Methanol ICE - Fact Sheet No.1

Methanol ICE

Fact Sheet N 1

Edition I - October 2024

Key Facts

Easy to handle and liquid at ambient conditions
Burns very clean without soot

Funded by the Horizon Europe Programme of the European Union under grant agreement No 101096809

Funded by the Horizon Europe guarantee of the United Kingdom, under project No 10068310

Funded by the Swiss State Secretariat for Education, Research and Innovation

Catalogue of

Greening Technologies

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Introduction

Methanol Facts

Methanol has a number of properties that make it a useful marine fuel. It is liquid at ambient temperature and pressure and can therefore be stored in normal, prismatic fuel tanks on board. The three main disadvantages of its use are its toxicity, its low energy density - around 20 MJ/kg as opposed to around 42MJ/kg for diesel - and its low flash point of 12°C, which contributes to an increased risk of fire and explosion. Methanol burns cleanly compared to conventional marine diesel. No sulphur oxides are formed during combustion. Particulate matter and soot emissions are also low; their source tends to be the lubricants in the engine.

Methanol is lighter than water, but also highly soluble, so that the fuel dissolves quickly in water in the event of a spill. As it is only dangerous for aquatic organisms in very high doses and is quickly broken down, no large-scale environmental pollution is to be expected in the event of a spillage, as is the case with diesel.

Methanol is today mainly produced from fossil sources (natural gas), but can also be produced sustainable. There are various ways to produce renewable methanol. One is to capture CO₂ from geothermal power generation which is then reacted together with renewable hydrogen (produced via electrolysis) into renewable methanol. Other methods are to convert biogas from fermentation or gasification of sustainable biomass into bio-methanol as well as producing it from solid waste feedstocks. It is also produced as a by-product of the kraft pulping process in paper production.

Formaldehyde emissions

From the study "Methanol as a marine fuel – Advantages and limitations” by the Öko-Insitut it becomes clear that the formaldehyde emissions from methanol engines are a field that still requires research, but might be easily overcome with appropriate exhaust gas aftertreatment:

“Formaldehyde (CH₂O) emissions can also occur in the exhaust gas from marine engines and represent a significant risk to human health given its carcinogenic properties. According to AakkoSaksa et al. (2023), CH₂O emissions result from the incomplete combustion of a carbon-containing fuel. These emissions generally vary depending upon different variables, such as the engine and the fuel used. The following values from literature have been compiled by Aakko-Saksa et al. (2023):

Medium speed diesel marine engines using HFO or distillate fuels (MGO) reported average emission factors for CH₂O ranging from 0.017–0.048 g/kWh.
For a DF natural gas (LNG) engine, an average emission factor for CH₂O of 0.189 g/kWh was reported.
For a DF methanol engine, the CH₂O emissions reported have been negligible (0.00049 g/kWh) and also low for small alcohol diesel HSD engines using methanol additised with an ignition improver (0.004–0.014 g/kWh).

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In contrast, Güdden et al. (2021) came to a very different conclusion regarding the significance of CH₂O emissions associated with the performance of a high speed marine engine converted from a diesel to a methanol combustion system. The experiment revealed comparably high formaldehyde emissions (~1 g/kWh). Hence, Güdden et al. (2021) suggest that the use of an oxidation catalyst should be obligatory in the future and that the additional effort required should be “manageable” as the catalyst technology required for the reduction of formaldehyde is not as sophisticated as that for natural gas engines due to the stability of the methane molecule. CIMAC (2014) and Verhelst et al. (2019) also suggest already available oxidation catalysts to reduce CH₂O emissions from marine engines. The number of studies on formaldehyde emissions from marine methanol engines is limited. Therefore, further research will be required to comprehensively determine CH₂O emission levels from different engines, the associated level of health risks posed using methanol as a marine fuel and the need for mitigating actions. The conclusions from the two studies cited above may reflect the fact that they focus on different engine types and sizes, but further comparison is beyond the scope of this study. Except for the uncertainties around CH₂O, methanol has a lower emissions impact.”

