How the Kopernikus project P2X converts renewable electricity into plastics and fuels, gases and heat
To make Germany climate-neutral by 2050, the transport, industrial, and heating sectors require low-emissions solutions. The Kopernikus project P2X studies one of the most promising avenues for this: power-to-X technologies. These are technologies which convert renewably generated electricity into other forms of energy, for example fuels, plastics, heat, gases, chemicals, and cosmetics.
In order to limit global warming to under 2 °C, Germany hopes to be largely climate-neutral by 2050. This can only be achieved with the help of renewable energy – which means that solar, wind, and hydropower have to replace fossil fuels. The goal of the Kopernikus project P2X is to store renewable energy in physical substances. Accordingly, the project researches possibilities for converting electricity into chemical energy. The renewable energy stored in this way can then be used in high-emissions sectors such as transport and industry, or even for heating for industrial processes, making them more environmentally friendly.
Power-to-X: electricity in, material solutions out
Scientists call the conversion of electricity into other substances “power-to-X”, or P2X for short. For example, power-to-gas produces gaseous substances such as hydrogen or methane. Power-to-chemicals produces chemicals that undergo further industrial processing. The result of power-to-fuel is environmentally friendly fuels, produced using carbon dioxide (CO2) captured from the air or exhaust gases. This approach enables a significant reduction in total emissions from fuel combustion.
In the second of three planned funding phases, the Kopernikus project P2X studies two source materials that can be produced with power-to-X technologies, one being hydrogen, and the other being syngas, a mixture of hydrogen and carbon monoxide. Hydrogen is produced by applying electricity to water in a process called electrolysis. If CO2 is also added during electrolysis (co-electrolysis), syngas is produced.
Focus of hydrogen research within P2X
The hydrogen electrolysers studied in the P2X project currently require large amounts of the rare and expensive metal iridium. The P2X scientists are looking for possibilities to use as little iridium in electrolysis as possible – without the process losing efficiency as a result.
Once the hydrogen has been produced, there are a number of uses for it. For example, the P2X researchers study how hydrogen together with CO2 can be converted into polymer components that the chemical industry urgently needs.
Another potential use for hydrogen is as a fuel for road transport. Therefore, the P2X team also develops concepts for the optimal operation of hydrogen filling stations.
Because hydrogen burns at a high temperature, the P2X partners also study how industrial furnaces could be heated using hydrogen at a low cost. They are specifically testing this in a company that produces glass.
- One of the associated problems that needs to be overcome is that hydrogen can only be easily transported when in liquid form, which it only becomes at high pressure. This is complicated and expensive. Because of this, the P2X team also conducts research on temporarily bonding the hydrogen to liquids, known as liquid organic hydrogen carriers, thus making it easier to transport.
Syngas: raw material for fuel and cosmetics
In the field of syngas, research within P2X focuses mainly on possibilities for producing the gas mixture more efficiently than to date, since syngas has the potential to play a key role in the transformation of the transport sector. As yet, there is little to indicate that all trucks, ships, and airplanes will ever run exclusively on electricity. However, fuels that impact the environment much less negatively than modern fuels can be produced synthetically from syngas. The reason they cause less harm to the environment is that the CO2 that they emit when combusted was previously extracted from the air during production. P2X hopes to build a plant by 2022 that can produce 200 litres of synthetic fuel every day. Parts of this synthetic fuel can replace diesel, petrol, and even aircraft kerosene.
Finally, P2X researches how CO2 can be converted into chemicals on a large scale using microorganisms, for example for use in the cosmetics industry to produce creams and other toiletries.
P2X is developing a roadmap to monitor the developments achieved in the various P2X technologies and assess them according to ecological, economic, and social sustainability criteria. Its results will then be reintegrated into the further development of the P2X technologies.
Achievements so far
In order to break down water into oxygen and hydrogen through electrolysis, electrolysers that require iridium are being studied in the P2X project. This noble metal is extremely rare and in limited supply. P2X researchers managed to reduce the proportion of iridium in hydrogen electrolysis by a factor of 10 – without compromising on the output. This has made significantly more affordable production of hydrogen electrolysers possible. Further work is now being carried out to build on this success.
Syngas is a mixture of hydrogen and carbon monoxide. P2X uses it to produce raw materials for the chemical industry and for fuels. However, the necessary ratio of hydrogen to carbon monoxide varies depending on the product that is to be made. The project developed a method that converts water and CO2 into syngas in a single step at a temperature of 800 °C using electricity from renewable sources (solar, wind). The method used to do this is called high-temperature co-electrolysis. What makes the P2X plant so special is that it can produce syngas with differing mixing ratios of hydrogen and carbon monoxide. Mixing ratios between 4:1 and 1:1 can be selected depending on the chosen ratio of the input mixture.
P2X put the world’s first integrated plant into operation to produce fuel from air and renewably generated electricity in four stages. Currently the plant, which is about the size of an industrial container, produces approximately ten litres of fuel daily. The successor model is scheduled to produce twenty times as much (200 litres) by 2022.
Hydrogen can only be transported at high pressure or when liquefied at extremely low temperatures. Both methods are complex and expensive. However, a less energy-intensive option is to bond the hydrogen to a liquid organic hydrogen carrier (LOHC) and then transport it, and finally to separate it from the liquid again at the location where it is needed. In order to release the hydrogen from the liquid carrier, dehydrogenation catalysts are needed. P2X succeeded in developing a catalyst that can release large amounts of bound hydrogen without large quantities of noble metals. The P2X catalyst is so successful that it has already been launched commercially under the name “EleMax D101”.
Oxymethylene ethers (OMEs) can be used as low-emissions fuels and for producing plastics. The P2X researchers manufacture OMEs from carbon monoxide, hydrogen, and an alcohol called methanol. Until recently, however, they had to use expensive catalysts coated with rare noble metals for this process. Now the project has developed options for using catalysts that work without noble metals and achieve more efficient conversion.