Hydrogen as a future fuel?

Hydrogen, and the suggestion that it could be a future fuel, seems to attract polarised views with some suggesting that it is the future whilst others say it has been tried, tested and failed.

SYSTRA’s Director of New Technology, Jorgen Pedersen, delve into hydrogen technology and ask if this emerging fuel technology can be used in the short term to help meet Net Zero by 2050.

How energy intensive is hydrogen to produce?

The conversion process from water to hydrogen through electrolysis is conventionally very energy intensive, requiring about half of the energy created for the conversion process. The ‘Steam Methane Reforming Process’, while 74-85% efficient, still requires the use of fossil fuels and has therefore been discounted as a viable long-term approach.

However, newer technology innovations such as ‘zero gap’ electrolysis have increased efficiency to 75-80% and the Australia company Hysata is now claiming 95% efficiency by using capillary action to ensure that bubbling cannot not occur around electrodes.

If the claims are correct, this will prove even more efficient than EV charging which in general achieves 93% efficiency. When coupled with renewable energy sources, this process can deliver carbon-friendly and efficient hydrogen production.

Hydrogen can be created using renewable sources such as offshore wind turbines when they would otherwise be tethered or spinning aimlessly at night. Any excess energy from these sources could be used to create hydrogen, which would provide a renewable and storable energy source.

Is hydrogen dangerous?

Hydrogen has an unusually broad flammability range (Stoichiometric Ratio) when mixed with air, between 4-74%, requiring hydrogen units to be fully sealed to prevent hydrogen seepage. But, has anyone tried to extinguish a lithium polymer battery?

It is almost impossible: one can smother it or immerse it in water, but as soon as air is re-exposed to the elements the chemical reaction continues and the battery can burst back into flames, a process known as Thermal Runaway.

Is hydrogen difficult to contain?

Hydrogen has a very small molecule size. Some will say that the size of the hydrogen atom makes it virtually impossible to develop hydrogen vehicles because the hydrogen atomic radius makes it almost impossible to contain.

But let’s explore that in a little more detail. Hydrogen has an atomic radius of 0.53, Helium 0.31, Neon 0.38, Fluorine 0.42, Oxygen 0.48, Nitrogen 0.56. So, it’s small but not necessarily the smallest. Furthermore, helium, neon, oxygen and nitrogen have all been used in commercial applications including glass purification, petrochemical refinement, semiconductor manufacture for decades.

Can hydrogen be stored easily?

The main difference is that unlike electricity, and despite the small molecular size, hydrogen can be stored in significantly larger quantities. The molecular size presents challenges and will require additional safety measures if hydrogen is to become more mainstream. Using renewable energy sources which are not being fully utilised, hydrogen could be produced, stored and made available to fill energy gaps.

Is the creation of hydrogen carbon friendly?

Finland is the world leader in the production and utilisation of ‘green hydrogen’ – manufactured from sustainable sources using sustainable power. In Norway, the Kvaerner process first developed in the 1980s produces carbon neutral ‘green hydrogen’.

The efficiency of both these processes are being improved upon year-on-year and it is predicted that by 2030, energy conversion via electrolysis will be as high as 82-86%, which is not wildly dissimilar to the energy transfer loss of charging an electric vehicle.

There is some speculation that the production of ‘blue' hydrogen (produced using both renewable and fossil fuel energy sources) can have a higher carbon footprint that using conventional hydrocarbon fuels.

However, blue hydrogen generation should not be discounted, especially when produced using currently available carbon capture and storage (CCS) processes or when using autothermal reformers (ATR) with integrated carbon capture. Both of these processes have been shown to reduce the carbon footprint to below that of conventional fossil fuels.

Is using hydrogen cost-effective?

Unlike other countries, the UK has been slow to embrace the use of hydrogen as a fuel. Finland, for example, has already gone all-in with hydrogen production, and now has the biggest hydrogen production facilities in Europe. Utilising hydrogen fuel cells, Finland believes, will change not only our future transportation landscape but can be used for everything from residential to commercial heating applications, and even industrial ore smelting.

The city of Edmonton, Canada, recently announced an investment of $470M in a blue hydrogen production facility. In the USA, California began building a large hydrogen production facility in 2021 which will turn waste plastics into hydrogen. It will come on-line later this year.

The Californian facility adds to a growing US national hydrogen production network including New York, Georgia, and Tennessee. Closer to home, Scottish Power has announced its intention to build a £150m hydrogen production facility at the Port of Felixstowe, which will provide sufficient fuel for 1300 HGVs.

Are hydrogen vehicles available?

Some hydrogen vehicles are available today. The Hyundai Nexo and the Toyota Mirai were released in 2018 and 2015 respectively. The Mirai had sold 10,000 units up until 2019 mainly in California, Denmark, and Norway. And, there is of course the BMW iX5, currently in development.

Hydrogen can be used as a fuel like petrol and used to power modified or redesigned internal combustion engines (ICE). In fact, hydrogen has the best power to weight ratio of any other fuel.

On the plus side, since hydrogen is not a hydrocarbon it does not produce CO?, however its main drawback when burned it that it produces NOx (nitric oxide and nitrogen dioxide). That said, with the introduction of more efficient NOx reduction systems including exhaust gas recirculation and selective catalytic reduction, NOx emissions can be significantly reduced.

Several car manufacturers have already realised the benefits of hydrogen fuelled ICE and are producing vehicles as well as retro fitting. This is not new technology the earliest example of a hydrogen ICE was in Russia during WWII when 200 vehicles were retrofitted to run on hydrogen when petrol and diesel became unavailable.

Over the last few years JCB, one of the word’s largest manufacturers of construction equipment, has been redeveloping their engines to use standard components to run on hydrogen. These vehicles are already being used across a number of commercial applications from mining to farming. And let’s not forget the Toyota GR Yaris H2, while not yet commercially available has proven itself a force to be reckoned with on the world rally car circuit.

Hydrogen must be part of the solution

Given that the average replacement time of a new vehicle is 15-years and even if we cease to purchase new petrol or diesel cars by 2030, vehicles burning petrol will still be on the road well past 2050. Providing an alternative to petrol which also removes CO? seems to be the best stepping stone towards net zero.

It’s unrealistic to consider converting all vehicles to burn hydrogen, but for freight this could provide a quick and efficient opportunity to provide an alternative to battery electric vehicles whilst maintaining our carbon reduction goal.

At present there are just 12 hydrogen filling stations in the UK, so to get started we would urgently need a commitment to invest in hydrogen production and for it to be readily available as part of the existing filling station infrastructure mix.

A purpose-built network could reasonably easily accommodate multiple technologies including hydrogen fuel cell, hybrid vehicles and hydrogen ICE vehicles.

Original article at www.transportextra.com