Power Electronics for Hydrogen Mass Production: State of the Art, Challenges and Outlook

00:00:00: (gentle music)

00:00:01: - "Sound On Power On",

00:00:03: your Power Electronics podcast.

00:00:06: Powered by PCIM Europe.

00:00:09: - Hello everybody and welcome to the new episode

00:00:12: of "Sound On Power On".

00:00:14: Your power electronics podcast powered by PCIM Europe.

00:00:18: My name is Marco Jung.

00:00:19: I'm a professor for e-Mobility and Electrical Infrastructure

00:00:22: at the Bonn-Rhein-Sieg University of Applied Science

00:00:25: at Sankt Augustine,

00:00:26: as well as Head of Department Converter

00:00:29: and Electrical Drives at the Fraunhofer Institute

00:00:32: for Energy Economics and Energy System Technology at Kassel.

00:00:36: Both are located in Germany.

00:00:38: Additionally, I'm the chairman of the IEEE Joint

00:00:41: IES/IAS/PELS German chapter

00:00:45: and active member of several national

00:00:47: and international communities and committees.

00:00:50: And today our technical theme is

00:00:52: Power Electronics for Hydrogen Mass Projection,

00:00:56: State of The Art, Challenges and Future Outlook.

00:01:01: Before we start with the power electronics,

00:01:03: let us have a look to the motivation.

00:01:06: Why is hydrogen so important for the future power supply

00:01:09: of countries and industry?

00:01:11: First of all, I think clean energy source

00:01:15: because hydrogen can be produced with electrolyzers,

00:01:18: powered by renewable energy sources such as wind and solar.

00:01:23: I think that the second point is decarbonization.

00:01:27: Hydrogen offers a promising pathway

00:01:30: for decarbonization sector

00:01:33: that are difficult to electrify directly,

00:01:35: such as heavy industry,

00:01:37: long haul transportation and heating.

00:01:41: And third one is energy storage.

00:01:43: Hydrogen can be stored and transported relatively easily

00:01:48: and this makes it to a valuable option for energy storage

00:01:53: and for balancing intermediate renewable energy sources

00:01:57: like wind and solar.

00:02:00: And the fourth is versatility.

00:02:03: Hydrogen can be used in a variety of applications

00:02:07: including fuel, cells for transportation,

00:02:10: power generation, heating and industrial processes.

00:02:15: So you see overall,

00:02:17: hydrogen holds a significant promise

00:02:21: as a clean, versatile and sustainable energy courier

00:02:25: that can play a critical role in the transition

00:02:27: to low carbon future.

00:02:32: And if we have now the next step,

00:02:35: so if we want to clean hydrogen,

00:02:37: we have to integrate it into existing system,

00:02:41: but the question is, how we can do it?

00:02:44: So we have the possibility to produce the hydrogen directly

00:02:48: next to the re-enable energy

00:02:50: and transport it via gas line or ships and so on

00:02:55: to the customer.

00:02:56: Or we can transport the power via the electrical grid

00:03:01: to the electrolyzer station

00:03:03: and produce at the custom area the hydrogen.

00:03:07: So both options have the advantages and considerations

00:03:11: and the choice between them depends on various factors

00:03:15: such as infrastructure capability,

00:03:18: cost effectiveness, energy efficiency

00:03:21: and specific requirements of the end user.

00:03:25: But let us come now to our topic in this podcast.

00:03:30: The question I think so for the future is,

00:03:33: what are the future requirements for electrolyzer rectifier?

00:03:38: Basically we can say electrolyzer rectifier must combine

00:03:43: high efficiency, easy scalability,

00:03:46: high reliability and cost effectiveness.

00:03:49: I think so, that is a topic for all products,

00:03:53: what we want to introduce in markets markets.

00:03:56: But if we go now more in the power electronic side,

00:03:59: let us has a few state of the art.

00:04:03: So electrolyzers must be supplied by DC power.

