Hydrogen production will be an essential part of the net zero economy in the UK, so we support funding for developing its technologies.
However this gas is not a panacea for everything. In particular its scope does not include balancing renewable generation or the electricity grid. As with all technologies, it has strengths and weaknesses. Those strengths mean that hydrogen should be (with electricity) one of the UK’s and the world’s principal “energy vectors” or ways of transferring energy from source to point of use.
Current State of Hydrogen Production
Because hydrogen will become such an essential part of the UK economy, the scale of its production must be large, and so must the potential scale of all beneficiaries.
The main way of generation hydrogen is electrolysis, which currently follows one of three processes. All of these are totally unsuitable to meet the demand:
- Membrane technology is intrinsically small-scale and expensive, with the membranes themselves being costly consumables;
- Acid and alkali processes are larger scale but of similar costs due to their input materials of acids, alkalis and catalysts.
All these technologies, to be net zero, have to include consumables within the net zero calculation.
Current alternatives to these processes are Steam Methane Reformation (SMR) with Carbon Capture and Storage (CCS), and Coal Gasification.
Steam Methane Reformation
Steam Methane Reformation generates hydrogen by reacting water and methane. The end products of this reaction are hydrogen that can then be used as fuel, and waste products carbon dioxide and carbon monoxide.
The way the waste product is managed affords this hydrogen process a different classification. If the carbon is released into the atmosphere, the hydrogen is considered ‘grey hydrogen’, if captured, transported and stored, it is ‘blue hydrogen’, which is more preferable for climate reasons.
Carbon Capture and Storage Integration
Capture is relatively easy, as it only requires the removal of the hydrogen, but it imposes inefficiencies on the gasification plant, mainly by means of its back-pressures. While carbon capture reduces power station efficiency by 30-40% (see, for example, studies by Harvard and Stanford Universities), the reduction imposed on a gasification project is less likely to be owing to the higher concentrations of CO2 and the greater difference in molecule size between it and H2; nevertheless, the efficiency penalty is likely to be substantial.
These processes are difficult since CO2 is notoriously prone to changing its phase and physical flow properties, but they are relatively well known. Here the issue is leakage: what happens if there’s a leak in the capture plant, the pipeline or the final store (e.g. an earthquake disturbing the cavern, depleted hydrocarbon well or injection site)?
The resultant gas emission is half as dense as chlorine gas, notoriously used as a poison in World War 1. While CO2 doesn’t attack the lungs (though carbon monoxide does), it can asphyxiate as a dense cloud of gas when isolated from oxygen. With this increased density, it would hang around much longer than chlorine, and be blown in light winds, potentially over population centres and (if at sea) shipping. Whilst chlorine gas is visible, can be smelled and can be counteracted by measures as simple as breathing through a wet cloth, carbon dioxide cannot be detected so easily.
It is true that methane is stored naturally underground, but when there’s a natural emission there is no legal culpability as it is considered an “act of God”. But if a company or country had put the gas there, it would be liable for the gas until the tectonic plate is subducted some tens of millions of years later. It is this liability that the six countries around the North Sea said that they could not underwrite, asking the European Union to do so; when the EU said in 2015 that they could not do so either, about a fortnight later the White Rose and Peterhead CCS projects were cancelled. This may be a coincidence. There has, more recently, been some progress on developing liability protocols internationally, but there is (as yet) no legally binding treaty: it would be hard to defend in law as life is the most fundamental of human rights.
CCS is not 100% efficient, and it uses consumables (such as catalysts) that also have a substantial carbon footprint, so all emissions would need to be balanced by negative emissions elsewhere. It is unlikely that any SMR+CCS application would qualify as “net zero hydrogen” at any cost, and even less so at reasonable cost.
Coal Gasification
In coal gasification every single molecule of carbon becomes a greenhouse gas. The process is a much more energy-intensive process than SMR and also produces four times as much CO2 per unit of hydrogen than does methane reformation, which can be seen by comparing each reaction’s chemical formula:
Coal gasification: C + 2H2O = H2 + CO2
Steam Methane Reforming: CH4 + 2H2O = 4H2 + CO2
Due to process inefficiencies there will be some carbon monoxide (CO) mixed into the end product, but this can be treated as carbon dioxide, so it’s not a big issue – except that it’s even more corrosive than carbon dioxide.
The bigger issue is other outputs, such as carbolic acid (C6H6O) and other acids which will also be formed by the process. And, of course, it must be done anaerobically otherwise one of these products (Toluene, C7H8) may react with the 78% nitrogen in the air to form tri-nitro-toluene, better known as TNT. And, of course, there’s benzene (C6H6) and other such by-products, all of which will need to be minimised (hard to control a process finely down a coal mine), extracted and disposed of in some way.
For these reasons coal gasification should be ruled out instantly as a way of producing hydrogen.
Targets for Hydrogen R&D
Therefore the biggest focus for R&D should be on high volume electrolysis that does not involve noxious or carbon-intensive inputs including electrolytes and catalysts. There are such technologies around, but their development is not being funded – promising start-ups in this field have been founded and gone bust for lack of funding.
A secondary scope for R&D would be innovations to support the conversion from methane to hydrogen, reducing its costs and disruption. This would include gas networks, storage, industrial equipment and domestic appliances. It could (for example) involve some way of coating or treating components to make them resistant to leakage and/or embrittlement.
A third R&D focus should be for decarbonising industrial processes, such as:
- Reduction processes in iron and steel making;
- Alternative processes and chemical pathways in any other carbon intensive process, prioritising lime/cement/concrete;
- Scale-up of processes.
These processes account for over 5% of global emissions (excluding the 24% of global emissions which are for energy input to industry, including these sectors, which is energy decarbonisation, not process decarbonisation), more than half of which is for cement. Moreover, this 5% is some of the hardest to decarbonise because it’s determined by the chemical processes involved, hence the need to develop new processes.
A fourth area to target should be synthetic fuels by:
- Eliminating their carbon footprint, including in their formation from hydrogen;
- Reducing their cost;
- Improving high-volume manufacturing processes.
This is because some transportation segments are very hard to decarbonise, notably aviation (a fast-growing 2% of emissions) and shipping (almost as much, also growing). Both ammonia (NH4) and methanol (CH3OH) are strong contenders for shipping. Methanol can be made from methane but, like methane, carbon dioxide is a combustion product, so it will not help decarbonisation unless the methanol were to be made from CO2 captured directly from the air; therefore ammonia should probably be favoured.
A final portion of R&D should be for “any other related innovations” that don’t fit the above criteria. Examples may include:
- Methods for roll-out;
- Detection of and response to leaks;
- Safety measures in operation;
- Safer and easier transportation (including in the fuelling of fuel cell vehicles).
Storelectric’s Hydrogen Patent
Storelectric holds a patent (WO2019GB52168) for using the heat of compression to catalyse electrolysis, making it more efficient. The protection is broad and strong, and Storelectric is looking for partners to develop it into a commercial process. It will enable a much more synergistic integration of the electricity and hydrogen energy vectors, their integration with renewable generation, and applications that require heating and cooling.
