Bridging Renewable Molecules into the Energy System with Stefan Judisch

We are pleased to share this interview with you, originally published by Energieblog on January 8, 2025. The conversation with Stefan Judisch provides valuable insights into e-NG and its role as a bridge for gradually integrating renewable molecules into the energy system. We extend our sincere thanks to Energieblog and Mr. Judisch for allowing us to feature their discussion here on the TES blog. Enjoy reading!

In the past, when someone in the German energy industry mentioned “gas,” everyone knew they meant natural gas, and the only question that followed was whether it was what calorific value it had. By now, everyone has also grown used to the term LNG. However, in your materials we keep coming across something called “e-NG.” What is that exactly?

Stefan Judisch: e-NG is a climate-neutral synthetic methane that is chemically identical to conventional natural gas. The key difference is that e-NG is fully renewable and carbon-neutral. It’s produced from green hydrogen and climate-neutral CO₂ - for example, from biogenic sources or if future via direct air capture. It allows for an immediate reduction in fossil CO₂ emissions and thus helps build a defossilized energy supply without abruptly abandoning existing systems. The advantage is that the economic costs of transformation can be spread out over a longer period.

Stefan Judisch: Exactly. Because it is chemically identical to methane, it can be used normally within the existing gas infrastructure. This allows for blending or a 1:1 replacement of fossil gas. But it’s also interesting in view of the political goals for a German hydrogen economy: e-NG is ideal for connecting the old gas world with the new hydrogen world.

Stefan Judisch: Imagine using e-NG as a bridge to gradually integrate renewable molecules into the energy system until a fully established hydrogen economy is in place. One of the biggest challenges is that hydrogen, in essence, requires an entirely new ecosystem: from hydrogen production, through a dedicated hydrogen grid, all the way to hydrogen-compatible consumers and their infrastructure. To connect the supply chain everything needs to be ready at the same time, and everyone needs to rely on everyone else. e-NG solves this problem by introducing a time buffer into the system. Not yet converted to hydrogen use? Then we’ll just deliver hydrogen as e-NG for now. Is the connection to the hydrogen grid delayed? We can supply e-NG through the existing natural gas network and separate it back into hydrogen and biogenic CO₂ at the customer’s site. The same applies to imports and storage: unlike pure hydrogen, e-NG has a three times higher energy density and lower liquefaction temperatures, which significantly reduces long-distance transport costs (as well as storage costs). Once the hydrogen ecosystem is fully established, we can reconvert e-NG into hydrogen and biogenic CO₂ at the import terminal or at the storage facility exit.

Stefan Judisch: You can imagine we get asked that question a lot. But yes, it does pay off in the end. However, we need to differentiate a bit:

From a macroeconomic standpoint, the cost advantage is that by using existing infrastructure and end-use applications, e-NG reduces - or at least stretches out - the overall transformation costs of decarbonization compared to alternatives. (Just consider the discussions about the accelerated write-downs of gas networks!) You don’t need to rush to build new storage and distribution systems; instead, you can use e-NG in existing natural gas networks and storage facilities, as well as in existing burners and industrial processes, without conversions. And compared to direct electrification - which requires extensive investments in power grids - e-NG offers clear cost benefits.

Looking at the customer, we assume that even when reconverted to hydrogen, e-NG can remain competitive. Thanks to its high energy density and the existing infrastructure, it can offer cost advantages under certain scenarios. Naturally, e-NG shows its most significant benefits when used directly, avoiding the additional energy losses that occur during reconversion.

Stefan Judisch: As I mentioned, e-NG can be used in different ways. If it primarily serves as a cost effective transport medium - meaning we convert it back into hydrogen and biogenic CO₂ before use - then it definitely belongs in that discussion. If the CO₂ is captured and returned for reuse in future methanation processes, a closed loop is created, which we find very exciting - and it’s also carbon management in its purest sense.

However, CCU/CCS is usually debated with a different focus: prolonging the life of fossil power plants or locking in fossil fuels. Here it’s important to emphasize that e-NG is not natural gas - it actually comes from the hydrogen world. e-NG simply uses existing infrastructure to accelerate emission reductions. Instead of slowing down the hydrogen economy, e-NG facilitates its gradual buildup without relying on expensive new networks. This is particularly relevant because only 10% of the investment goes into the methanation process for e-NG, with the remaining 90% directly supporting the hydrogen economy.

Stefan Judisch: That’s correct. Of course, it would be nice if we could produce all the hydrogen needed by our industry - and everyone else - right here at home, but that’s just not realistic. Domestic production capacity for green hydrogen is far from sufficient to cover the expected demand. As early as 2030, up to 70% of the hydrogen needed will have to be imported. But that also means that importing via pipelines and ships gives us access to more favorable production costs - say, from regions with better wind and solar conditions. And this is exactly where e-NG can help significantly simplify transport to our region.