Using liquid manure to get through the dark period of low wind: "Biogas performs the same as gas-fired power plants - 50 billion euros cheaper"

Is biogas the solution to Germany's energy problems? It can be used to generate electricity and heat. "Whenever the sun isn't shining and the wind isn't blowing," says industry spokesperson Sandra Rostek in ntv's "Climate Lab." "The plants do what gas-fired power plants are supposed to do, but much more cheaply." There are already 10,000 biogas plants on farms and agricultural businesses across Germany. Expensive and lengthy tendering processes aren't necessary. Another advantage: Biogas doesn't make Germany dependent on foreign energy sources, but rather provides domestic farmers with additional income. Unlike American liquefied natural gas (LNG), biogas is also a renewable energy source. According to Sandra Rostek, there's only one problem: The industry is being ignored by politicians. She managed to convince Robert Habeck of its advantages three years ago. Will she succeed with Katherina Reiche as well?

ntv.de: In the bioenergy sector, there are biogas, biomass, and biomethane. What are the differences?

Sandra Rostek: Bioenergy is the umbrella term for everything that is extracted from various biomasses and subsequently used in the energy sector in various ways. Biogas is produced through an anaerobic fermentation process.

Anaerobic?

Yes, without oxygen. This process takes place in an airtight container. These are usually large green containers. You sometimes see them along the highway or on a farm. Liquid manure, crop residue, or even waste from the organic waste bin goes into them. Then it bubbles away until it turns into biogas. This can be processed directly in combined heat and power plants, the electricity fed into the grid, and the heat used to warm the local swimming pool. The biogas can also be refined until it reaches natural gas quality and then fed into the gas network like fossil gas – and used for the same purposes as natural gas.

Natural gas has a higher purity level than biogas?

It depends on what you put into these containers, but yes: biogas consists of approximately 45 to 55 percent methane. To be able to feed it into the gas grid, it has to be "purified" to well over 90 percent.

And biomass?

Solid biomass typically originates from forestry. This includes wood energy from pellets and wood chips. The most familiar example is probably sawn timber: boards and beams don't grow perfectly square in the forest. When a tree trunk is turned into a beam, up to 40 percent sawdust and residual wood are produced, which can be used for energy production.

In a wood-burning stove? They are listed as a renewable alternative to heat pumps in the Building Energy Act.

Exactly, pellet stoves meet the requirements. But there are also liquid forms of biomass. Rapeseed oil for frying or even as fuel can be made from flowering rapeseed fields. Or rapeseed cake can be produced, which is a protein-rich animal feed.

These are the most common forms of bioenergy?

There are several sub-forms. For example, hydrogen can also be produced from biogas.

Or how about using biogas to help during periods of low wind and solar output? This has been discussed extensively in recent weeks, but your industry hasn't been considered. Do you feel forgotten or ignored by Economics Minister Katherina Reiche?

Yes. There are approximately 10,000 biogas plants of varying sizes across Germany. Their distribution reflects the agricultural landscape, but the important thing is: they're there. These plants have great potential if we're put on a level playing field with gas-fired power plants.

But?

When the energy transition began, the goal was: produce as much biogas as possible. The aim was simply to implement a form of renewable energy. Twenty-five years ago, solar and wind power were still in their infancy. Even then, it was clear that biogas plants could be fed with fuel and generate energy for 8,760 hours a year. The key is that biogas plants are flexible. This production can be shifted to times when the sun isn't shining and the wind isn't blowing, in order to cover the notorious periods of low wind and solar output. Studies show that they do exactly what fossil gas power plants are supposed to do – and, if the plants are retrofitted, even better than before.

In what way?

We want to equip the plants with heat storage systems and additional combined heat and power units. While this doesn't increase annual electricity production, it allows for faster feed-in of existing power – unlike gas-fired power plants that use domestically sourced and, above all, renewable inputs. This potential for flexibility should be leveraged to keep the need for new gas-fired power plants as low as possible. In the final stages of the Scholz government's term, the SPD and the Greens, together with the CDU/CSU, even managed to push through a biomass package in the Bundestag. This package specifically addresses this flexibility, but unfortunately, we are still being overlooked in Katherina Reiche's power plant strategy .

