Illustration: Claus Lunau

Power-to-X: An essential part of the smart energy system

fredag 08 okt 21


Jacob Østergaard
Professor, Centerleder
DTU Elektro
45 25 35 01


Henrik Madsen
Professor, Sektionsleder
DTU Compute
45 25 34 08


Søren Linderoth
Institutdirektør, Professor
DTU Energi
46 77 58 01


Marie Münster
Professor MSO
DTU Management
46 77 51 66


Poul Ejnar Sørensen
DTU Vindenergi
21 36 27 66

Theme about sustainability

Theme about sustainability
Why is Power-to-X so important in a smart energy system and what are the challenges in meeting the goal? Five DTU researchers present their take.

Green technologies like Power-to-X play a significant role in constructing a 100 per cent renewable energy system. Using this technology, power from solar and wind energy can be converted into hydrogen or hydrogen-based substances—such as ammonia, methanol, and methane—and be used as sustainable fuels in ships, aircraft, trucks, and heavy industry.

This gives Power-to-X the potential to help meet our climate challenges. But how does the Power-to-X technology actually fit into a smart energy system? See the infographic below and hear five DTU researchers each give their take on it.

According to Søren Linderoth—Head of Department and Professor at the Department of Energy Conversion and Storage at DTU—Power-to-X is vital part of tomorrow’s energy system.

Power-to-X has a central position in the future energy system in which the technology both supplies the transport sector with green fuels and ensures that energy can be stored for future use. According to Søren Linderoth, this means that the energy system will only function if we can make the Power-to-X technology function.

“It’s important to make Power-to-X work in the energy system because—together with other energy storage technologies like thermal energy storage and batteries—the technology will help stabilize the energy system and ensure that we have the energy we need at all times, and not just when the sun is shining and the wind is blowing,” says Søren Linderoth.

Invest in Power-to-X projects

Professor Marie Münster from DTU Management agrees. In her day-to-day work, she conducts research into mathematical models that can provide guidance for how we need to prioritize in relation to the energy of the future from an economic perspective and a climate perspective for example.

Analyses done at DTU Management indicate that if Denmark is to avoid importing biomass and green biofuels—and if our international transport by sea and air is also to be green—it is a prerequisite that we continue to make massive investments in Power-to-X projects and infrastructure.

“Power-to-X is important in a smart energy system—especially if we’re to produce green fuel to cover both the national and international parts of our transport. In fact, we can expect limited access to imports of inexpensive sustainable biomass,” said Marie Münster.

“Such a great need requires that we optimize our technologies and interconnect our energy sectors. For even though—according to our analyses—Power-to-X will only become truly relevant and competitive on a large scale towards 2050, it’s vital that we prepre now.”

Illustration: Claus Lunau
Illustration: Claus Lunau

The biggest challenges

Some of the challenges that lie ahead entail figuring out how the different technologies can work together. This includes conducting research into how to upscale Power-to-X for industrial and commercial use, and how to convert wind and solar energy into first hydrogen and then liquid fuel. Solutions must also be found for how to produce, store, and distribute the fuel.

To meet the many challenges, Professor Jacob Østergaard from DTU Electrical Engineering calls for a coherent strategy. He points out that the current projects are driven by individual business ideas and that there is a need for a more holistic approach to the inclusion of Denmark’s Power-to-X plants in the overall energy system.

“The big challenge for Denmark and other leading energy countries is to integrate the Power-to-X plants into the overall energy system. We need to focus on how we can make the overall energy system green efficient, and how we implement the transition for sectors such as heavy goods transport and parts of industry—which are difficult to electrify—without compromising our high security of supply,” says Jacob Østergaard.

Energy islands must be future-proved

He points out that—under the Government’s research strategy—we are to increase the research into Power-to-X and carbon capture, among other areas. But the technologies cannot in themselves make a significant difference to our carbon emissions before 2030. Only when we have developed an energy system in which green fuels replace fossil fuels will we achieve a CO2 reduction, according to Jacob Østergaard:

“We should focus on digitalizing and interconnecting the energy system. We need to adopt a holistic approach to our energy system in which the various solutions are integrated to a far greater extent than today. Wind and sun are—by their very nature—fluctuating energy sources. So to create a balance between production and consumption in an energy system based on renewable energy, there is a need for flexible Power-to-X plants which adapt to the current operational situation in the energy system through digital markets and smart management,” says Jacob Østergaard.

As an example, he mentions the new energy islands which the Danish Parliament has decided are to be built in Danish waters. According to Jacob Østergaard, they will become an expensive investment without future-proving if they are not built smartly, and you simply combine the known technologies like offshore wind turbines and Power-to-X as they are. He believes there could be big gains in synthesizing the energy islands and the Power-to-X technologies in new ways that make the overall system inexpensive. For example, fuel can be produced cost-effectively directly on the energy islands. In the long term, ships will thus be able to refuel at sea at energy islands or hydrogen can be produced that is piped onshore through inexpensive pipelines.

Need to start now

Henrik Madsen, Professor at DTU Compute, points out that—concurrently with the research into Power-to-X—we can reap large CO2 gains by digitalizing the energy system. Through Denmark's largest smart city project CITIES (Center for IT-Intelligent Energy Systems), he has helped identify advanced digital solutions that can significantly contribute to reducing carbon emissions. The examples include streamlining the operation of buildings and energy systems such as district heating systems by means of forecasting models that use local weather forecasts, among other sources. This allows the systems automatically to turn the heat up or down as needed in buildings.

Another example is to install sensors on buildings and see what they register. For example, if the heat consumption always increases when the wind comes from a specific direction, you need to look at that side of the house and see where it needs to be renovated.

“We shouldn’t forget Power-to-X and electrolysis, but let’s get started—it’s urgent—and there are many low-hanging fruits,” says Henrik Madsen.

“By digitalizing and interlinking energy systems, we already have solutions to store energy from minutes, over days, to seasons. And with Center Denmark—a national hub for green research—we have a partnership and a platform that provide Denmark and the Danish business sector with a good starting point for delivering the solutions that can help implement an effective green transition globally.”

We want to do the right thing

The transition also means changes in the lives of ordinary citizens. As so-called prosumers, we will have an active role in the energy system and can, for example, form part of local energy communities where we buy and sell local green power to the surrounding houses. This requires a behavioural change, according to Poul Ejnar Sørensen, Professor at DTU Wind Energy:

“For the ordinary citizen, it’s important that we maintain a welfare society with a stable and reliable supply during the coming transition. But we also need to learn that it pays to show awareness, so that, for example, we do not choose to recharge our electric cars when we get home from work and the electricity grid is already at peak load.”

“The technology must help us all better understand how we can do things best without incurring large costs. In fact, we can see with waste sorting and other initiatives that the vast majority are more than willing to help and do the right thing, as long as it’s not too cumbersome and makes good sense.”