Rolls-Royce is ditching diesel for methanol with its new maritime engine, described as the world's first high-speed marine engine in its performance class to operate exclusively on pure wood alcohol for a potentially CO₂-neutral drivetrain.
Maritime shipping makes up 90% of the world's commercial traffic, with almost 100% of it running on diesel fuel. Small wonder, therefore, that it accounts for a sizable percentage of global emissions, including 3% of greenhouse gases, 13% of sulfur oxides, and up to 30% of nitrogen oxides. While reducing these emissions would be a good thing, there are very practical obstacles to doing so.
The fact is, operators of ferries, yachts, supply ships, and other vessels burn diesel fuel for very good reasons. It's cheap, energy dense, has a lower fire risk, and is available globally. In addition, diesel engines are thermally efficient, high powered, reliable, and have much lower maintenance costs than other engines. That means the bar is set very high for any alternative fuels.
It's a challenge that Rolls-Royce has accepted for its meOHmare project, along with Woodward L’Orange and the WTZ Roßlau technology and research center. The goal is to create a practical marine engine that can run on pure methanol, with a demonstration concept expected this year. This engine could one day become the heart of a carbon-neutral cycle where the fuel is made from green sources.
Aside from potentially being carbon neutral, methanol promises much lower levels of sulfur oxides, nitrogen oxides and soot particles, as well as being biodegradable and easy to store. However, unlike diesel, liquid methanol does not ignite spontaneously in the high heat environment of a diesel engine. This required a fundamental redesign of the engine's core components, especially involving the basic combustion process, turbocharging systems, and engine controls.
One particularly tricky bit is that methanol is a poor self-lubrication fuel, which means that the ultra-high-pressure injection systems typical of diesel engines have to be re-engineered.
Details of the prototype engine have not been released, but since it is supposed to dovetail with the company's plan to introduce a dual-fuel engine to handle the crossover to a methanol infrastructure, it's likely to be a variant of an existing Rolls-Royce mtu high-speed engine platform such as the Series 4000.
“This is a genuine world first,” said Dr. Jörg Stratmann, CEO of Rolls-Royce Power Systems AG. “To date, there is no other high-speed engine in this performance class that runs purely on methanol. We are investing specifically in future technologies in order to open up efficient ways for our customers to reduce CO2 emissions and further expand our leading role in sustainable propulsion systems.”
Source: Rolls-Royce
