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British firm boosts hydrogen compression and storage

A British firm is hoping to spur small-scale hydrogen production by making it easier and cheaper to compress and store the gas.

RE Hydrogen has developed a device that it claims can compress hydrogen to the high pressures needed for storage at just 30 per cent of the cost of existing equipment.

The company believes the compressor will make it easier to produce hydrogen from water and electricity using small electrolysers because, unlike most conventional equipment, it can raise the pressure of gas with a small flow rate to 350 bar in a single step.

‘There are very few manufacturers in the world for hydrogen compressors and the cost is often almost higher than an electrolyser,’ RE Hydrogen’s chief executive officer Dr Amitava Roy told The Engineer.

‘You can get large compressors that run at atmospheric pressure, but then you need to have a large electrolyser to work with it. Apart from the high capital costs and low efficiency there is also a high maintenance requirement.

‘We’re focusing on the conventional gas compressing market not just hydrogen, but it will help the hydrogen economy significantly having a low-cost hydrogen compressing device.’

Small-scale hydrogen production is a potential way to capture and store energy from renewable sources and provide fuel for hydrogen-powered vehicles in place of large-scale infrastructure, as well as for industrial usage.

RE Hydrogen has already developed an electrolyser that operates at up to 5KW at atmospheric pressure and is more than 90 per cent cheaper than most conventional models. Its latest compressor is designed to increase pressure from 1 to 350 bar in a single step.

Most conventional devices would either require around five stages of compression with cooling in between to get up to the levels needed for storage or need the hydrogen to be produced at a higher pressure increasing the cost of the electrolyser.

Roy said RE Hydrogen’s technology uses a non-mechanical-based method of compression with few moving parts. It avoids the need for cooling by utilising the heat naturally produced by the compression process and containing it within the system.

The firm has produced a working model of the technology and is now looking for private investment to commercialise it. ‘Most of the parts we buy from the market so the scalability is very straightforward,’ said Roy.

Readers' comments (10)

  • Fantastic...we should not let the storage question hinder the Hydrogen economy as simple compression is still a workable answer!

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  • The article title is inaccurate, there is no described improvement in storage technology, just that they have supposedly created an 'improved' method for compressing the gas.

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  • All very interesting, but what is the specific energy required for this compression process?

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  • Physical Principal behind? I guess electrochemical membrane. Energy input required would be true value.
    Yes, decentralised H2 will be facilitated by such units

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  • Hydrogen can be produced by electrolysers by converting the excess electricity from the grid at home (i.e. equivalent to home recharging cars). It can also be done at depot for refuelling fleet vehicles. It then becomes more mainstream at forecourt refuelling in the coming years.

    The thing which is important to evaluate at this stage that fuel cell battery-petrol hybrid cars work fine. Their life is getting better and better.

    The cost of ownership of fuel cell cars will get reduced due to the rising cost of petrol and diesel for standard cars in this decade and beyond.

    Hydrogen can also be used by mixing with natural gas at low concentration while using conventional gas engines or gas turbines.

    Hydrogen does have an exciting future to capture the excess electricity from the grid when we have so much excess and intermittent renewables energy on the grid (solar, wind, wave) in transport, energy storage applications.

    I believe there will be other complementary technologies too e.g. battery cars, compressed air, flow cell batteries etc. Bear in mind all this electric charging points can be easily used to run electrolysers too for hydrogen production.

    The UK is in a strong position globally with world beating electrolyser companies. It has a couple of exciting fuel cell companies.

    In terms of hydrogen compression and storage, the above company seems to have solved a major technology hurdles for cost effective and efficient hydrogen compression.

    The UK has a tremendous capability to make a global impact collectively in the world hydrogen markets by exporting its technologies and products.

    The UK Govt is doing the right thing by supporting electric cars, hydrogen fuel cell vehicles and smart grid technologies as all encompassing technology group.

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  • @ ANON

    You fail to mention, the fact that the amount of energy required to extract the Hydrogen from water by electrolysis is vastly higher than that converted into electricity/burned when used.

    Typical figures when transport, storage is included this works at 35 times the energy in to the energy out.

    This compression technology may help reduce this factor, but it's still going to be significantly higher than using the energy in a directly in a battery powered vehicle.

    (Yes I understand electric vehicles current limitations!)

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  • Do not know where this figure comes from that "35 times the energy in to the out."

    If I take your figure for the sake of it: then an electrolyser would be consuming 125.5kWh/Nm3 hydrogen production, which can’t be true.

    The electrolysers on the market consumes about 5kWh/Nm3 hydrogen, which makes them 70% energy efficient which is verifiable.

    It seems cost efficiency is more important commercially than just the electric efficiency. One good example in this regard would be that wind turbine has much higher efficiency than the efficiency of solar PV but solar PV is becoming highly competitive due to its added values over wind.

    The energy density (kWh/kg and kWh/lt) in compressed hydrogen at 300 bar is higher than most batteries, an important feature for transport application. Hydrogen storage at 300bar is about 15-20 times more compact than lead acid batteries.

    If we want to rapidly store 100 MWh excess grid energy hydrogen does provide a very compelling case over batteries w.r.t. initial system cost, life of stationary H2 cylinders (20-50 years) and its foot print. You will also get oxygen free of charge which has a high commercial potential.

    Fuel cells have 50% electrical efficiency (PEM to Alkaline) with additional by-product heat.

    Battery powered cars are attractive for short trips. Battery does have practical challenges e.g. high charging time, self discharge over a longer duration, diminishing capacity with cycling. We know that a 3.5hour laptop battery drops below 1 hour capacity within 1.5 years.

    The debate is not on whether battery or electrolyser-fuel cell. We need both technologies at this stage as an industry. The car makers are going for fuel cell battery hybrid to combine the strength together.

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  • I'd like to see some operating data, to compare it to alternatives (such as directly generating high pressure hydrogen in a PEM electrolyzer.)


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  • Since the article states that there are few moving parts. I would presume that they are utilizing metalhydrites as a buffer storage and then releasing the stored hydrogen at quite high pressure to the tank.

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  • A very big problem for many of the arguments supporting a Hydrogen economy is that of the cost of the infrastructure to harness and deliver the Hydrogen. All too often figures quoted never express the cost of the large generators required to supply the electricity for electrolysis or indeed, the cost of the energy to run these generators. Then there is the costs to manufacting at the coal face and various supporting industries. When I see 35 times, I think, someone has done a very detailed cost analysis of the industry. The only way, at the present time that Hydrogen is going to become cheap is for 1) people to work for nothing, 2) build the various equipment required for nothing and 3) because we are all working gratuitously, we all starve to death, so then we don't actually need any more energy.

    Have a good day

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