00:04:09: Typically the rectifier of the electrolyzer is connected

00:04:13: to the medium at high voltage AC grid

00:04:15: depending on the power class.

00:04:17: The rectifier converts power from the electrical AC grid

00:04:21: into the direct current

00:04:25: to powering the electrolyzer system.

00:04:28: So then we have two interfaces.

00:04:31: Power grid with its electrical grid compliance,

00:04:34: requirements and use cases,

00:04:38: and electrolyzer stack with the correct current and voltage

00:04:42: for the electrolyzer process.

00:04:45: And here we have changing requirements.

00:04:49: If you look to the state of the art

00:04:51: or better conventional rectifier,

00:04:53: we see Teresa based B6 rectifier are currently used

00:04:59: to increase power quality at rebel reduction to topology

00:05:03: can be extended to a 12 pulse rectifier

00:05:07: using a special sigma delta transformer at grid side

00:05:11: and at the DC outputs,

00:05:12: the B6 rectifier can be connected in series or parallel

00:05:16: depending on required output current and voltage.

00:05:21: To adjust the rectifier output voltage level

00:05:23: to the stack level,

00:05:25: A DC-DC converter can be connected in serial as well.

00:05:30: This is not absolutely necessary,

00:05:32: but it increases the grid power quality

00:05:34: as well as the quality of the DC current

00:05:36: over the whole power,

00:05:38: or let's say voltage range of the stack

00:05:40: over the whole lifetime.

00:05:43: But if this is enough in the future, what we see?

00:05:47: We have a transformation of our power grid.

00:05:50: For example, in Germany we have a high penetration

00:05:53: of renewable energy more than 50%, 60% on many days a year.

00:05:58: This is still increasing in our power system.

00:06:01: Centralized power plants

00:06:03: with big electrical machines provides a combination

00:06:07: of the decentralized renewable energy system services

00:06:10: or ancillary services.

00:06:12: If you want to achieve the goal

00:06:14: of nearly 100% renewable energy in our power grid,

00:06:18: somebody else must provide system services

00:06:22: or ancillary services together with the renewable energies.

00:06:27: So in the future,

00:06:27: the huge load must provide system services

00:06:30: or ancillary services for grid stability issues as well.

00:06:35: So the question right now is, which one?

00:06:38: What are the grid operator requirements

00:06:40: for the gigawatt scale electrolyzer park?

00:06:44: I think so actual the power electronics

00:06:46: must provide click compliant power consumption.

00:06:50: So that means flicker, voltage limits

00:06:53: under and voltage, for example,

00:06:55: harmonics, because if you have a huge

00:06:58: gigawatt scale power plant,

00:06:59: you must connect it to high voltage level

00:07:01: and the requirements are really high

00:07:04: in regarding to the THD or reactive power consumption

00:07:08: or providing behavior in the event of a grid failure

00:07:12: and several more.

00:07:16: So what happens in the future?

00:07:18: I think a good start is to analyze the behavior

00:07:21: and requirements for renewable energy sources.

00:07:24: And if you want to integrate more and more renewable energy,

00:07:27: and we want to use it as a green production

00:07:29: possibility for hydrogen.

00:07:31: So we have now a dynamic power range

00:07:34: depending on the fluctuating green energy production

00:07:37: and this leads in more dynamic behavior

00:07:40: for the electrolyzer system.

00:07:43: And in the standards

00:07:45: or in some papers which were published in the last month,

00:07:50: a lot of system services

00:07:51: and ancillary services are written down.

00:07:54: So in the future maybe,

00:07:56: reactive power provision must be provided from huge loads

00:08:01: which are connected to the grid with power electronics

00:08:04: or reduction of power consumption.

00:08:06: Another one is, for example,

00:08:08: fault right through and overworked right through.

00:08:11: But I think though in this case maybe a passive way.

00:08:14: So that means to endure grid stability,

00:08:18: the load must resume power immediately after the voltage dip

00:08:21: and don't get in idle mode or something like this.

