Which way now for fleet vehicles – EVs or hydrogen-powered conventional vehicles? This could soon become the choice as pressure builds on fleet operators to reduce carbon emissions.
Up to last week, when the government announced it was investing a further £9 million in chargepoints, EVs or hybrids seemed the likely way forward. Then came news that scientists at the UK’s Science and Technology Facilities Council (STFC), had overcome a number of complications relating to the use of hydrogen as an alternative ‘green’ fuel for automotive purposes.
Those challenges concerned hydrogen’s safe and efficient storage and the costs involved with providing a suitable transportation infrastructure.
Now the researchers believe they have overcome the difficulties by using ammonia as a clean and secure hydrogen-containing energy source to produce hydrogen on-demand in situ.
When the components of ammonia are separated (a technique known as cracking) they form one part nitrogen and three parts hydrogen. Many catalysts can effectively crack ammonia to release the hydrogen, but the best ones are very expensive precious metals. This new method is different and involves two simultaneous chemical processes rather than using a catalyst, and can achieve the same result at a fraction of the cost.
Ammonia can be stored on-board in vehicles at low pressures in conformable plastic tanks. Meanwhile on forecourts, the infrastructure technology for ammonia is as straightforward as that for liquid petroleum gas (LPG).
Alternative to fossil fuel
Professor Bill David, who led the STFC research team at the ISIS Neutron Source, said: “Our approach is as effective as the best current catalysts but the active material, sodium amide, costs pennies to produce. We can produce hydrogen from ammonia ‘on demand’ effectively and affordably.
“Few people think of ammonia as a fuel but we believe that it is the natural alternative to fossil fuels. For cars, we don’t even need to go to the complications of a fuel-cell vehicle.
“A small amount of hydrogen mixed with ammonia is sufficient to provide combustion in a conventional car engine. While our process is not yet optimised, we estimate that an ammonia decomposition reactor no bigger than a 2-litre bottle will provide enough hydrogen to run a mid-range family car.
“We’ve even thought about how we can make ammonia as safe as possible and stop the release of NOx gases. This fundamental science, therefore, has immense potential to change the use of hydrogen as a fuel.”