Power-to-X and Green Fuels: Fruit from the ‘Decision Tree’

There is no doubt but that green hydrogen is a key element on the path to decarbonisation. Nor is there even the least surprise these days that green hydrogen – and Power-to-X in general – has gained so much popularity and public attention. For good reason, this will not be a flash in the pan.

Strong drivers like the EU’s ‘Fit-for-55’ programme underline the reality that decarbonisation has now become a serious target and many countries have already published ambitious hydrogen strategies. Companies like MAN Energy Solutions can already provide the necessary, key technologies along the Power-to-X and green-hydrogen value chain and have serious skin in the game through significant investments aimed at further extending the base of necessary technologies.

Mature technologies, for instance for eFuel production, are available that enable the use of existing infrastructure, but much remains to be done in order to create more viable business cases. It can be shown how derivative fuels, or eFuels, can successfully complement green hydrogen in its elemental form and be an important enabler in the ramp-up to a green hydrogen economy.

One thing is clear: elemental green hydrogen will not be a one-fits-all solution. Instead, we will have a multi-option scenario where pragmatic approaches will aim at maximum efficiency, whilst at the same time ensuring that a solid base and ramp-up path for long-term transition to green hydrogen is created.

To get the full picture, it is helpful to look at the topic from two perspectives: firstly, viewing Power-to-X in the context of how it can play an important role in reaching decarbonisation targets; and, secondly, looking at the main hurdles – but also success criteria – in getting a green-hydrogen economy ramped up at a global level.

If we agree that decarbonisation is an underlying imperative in order to save the planet, then a policy comprising four elements can be identified, beginning with replacing fossil-fuelled power generation with renewable energy sources. The use of green hydrogen and employing eFuels (based on green hydrogen) are two further elements. And the fourth – for the hard-to-abate carbon sources – is carbon capture and storage technologies, again combined with Power-to-X technologies.
 

These four elements may be viewed as a type of ‘decision tree’ such that, when addressing an application that acts as a considerable carbon source today, all four means of decarbonisation need to be assessed in the order shown to find the ‘best fit’ – i.e., the most effective way to achieve decarbonisation considering all current, boundary conditions.

Needless to say, decarbonisation is reliant upon an abundant availability of renewable energy. Accordingly, extending the capacity of renewable energy generation is of paramount importance. The first question in our quest for decarbonisation is then: ‘Is direct electrification possible?’. This means, first of all, replacing all fossil-fuelled power generation with renewable energy. However, natural-gas-fuelled power plants, for example, may be tolerated as ‘backup’ or ‘peakers’ as they facilitate the maximum use of renewable energy in the grid while simultaneously ensuring maximum reliability and grid stability.

Besides electrical energy, heat generation is another of the largest contributors to carbon emissions. In this respect, heat pumps will undoubtedly become a big success. These could cover the demand for heating buildings but it is no secret that heat-demanding industrial processes are another large contributor to carbon emissions. In many of these cases, direct electrification with heat pumps powered by renewable energy could be an optimal solution. Largescale heat pumps that can achieve temperatures rising to hundreds of degrees Celsius are already available in the market.

Continuing through the ‘decision tree’, for applications that cannot be directly electrified as of yet or even in the longer term, the use of green hydrogen could be a good option and many examples exist. However, following the Pareto principle, some prominent areas especially suited for decarbonisation can be identified, such as steel production where production with green hydrogen instead of coal would cut carbon emissions considerably.

Another good example of a sector ripe for decarbonisation with green hydrogen is within processes that already require large amounts of hydrogen today. Here, ‘grey’ hydrogen is currently used and produced by steam reformation with natural gas. One such example is fertilizer production where ammonia as a main feedstock requires large amounts of hydrogen.

Which leads us to the third stage in the ‘decision tree’ when neither direct electrification nor the use of green hydrogen as a molecule is possible. In such instances, eFuels may be a solution. Derivative fuels or eFuels in this context are carbon-neutral fuels based on green hydrogen. This includes synthetic methane, methanol or ‘e-Kerosene’ – or ammonia produced from green instead of grey hydrogen, which provides a carbon-free option.
 
As such, derivative fuels could play an extremely important role: acting as a bridge technology and replacing their fossil twin, leading to carbon-neutrality; as a carrier medium for green hydrogen; or even as ‘green’ feedstock as for the prior-mentioned ‘green’ ammonia for fertilizer production. One of the great advantages in derivative fuels is their direct applicability today!

But even if we picture a fully electrified, green hydrogen and eFuel-powered world, we must not forget that there are still applications or processes that intrinsically emit larger amounts of carbon. One very prominent example is cement production where, during the calcination process, large amounts of CO2 chemically bound within limestone are released. Pilot projects have already demonstrated, in order to reach the targeted ‘net zero’ for atmospheric emissions, that these carbon emissions can be captured, liquefied and stored in subsea locations. Another method of reaching ‘net zero’ would be to use this CO2 to produce methanol as a chemical feedstock. In this way, carbon can be bound again as part of a cycle.

In conclusion, a carbon-neutral world – the desired “net zero” – to avoid further climate change is within reach and without having to completely change the world, the products we use, nor our way of life. We can also see that green hydrogen and Power-to-X are key elements in this transition. The question then is: how do we ramp up the green-hydrogen economy? For this, we will have to consider the whole value chain: the production of green hydrogen and derivatives, its transport to its application, and of course the application itself where – as in the case of direct reduction ovens for ‘green steel’ production – some considerable investments will be needed.

Accordingly, all parts of the value chain need to be pushed and ramped up simultaneously. Large, industry-wide programmes like Germany’s ‘H2.Giga’ initiative are helping to scale up electrolysis to industrial levels with accompanying cost-reductions. However, the cost reduction of green-hydrogen production alone does not make for a feasible business case when green fuels have to compete with their fossil twin without integrating the external cost of additional carbon introduced to the atmosphere. Thus, respective carbon taxation is needed as well as – at least for the ramp-up phase – smart ‘Carbon Contracts for Difference’ schemes like the German ‘H2.Global’ to finally make larger Power-to-X projects bankable.

Setting up a global hydrogen economy is necessary to leverage renewable-energy potential in regions where it cannot be otherwise used and in order to not cannibalise renewable-energy capacities in regions with high demand. This would also help to bring sustainable prosperity to more parts of the world and could solve strong global (inter)dependencies in energy trading.

Large-scale off-takers such as steel production have to be created – for example, in line with EU IPCEI projects. Even if they had to rely on ‘blue hydrogen’ in a starting phase, this means that investments could be made and hydrogen-pipeline infrastructures created. Subsequently, as soon as green-hydrogen production was at scale, a ‘switch’ to green hydrogen would be possible with all the major investments made up to that point in time. As such, it’s acceptable for many of the first, large Power-to-X projects to rely on derivative fuels since ocean transport of elemental hydrogen is a challenge. eFuels can complement a green-hydrogen economy, are an enabler for larger electrolyser plant setups, and can resolve the chicken or egg dilemma until hydrogen grids become available to provide inexpensive transport, storage and distribution options.

Seen from an industry perspective, we can say that we are ready and eager to shape the future. We are taking the risk and investing in the transformation of our portfolios and to provide the necessary technologies. Now we need the necessary political action in order to ramp up a global green-hydrogen economy and to convert decarbonisation targets into reality.

- Florian Gruschwitz, Senior Business Development Manager, MAN Energy Solutions SE