Company logo of Berger Maritiem featuring a green leaf, symbolizing global sustainable maritime innovation and solutions.
Small logo version of Berger Maritiem featuring a green leaf, symbolizing global sustainable innovation and solutions in the maritime sector.
Contact
Inland vessel with dual-fuel LNG engine reduces emissions on European inland waterways through efficient cryogenic storage

LNG in Inland Shipping: A Realistic Path Toward Sustainability and Emission Reduction

Author: Jeroen Berger • Publication date:

Inland shipping must operate near climate neutrality by 2050 at the latest. This obligation stems from European climate policy, ranging from the internationally ratified Paris Agreement to national implementation through the Inland Shipping Green Deal and the European Climate Law (EU 2021/1119). Yet a clear gap remains between ambition on paper and practical feasibility. Many inland vessels still run on diesel and were designed for long-term use. Transitioning to fully emission-free propulsion, such as hydrogen or battery-electric, requires new infrastructure, adapted vessel designs, and substantial investments. For many shipowners and shipping companies, such a shift is simply unfeasible in the short term.

In this context, LNG (Liquefied Natural Gas) offers a practical interim solution. This fuel significantly reduces emissions of nitrogen oxides (NOx), particulate matter (PM), and carbon dioxide (CO2), without requiring a complete overhaul of a vessel’s energy system. LNG is also compatible with existing navigation routes and design principles. In addition, the network of bunkering facilities in the Netherlands, Belgium, and Luxembourg continues to expand, enhancing operational availability and simplifying logistics. This creates an immediately deployable path to cleaner navigation, with the flexibility to transition later to more sustainable alternatives such as bio-LNG or hydrogen.

This article outlines how LNG is applied onboard, the resulting environmental benefits, the development of infrastructure, and how LNG compares to other green fuels and emission-reduction measures.

How LNG Works Onboard

LNG stands for Liquefied Natural Gas: natural gas that has been liquefied by cooling it to −162 °C. In liquid form, it occupies up to six times less space than gaseous natural gas. This allows LNG to be efficiently stored in double-walled, insulated tanks, without compromising cargo capacity or vessel stability.

Most LNG-powered inland vessels are equipped with dual-fuel engines. These engines can combust both LNG and conventional diesel (gasoil), typically in a ratio of 80% LNG to 20% diesel. This enables a switch to LNG without requiring a complete vessel conversion. For newbuilds, this can be incorporated during the design phase; for existing vessels, a technical retrofit with an LNG kit from the engine manufacturer is often sufficient.

However, LNG imposes specific requirements in terms of onboard technology and safety. Cryogenic storage, due to its extremely low temperature, demands well-insulated piping, leak-proof connections, pressure regulation, and certified bunkering facilities. In practice, these requirements are manageable. A well-known example is the inland vessel Argonon, which has been operating on LNG since 2011. In daily operations, this vessel has demonstrated that LNG can be safely, reliably, and emission-efficiently applied in inland shipping.

Environmental Benefits and Key Considerations

LNG contributes significantly to the reduction of air pollutant emissions. Nitrogen oxide (NOx) emissions are reduced by 80% to 90%. Particulate emissions are virtually eliminated, and the sulfur-free combustion results in no sulfur oxide (SOx) emissions. CO2 emissions per unit of energy are on average approximately 20% lower compared to conventional diesel. Moreover, LNG combusts more smoothly, resulting in less vibration and noise, which is beneficial for onboard comfort and for the environment along busy waterways.

Nevertheless, there are clear limitations. Methane slip occurs: approximately 6.4% of the methane does not fully combust and is released into the atmosphere. Because methane is a far more potent greenhouse gas than CO2, this partially offsets the climate benefits. Additionally, LNG remains a fossil fuel. To achieve true climate neutrality in inland shipping, a transition to renewable alternatives such as bio-LNG, hydrogen, or synthetic fuels is ultimately required.

LNG also demands high technical standards onboard. Storage at extremely low temperatures requires specialized installations and well-trained personnel, both onboard and during bunkering.

