Power-to-X: Integrating fluctuating renewable energy
Power-to-X may revolutionise the energy sector. By linking energy, industry and transport, it opens new business opportunities for visionary companies.
Power-to-X contributes to the solution of several problems that arise when changing from fossil energy sources to green sources such as wind and solar:
- It provides liquid fuels for long distance transport such as planes and ocean-faring ships
- It provides energy storage in periods when batteries and smart grid are not feasible, i.e. from weeks to seasonal
- It absorbs peak loads of wind and solar, sized to provide average electricity consumption
There are partial solutions using other methods to all three of the above issues. However, Power-to-X is the only one that solves all three. Therefore, touching on all three aspects should be beneficial for a successful business case for Power-to-X.
A technology with electrolysis at the core
Power-to-X essentially means: ‘Converting electrical power into something else’. This definition is quite broad. However, it is typically constrained on both the ‘Power’ and ‘X’ side. First, the electrical power in question should come from a non-CO2-emitting source, mainly renewable energy such as wind and solar. Second, the ‘X’ is typically a form of storable chemical energy.
Conversion of renewable electricity into storable chemical energy typically starts with generating hydrogen by means of water electrolysis. Technologies exist to generate a more complex chemical directly by co-electrolysis of water and e.g. CO2 but those have not yet matured to industrial applications on the scale for which Power-to-X is intended.
The hydrogen from electrolysis can be used directly for several applications. In the past, hydrogen has mostly been touted as a transport fuel. Now, the widespread application is equally likely to start in the already existing markets for hydrogen for industrial applications like the chemical industry and refineries. Additional usage of hydrogen in the industrial sector, such as steel production, is considered an important pathway to decarbonisation.
Combining hydrogen with CO2 from biological sources enables production of synthetic hydrocarbon fuels like the already known fossil fuels, such as methane, methanol and, by further refinement, gasoline, diesel and jet fuel. For this conversion, suitable and sufficient sources of CO2 are required, which may limit the amount of gasoline/diesel that can be produced.
Combining hydrogen with nitrogen, taken from the atmosphere, enables production of green ammonia; the most widely used chemical, second only to fossil fuels in tonnage. Ammonia could also be used in marine engines as propulsion fuel, provided important safety aspects can be resolved.
"I see innovative initiatives and a keen interest in the energy, industry and transport sectors in getting started with Power-to-X. It requires many and diverse projects for technologies and value chains to mature and be tested at pilot scale before decisions on game-changing green investments can be made. Implementation of Power-to-X also requires stable regulatory framework conditions. Otherwise, the less expensive fossil fuel solutions will prevail."
– Mogens Skov, Global Division Director, Ramboll Energy.
Stakeholder interests in Power-to-X
Few Power-to-X projects are likely to have just one stakeholder. In fact, the Power-to-X value chain involves several stakeholders from different business areas, which is part of the challenge.
Renewable energy producers experience low electricity prices when production is high. Power-to-X provides an additional outlet for the ‘excess’ electricity. They are likely owners of the electrolysis process; partly because it provides additional control of the sales of electricity to the market but even more so because co-location may exempt them from costly grid tariffs in many markets. Finally, investment in an electrolysis plant is typically only a fraction of the cost of the wind or solar electricity plant making it relatively easier to absorb.
Large emitters of CO2 from biomass like power plants and waste-to-energy plants will play an important role in the production of green hydrocarbon fuels by providing fossil-free CO2 sources through carbon capture. These plants do not necessarily need to be co-located with neither electrolysis nor hydrocarbon synthesis. However, if they are and if they also produce district heating, they can utilize the waste heat from electrolysis and/or the synthesis process. While often thought of as expensive, the carbon capture process is actually a relatively minor part of the total investment in the Power-to-X value chain. As electrolysis also provides large amounts of pure oxygen, this could potentially be useful in the combustion process and reduce the cost of carbon capture by lowering the volume of flue gas and increase the concentration of CO2 to be captured.