Emission

When talking about emissions, there are initially different ways of looking at them: On the one hand, a distinction is made between toxic and climate-impacting emissions. On the other hand, a distinction is made between local and global emissions. Examples of toxic emissions are nitrogen oxides, particulates, formaldehyde, etc., while climate-impacting emissions include CO₂, methane, laughing gas, etc. Local emissions have effects on the immediate surroundings of the source, such as toxicity. The effects of global emissions are not limited locally; they can be climate-impacting substances, for example, or the now banned CFC, which damages the ozone layer or sulphur emissions from the seagoing sector. The following table shows the relevant emissions for this fact sheet.

If the emissions caused by a propulsion technology or an energy source are to be assessed, there are again various approaches. The most common are the well-to-wake and the tank-to-wake approach. In the well-to-wake approach, the emissions from the entire upstream chain required for the production and supply of an energy carrier are considered. For an engine, a fuel cell or a battery this approach is called Life-Cycle-Analysis. The tank-to-wake approach looks at the emissions generated by the ship during use. Everything that happened before the energy carrier, storage system or energy converter came on board is excluded.

Emission compared to conventional diesel

Local

Global

GHG

NO_x

SO_x

PM

The global GHG emissions are dependent on the methanol source.

neutral

better

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These two definitions can produce very different results in the assessment of the technologies. For example, when considering the overall chain, the choice of a methanol combustion engine could be better than that of a battery-electric drive. This is the case if the production of the battery causes more emissions than the combustion of methanol. It is important to note that this type of consideration is also different for each ship and depends on its operating time and energy requirements.

Regulations

ES-TRIN

Under the ES-TRIN 2025 framework, derogations would only be necessary in case of solutions for methanol storage and engine room design technically deviating from the requirements laid down in Chapter 30 (in particular risk assessment and safety organisation), Annex 8, Section II, Chapter 2 (fuel storage methanol) and Annex 8, Section III, Chapter 3 (engine room design methanol).

ADN

Methanol propulsion systems in compliance with the requirements of ES-TRIN 2025 are covered by the general exemptions of paragraphs 7.1.3.31 (use of engines) and 9.x.0.31 (rules for construction), meaning that a separate derogation in accordance with section 1.5.3 of the ADN would not be necessary.

However, for methanol propulsion systems benefitting from a derogation under the ES-TRIN framework, an additional derogation under the ADN framework would be required for vessels intended to carry dangerous goods.

Methanol, UN 1230, is permitted to be carried in tank vessels as cargo in type N tank vessels, closed, integral cargo tank, water-spray system. Methanol is assigned to temperature class T2 and explosion group IIA, anti-explosion protection is required.

Passenger Vessels

There are no specific requirements applicable to passenger vessels with methanol propulsion systems, however, the presence of passengers on board has to be taken into account in the risk assessment to be performed in compliance with Article 30.04 of the ES-TRIN.

IMO Rules

For seagoing ships, the IMO Circular 1621 “Interim guidelines for the safety of ships using methyl/ethyl alcohol as fuel” contain functional requirements for all appliances and arrangements. Currently, the introduction of methanol and hydrogen internal combustion engines for the inland waterway sector faces on major barrier: so far, methanol and hydrogen have not yet been included as reference fuels in the NRMM directive. This means for the OEM that it is not allowed to bring these engines on the market.

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In ES-TRIN 2025, no type approval for the engine required under exemption in accordance with Article 9.01 (6) with the restriction that the inland navigation vessel certificate shall not be valid for longer than the duration of the field test in accordance with Article 34 of the NRMM-Regulation. (This is of course still a major limitation as an INVC can only be obtained for a duration of 24 months with a single possible extension of another 24 months – in total only 4 years with currently no perspectives for further legal operation).

