News

Robert Wiseman Dairies is starting a £500,000 trial of two alternative fuels - liquefied natural gas (LNG) and bio-diesel - in a bid to go green and cut fuel costs. The East Kilbride-based company says an earlier small-scale trial with dual-fuel LNG-diesel operation gave encouraging results. The plan now is to undertake Clean Air Power conversions on up to 20 of the DAF CF85 tractor units working out of Wiseman's Bellshill, Glasgow depot.

The choice of LNG, rather than natural gas in its  more usual compressed form (CNG), enables sufficient fuel for Wiseman's long-haul bulk milk movements, mainly from dairies to its Carlisle and Manchester distribution centres, to be carried in the limited space available on the side of the DAF's 4x2 chassis.

As many as 35 of Wiseman's Bellshill-based rigid milk collection tankers are due to be switched to B20 bio-diesel fuelling, where possible sourcing the fuel from used cooking oil and tallow feedstocks.

The company says the decision to go for 20% blend bio-diesel fuelling rather than natural gas dual-fuel operation on the rigid fleet was made because of dual-fuel's limitations on relatively low-mileage stop-start operations, exemplified by Wiseman's three- and four-axled DAFs and Volvos collecting milk from farms.

For the percentage of gas in the dual-fuel mix to be maximised for greatest emission reductions, high engine temp-eratures, obtainable only during prolonged high-load working, need to be maintained.