Green methanol, as a universally usable energy source of the future, is being followed with great interest by the engine community. At the same time, however, the technology is not without controversy: critical voices point to a lack of economic viability and efficiency. What position will you take at the Engine Congress?
Martin Wieser: I will highlight the many different ways in which green methanol can be used, from powering cars to shipping. The basic message is that methanol is a highly flexible energy source. However, it is essential that we use green methanol. It makes no ecological sense to use gray methanol from fossil sources, as this would not improve our carbon footprint at all.
How do you position methanol engines in comparison to battery electric drives or hydrogen engines?
Martin Wieser: We need electrification, we need hydrogen – but we also need pragmatic approaches to drive defossilization forward quickly enough in all segments. Take off-road applications on remote construction sites, for example: there is no way to refuel with hydrogen there in the foreseeable future because the logistics are lacking. Even with battery-electric drives, you quickly reach your limits in continuous operation of heavy equipment. With a liquid fuel such as methanol, on the other hand, supply can be ensured much more easily and efficiently. In addition, it is relatively easy from a technological standpoint to adapt existing diesel or gasoline engine concepts.
Let's dive deeper into the technology. A car engine works differently than a marine diesel engine. How do you deal with the different combustion processes when using methanol?
Martin Wieser: That is a crucial point. In the passenger car sector or even in truck gas engines, it makes sense to use a spark-ignited gasoline engine principle. However, when it comes to marine diesel engines or large engines, we are moving toward dual fuel in the medium term and, in the long term, toward diffusion flame combustion using the HPDI (High Pressure Direct Injection) process. With the HPDI process in particular, we can make significant leaps forward in terms of efficiency compared to classic gasoline engine concepts.
At the conference, you will report on a joint project with Graz University of Technology and Liebherr. What is behind this collaboration?
Martin Wieser: The original catalyst was a funding project that primarily focused on hydrogen engines. However, we established a side branch there and are currently working on a methanol engine that has been undergoing testing at Graz University of Technology since fall 2025. Liebherr is an essential partner in the project, contributing both the methanol injection system and the fuel pump.
What type of engine is it?
Martin Wieser: We use an AVL R&D engine that we derived from gas operation. The exciting thing about it is the versatility of the base engine: we now operate this 12.8-liter engine as a diesel, gas, hydrogen, and now also methanol engine. It is basically always the same base engine with the appropriate adaptations. This enables us to arrive at solutions that are industrially scalable under the given economic conditions. Our goal is to achieve defossilization with as few changes as possible – in other words, with a high rate of carry-over parts.
Compared to diesel, methanol has a significantly lower energy density. Isn't that a deal breaker in the heavy-duty or marine sectors?
Martin Wieser: It is a challenge, but not an obstacle. The energy density is about half that of diesel, so you have to carry more fuel. But methanol is a liquid energy carrier and, in the broadest sense, an excellent hydrogen carrier. Its feasibility in application is much easier than with gaseous hydrogen. We are already seeing this in the shipping sector: shipping companies such as Maersk are already using ships powered by methanol in pilot projects. In addition, methanol can largely use the existing infrastructure for liquid fuels, which is a considerable advantage in terms of rapid availability and a short time-to-market.
The engine technology appears to be ready. But where will the green methanol come from, and who will invest in the engines as long as the fuel is not available in sufficient quantities?
Martin Wieser: Technically, we are indeed ready. In China, for example, methanol engines are already running excellently and in series production under the label “New Energy Vehicle.” What is currently still lacking in Europe is the political will and the appropriate framework conditions – comparable to the hydrogen infrastructure, where we are also lagging behind. For an OEM, the use of methanol must also make sense from a legislative perspective, for example, by being included in the CO2 fleet balance. If methanol is left out of this consideration, there is little economic incentive for manufacturers.
Are there also technical hurdles that currently hinder the widespread use of green methanol?
Martin Wieser: Issues such as evaporation, fuel deposits on walls, and the resulting challenges with cold starts are much more difficult to overcome with methanol than with diesel. But compared to the infrastructural and political conditions, these are solvable tasks for us engineers. I am convinced that green methanol will find its place, and not just as a niche application.
Finally, where should green methanol come from? Do we need to produce it in Europe in order to be independent?
Martin Wieser: This is a key issue that still needs to be discussed. In terms of security of supply and independence, it certainly makes sense to produce at least part of the green methanol in Europe. However, we will also be dependent on imports – this is particularly useful for regions that are able to produce hydrogen and thus methanol particularly efficiently thanks to favorable conditions for solar energy.