Technical Concept

Engine Types

When methanol is used as fuel for an internal combustion engine, several design challenges are to be met. First, methanol is a low flashpoint fuel which means that the regulations for the use of low flashpoint fuels on board vessels must also be complied with. In addition, the methanol flame is virtually invisible in daylight. This can pose a safety risk for the crew and special sensors would also have to be used for detection; for example, infrared cameras or temperature measurement would be suitable. One advantage of burning methanol is that the flame temperature is significantly lower than that of diesel and water can be used very well as an extinguishing agent. In contrast to diesel, methanol is significantly more corrosive, and the lubricating effect of alcohol is also significantly poorer than that of diesel. The metals and rubbers that encounter methanol must therefore be selected very carefully. This also applies to spare parts in later use. The following engine concepts are relevant for the use of methanol as fuel in marine applications. For the dual fuel concepts the baseline is to replace 50 % to 80 % (energy ratio) of diesel with methanol. The following engine concepts are relevant for the use of methanol as fuel in marine applications:

Dual fuel high pressure direct injection (DF-HPDI) as 2-stroke and as 4-stroke
Dual fuel port injection (DF-PI)
Port injection spark ignited (SI)
Compression ignited, with ignition improver (CI)

DF-HPDI - Dual Fuel High Pressure Direct Injection

A four-stroke engine has both inlet and exhaust valves in the cylinder head, typically two of each. The fuel injection valve is placed in the centre and there is normally no space available to fit another fuel injection valve.

The injection mechanism can be controlled in several different ways, either by hydraulic pressure (oil), solenoid or a piezoelectric controller. The illustration below shows the operation of a 4-stroke dual fuel high pressure direct injection methanol engine.

Figure 1: Cylinder head of a methanol engine

Source: MAN Energy Solution

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Emissions of particles are heavily reduced and limited to the pilot diesel. NOX emissions are on IMO Tier III levels without exhaust gas aftertreatment. The fraction of unburnt fuel and thereby formaldehyde emission are very low.

As methanol is injected to the ongoing combustion at TDC the cylinder liner and air channels are not exposed to methanol. Likewise blow-by gases should not contain methanol that could increase decomposition of lubricating oil in the crank case. Modifications to the engine should be limited to the fuel injection system with full flexibility to operate on conventional diesel fuel with no loss of performance.

DF-PI - Dual Fuel Port Injection

All major marine engine suppliers have dual fuel engines where methane gas (LNG) can replace a significant part of the HFO or MGO. Especially for large 2-stroke engines this is a proven and reliable technology. The same concept can be used for methanol by replacing the gas valve with a methanol injector. This methanol injector is placed upstream of the inlet valve.

The piston moves down, and air enters the cylinder.
The piston moves up and compresses the air, temperature and pressure are increased.
Close to TDC the fuel is injected, the diesel pilot fuel a fraction before the methanol, The piston is then pushed down by the expansion of the hot gases.
The emission gases are pushed out through the exhaust valve.

The piston moves down; methanol injects from the port with inlet air.
The piston moves up and compresses the air-methanol mixture, temperature and pressure are increased.
Close to TDC the diesel is injected as pilot fuel and ignites the compressed methanol air mix in the cylinder. The piston is then pushed down by the expansion of the hot gases.
The emission gases are pushed out through the exhaust valve.

On diesel mode, the engine runs as normal diesel. When switch to methanol mode, the engine runs on Otto cycle. The main fuel is injected from the methanol injector and into the combustion chamber with intake air, and a burst of pilot fuel initiates the combustion at top dead centre (TDC).

Figure 2: The combustion principles of a 4-stroke diesel engine with combined methanol and diesel pilot injector Figure 3: The combustion principles of a 4-stroke port injected engine with diesel pilot ignition

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Dual fuel engines normally operate on lean mixtures in methanol mode as the pilot fuel is sufficient to ensure combustion. This allows for higher compression ratio and thus higher efficiency.

Port Injection Spark Ignited (SI)

The spark ignition (SI) concept is similar to the port injection dual fuel concept, but uses spark plugs to replace the function of diesel injectors. The advantage with the spark plug is that no other fuel is needed to initiate the combustion, but it also limits the flexibility as dual fuel operation is not supported. The ignition power of a spark plug is also much lower than the ignition power from pilot fuel. This limits the size of engines where an open spark plug can be used for ignition of combustion. For larger engines, the spark plug is placed in a pre-chamber where a small part of the fuel mix is ignited. This ignited fuel mix generates a jet that ignites the rest of the fuel. Compared to a dual fuel engine the compression ratio is lower to prevent knocking. Combustion temperatures are kept low with a lean fuel/air mixture and emissions are comparatively low.