You are not currently allowed to make production more flexible?

Yes, but we have the same problems as fossil fuel power plants: solar and wind power generate the cheapest electricity. Biogas plants are only profitable if they run around the clock. Therefore, we need a subsidy for viable operation.

It's all about money, as always?

Always (laughs) . But unlike the gas-fired power plants, our facilities are ready to go. The EU Commission recently approved the biomass package, so the conversion could begin. We currently have 6 gigawatts installed and could easily provide 12 gigawatts by 2030 – that corresponds exactly to the capacity the German government has applied for from the EU for new gas-fired power plants. Even more would be possible in the long term. And we would complete the conversion much faster than building the new gas-fired power plants. Those projects haven't even been put out to tender yet.

Do you have an explanation for why they are forgotten?

These are just assumptions. Doubts about renewable energy sources, whether wind or solar, have been raised repeatedly over the years. Perhaps it's simply difficult to imagine that many small, decentralized power plants, owned by many different entities, can secure Germany's electricity supply as efficiently as the well-known large players.

And now?

I'm putting my faith in the power of facts: We will prove in the competition that we are faster than the big players with their gas-fired power plants and offer exactly the same output – renewable and regional. And we will continue to point out that climate goals cannot be achieved with fossil gas-fired power plants. Sometimes it's vaguely mentioned that they are supposed to be converted to hydrogen later, but as we can see, the hydrogen rollout isn't progressing as planned. If, instead, we were to focus on CCS, i.e., carbon capture and storage, and capturing the emissions, we would reach a cost level where biogas plants would even be cheaper to operate.

Good point. What would your offer cost?

It's difficult to quantify precisely. As a rough estimate, we believe we can secure Germany's energy supply for 50 billion euros less than planned in the power plant strategy with gas-fired power plants.

50 billion euros cheaper?

Yes, we see that figure. Simply because we offer existing power plants. However, the pure electricity generation costs are higher: electricity from biogas costs about twice as much as electricity from natural gas. Even if you don't cultivate energy crops specifically for this purpose, but use waste. Manure contains toxic substances that first have to be purified and sanitized. That's more expensive than extracting natural gas. But if we want to stick to our climate goals, it makes sense: biogas ensures that manure isn't simply dumped on the fields.

What does the Federal Ministry of Agriculture say about your plans? Surely they should be thrilled that they are providing farmers with new sources of income.

Biogas plants are often an important part of agricultural operations. This generates additional value in rural areas and communities, as the plants are more operationally intensive than solar or wind power plants. This creates jobs and local income.

Perhaps Federal Agriculture Minister Alois Rainer would be a better contact person for you than Katherina Reiche? Perhaps he can mediate?

Alois Rainer knows all this. He comes from Bavaria, and there are many biogas plants, especially in southern Germany. However, I fear that he won't fully convince the Ministry of Economic Affairs, because this biomass package touches on many areas: the energy sector, agriculture, and, particularly with energy crops, environmental aspects must be considered. It's likely that every department is looking at the issue with blinders on – and failing to recognize its true value.

Let's add a fourth department: security and defense. Biogas plants provide energy from Germany. There's no need to transport it here via pipelines from Russia or LNG tankers from the USA.

This aspect changed Robert Habeck's mind. Initially, he wasn't the biggest fan of bioenergy because the Green Party was debating whether animal husbandry would even exist in the future. Without animal husbandry, there would be no manure for biogas plants…

And then Russia attacked Ukraine?

And it turned out that, unfortunately, we had relied on an unreliable gas supplier. Do we have an alternative? Biogas plants! They were later required to expand production under the Energy Security Act , but we've moved away from that...

Christian Herrmann spoke with Sandra Rostek. The conversation has been shortened and edited for clarity. You can listen to the full conversation in the "Climate Lab" podcast.