By Chris Chatterton, Chief Operating Officer, The Methanol Institute
Faced with the towering challenge of decarbonization within the space of three decades, the shipping industry is in something akin to receive mode; absorbing new ideas and concepts on a scale not seen for decades.
Methanol as a marine fuel has already taken its place in the roster of practical solutions that the industry can employ both for short term emissions reductions and longer term greenhouse gas mitigation.
Most recently the industry has been talking more about hydrogen (H2) as a potential answer to the carbon emissions challenge and in the longer term, it will be an important contributor, powering the fuel cells that can contribute to a low carbon shipping industry
Fuel cells have distinct technical advantages over conventional batteries, which have a much shorter operational life and are challenged by problems of raw materials sourcing, recycling and disposal.
In a marine application, the difference between batteries and fuel cells could be compared to the difference between using a scrubber and burning gasoil. The scrubber is there to treat the waste stream to an acceptable level, not to eliminate it, just as the production of and charging of batteries could be with power produced from a dirtier fuel, or with disposal in a non-environmentally friendly manner.
What is sometimes overlooked is that – like LNG, hydrogen supplied at scale is usually a cryogenic fuel. It must be chilled to -253degC (even colder than LNG at -161degC) to enable it to be stored efficiently, creating potential space, operational and safety issues.
As one of the coldest cryogenic gases, hydrogen places system components and materials under extreme stresses. The only other way to supply the most abundant gas on the periodic table is in compressed form, but as hydrogen is also the lightest gas, compressing it to a level which would allow for it to be stored cost effectively and safely is perhaps its Achilles heel.
A recent DNV report noted that high costs, increased storage space and the ‘chicken and egg dilemma’, akin to LNG, are among the current challenges for hydrogen as marine fuel. Additionally, regulations for storage of hydrogen as fuel on ships do not presently exist, making class approval more complicated and costly. Pilot projects are underway but news headlines describing it as ‘a reality’ should be taken with a pinch of salt.
Hydrogen would only be competitive as fuel under the assumption of massive subsidies, or of heavy taxes on conventional fuels, says the report and since nearly all hydrogen is produced from natural gas it is therefore more expensive than natural gas itself.
Hydrogen as fuel is challenged from a supply chain point of view, especially compared to Methanol which can draw on an established presence at every major port in the world.
So if fuel cells really are the answer to shipping’s carbon conundrum – then the question must be – why not use Methanol?
Conventional Methanol is an extremely efficient carrier of hydrogen atoms, with the highest hydrogen-to-carbon ratio of any liquid fuel. Liquid Methanol at ambient temperature and pressure packs 40% more H2 by volume than hydrogen in a liquid state (-253C) and 140% more H2 than compressed hydrogen at 700bar. So rather than incur the cost and complexity of hydrogen, Methanol could be re-formed on-board ship and consumed as hydrogen in fuel cells or internal combustion engines.
Methanol’s well-to-wake emissions profile is similar to that of LNG since it has conventionally been derived from natural gas. However, unlike LNG, renewable methanol can be cost-effectively produced, with gasification, fermentation, electrolysis or CO2 capture technologies from a range of feedstocks and blended with conventional methanol to produce incrementally cleaner fuel with each additional percentage of renewable methanol. Production of low-carbon, renewable and bio-methanol is increasing, with numerous projects in the planning or commissioning stages.
On a volumetric basis, enough renewable methanol is currently produced annually to support a reasonable blending margin (as a percentage) for all existing Direct Methanol Fuel Cells (DMFCs) globally.
DMFCs are suitable for small scale applications such as land and marine based mobile applications, whereas Reforming Methanol Fuel Cells (RMFC) are more practically suited for main propulsion units, if in a marine application.
One major European shipowner who burns conventional methanol to 100% (M100) in one of their vessels with over 20MW of installed internal combustion engine capacity, has already completely displaced diesel with a vastly improved emissions profile. If this ship owner then begins to incrementally blend in renewable methanol, the vessel moves that much closer to being carbon free with every increment.
Clearly, renewable production volumes will have to rise if industries like shipping start to switch over in large numbers, but the incentive is there to be chased for investors, producers and consumers alike.
In fact, we already see fresh investment interest coming into renewable methanol in particular as private equity players and others recognize it as a serious long term energy play.
Using an increased level of blending for renewable methanol in fuel cells or internal combustion engines burning methanol would effectively drive the shipping industry towards zero ‘in sector’ carbon emissions as well as zero sulfur and negligible nitrogen and PM emissions.
Using Methanol powered fuel cells means fewer moving parts in the propulsion system and the potential to quickly make this combination a mainstream choice for particular types of craft.
Not all vessel types are going to use fuel cells, but the intersection of the technology with Methanol as a fuel source compared to battery electric or LNG is exactly where the biggest savings need to be made. Coastal and short sea vessels, ferries, inland waterway vessels, not to mention ports and harbour craft could easily adopt methanol as a liquid fuel or use it to power fuel cells.
Conventional Methanol continues to provide a sustainable bridge to a future in which fuel cells and hydrogen emerge as a more sustainable means of marine propulsion. In its conventional form it has very low, ‘in sector’ carbon emissions, meaning it can be used to mitigate the problem while the renewable inventory builds.
In stark contrast to traditional marine fuel, which frequently suffers from quality and on/off-spec issues, there are negligible differences in specification and quality in Methanol around the world. Methanol traded internationally on IMPCA specification is naturally very high quality – at least 99.85% as it is used to produce fine chemicals. Vessel grade methanol, which would be burned in ICEs could be a different spec to IMPCA and this might be reflected in a lower price.
By itself, Methanol is not going to decarbonize the shipping industry but this safe, simple, highly versatile alcohol has the ability to support the shipping industry’s transition to a cleaner future without delay. It can also support the adoption of new technologies such as fuel cells without any of the issues holding back hydrogen. Once again, it seems, when asking the big questions, Methanol is large part of the answer.