Potato chips are usually fried with gas in European factories. However, strict regulations in the Netherlands, for example, ensure that these heat processes also have to be decarbonised. The US food company PepsiCo relies on a solution from Germany: the energy company Kraftblock builds so-called high-temperature storage tanks from freight containers and ceramic golf balls that can store heat. The system is sustainable, lasts a lifetime and is significantly cheaper than hydrogen in many applications, promises Kraftblock founder Martin Schichtel in ntv’s “Climate Laboratory”. “It’s just not economical enough compared to our technology.” But orders from Germany have so far been few and far between. Compared to other countries, German energy policy is unfortunately very sluggish when it comes to heat requirements, as the Kraftblock boss explains.
ntv.de: You recently got into the production of potato chips in the Netherlands as a partner of PepsiCo. Can you introduce this project?
Martin Schichtel: Like many other companies, PepsiCo has to achieve decarbonization goals. In this case, it’s about heat, which I need to make potato chips because I need to somehow heat the frying oil. This is still done with gas in Europe today. How can I replace that and still produce potato chips? We proposed converting renewable electricity into heat that can be stored and released into the frying process when needed.
Do you help other companies with heat storage to reduce their gas consumption?
Yes. Electricity, wind power, photovoltaics fluctuate. Sometimes I have more, sometimes less and sometimes nothing at all. With a memory, I can absorb these fluctuations wonderfully and still provide energy for frying the chips for 24 hours.
But isn’t it often said that hydrogen is the energy supplier of the future?
You can talk about hydrogen in production, but it’s just not economical enough compared to our technology. Heat pumps or the direct production of thermal oils would also be options, but they are not suitable for higher temperatures. Everyone likes to wave the green flag and say: I’m decarbonizing, I’m green! But in the end it’s about not losing money or even being a little better off economically.
How big is the gas consumption of such a potato chip factory?
With that I can supply a small town with 3000 or 4000 inhabitants.
And hydrogen is not an economical solution for this?
Hydrogen is an important building block for building the energy supply of the future in Germany and Europe. Technically, I can also change everything to it. But is that efficient? Because I have to generate electricity and then convert it into hydrogen. I lose 15 to 20 percent of my energy in the process. If I then burn the hydrogen, I have another energy loss.
If I convert electricity directly into heat instead, I have a loss of one percent, maybe two. So I can use a lot more of that valuable energy for the actual process than when using hydrogen. It’s great if I want to make steel at 1400 degrees. It also makes sense as a long-term energy store or as a safety reserve for power plant operation.
One argument for hydrogen is that you can’t easily reach these high temperatures with electricity. But isn’t that a requirement when making potato chips?
High temperatures can also be reached by converting electricity into heat. This already works today up to 1000 degrees. Our power blocks are high-temperature heat accumulators.
high-temperature heat accumulator?
When people used the term, they often thought of water. But hot water tanks or water pressure tanks only work up to 120 degrees. When it comes to high-temperature heat storage, we’re talking about 800, 900, 1000 or even 1300 degrees. It works nowadays. Many industries can work with these temperatures. Between 250 and 300 degrees are required for the application at PepsiCo.
For the fryers?
Exactly. I can’t do that with systems such as hot water tanks or heat pumps. If you are lucky, a heat pump can generate 180 degrees. Such temperatures are not a problem for hydrogen. But then I lose energy when I craft it and some more when I burn it. The efficiency is low.
And that makes it expensive?
Yes. Due to the losses, I need significantly more electricity to generate the same heat output. This makes neither economic nor ecological sense. I need to build more wind turbines and more solar panels to meet demand. That’s why our solutions are in high demand in temperature ranges below 1400 degrees: We offer highly efficient solutions at reasonable costs. This applies, for example, to the food industry, the paper industry and many other branches of industry.
So how exactly do your power blocks work?
From the outside, they actually look like black blocks. There’s a bit of technology in there, some steel and insulation to keep the heat in.
How big is such a block?
Our standard unit is a 20ft container: these are the containers you see on cargo ships or trucks. They are 6 meters long, 2.40 meters wide and about 2.50 meters high.
And what is in these containers?
They are filled with memory granules. This looks like some kind of ceramic golf ball. You could also use natural materials such as volcanic rock, sand or gravel, but they take a relatively long time to release heat again. If PepsiCo wants to fry, however, the energy has to be there immediately and not in half an hour. We have developed this granulate specifically for heat storage. There is a lot of chemistry and materials science in it.
In terms of sustainability, we also use raw materials such as steel slag that are suitable for a circular economy. It comes from the steel industry and usually ends up in landfill. For the granules, it is mixed with phosphate. The whole process only takes a few minutes and requires a bit of electricity. We don’t need heat or an oven.
And this granulate stores the heat later in the container?
Exactly. A heat transfer medium such as hot air is fed into the insulated container. The brushes over the granules. This pulls the heat out of the air and retains it. When the storage tank is fully charged, I turn the whole thing over and push cold air in. This absorbs the heat again and brings it into the customer’s process. That’s the principle.
That doesn’t sound all that complicated.
Our development motto is “KISS”: Keep it simple and stupid, because little can go wrong in a technically simple system.
How long do these granules last? How long can you use a power block like this?
In our test, we loaded and unloaded the granules 15,000 times. If I do that once a day in my company, that’s more than 40 years of life. However, we stopped this test at some point after the 15,000 cycles because the quality was still the same. It would not be wrong to say that the granules last for life.
And the greater my heat requirement as a company, the more of these containers will I buy from you?
You can put it that simply, but we make it a bit more complicated in order to keep the system as small as possible: If a 100 MWh storage system is mathematically worthwhile, we would check whether, with intelligent use, a 60 MWh storage system would also suffice. Because to operate the storage system, I need electricity. A blower is running, control instruments are installed. We also want to minimize this energy requirement and make it as efficient as possible. After all, customers need to know how much electricity they need and where it should come from and at what price.
And why is this project implemented in the Netherlands and not in Germany?
We have often asked ourselves that question. There are different reasons, but the great thing about the Netherlands is the very strict regulation. It is much stricter than in Germany.
You rarely hear that as an advantage.
But it is actually like that. For example, gas heaters may no longer be installed in living areas from 2025. In industry, new production plants may no longer burn gas from 2030, but must use alternative energy sources. The Netherlands and the Nordic countries have looked much further into the future with the energy transition – and also thought a step further: How can I decarbonize heat? How can I convert this area to renewable energies? Germany is lazy in this respect. The Renewable Energy Sources Act brings us a lot of wind and solar power. But especially in industry, fossil fuels were subsidized until recently. Companies with high gas consumption were able to buy them so cheaply that energy efficiency measures made no economic sense at all.
Clara Pfeffer and Christian Herrmann spoke to Martin Schichtel. The conversation has been shortened and smoothed for better understanding.