Manufacturers of chemicals and industrial gases also have an important part to play in the Power-to-X value chain. Being usual providers of hydrogen but also oxygen, they can apply their usual sales channels, as well as technical expertise, to hydrogen but also to monetize the stream of pure oxygen, which also results from electrolysis. The conversion of hydrogen and CO2 into e.g. methanol and possibly more advanced substances as well as the knowledge of the use and commercial outlets of such substances would fall naturally within the experience and capability of many stakeholders in the chemical industry.
Oil companies, particularly the ones that currently operate after the crude oil has been produced, have a tremendous amount of technical and commercial expertise to add to the Power-to-X value chain. It may even be possible to add certain Power-to-X outputs to existing feedstock and produce a fossil-renewable hybrid rather than traditional ‘drop-in’. Oil companies will also be important in choosing which ‘X’ to start the hydrocarbon value chain with; typically methane or methanol.Transport sector stakeholders are very important in the Power-to-X value chain because they constitute a considerable fraction of future end use of the Power-to-X final output, or e-fuel. Using e-fuels as ‘drop-in’ replacement of part of the current fossil fuels could be an important enabling mechanism for the Power-to-X value chain. At least part of the transport sector is close enough to end uses to potentially monetize the zero-carbon aspect of Power-to-X fuels.
“Ramboll provided new insights and added to our existing perspectives of PtX and what this new concept can do for our industry. They did a high-level study of opportunities and limitations for PtX at our premises, looking at location, infrastructure, rules & regulations as well as existing and planned plants.”
- Kim Winther, Business Development Manager, Fjernvarme Fyn
Power-to-X stakeholdersPower-to-X stakeholdersPower-to-X stakeholdersPower-to-X stakeholdersPower-to-X stakeholders
Renewable energy producersRenewable energy producers benefit from Power-to-X by increased electricity demand and in particular greater variable demand to help monetize periods of high production. Power-to-X helps install a ‘price-floor’ corresponding to the price of carbon-free hydrogen.
Large emitters of CO2 from biomassBiomass conversion plants or other unavoidable processes can supply carbon-neutral CO2 to pair with the carbon-free hydrogen. District heating producers can utilise waste heat from electrolysis or e-fuel conversion if co-located.
Chemical and industrial gas producersIndustrial gas producers can play an important role in receiving and distributing hydrogen and oxygen. Combining hydrogen with CO2 or nitrogen could fall within the capabilities of the current chemical industry and open new business opportunities; not least for ‘green’ chemicals used as raw materials for a variety of end user products, such as plastics, synthetic garments etc.
Oil companiesOil companies can leverage their technical and commercial expertise in the hydrocarbon fuel value chain with a new type of ‘crude oil’. Typically, a common product, either methane or methanol, will be the starting point. From here more complex substances, such as gasoline, diesel and jet fuel can be produced.
Transport sectorAviation or ocean-faring ships require large quantities of storable and compact fuels. E-fuels generated from Power-to-X can provide such fuels without emitting fossil CO2 into the atmosphere.
Eva Ravn Nielsen
Chief Consultant, PhDT: D: +45 51 61 04 83
Thomas Paarup Pedersen
Senior Process EngineerT: +45 5161 3375
Meet two of our Power-to-X experts
Eva Ravn Nielsen is a well-reputed Power-to-X specialist with a PhD in Chemistry.
For the last ten years, she has led a test center for fuel cell and hydrogen technologies at the Technical University of Denmark where she was managing large-scale European demonstration projects in private-public partnerships. Her focus has been on electrolysis and fuel cells, energy systems, R&D, data analysis, test standards, and impact analyses.
Eva joined Ramboll in September 2020 with a keen interest to accelerate the green transition by assisting the mass uptake of Power-to-X solutions world-wide.
Thomas Paarup Pedersen has a solid background in the energy sector with conventional heat and power generation, heat pumps and especially Carbon Capture as the main highlights.
This has culminated in a focus on Power-to-X, mainly systems and systems integration.
Thomas has extensive knowledge of the technologies involved and a keen eye on value generation. His specialism is concept development, finding synergies while being mindful of limitations and ultimate value generation for the owner.