first shipload of 3,546t of wood chips arrived at the power station on 4 April.

Chips will be transported to the power station during the winter months by ships and barges, which will have a carrying capacity between 6,000m³ and 16,000m³, and will be accommodated at the 175m-long quay at the power plant.

Power generation using biomass fuels

The Skaerbaek CHPP will have the potential to combust up to 154t/h of wood chips. Each boiler is designed to operate 24/7, having a running time of at least 8,000 hours a year.

Wood chips will be unloaded from the ships and barges using a new conveying system and two new unloading cranes at the quay. Conveyor belts will be used to transport the wood chips to the open wood chip storage facility, which will have a capacity of up to 80,000m³.

Chips will be initially placed at the top of the storage facility's chip pile and delivered to the boilers by using the conveyor belts from the two screw conveyors located at the bottom of the facility.

Steam and water generated in the boilers will be separated by two steam drums, which will be used for the production of heat for district heating. The steam will be fed into the existing turbine of the CHP plant to generate heat and electricity.

Heating supply agreement with TVIS

TVIS entered a heating agreement with Dong Energy for the Skaerbaek power station in June 2014.

Until 2037, TVIS will pay 80% of the construction costs of the wood chip-fuelled plant and will have the right to the heating capacity generated by the CHPP.

TVIS currently purchases the heat produced by CHP plants and in-turn supplies to households and companies in Fredericia, Kolding, Vejle and Middelfart cities.

Contractors involved with the Skaerbaek power station development

Babcock and Wilcox Vølund was awarded an $80m contract for the supply of two biomass-fired boiler systems and equipment for the CHPP. Its contractual scope includes design, manufacture, supply, construction, and commissioning of the plant's boiler system.

Sweco is the engineering consultant in the analysis, site-development and execution phases.

Dong Energy engaged Bilfinger Duro Dakovic for the erection of two bag filters and the flue gas duct at the existing Skaerbaekverket gas-fired power plant.