Zero Emissions Vessels

Zero emissions ships are vessels that do not emit any greenhouse gases or air pollutants during their operation. They are considered as one of the potential solutions to reduce the environmental impact of the maritime sector, which accounts for about 3% of global CO2 emissions and 15% of global NOx emissions. One of the main challenges for zero emissions ships is the availability and affordability of alternative fuels and energy sources that can replace fossil fuels. Currently, most ships use heavy fuel oil (HFO) or marine diesel oil (MDO) as their primary fuel, which have high energy density and low cost, but also high emissions and environmental risks. Some of the possible alternatives are hydrogen, ammonia, biofuels, batteries, and wind or solar power. However, each of these options has its own limitations and trade-offs in terms of cost, safety, storage, infrastructure, and performance. For example, hydrogen has a very high energy density per unit mass, but a very low energy density per unit volume, which means that it requires large and expensive storage tanks on board. Ammonia is easier to store and transport than hydrogen, but it is toxic and corrosive, which poses safety and environmental hazards. Biofuels are compatible with existing engines and infrastructure, but they have limited availability and sustainability issues. Batteries can provide instant and emission-free power, but they have low energy density and high weight, which limit their range and capacity. Wind and solar power can harness renewable energy from the environment, but they are intermittent and variable, which require backup systems or hybrid solutions. Another challenge for zero emissions ships is the regulatory and policy framework that can support and incentivize their development and deployment. Currently, there is no global or regional regulation that mandates or rewards zero emissions ships, although there are some voluntary initiatives and standards that promote them. For example, the International Maritime Organization (IMO) has adopted the Energy Efficiency Design Index (EEDI) and the Ship Energy Efficiency Management Plan (SEEMP) as measures to improve the energy efficiency and reduce the emissions of new and existing ships. However, these measures are not sufficient to achieve the IMO's target of reducing the carbon intensity of international shipping by at least 40% by 2030 and 70% by 2050 compared to 2008 levels. Therefore, there is a need for more ambitious and binding regulations that can create a level playing field and a clear roadmap for zero emissions ships. Some of the possible instruments are carbon pricing, emission trading schemes, fuel taxes or levies, subsidies or grants, green financing or loans, port fees or discounts, or green procurement or certification. Despite these challenges, there are also many opportunities for zero emissions ships in terms of technological innovation, market potential, and social benefits. Technologically, there are many ongoing research and development projects that aim to demonstrate the feasibility and viability of zero emissions ships. For example, the European Union has funded several projects under its Horizon 2020 program that focus on different aspects of zero emissions ships, such as fuel cells, batteries, wind propulsion, ammonia engines, or hydrogen production. Similarly, the International Association of Classification Societies (IACS) has established a working group on zero emission vessels that aims to develop common technical standards and guidelines for alternative fuels and energy sources.