Compression ignited, with ignition improver (CI)

The low cetane number and high-octane number of pure methanol makes it more suitable for spark ignited Otto combustion. However, by adding an ignition improver the characteristic of methanol is changed so it can be used as single fuel in a compression ignited engine. Scania developed this concept for ethanol in the 1980s and have used it extensively for busses and trucks were. Ethanol and methanol have similar combustion characteristics and the concept has now been adopted for marine and industrial compression ignited methanol engines.

The concept is based on the modification of Scania marine and industrial engines by using original Scania components from their ethanol (ED95) bus and truck engines.

Figure 4: The combustion principles of a 4-stroke engine with port injection and spark ignition

The piston moves down, methanol injects from the port with inlet air .
The piston moves up and compresses the air-methanol mixture, temperature and pressure are increased.
Close to TDC the spark plug ignites methanol. The piston is then pushed down by the expansion of the hot gases.
The emission gases are pushed out through the exhaust valve.

Figure 5: Compression ignited methanol (MD97) engine 16LV8 415 kW at 2100 rpm, available from Enmar Engines AB Source: ScandiNAOS AB

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Today Enmar Engines are selling compression ignited methanol engines that uses MD97 fuel. The fuel contains methanol and 3% Beraid ignition improver as well as a small fraction of lubricant. The engines are based on the Scania marine engines with several modifications, including alcohol fuel injectors and higher compression ratios. With the ignition improver, the engine can run on diesel cycle with methanol and provides similar performance as a diesel engine with high efficiency and fulfils IMO Tier III NOx emission levels without after treatment system.

Within SYNERGETICS the two options Compression ignited, with ignition improver (CI) and the Dual fuel port injection (DF-PI) will be compared.

Equipment for Methanol Powered Vessels

Tanks

Due to the corrosiveness, materials for piping and tanks need to be selected carefully. Stainless steel or appropriate coatings are proven solutions.

For inland vessels the following aspects are to be considered form ES-TRIN 2023:

Methanol tanks can be either inerted or non-inerted
Secondary barrier required for all equipment and piping containing liquid methanol fuel, except on open deck
Designed to prevent electrostatic charges
Methanol tanks not to be located forward of the collision bulkhead and aft of the aft-peak bulkhead
Distance of methanol tanks in general not less than 0,60 m to vessel’s side and 0,50 m to vessel’s bottom
Tank venting to be equipped with suitable flame arrestors
Gas detection systems required for spaces where fuel vapours may accumulate

For coastal vessels the Circular 1621 states that:

Methanol fuel tanks can be either portable or fixed.
All fuel tanks should be inerted at all times during normal operation.

Fuel Preparation Space

The fuel preparation space can either be a dedicated room or a cabinet that are both gas-tight separated from other spaces. In the fuel preparation space, the single-walled pumps, valves, filters, etc. create a hazardous area that therefore needs a second barrier.

Engine Room

For inland waterway vessels there are two options for engine room design: The gas safe and the ventilated engine room. In the following, some of the main characteristics of the two concepts are listed.

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Gas Safe Engine Room

Gas safe under all conditions (“inherently safe concept”). A single failure within the methanol system shall not lead to a leakage of methanol into the engine room.
Methanol piping and equipment within the engine room boundaries surrounded by a secondary barrier for leakage containment and detection
Methanol leakage inside the ventilated ducts or enclosures shall be detected by means of suitable detectors
Methanol leakage must be safely collected and drained by means of leakage collecting arrangements.

Ventilated Engine Room

Possible hazardous areas within the ventilated engine rooms shall be classified in accordance with EN 60079-10-1 : 2020 und EN 60079-10-2 : 2015
Only equipment suitable for the hazardous areas as classified is permitted. This shall be deemed to be fulfilled if the equipment meets the relevant provisions of the European Standard series EN 60079.
Ventilated engine rooms shall be designed to provide a geometrical shape that minimises gas release from leakage pools as well as the accumulation of gases or formation of gas pockets. Good air circulation shall be ensured. Air inlets and outlets shall be located in appropriate positions, taking into account the characteristics of methanol.
Suitable alarms shall be provided to detect and indicate a leakage in the engine room, by means of liquid detectors and high sensitivity gas detectors at suitable places
Drip trays with self-draining lines to closed collecting tanks shall be provided under all equipment which contain methanol and from where leakage cannot be excluded.
Spray guards shall be provided on pipes and joints where fuel spray cannot be excluded.

