Could emission-free hydrogen be produced in a way that requires little or no electricity?

In the Finnish and EU hydrogen strategy, the aim is to produce hydrogen mostly through electrolysis. This requires a huge amount of zero-emission electricity. Other carbon-free means of producing hydrogen are also needed. Cutting-edge methane pyrolysis and future solar hydrogen technologies could be part of the answer, writes Marko Huttula and Ulla Lassi.

The article was originally published in Tekniikan Maailma on 1.4.2022.

To obtain a radical reduction in carbon dioxide emissions, many polluting sectors need to transition to a hydrogen economy. In this transition, fossil-based energy sources are replaced by hydrogen.

The debate on the hydrogen economy is a heated one both in Finland, the EU and the world as a whole. Expectations are high, and the use of hydrogen is estimated to be able to cover almost a quarter of the EU’s energy needs by 2050. The race to make use of hydrogen innovations in industry is already gathering pace, and major investments are being made, for example, in northern Sweden. Hydrogen can significantly reduce CO2 emissions if the hydrogen is produced with low or zero emissions.

Hydrogen produced with renewable electricity, such as wind power, is referred to as green hydrogen.

In many of the current plans, the hydrogen will be produced by electrolysis, which requires a huge amount of electricity. In order for hydrogen use to significantly reduce emissions, this electricity must also be produced with little or no emissions. Is that a realistic goal? Could emission-free hydrogen be produced in a way that requires little or no electricity?

New hydrogen production methods are needed

A major problem with the current hydrogen strategy in Finland and the EU is the shortage of electricity. In these strategies, the aim is to produce hydrogen mostly through electrolysis. This method requires a huge amount of electricity, which ideally would have been produced from renewable energy. For example, if the Raahe steelworks would produce steel entirely with fossil-free, electrolysed hydrogen, this would require almost the entire energy production of one nuclear plant.

Currently, around 80 million tonnes (Mton) of hydrogen are produced worldwide each year for various purposes. If all the steel produced in the world were to be produced with hydrogen, we would need about 90 Mton more hydrogen. This means that more than twice as much hydrogen would then be needed as is currently produced worldwide.

If this additional 90 megatons of hydrogen would be produced by electrolysis and using zero-emission electricity, the world would need nearly 250 more nuclear power stations. One nuclear power plant roughly corresponds to 800 wind turbines, and the power output of wind power in Finland is only 33.8 per cent of the nominal power. In the energy and hydrogen debate, it is therefore important to take a realistic perspective on the amount of electricity available.

Increasing wind power is part of the solution, but new hydrogen production methods are also needed. The need for hydrogen innovations is all the more urgent in light of the rapid increase in the price of electricity and the simultaneous increase in Finland’s electricity deficit – the gap between domestic consumption and production – as shown by our analysis of open data from Fingrid and Nord Pool. It is an unfortunate fact that the forecasts for the coming Olkiluoto 3 nuclear power unit estimate that it will fill only 15–25% of Finland’s electricity deficit, which is significantly less than was anticipated. According to one report, the cost of Finland’s electricity deficit at market prices amounted to EUR 1.4 billion in 2021. This is a matter of major economic importance.

Alternative means of producing hydrogen that require little or no electricity should be rapidly developed. Japan, for example, is competing with Finland to rapidly develop hydrogen inventions.

New methane pyrolysis technique for producing hydrogen and carbon nanotubes

CO2-free methane pyrolysis, for example, is already an effective and scalable method for hydrogen production. In methane pyrolysis, the methane (natural gas or biogas) is broken up in such a way that the hydrogen contained in it is separated from the carbon and collected as pure hydrogen gas.

In this process, the carbon becomes solid and no carbon dioxide is produced. The latest technology uses a heterogeneous catalyst to break down methane at temperatures much lower than the traditional thermal process. This enables a highly energy-efficient production process.

By modifying the catalytic process, it is possible to influence what kind of carbon is formed. One option is to form carbon nanotubes from the clean carbon produced, and these can be used, for example, in new battery technologies used for energy storage.

Methane pyrolysis is a method of producing hydrogen that fits with sustainable development values, as it generates no side streams but rather only two primary products: hydrogen and nanocarbon. Methane pyrolysis is also a carbon-free production technology that requires only about a tenth of the amount of energy needed to produce, for example, ‘green hydrogen’ from water electrolysis.

Solar hydrogen inspired by nature’s genius

Solar hydrogen is a technology of the future that is currently being studied and developed. It involves producing hydrogen from sunlight and water. This method is called photocatalysis. Solar hydrogen is hydrogen produced from water by photocatalysis using only light – no electricity is needed.

In this method, the light energy absorbed by the catalytic material is sufficient to split the water molecules into hydrogen and oxygen, which are then collected. The process is completely emission-free. A solar hydrogen panel is similar in operation to a conventional solar panel, but it also contains water. At the moment, we are able to utilise 1–5% of the sunlight’s energy, but the light itself is free and emission-free.

The efficiency will be improved by developing catalysts and, for example, nanofilm structures that mimic nature and reduce energy losses. They get their inspiration from the ingenuity and effectiveness of nature in phenomena such as butterfly wings and grass structures.

As a result of evolution, plants can absorb solar radiation in an optimal way. Scientists have worked to replicate on membranes the surface structure of the leaves of different plants. For example, when such a film is placed on a photoelectric cell, light collection increases by as much as 17%. The cell does not receive any more night energy, it just reflects less of it away. Nanostructures that mimic the scales of butterfly wings can also significantly improve solar panels by making them less reflective.

In addition, the material efficiency and environmental load of solar hydrogen cells will be significantly better than that of photovoltaic cells, for example.

Research is a top priority also in hydrogen production. Finnish higher education institutions that are carrying out hydrogen research are currently developing action plans for research and education that take into account the effects of the hydrogen transition on society as a whole.

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Read more: Solar Energy Harvesting Through Biomimicking the Wings of a Butterfly

Last updated: 8.11.2022