Future fuels for a greener plant
Green fuels are carbon-neutral or even carbon-free alternatives to fossil fuels. Produced from hydrogen and electricity from renewable sources, they are seen as crucial to decarbonize heavy industries, shipping or head generation in the future. In sectors, where direct electrification is not feasible, green fuels allow a smooth transition from fossil to sustainable energy sources – as they can be used in existing storage and propulsion systems.
How are green fuels produced from renewable energy and hydrogen?
The production of green fuels makes use of renewable energy such as wind or solar power. Green fuels, also termed synthetic or electrofuels (e-fuels), are liquid, or gaseous fuels produced with electricity from renewables. Examples for such e-fuels are synthetic natural gas (SNG), green methanol or ammonia. They are carbon-neutral when burned, emitting only the amount of CO2 absorbed during its production.
Green hydrogen is the most basic e-fuel. It is created by splitting water (H2O) into oxygen (O) and hydrogen (H2) in a process called electrolysis, using power from renewables. Hydrogen can then be used either directly as fuel e.g. for internal combustion engines – or as core component for the synthesis of other green fuels such as ammonia (with nitrogen) or methanol, SNG (with carbon, captured from the air, biomass or industrial plants' exhaust gases).
For electrolysis, the use of renewable, i.e. carbon-free, electricity is crucial. This method of producing e-fuels is called Power-to-Gas or Power-to-X (x for all kinds of e-fuels) and enables electric energy to be long-term stored and securely transported as liquid or gaseous fuel.
Green future-fuels are key to the decarbonization of shipping. […] We will make future-proof solutions available to our customers, which will make the diversified use of green fuels possible.
Why are green fuels relevant for the industry?
As marine and air transport, heavy industry and heat generation all seek to lower their carbon footprint, green fuels offer important benefits in order to reaching net zero. With stricter environment regulations and increasing customer demand for decarbonization, a timely, yet smooth fuel transition is necessary. For shipping, the United Nations International Maritime Organization (IMO) has set a target to reduce carbon emissions by 50 percent in 2050, but many players in the industry have even more ambitious goals, reaching net zero by 2050 or even 2040, for example.
Many green fuels can be blended with conventional fuels and used interchangeably. SNG and methanol, work in existing storage systems and engines, making the transition easier and faster. This flexibility is an important advantage, as shipping and heavy goods transport may require a range of different green fuels in the future.
Big advantages, but what are the challenges?
Due to their high energy density, green fuels are well suited for both transport and power generation. However, their production is energy-intensive and not yet economically viable. Even though they are being tried and tested extensively, there is still a lack of infrastructure for mass production. Therefore, facilities have to be scaled-up to reduce costs, and renewable power generation must be expanded.
Today, most hydrogen is not produced from carbon-neutral energy sources, but with natural gas (gray hydrogen), coal (brown or black hydrogen), nuclear power (pink or red hydrogen) or from fossil fuels combined with carbon capture (blue hydrogen). But in order to reduce the carbon footprint, green hydrogen is paramount. Hydrogen requires storage and transportation at either high-pressure or very low temperatures; conversion to other green fuels with higher energy density can mitigate that issue.
Are engines ready for a green fuel future?
For carbon-neutral propulsion, shipping requires not only green fuels, but also suitable engines. MAN Energy Solutions develops these as both two- and four-strokes versions.
Already today, MAN's gas and dual-fuel engines can be operated climate-neutrally, using Power-to-X fuels such as SNG. In 2023, the world's first carbon-neutral container feeder vessel, powered by green methanol and a MAN two-stroke engine, is set to enter service. In 2024, more large container ships running on green methanol are to be launched. Also in 2024, MAN aims to present a market-ready two-stroke ammonia engine.
MAN's stationary gas engines today are ready for power generation with a hydrogen proportion of up to 25% by volume in the gas mixture.Learn more about developing the carbon-neutral engines of the future