Methane Slip is Growing Decarbonisation Threat for Shipping: VPS
Addressing Methane Slip in the Maritime Industry
The maritime industry plays a significant role in global emissions, with the shipping fleet consuming over 230 million metric tons of fuel annually, resulting in 716 million metric tons of CO2-equivalent emissions. However, the industry is undergoing a major transition towards sustainability, with a focus on reducing emissions through various means, including alternative fuels and engine configurations.
The Rise of Alternative Fuels:
According to Clarksons Research, nearly 30% of vessels on order are designed for alternative fuels, indicating a growing trend towards greener shipping solutions. While there is an uptake in sustainable biofuels and Renewable Liquid & Gaseous Fuels of Non-biological Origin (RFNBO), such as methanol, LNG has emerged as a leading transition fuel for the maritime sector.
The Challenge of Methane Slip:
Despite the benefits of using LNG as a marine fuel, methane slip poses a significant decarbonisation threat. Methane, the primary component of LNG, has a high global warming potential, emphasizing the importance of reducing methane emissions across the entire lifecycle of LNG.
Mitigating Methane Slip:
Efforts to address methane slip range from proactive collaborations with engine manufacturers to practical onboard measures at the vessel level. While future fuels like biofuels and renewable methanol are considered, immediate actions are needed to reduce methane slip in existing LNG-fuelled operations.
Regulatory Landscape:
The regulatory landscape is evolving to include measures targeting methane slip, such as the EU’s Fit for 55 package and the Global Methane Pledge. The upcoming IMO Guidelines on Life Cycle GHG Intensity of Marine Fuels may drive stricter measures related to methane slip, indicating a shift towards tighter regulations and stronger enforcement.
Key Strategies for Reduction:
Engine design improvements, after-treatment solutions, and operational practices are essential in reducing methane slip. From optimizing engine components to installing methane oxidation catalysts, various strategies can help lower methane emissions and enhance the sustainability of LNG-fuelled shipping.
Operational Adjustments
To address these challenges, shipowners and operators can implement operational adjustments to improve the performance of LNG-powered engines. One crucial aspect is to avoid prolonged low-load gas operation, which can lead to inefficiencies and increased methane slip emissions. By planning voyages and engine use to maintain higher loads when running on LNG, ships can optimize their fuel efficiency and reduce emissions. Additionally, operational strategies such as scheduling heavier loads or adjusting speeds can help minimize low-load scenarios.
Another effective strategy is to switch between gas and fuel oil at low loads. Utilizing the dual-fuel capability of LNG-powered engines to switch to fuel oil when combustion efficiency drops at low loads can help maintain optimal performance. Establishing clear operational thresholds for switching based on load conditions and engine performance data is essential, as dual-fuel engines often require a higher pilot fuel percentage to prevent maintenance issues with fuel injectors.
Hybrid or Battery Integration
Incorporating hybrid systems or batteries into LNG-powered vessels can also enhance operational efficiency and reduce emissions. By installing batteries or hybrid power systems to assist during periods of low power demand, ships can maintain engine operation at higher, more efficient loads. Designing the ship’s power management system for seamless interaction between the engine and battery allows for consistent high-load operation, optimizing fuel and emission performance.
Furthermore, proper maintenance and engine optimization are crucial for ensuring the long-term efficiency and sustainability of LNG-powered vessels. Implementing routine inspections and cleaning of fuel injectors, valves, and sensors, as well as regularly calibrating and tuning engine settings for optimal combustion, can help prevent issues and maximize performance. Training crew members in best practices for engine management and maintenance procedures is also essential for ensuring smooth operations.
If you’re already using—or considering—LNG as a fuel, tackling methane slip should be your top priority. This is crucial not only for environmental stewardship but also to meet tightening regulatory requirements. By applying operational best practices and adopting next-generation technologies, such as advanced engines and methane catalysts, shipowners can make significant strides in reducing methane emissions and improving overall sustainability.
