Back to the future

Dr Ben Todd looks at what’s new in the area of using hydrogen for energy

Hydrogen is neither a new molecule nor new to industry. But it’s emerging role in the energy system is new and businesses are waking up to the energy opportunities in hydrogen. The increasing influence of the global Hydrogen Council, with representation from global energy and manufacturing players, illustrates this. In the UK, much of the work is being supported by the Government’s Hydrogen Economy programme, bringing together the various strands of possibility for hydrogen into a coherent systems approach.

Low carbon hydrogen
The big win for hydrogen is that in use it is zero carbon and low or zero in other emissions too, improving air quality. So, like electricity, the question is how to produce it in a way which is low carbon, and at sufficient scale to provide a meaningful contribution to global carbon emission reductions.

Again, like electricity, there are many ways to make hydrogen, including chemical and biological routes. But there are two main approaches likely to dominate low-carbon hydrogen production in both the short and the long term.

The first is electrolysis, using electrical power to split water. If that electricity is renewable then you have low carbon hydrogen. But perhaps more importantly, there is an electricity network benefit for the use of electrolysis as an enabler of increased renewable penetration. Mopping up excess power on the grid and conversion to hydrogen is being explored as a route to addressing intermittency challenges of renewables. Unlike electricity, hydrogen can be stored at truly grid-scale, even for long periods of time, and transported to where it is needed in trucks or pipelines.

The second production route is the more familiar steam reforming of methane. Looking ahead to large scale hydrogen production for energy, reforming is well known and relatively cheap. As the reforming reaction produces a clean stream of CO2, carbon capture is relatively straightforward, and so this potentially provides a cost-effective long-term route to low carbon hydrogen, provided carbon storage mechanisms are realised.

Hydrogen for heat
So, if low-carbon hydrogen production is possible, what are the new uses of hydrogen that will drive demand in the energy sector? The big one is heat, getting serious attention at the moment, not least as Government has realised how big a challenge it is to ‘decarbonise heat’. Hydrogen offers something conceptually simple in countries with an established gas grid – displacing methane with low-carbon hydrogen. Cue ‘Power-to-Gas’ – using renewable energy to make ‘green’ hydrogen for injection into the gas grid; which is being trialled in Germany and soon in the UK. The parallel methane reforming route, with sequestration of CO2, could provide the scale for long-term complete grid conversion to hydrogen.

Practically, up to 20 per cent of the natural gas in pipelines can be replaced with hydrogen without any modification of end use appliances, and the recent Leeds H21 study showed that 100 per cent conversion is feasible. Gas networks are now looking at the implications and opportunities for hydrogen in the gas grid. Cadent is leading a significant project in the North West to explore the use of the gas network. As part of the Government’s Hy4Heat programme, appliance manufacturers are developing boilers and other devices that can use 100 per cent hydrogen. A whole town conversion pilot is planned for in the next few years.

Greening industrial processes
Hydrogen has been produced and used for decades in many parts of the oil, chemical and steel industries. So, if we can make it renewably, why not transform the carbon impact of these energy intensive processes? Several established industries are exploring just this. Shell is piloting a 10MW electrolyser to produce hydrogen for a refinery, and there are developments in steel and ammonia production. Fuel switching for energy intensive industries is an active area of exploration for the UK government’s programme.

Zero emission transport
Transport has long been a key part of the strategy for hydrogen adoption, with fuel cell cars offering zero emissions and performance similar to conventional vehicles. Indeed, you could say that much of the recent interest in hydrogen was kicked off by the arrival of the Toyota Mirai on UK streets in 2016.

But the short-term development of hydrogen for transport is more likely to be in heavy-duty vehicles. With city air-quality high on the political agenda, zero emission buses are a priority for public transport now and delivery trucks and refuse collection vehicles will be next. These vehicles with high duty-cycles and high capacity requirements are hard to address with current battery technology. Fleets of back-to-base vehicles make the development of refuelling infrastructure straightforward and the high-volume use makes hydrogen supply close to commercial even today.

With these new opportunities emerging there are many who now think that a shift to widespread use of hydrogen in many sectors is inevitable. The question now is not if, but when, and more importantly, who. Who will step up and lead this transformation?

Arcola Energy
Dr Ben Todd is Managing Director of fuel cell and hydrogen system engineering business Arcola Energy. Working as specialist engineers and Tier 1 suppliers to vehicle manufacturers, Arcola Energy is a leading developer of zero-emission buses and heavy-duty vehicles. Arcola Energy also designs and deploys energy systems integrating hydrogen storage and fuel cell power generation.

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