Infrastructure and Market Dynamics

The growth of LNG in inland shipping accelerated when energy company Shell announced plans for a large fleet of new dual-fuel tankers. Several of these vessels have been realized, generating economies of scale, valuable operational experience, and greater standardization in design and implementation. Supporting infrastructure has developed in parallel: LNG terminals and bunkering vessels are now operational in ports such as Rotterdam, Amsterdam, and Antwerp. Increasingly, inland ports also feature pontoons with tank installations.

These developments are supported by European legislation. Under the Clean Power for Transport program, EU member states must provide sufficient LNG bunkering points along key corridors of the TEN-T network by 2025. As a result, LNG is becoming more accessible for vessels operating regularly toward Germany.

Stricter environmental regulations also incentivize the switch to LNG. Since 2020, inland vessels must comply with Stage V emission standards for engines. According to the European Commission, these standards are realistically achievable only with LNG-powered engines. Vessels continuing to operate on conventional diesel are often required to install exhaust after-treatment systems such as SCR catalysts or closed diesel particulate filters. Additionally, certain port authorities, such as the Port of Rotterdam, offer financial incentives. LNG-powered vessels that meet stricter environmental standards may qualify for reduced port dues via the Green Award program.

LNG Compared to Other Fuel Options

Within inland shipping’s sustainability transition, LNG is currently the only fuel that effectively combines scalability, infrastructure, and commercial viability. Electric propulsion is primarily used on short routes due to limited range, heavy battery systems, and a shortage of charging stations.

Hydrogen theoretically offers higher energy density and lower emissions but requires entirely new tank systems and additional safety measures. Its use in inland shipping remains in the testing phase.

Methanol and ammonia are considered promising zero-emission fuels for the future. However, the required engines, bunkering systems, and safety standards for large-scale deployment are not yet in place, making them unsuitable for broad application at present.

Biofuels such as HVO and FAME can be blended with conventional diesel, but they remain relatively expensive and are available only in limited volumes.

A notable exception is bio-LNG. This renewable variant is produced from biogas, for example through anaerobic digestion of organic waste, and can be used directly in existing LNG installations. The existing logistics infrastructure remains fully functional. For operators already using LNG, bio-LNG offers a logical next step toward climate neutrality without major technical modifications.

Frequently Asked Questions About LNG in Inland Shipping

Converting an inland vessel to run on LNG requires a substantial investment, typically between €1 million and €1.5 million. The exact cost depends on factors such as vessel size, existing engine type, and the required onboard LNG storage capacity.

However, the investment can pay off over time. LNG is generally cheaper than diesel per unit of energy. Shipowners consuming around 500 cubic meters of diesel annually can, under favorable conditions, recoup their investment within five to ten years. Government programs such as LNG price subsidies (e.g., €0.19 per kilogram in 2021) contribute to this. Additionally, some ports offer discounts for cleaner-fueled vessels, and engines require less maintenance due to cleaner combustion.

In short, for intensively operated vessels, fuel savings and lower maintenance costs can result in a viable business case, especially when subsidy opportunities are leveraged.

Several technical adjustments are required to make a vessel LNG-ready. In most cases, the diesel engine is replaced with a dual-fuel engine capable of running on both diesel and LNG. Alternatively, an existing engine can sometimes be retrofitted with an LNG conversion kit.

An LNG tank must also be installed onboard. This tank is double-walled and vacuum-insulated to keep the LNG at −162 °C. From the tank, LNG flows through specialized piping to a vaporizer, where it is converted into gas before being supplied to the engine. Despite the size of the installations, the tank can often be placed on deck or in the aft without significantly affecting cargo space. A good example is the container vessel Eiger-Nordwand, which was successfully retrofitted with a 60-cubic-meter LNG tank.

