UK bus and coach operator Stagecoach Group has converted 11 Optare Solos in Lincoln to dual-fuel operation (biomethane/diesel). The £260,000 (USD 426,000) conversion cost of the buses has been funded by Lincolnshire county council and the East Midlands Development Agency. A further £100,000 of joint funding has been invested in fuelling infrastructure. Optare has an exclusive conversion agreement with the Nottinghamshire based Hardstaff Group to offer their OIGI® (Oil Ignition Gas Injection) system in passenger vehicles.
Optare can now offer dual-fuel conversions for both four-cylinder Mercedes-Benz and six-cylinder Cummins engines that are Euro 3 (or later) emissions compliant. The conversion can be from new or as a retrofit and in the case of the Lincoln Solos these were between six and seven years old and had clocked up an average mileage in excess of 300,000 miles.
As a result of carrying out this conversion operators can expect up to a 40% reduction in CO2 emissions and improved fuel economy. The biomethane can be produced from food and animal waste using a process called anaerobic digestion, which also avoids the cost of sending this material to landfill. And as vehicles converted to dual-fuel operation are classed as low carbon buses, operators can also benefit from an extra 6p per kilometre in BSOG (bus service operators grant).
Preparation of the vehicles began at Optare’s low carbon conversion centre in Blackburn where the Cummins engines were taken out and delivered to Hardstaff whose engineers assessed and ‘mapped’ the fuel system in readiness for the fitment of a new ECU calibrated to the performance characteristics of each engine and its future dual-fuel operation. A new exhaust system was also designed at this stage. On completion of this operation the power packs were returned to Optare.
Whilst this work was being carried out Optare modified the roof structure in order to fit a purpose-built cradle for the gas tanks along with a fibreglass cover. The engines were then refitted and the vehicles sent to Hardstaff for final connections to be made. The conversion work also required re-certification of the Solos, including tilt-testing which was carried out at Optare’s Leeds plant.
Optare Chief Operating Officer, Glenn Saint, said: “This is a very good application of the green technology that we can offer under our Eco Drive programme. It solves a number of issues at a stroke. CO2 emissions and fuel costs are reduced and material that would otherwise be buried in the ground – at considerable cost – can be used to produce the biomethane with the resultant waste providing a useful fertiliser for agricultural use.
“ The fact that we are able to offer it as a retrofit on two widely used engines and that such conversions qualify for the higher rate of BSOG, makes this an attractive and viable option for any operator seeking to ‘green’ their fleet quickly without having to buy new vehicles, although we are happy to fit the dual-fuel system during new vehicle build too.”
This article compiled using information from an Optare press release.