According to Circular 1621 the engine rooms of coastal vessels shall fulfil the following requirements:

A single failure within the fuel system should not lead to a release of fuel into the machinery space.
All fuel piping within machinery space boundaries should be enclosed in gas and liquid tight enclosures […].

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Special Safety & Other Requirements

Bunkering

The Methanol Institute provides a map (see figure 6) with the large methanol bunker and storage facilities. Nonetheless, the current option for most coastal and inland ships will be the bunkering via truck.

For seagoing vessels there are already guidelines on bunker procedures available, e.g., Lloyd’s Register, ABS, or the Port of Gothenburg. As of today, 10/2024, no bunker guidelines for inland vessels are available.

Economics

Investments Costs

The investment for a methanol engine is between 500 €/kW and 700 €/kW. The installation cost is dependent on the vessels size and is approximately around 50 000€.

Operational Costs

The price for grey methanol is around 400/t at in Rotterdam. Current estimations give the name the price for green methanol three times higher. The maintenance cost for the system is about 7% of the investment.

Considerations for Deployment

Strongly dependent on the infrastructure that is yet under construction
Training of personnel
Restrictive safety rules
Risk assessment is necessary (e. g. HAZID study)
Bunker process

Figure 6: Large methanol bunker and storage facilities in Europe

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Source: Port of Antwerp Bruges

Vessel type | Tug boat

IMO | 9247338

Vessel Size | 29.5 m × 11 m

Year Built |

Propulsion | Two ABC 8DZC Dual-Fuel

Methatug

Source: Stela Line

Vessel type | Ferry

IMO | 9145176

Vessel Size | 241 m × 28.7 m

Year Built | 2001

Propulsion | 4 x Sulzer 8ZAL40S diesel engines with 23 000 kW total

Stena Germanica

Source: Swedish Maritime Administration

Vessel type | Pilot boat

MMSI | 265519660

Vessel Size | 13 m × 5 m

Year Built |

Propulsion | Compression ignited ScandiNAOS Methanol-MD97, 415 kW

120 SE

Deployment Examples

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Contact

DST

+49 203 99369 0

www.dst-org.de

Igor Bačkalov

+49-203-99369-27

backalov@dst-org.de

Benjamin Friedhoff

+49-203-99369-29

friedhoff@dst-org.de

Argo-Anleg GmbH (DE)

FPS – Future Proof Shipping (NL)

Mercurius Shipbuilding BV (NL)

ZES – Zero Emission Services (NL)

Compagnie Fluviale de Transport (FR)

Sogestran (FR)

Koedood Diesel Service BV (NL)

CMB – Revolve Technologies Ltd. (UK)

SPB – Stichting Projecten Binnenvaart (NL)

Scandinaos AB (SE)

MARIN – Maritime Research Institute Netherlands (NL)

viadonau – Österreichische Wasserstraßen-GmbH (AT)

TTS – Transport Trade Services GmbH (AT)

ZT Büro Anzböck Richard (AT)

EUFRAK – Euroconsults Berlin GmbH (DE)

CRS – Hrvatski Registar Brodova (HR)

OST – Ostschweizer Fachhochschule (CH)

Project Coordinator

DST - Development Centre for Ship Technology and Transport Systems

Partners

Disclaimer

The content of the publication herein is the sole responsibility of the publishers and it does not necessarily represent the views expressed by the European Commission or its services. While the information contained in the document is believed to be accurate, the author(s) or any other participant in the SYNERGETICS consortium make no warranty of any kind with regard to this material including, but not limited to the implied warranties of merchantability and fitness for a particular purpose. Neither the SYNERGETICS Consortium nor any of its members, their officers, employees or agents shall be responsible or liable in negligence or otherwise howsoever in respect of any inaccuracy or omission herein.