Earlier this year, the government launched a ground breaking project to ensure the UK is well positioned for the commercial roll-out of hydrogen-powered cars. The new initiative, UKH2 Mobility, aims to develop an action plan to make the cars available to British consumers by 2015.

Recently we were part of a trial of a hydrogen powered light goods vehicle conducted in Stornoway; examining the reliability, ease of fuelling and usability of the vehicle and fuelling regime, and the suitability of the hydrogen internal combustion engine (HICE) vehicle in fleet operation. Although the trial proved that hydrogen fuelled vehicles are able to substitute for conventional light goods vehicles in rural and urban settings, the trial also revealed a few unpredictable issues and lessons were learnt along the way.

To avoid dependence on imported fuels and energy, and as a driver of economic regeneration, the Western Isles Council, Stornoway, is seeking to exploit the region's natural resources. So for the trial, the Council's H2seed facility provided hydrogen fuel, produced by feeding electricity generated by a biogas engine to an electrolyser. The trial involved the use of a demonstration Ford Transit, converted to a bi-fuel petrol/HICE vehicle that was operated by Royal Mail on two delivery routes over a six week period.

The first challenge was to get a Vehicle Special Order so that we could operate a hydrogen vehicle on UK roads. We obtained this from the UK Department for Transport by certifying the vehicle's compliance with EU and UNECE regulation. As the trial involved the first use of the Stornoway facility to refuel vehicles, pre-trial work was essential to commission the station and establish a suitable vehicle refuelling regime.

This led to two recommendations for operation during the trial: firstly, due to limitations identified with the hydrogen leak detection strategy employed by the vehicle, the hydrogen tank was only filled to around two-thirds of its rated capacity. Initial efforts to refuel to its fuel capacity of 4.5kg at 350bar, triggered the vehicle's major leak alarm resulting in the vehicle being disabled from further operations. To resolve this issue, we monitored the temperature and pressure of the on-vehicle storage vessel every 10 seconds during and after a 3.8 minute fill from empty to 350bar. Secondly, the vehicle was fuelled with hydrogen at the end of its daily duty and the hydrogen fuel left to equilibrate overnight before operation. The reason for this was to eliminate issues of gas heating when fuelling and is another necessary step to avoid triggering a false leak alarm.

The trial period which we monitored, involved 19 trips (17 rural, two urban) and were either completely or partially fuelled by hydrogen for a total of 723 miles. Driver feedback revealed that the HICE substituted ably for the conventional vehicles that typically operate the delivery routes. The main negative feedback on the vehicle was its perceived lack of power in hydrogen mode when compared to petrol mode and to conventionally-fuelled vans, an issue that manifested itself most clearly on the hillier section of the rural delivery route.

The final results revealed that hydrogen fuelled vehicles are able to substitute for conventional light goods vehicles; however predictable issues were also exposed. This includes trialling early demonstrator vehicles in remote locations, primarily due to the distance between maintenance personnel and refuelling equipment. These issues will easily be solved in future deployments by the local presence of trained personnel and Stornoway Council itself has plans under development for new trial activities.

Commercial availability of hydrogen-powered vehicles will be a reality sooner than many people think and there is growing evidence of UK enthusiasm for trialling hydrogen vehicles. For example, Sheffield-based electrolyser developer ITM Power received a very positive response for its Hydrogen On-Site Trial (HOST) project in which ITM Power delivered an on-site electrolyser to produce hydrogen and a hydrogen van for a company to operate within its fleet. It will be in the fleet market that these vehicles will prove their value, and it is vital that the UK fleet operator community takes the opportunity to participate in trials of these vehicles to provide a robust evidence base for wider adoption.

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