DRIVING THE FUTURE
HYDROGEN FUELS NET-ZERO MOBILITY Mark Griffin, Hydrogen Market Development Manager for Clean Fuels, BOC, explains how using hydrogen as a transport fuel benefits councils and fleet operators.
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he government’s ‘Road to Zero Strategy’ is driving the transition to zero emissions across all vehicle types for public and private modes of transport. The end of the diesel vehicle is in sight and forwardlooking councils and fleet operators are taking action to provide clean transport alternatives, from delivery vans to refuse trucks and bus fleets. Zero-emission vehicles produce no greenhouse gas or air pollutant emissions at their tail pipes. Currently, only hydrogen fuel cell and pure battery electric vehicles can deliver zero emission transport. Both battery and fuel-cell vehicles use electricity to drive electric motors, and both electricity and hydrogen can be produced using power from renewable energy sources.
HYDROGEN AS A FUEL Hydrogen is the most abundant element in the universe. It is produced in a number of ways, which vary in efficiency, carbon intensity and cost including as a by-product from the chemicals industry or through a process called steam methane reformation (SMR). It is also possible to produce green hydrogen from electrolysis – a process that extracts hydrogen from water with no emissions. Hydrogen is stored as a compressed gas at the refuelling station until it’s needed and is then pumped into a vehicle under pressure. One of the key benefits of hydrogen is that refuelling is a fast and familiar process, similar to refuelling a diesel vehicle. It takes around 10 minutes to refuel a bus, which can cover a range of around 350km, and 5 minutes for a car enabling a range of 500km. There are zero emissions from the fuel-cell vehicle – just clean water from the tail pipe – and they are virtually noiseless.
REFUELLING STATION INFRASTRUCTURE Refuelling stations need a hydrogen supply, which can either be delivered to
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site from an offsite production plant or produced onsite. To produce hydrogen on-site, an electrolyser is required to extract hydrogen from water. A compressor unit takes the extracted hydrogen and compresses it for efficient storage. The station also requires a hydrogen store, which is capable of storing hydrogen under pressure, and a dispenser for pumping the hydrogen gas to the vehicle under pressure. For any refuelling station, ensuring reliability is essential. At BOC’s Kittybrewster facility in Aberdeen, every refuelling has been successful since the station’s launch in 2015, and the reliability rate is 99.5% with no failed refuels. Also important is the need to ensure that the refuelling capacity is large enough to supply the vehicle fleet for which it is intended. Producing 300kg of hydrogen daily is enough to fuel ten 42-seat buses, with each bus able to travel up to 350km between refuelling. By using a modular design, it is possible to scale up hydrogen production to match the needs of a growing fleet.
COST OF OWNERSHIP There are several factors that contribute to the cost of operating a hydrogen refuelling station. Two of the main determinants are the volume of hydrogen produced (cost reduces with increasing volumes) and the cost of electricity used in the
ENERGY MANAGER MAGAZINE • JUNE 2020
electrolysis process. For a low-carbon solution, operators typically source power from renewable sources or a supplier offering a green tariff. Some operators aim to achieve cost parity with diesel at the pump, while others recognise that there is a significant value associated with reducing air pollution and carbon emissions. Producing hydrogen using methods other than electrolysis does create some CO2 emissions. It can, however, be cheaper, improve local air quality and provide a pathway to using green hydrogen in the future. With any new project, BOC works with local councils and vehicle fleet owner/operators at the outset to help them understand the economics of hydrogen use, align the costs with their objectives and identify potential sources of funding. Element Energy, a specialist low carbon energy consultancy, reports that by the mid-2020s bus manufacturers expect it will be possible to purchase a fuel cell bus for less than £350k. This
