Type of CHP system: Gasification

Plant owner: Babcock & Wilcox Voelund

Commissioned: (reconstructed):1993 (2000)

Status of plant: Commercial

Contractor details:

Buildings: Monberg & Thorsen

Gasifier: Vølund

Engine and generator: Jenbacher

SRO-unit: DA Automation

Power generation: Gas engine

The Harboøre plant now includes a counter-current gasifier, a gas scrubbing unit, a gas boiler where gas is combusted in the heat production process, and the two gas motors.

Main fuel: Wood chips

The gasifier can be fired with wood fuel ranging in size from wood chips to logs. The majority of the fuel is wood chips, which are fired without prior drying. The updraft (counter-current) gasifier can operate on a fuel with a water content of 30 % to 55 %.

Approximately 2 tons of fuel per hour, or 8,000 tons per year are consumed at the Harboøre plant. The fuel depot can house 170 tons, a 3-4 day supply.

Nominal capacities & efficiencies:

Thermal input, biomass & waste: 4,8 MW

Total thermal input, incl. fossil fuels: 4,8 MW

Gross electrical output: 1,52 MWe

Net electrical output: 1,44527671232877 MWe

Heat output: 2,8 MJ/s

Electrical efficiency, gross: 31,6 %

Electrical efficiency, net: 32 %

Overall efficiency, gross: 90 %

The electrical efficiency at the plant calculated from the quantity of fuel consumed in electrical production is approximately 32-34 % , based on the operational data for the gasification unit and the specifications provided by the enginge supplier. The heat efficiency is expected to be approximately 55 % and the combined efficiency 87-89 %.

Heat backup: Besides the gas engines, the plant consists of boiler producing heat from gas and tar. Capacity: 4 MJ/s (4,68 MJ/s with condenser)

Heat usage: Heating only

Energy usage: The heat supplies approximately 595 consumers as well as the city’s public buildings.

District heat coverage (% of total demand in DH network): 95 %

Heat storage size: 1050 m3

Hours of full load that the heat storage can meet: Equal to a maximum 15-hour supply

Fuel storage: Approximately 2 tons of fuel per hour, or 8,000 tons per year are consumed at the Harboøre plant. The fuel storage capacity is 170 tons, corresponding to 3-4 day supply.

Waste water:

The heavy tar fraction which is stored in a 150 m3 tank is combusted as a replacement for fuel oil (during peak load periods and as a reserve fuel source). The watery tar fraction has, up until 1998, been stored and combusted together with the gasification gas in the boiler, however, this is not a long term solution. An excessively large storage facility would be required in order to ensure that the operation of the combined heat and power plant not be limited by the quantity of watery tar fraction available to be fired in the boiler.

A new trail water treatment system,  which has been operating since august 2001, involves evaporating the water so that only a tar residual remains. The water is then condensed and released. The first experiments are being run on a small-scale unit with a capacity of 50 litres/hour. The full-scale unit will be required to treat 1,500 litres/hour. The initial experiments with this new technology appear promising.

Ash discharge: Ash from the gasifier is removed via 3 augers to ash containers which are later driven to a disposal facility

Plant description:

The plant has been operating since 1993 producing heat only, and suppling Harboøre heating plant, which then supplies private consumers as well as the city’s public buildings. Two Jenbacher gas engines for combined heat and power production were installed in the beginning of 2000.

Fuel feeding system: The fuel is fed  with an auger via a rotary airlock.

Gasifier: Updraft (counter-current) gasifier

Gas cleaning: Gas scrubbing unit

Engine: Jenbacher

Staff:

2 people during daytime and on call on all other times. The gasifier has been optimised in order to run unmanned, and the Harboøre plant has the greatest number of unmanned operational hours for a wood chip fuelled gasifier in the world due to the gasifier’s stable operation.

Total capital cost: € 5,100,000

The price for the next plant of same kind (this plant was a demonstration plant)

Data collected and quality assured by: FORCE Technology.

Contact person: Anders Evald