6MW Biomass Heating

Newbridge Sawmill, BSW Timber

BSW Timber is the largest sawmilling business in Great Britain, producing over 1,000,000m³ of timber per year across sites in the UK and Latvia. Located in Mid Wales, the Newbridge site produces sawn timber products, much of which was previously dried on-site in oil fired kilns.


BSW wished to replace the existing 4.5MW and 350kW oil boilers with boilers fuelled by their low value wood co-products generated on site by the sawmilling activities.  By utilising biomass energy, the client’s main objectives were to reduce fuel costs, increase the value of the co-products and to reduce the environmental impact of the sawmill activities.  The design and installation of a new biomass heating system would also provided BSW with extra thermal capacity for future expansion of kilning activities.


  • Feasibility study to assess the different options available to BSW in terms of plant specification, size and cost
  • Outline design of boiler house, design of the integration with existing Medium Temperature Hot Water kilns and design of the district heating main around site
  • Planning support, boiler house and fuel store layout design
  • Role of ‘Client’s Engineer’ providing detailed design and specification and support through tendering, construction, commissioning and evaluation
  • Management of the RHI accreditation process; the plant was accredited for RHI in 2011


The biomass boiler solution comprises 2 x 3MW moving grate boilers suitable for combustion of high moisture content wood fuel (up to 60%) with high bark content and large chip size specification. The system includes thermal storage in order to match loads to boiler output, auxiliary oil boiler integration and a heat network to connect the wood drying kilns. The fuel store was designed as a moving floor extractor with chain and flight conveyers to the two boilers. Ongoing monitoring has confirmed that even when using fuel with moisture contents above 60%, the plant achieves a seasonal efficiency of over 82%.

“The 6MW plant at our Newbridge on Wye, Mid Wales facility was commissioned during June 2011. The project was on schedule, to budget and is exceeding our performance expectations.”

Dave Burd Mill Manager of BSW Newbridge

READ MORE: Carbon Trust Case Study