Additional systems are required to ensure safety: gas detection, emergency shutoff valves, pressure relief, and proper ventilation. Legally, the installation must comply with European safety regulations (ES-TRIN) and be certified by a recognized classification society, such as DNV or Bureau Veritas. Crew members must also be trained in LNG bunkering and operations and hold a dedicated certificate, typically referred to as “LNG Expert.”

LNG has been safely used worldwide for years, including in inland shipping. In liquid form, LNG is neither flammable nor toxic. It becomes flammable only when vaporized and mixed with air. As such, strict safety measures are required.

All piping onboard LNG vessels is double-walled, and connections are leak-proof. Sensors continuously monitor for gas leaks. During bunkering (filling the LNG tank), additional procedures apply. Crew wear protective gear, the ship’s surroundings are temporarily cordoned off (typically a 25-meter radius), and smoking and mobile phone use are prohibited. A specialized bunkering supervisor oversees the process.

Ports also monitor compliance during bunkering. Thanks to this combination of engineering, training, and oversight, LNG has proven to be demonstrably safe. The vessel Argonon, operating on LNG since 2011, is a strong example.

In the Netherlands and Belgium, the number of LNG bunkering points continues to grow. Major ports such as Rotterdam, Amsterdam, and Antwerp have permanent LNG bunkering installations, supplied via bunkering pontoons or dockside stations.

LNG can also be bunkered via tanker trucks (“truck-to-ship”) at many locations. In this method, an LNG tanker truck parks beside the vessel and transfers the gas via insulated hoses. On some routes, bunkering vessels supply LNG to other ships (“ship-to-ship”).

The European Union also mandates that member states establish sufficient LNG bunkering points along key inland waterways by 2025. As a result, a denser network is emerging, including on routes toward Germany and Eastern Europe. For most routes, LNG is readily available, and typically one or two bunkering sessions per journey are sufficient, comparable to diesel.

Yes, LNG helps meet the strictest emission standards. The European Stage V standard for new inland vessel engines requires significant reductions in NOx and PM emissions. Diesel engines typically need after-treatment systems such as SCR catalysts or particulate filters to comply. These systems are generally not required with LNG, as natural gas combustion is much cleaner.

In practice, LNG reduces NOx emissions by approximately 80% and PM emissions by up to 95%. CO2 emissions per unit of energy are around 20% lower than diesel. Due to methane slip, where a small portion of the gas is not fully combusted, overall greenhouse gas reduction averages about 10%. Nevertheless, governments recognize LNG as an environmentally friendly option, granting access to environmental zones and eligibility for sustainability programs.

Bio-LNG is a renewable alternative to fossil LNG, produced from biogenic methane. Chemically, it is identical to fossil LNG, meaning vessels operating on LNG today can switch seamlessly to bio-LNG in the future without modifying onboard systems. Bunkering and storage methods remain unchanged.

Hydrogen, by contrast, requires an entirely different tank system, different engines or even fuel cells, and additional safety measures. Hydrogen must be stored at −253 °C, which is colder than LNG, and demands stricter material and insulation standards. Existing LNG systems are not compatible.

For shipowners, this means: investing in LNG today provides a future-proof path toward bio-LNG and CO2 neutrality. While hydrogen requires new technology, operational experience with LNG already builds valuable knowledge for transitioning to cryogenic fuels.

A vessel’s performance on LNG is virtually equivalent to diesel. Dual-fuel engines typically use a small amount of diesel (5% to 20%) to initiate LNG combustion, maintaining engine behavior such as torque and rapid response, which are critical during maneuvers in locks or harbors.

LNG also combusts more smoothly than diesel, with reduced vibration and noise. This enhances onboard comfort. Because LNG has a lower energy density per liter than diesel, larger tanks are needed to achieve the same range. In practice, this is manageable. The vessel Eiger-Nordwand, for example, completes a full return voyage from Antwerp to Basel with a 60-cubic-meter LNG tank.

If LNG runs out, the vessel can switch to 100% diesel without issue. This guarantees flexibility, even on routes where LNG is less available, maintaining comparable range while lowering emissions and improving operational smoothness.