Heat and power out of the woods20 July 2006
Construction of SembCorp’s pioneering £60 million Wilton 10 power plant, the largest biomass project of its kind in the UK, is now under way. When operational in 2007, it will generate 30 MWe from wood fuel.
SembCorp Utilities UK, a subsidiary of Singapore generation utility SembCorp, has begun the construction of its Wilton 10 biomass fired CHP station at the Wilton International site on Teesside. The pioneering £60 million project will generate 30 MWe using wood, classified as renewable, as its fuel source, and around 10 MWt. This will be in addition to the 197 MWe of electricity being supplied from the existing power station.
The largest biomass project of its kind in the UK, Wilton 10 is expected to be operational by the middle of 2007. SembCorp Utilities UK and Foster Wheeler, the engineering, procurement and construction contractor, marked the occasion with a groundbreaking ceremony at the site in October. Under a $53 million contract Foster Wheeler will design, build and commission the complete boiler island including the fuel handling system, the biomass fuelled boiler and the flue gas treatment system. Around 15 permanent new SembCorp jobs will be created at the plant and at its peak the construction work will involve around 400 people. The project will also secure and create job opportunities within the farming, forestry, construction, wood recycling and transport sectors. SembSolutions, SembCorp Utilities UK’s in-house project team, will oversee the project.
The 35 MWe steam turbine and power island is to be supplied by Siemens PG. The contract includes the SST 400 steam turbin/generator set, with its condenser, Flender gearbox, oil system, and PCS7 control system. 30 MWe of power is to be sold direct to the grid, while around 10 MWt in the form of steam will be added to the site’s district heating steam circuit, mainly for process heating applications.
The plant will burn green and recycled wood and will be required to meet the emission limits of the EU's Large Combustion Plant directive and Waste Incineration directive. It will also be subject to a Best Available Techniques assessment subject to review by the Environment Agency of the UK. The power plant will burn around 300 000 tonnes of wood a year from a variety of sources including specially grown energy crops, forestry logs, sawmill chips and recycled timber. Foster Wheeler believes that it gained this contract mainly because of its track record over 30 years of supplying the Scandinavian pulp and paper industry with fluidised-bed boilers, and its experience in firing different biomass fuels and the demanding requirements that industry imposes concerning reliability.
The boiler will be designed to achieve maximum efficiency using high steam conditions. It is to be a bubbling fluidised bed type, a design suitable for high moisture content fuels and difficult ash characteristics or fuels that are difficult to handle, with very low levels of emissions. This makes it particularly suitable for forest waste and short rotation coppice material. A test burn of SRC delivered from the UK was carried out by Foster Wheeler in Finland specifically for the Wilton project.
The wood for the station will come from four separate sources. Around 40 % of the 300 000 tonne a year total will be recycled wood that will be received, stored and chipped on a nearby, separately owned site at Wilton. A further 20 % will come to the site already chipped as offcuts from sawmills. SembCorp is working with the Forestry Commission to bring a further 20 % from north east forests in the form of small roundwood logs – items sometimes left on the forest floor after routine tree felling operations. Finally, 20 % of the wood will comprise specially grown energy crops – in the form of a type of willow known as short rotation coppice – grown by farmers and other landowners within a 50-mile radius of the site. The new plant will require the growth of around 7500 acres of coppice in the area, an activity that will create wildlife havens throughout the region. All the wood needs to be chipped and mixed in careful proportions before being fed into the boiler, which will encompass technology already in use in Scandinavia and other areas.
Around £10 million of the investment has come from a grant made under the Bio-energy Capital Grants Scheme. SembCorp has also financed a significant element of its investment through a long-term project finance loan with French bank Calyon, the corporate and investment banking arm of the Crédit Agricole Group. A feasibility study is also being undertaken into the possibility of creating a separately owned and operated wood recycling facility on the same site to support the project as well as recycling initiatives of local government body Redcar and Cleveland council. Wilton 10 will operate separately from the existing 197 MW Wilton power plant, but will be partially situated within the existing building.
SembCorp’s new 'wood to energy' approach comes in response to a government call, following the 1997 Kyoto Agreement, for more energy throughout the UK to be generated from more environmentally friendly renewable sources. Generating power and steam by the burning of renewable fuels instead of fossil fuels is designated as carbon neutral because the carbon dioxide emitted to atmosphere is that absorbed by the trees during their growth cycle.
The new power plant has been designed to meet all UK and European emissions targets by applying Best Available Technology (BAT) philosophy. Paul Gavens, SembCorp Utilities UK managing director, said: 'This investment is extremely good news for SembCorp, the Wilton International manufacturing site and the people of Teesside and the North East. It will sustain jobs and play a part in helping the UK government meet its climate change and greenhouse gas reduction targets.'