“Climate Laboratory” on the key technologies: “CO2 will soon be a raw material”

Photovoltaics, wind power, batteries, electrolysers and CO2 vacuum cleaners known as Direct Air Capture (DAC) – we need these five technologies for a successful energy transition, says Christian Breyer. However, the solar economist at the Lappeenranta University of Technology (LUT) in Finland does not consider new hydroelectric power plants, geothermal energy and bioenergy to be convincing solutions. Neither does green hydrogen. This is a cumbersome energy source that should only be a building block for others, explains Breyer in ntv’s “Climate Laboratory”. The researcher sees the future of global energy supply on the world’s oceans: in 30 years, floating solar power plants could generate electricity that can be converted into green ammonia, methanol or kerosene in huge offshore factories for synthetic fuels and distributed worldwide – thanks to decades-old processes and the new raw material CO2.

ntv.de: The federal government is making big plans for hydrogen, people are dreaming about it Hydrogen heaters and liquefied natural gas terminals where green hydrogen will one day arrive, but it is missing from their list. Why?

Christian Breyer: The list only contains the equipment and devices with which we achieve the energy transition, not a specific product. Otherwise, electricity would always come first, as it is most important for the energy transition. That’s why photovoltaics and wind power are crucial, especially for Europe and North America. This is self-explanatory.

And what about hydropower?

This is important, but is already being used excellently around the world. The potential has largely been exhausted.

There is no more potential for improvement?

Hydropower capacity can certainly be increased by a third to 50 percent. But are we just looking for cheap and renewable energy systems or also sustainable ones? If sustainability is important to us, we have to treat rivers carefully. Large rivers such as the Mekong in Asia, the Congo in Africa and, to some extent, the Amazon in Brazil have the greatest potential for hydropower. Technically it would be possible to build hydroelectric power plants there, it might also be economically attractive, but it would relatively certainly destroy the river ecology. And in the Congo alone we are talking about a good 500 species that only live there. That’s why hydropower, where it exists, is always part of the solution, but like other sustainable energy sources, it is limited.

Why?

With geothermal energy, we have seen for decades that projects are not being realized to the extent that we would have liked. Bioenergy has the big disadvantage that there is no space for energy crops, because we need it for feed that we give to animals, which we in turn eat. Whether that is a smart idea is another question.

PV and wind occupy the top positions because they have proven themselves, work and are cheap?

Naturally. In the end, the energy transition is an economic question. There is potential for other technologies, but at a different cost level. Solar energy in particular is incredibly cheap and is now the cheapest form of electricity in the world. You have to let it all sink in: in 2021, half of the electricity capacity added worldwide was PV. By 2050, around 10 billion people will be living on Earth, around three quarters of them in the Sun Belt, where the sun shines all year round. This is cheap energy that is available everywhere. That’s why batteries are so important.

In the meantime the first ones are being made Solar farms on the water built. Because there is so much space for infrastructure there?

This is a beautiful technology called “floating PV” that has been implemented over the last ten years primarily on lakes, reservoirs or ponds, where connecting to the grid is comparatively simple. The question was always: Does this also work at sea? More and more parts of the world are trying this, of course in calm waters without high waves. You can control that. We have this using the example of the Caribbean examinedbecause as is well known, the space on many islands for energy supply is relatively limited.

Or in Singapore.

This is where the most research is being done on floating PV. But that will probably just be an addition to the energy mix, because if you look closely at the geographical location, there is a lot to be said for simply laying a power line to Sumatra. This huge Indonesian island is right next door. You wouldn’t need that much space there to supply a small country like Singapore with electricity. If you think about this vision 20 to 30 years further, huge factories for synthetic fuels in international waters would be possible: a large, floating PV power plant generates electricity and green hydrogen via electrolysis. There’s not much you can do with it, so you turn it into Ammonia, methanol or kerosene around. Tankers could in turn collect these substances from these offshore factories at regular intervals and distribute them to global markets.

The benefits of PV, wind and batteries are becoming apparent. But why does the green hydrogen have to be converted again?

In principle, you can do a lot with hydrogen, but hydrogen is the smallest molecule in the universe and is therefore difficult to handle. It tends to diffuse through materials, is highly flammable and is difficult to transport. This can be done technically, but it costs money. And at the end of the day, shipping and air traffic with electricity and batteries only work over short distances. I can easily charge the battery on the Rhine, but not on large oceans. Dense, chemical energy sources are needed there. And we already know that you don’t have to make kerosene from petroleum: we need hydrogen and a carbon, usually CO2. We can then use the Fischer-Tropsch process to produce synthetic fuels such as kerosene.

Are electrolyzers necessary for this process?

For the first step when we produce green hydrogen. The only thing missing is CO2, which is suddenly no longer an exhaust gas and causes emissions, but a raw material. Then we would have a solution for aviation that would not require major changes to the current aircraft fleet. Another advantage is that, in addition to kerosene, hydrogen can also be converted into almost all of the other important products that we need: methanol for the chemical industry or for shipping or into ammonia as fertilizer for agriculture. Hydrogen itself is primarily needed in steel production.

And where do we get the CO2 from? Is this the fifth key technology, the CO2 vacuum cleaners?

CO2 can come from all sorts of sources, but ultimately Direct Air Capture (DAC) is probably the most scalable solution. Because if we take climate change and the energy transition seriously, we will soon restrict gas-fired power plants, coal-fired power plants and coal-based steel production and thus all essential processes that produce large CO2 emissions. Waste incineration plants, paper mills and cement factories remained, but these would be small sources in terms of volume to produce methanol for the chemical industry, kerosene for aviation and ammonia for agriculture. How do you close this coverage gap? We take the CO2 out of the reservoir that already has too much in it, the atmosphere. The costs for this should be within an acceptable range.

Then all problems are solved – in theory anyway. But aren’t we already too late? Yes, a lot of solar parks are being built around the world, but there is a lack of storage capacity everywhere to be able to use solar power around the clock. And DAC has so far only been used on a small level.

Wind power works, even if not all of the teething problems have been resolved yet. But there they are actually only working on detailed questions. Photovoltaics as well. PV modules become on average 0.5 percentage points more efficient every year. This trend has been going on for 20 years and will continue for many more years, while at the same time becoming increasingly cheaper.

Then we check the boxes for wind and PV. What about batteries?

We are seeing the turning point. In recent years there have been problems with cobalt and nickel shortages, but electric cars and home storage systems now mainly use lithium-ion batteries, which are increasingly being built without cobalt and nickel. Do we have enough lithium? Opinions differ on this. In principle there is enough there, the world’s oceans are full of it, we just can’t get it out efficiently. That is the actual problem. This year, sodium-ion batteries were also introduced by the two global market leaders. There are no longer any material bottlenecks with them.

Is everything safe with the batteries too?

There is a lot to be said for it. These companies have a reputation to lose and wouldn’t be doing this if they didn’t know this worked. And the growth rates are enormous: If PV module production is growing at 30 percent per year, battery production is growing at 50 to 100 percent per year.

And electrolyzers?

The situation there is more critical because the market is much smaller. But we have been mastering the technology for 100 years and there are around two dozen manufacturers and suppliers from all over the world. It will be an exciting race to see who can ultimately offer the best products at the best prices. I’m not worried. With DAC, only the scaling remains questionable, because the technology also works in this case: it has been used in nuclear submarines and on space stations since the 1960s. All that is missing is major commercialization, and these manufacturers are now also well equipped with capital from investors.

Clara Pfeffer and Christian Herrmann spoke to Christian Breyer. The conversation has been shortened and smoothed for better clarity.