Uist Asco: Design and installation of 999kW woodchip boiler

999kW wet woodchip boiler at Uist Asco

re:heat is proud to have worked with Uist Asco, a company with a unique application for a woodchip boiler on the island of North Uist in the Outer Hebrides. Uist Asco Limited are named after Ascophyllum Nodosum, the seaweed which they process and dry using heat from their 999kW Binder woodchip boiler. The dried seaweed is sold as organic fertiliser, animal feed, alginate and for further refining into chemical products.

Trees are in short supply in the Outer Hebrides, but the MacIain family who have developed the drying plant, have 720 hectares of coniferous plantation on North Uist. It’s this timber – which has no competing markets on the island – which provides the sustainable source of fuel for the woodchip boiler. As well as creating jobs in the management and harvesting of the trees, and in the drying plant, the project has also created a number of jobs in the resurrection of the traditional industry of seaweed harvesting.

re:heat was involved with the project from the outset and has provided a range of services to Uist Asco.  These ranged from the design of the fuel store and boiler plant layout, to running a tender exercise for the supply of the equipment, and then project managing the final design and installation of the entire system.

The Uist Asco plant features a 999kW Binder step-grate boiler, capable of burning fuel of up to 50% moisture content – the same as a freshly felled tree. The robust nature of Binder boilers which are designed for heavy-duty space heating and commercial heat loads, means that it’s well suited to this demanding application. The hydraulic ram-feed system can deal with fuel which is way beyond the capabilities of the majority of other boilers, and the ability to cope with fuel with a high ash content means that low material recovered from forest operations can be effectively utilised.