Biopower / 1.83 MWe 3.5 MWth

On September 12 in 2003, Wärtsilä BioPower signed its first contract in Ireland to provide a client with a wood-fired biomass Combined Heat and Power (CHP) plant. The client is Independent Biomass Systems (IBS Ltd.), a special purpose company set up and owned by two Irish companies - South Western Services Co-operative Society Limited (SWS) and Irish Soft Woods Ltd (Grainger Sawmills) - to develop the project.

Mr. William Grainger, Chief Executive of Grainger Sawmills says: “This contract with Wärtsilä will benefit the sawmill in a number of ways, including the on-site generation of all the sawmill's heat requirements, the sale of RES-electricity (RES = Renewable Energy Source) and, potentially also, the sawmill's electricity requirements if required. By using the by-products of the facility instead of transporting them off-site, Graingers will also minimize environmental impact on the surrounding area. Environmental responsibility is of great importance to the sawmill industry and to Wärtsilä, and we are proud to have taken part in such an important project.”

Wärtsilä solution
The plant consists of a BioPower 2 Hot Water CHP plant with a Bio Grate™ biofuel combustion chamber, steam boiler and steam turbine, connections to the customer’s processes and an extensive 400 m long fuel conveyance system from the sawmills. Wärtsilä Service has also been awarded a five-year operation supervision and maintenance agreement with the plant.

Using by-products from sawthe mill in the form of wood residues (with a moisture content as high as 65%), the CHP plant generates both 1.83 MW of electrical energy and 3.5 MW of thermal energy in a single process. The thermal output is used to dry construction timber in the sawmill’s kilns. The installation enables Grainger Sawmills – one of the largest in Ireland – to address an electricity deficit in its current operations. The 1.83 MW of power generated at the CHP plant is sold under a 6th alternative energy requirement (AER VI) contract to the national grid. An AER VI involves the sale of ‘green’ or renewable electricity in a structured bid price to the grid. Under these contracts wind, biomass and biomass CHP are all capped at different prices.