Denmark’s waste-to-energy facilities have been optimized and existing capacity replaced, but no new thermal treatment capacity has been established since 2002.
KARA/NOVEREN in Roskilde is the first plant to receive the authorities’ approval since 2002 and has now established a new €175M waste-to-energy unit capable of meeting the capacity demands for thermal treatment of waste generated in its owner municipalities.
The Energy Tower
The new waste-to-energy plant, dubbed the Energy Tower, is built, financed, owned and operated by KARA/NOVEREN, which is an inter-municipal waste management company owned by nine municipalities west and south of Copenhagen.
KARA/NOVEREN is a non-profit company based on a cost coverage principle. The gate fee at the waste-to-energy facility is one of the lowest in Europe and amounts to only DKK200 (€27) per tonne of waste (excluding taxes and VAT). The low gate fee is attributable to the efficiently operated facility on the one hand and to the extensive energy recovery on the other.
The electricity produced at the waste-to-energy facility is sold to the national grid, and the heat is sold to the district heating network owned by the Copenhagen district heating transmission company, VEKS, which supplies heat and hot water to the equivalent of 150,000 families. In the summer, the entire consumption of heat and hot water in VEKS’s transmission area is covered by KARA/NOVEREN and one other waste-to-energy facility in Copenhagen.
The Energy Tower (25 tpa) has replaced two units from the 1980s, and including a unit from 1999 the facility now has a total annual capacity of 350,000 tonnes of waste.
The suppliers of the Energy Tower are MARTIN GmbH (grate and boiler), LAB SA (flue gas treatment system) and MAN Diesel & Turbo (turbine). The large, outspoken, amber-coloured façade is designed by Dutch architect Erick van Egeraat, and at night the backlighting of the perforated façade transforms the spire to an illusion of a glowing beacon, symbolizing the energy production inside the facility.
From planning to implementation
Ramboll has been a consultant to KARA/NOVEREN for many years. Ramboll assisted the waste management company in the extension of the plant in the 1990s and has provided day-to-day assistance and trouble-shooting services ever since.
In connection with the Energy Tower, Ramboll has been responsible for the procurement of mechanical and electrical equipment. Our services have included:
Conceptual design, technical specifications and project definition
Environmental impact assessment and permitting
Management of procurement process, preparation of tender documents, bid evaluation and contract negotiations
Overall supervision and planning
Site Management and HSE
Focus on energy optimisation
The energy content of waste at the Energy Tower is transformed into steam, which is subsequently converted to electricity as well as district heating. Earlier generations of waste-to-energy facilities stopped the energy recovery process at this point. However, the installation of flue gas condensation raises the temperature of the district heating water returning from the city, and heat production is increased by approximately 10%. The plant goes even further by incorporating a component cooling system that is driven by district heating, thereby reducing the amount of electricity required to operate the plant.
With a total energy efficiency rate of almost 100% and an increase in energy recovery of 35% compared to the facility’s old units, the Energy Tower is one of the most modern and efficient waste-to-energy facilities in Europe. The Energy Tower produces electricity corresponding to the consumption of some 44,000 households, while the production of district heating corresponds to the consumption of about 26,000 households.
Capacity: 200,000 tonnes per annum
Waste: Municipal Solid Waste (MSW) and commercial waste (C&I)
Energy performance: 20 MWe and 60 MWth
Steam Parameters: 50 bars, 425˚C
Energy recovery: Turbine with district heating condensers, flue gas condensation
Flue gas treatment: primary dust removal in bag filter followed by four stages wet scrubbing system