00:08:26: And these future requirements as well as THD

00:08:29: for the high voltage grid can only be achieved

00:08:32: with increased effort using RIS waste converters.

00:08:38: Let us come now to the other interface

00:08:41: so the electrolyzer side.

00:08:43: We have come types of electrolyzer cell technologies.

00:08:47: Three are typical promising technology for the future.

00:08:51: Client electrolyzers polymeric,

00:08:53: membrane electrolyzers,

00:08:56: solid oxide electrolyzers.

00:08:59: Though it's still open

00:09:01: which kind of technology we will use in the future.

00:09:04: So race is still open,

00:09:07: but what we see right now is, for example,

00:09:10: carbon technology has a water range,

00:09:13: let's say between 100 volts, 500-600 volts.

00:09:17: A little bit more

00:09:19: depending what kind of technology.

00:09:21: But in future, manufacturer are promising that it's possible

00:09:26: to raise up the voltage at the electrolyte

00:09:29: up to 1.5 kilowatts.

00:09:33: Then keep in your mind aging.

00:09:35: We want to have an operation time up to 20 years

00:09:39: and this leads in increasing of the internal resistance

00:09:42: and then increasing in electrolyzer voltage

00:09:45: And so a changing in the voltage range.

00:09:49: The other thing is about the DC power quality requirements

00:09:52: or because large electrolyzer seasons

00:09:56: needs a current approximately 10 to 20 kiloamperes.

00:10:01: We have a fluctuate agent energy production

00:10:04: from renewable energy,

00:10:05: though that means, for example,

00:10:07: the requirements regarding to the dynamics increasing

00:10:11: and one big point is a ripple count, the peak to peak.

00:10:14: What is allowed?

00:10:16: It's still open this question.

00:10:18: In addition, the rectifier also takes a safety related tasks

00:10:23: such as semi-galvanic isolation

00:10:25: of the electrolyzers from the power grid,

00:10:28: monitoring of isolation of fault currents

00:10:32: of the DC voltages and currents

00:10:35: and of the power grid.

00:10:38: So increasing requirements on power electronics

00:10:40: with regard to grid compliance,

00:10:43: though that means ancillary services,

00:10:45: system services, THD in high voltage grids and so on,

00:10:49: as well as the connection to the electrolyzer stack,

00:10:53: require a rethinking of the power electronic topology

00:10:56: which be used.

00:10:57: For this reason, self-loving semiconductor

00:11:01: can be used to replace, for example,

00:11:04: the Teresa technologies,

00:11:06: or a hybrid power electronics solution

00:11:11: is sufficient for the future.

00:11:14: So hybrid power electronic solution means for example,

00:11:18: in parallel connected at grid side IGBT converter

00:11:24: which provides for example,

00:11:26: harmonics compensation, reactive power compensation,

00:11:30: and then you have an active system in comparison

00:11:33: to the traditional passive compensation procedures.

00:11:39: But if we replace Teresa's

00:11:42: to more self blocking semiconductors,

00:11:45: that means the rectifier system can be a zigs bridge.

00:11:49: For example with a DC-DC converter in series connector

00:11:52: depending on the electrolyzer system voltage.

00:11:55: Or a Vienna rectifier can be used

00:11:59: or a B6 switch back PFC.

00:12:04: So for example, there are exists a lot of possibility,

00:12:08: still a research, still are state of the art,

00:12:11: but I think the next steps will be combine common solution

00:12:16: with more power electronics.

00:12:18: But in future I think we will implement

00:12:21: more power electronics, self blocking semiconductors.

00:12:25: For this technology we're doing research,

00:12:28: feel free to contact us, thank you.

00:12:31: To all the listeners,

00:12:32: wherever you might be,

00:12:34: thank you very much for listening.

00:12:36: We hope you have enjoyed today's episode

00:12:39: and gained some valuable insights.

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00:13:07: Until then, have a great time.

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