ELECTRICAL-HYBRID propulsion systems, first adopted by cruiseships in the 1990s, have now become standard in the cruise sector, offering insights into how this technology could shape the future of a broader range of vessels.

A key advantage of electrification is its flexibility in fuel choice. As the industry transitions towards alternative fuels, electrical systems allow vessels to integrate newer energy sources, such as liquefied natural gas, dual-fuel diesel engines, and emerging technologies like gas turbines and fuel cells. This flexibility is vital as companies prepare for stricter environmental regulations and the growing demand for more sustainable solutions.

“Electrification offers a versatile pathway to achieving decarbonisation. It enables the use of alternative fuels and innovative technologies, positioning the industry to meet future environmental standards,” says Giosuè Vezzuto, EVP Marine at RINA.

Although the adoption of electrical systems in cruiseships was initially debated, advantages were perceived as outweighing the higher upfront capital expenditure (CapEx). These included significant operational flexibility, allowing ships to switch between fuels based on availability and cost, and the integration of auxiliary energy sources, such as batteries, which reduce emissions during manoeuvres and in sensitive areas.

Hybrid propulsion systems, which combine traditional combustion engines with electrical motors, offer a bridge for vessels not yet ready for full electrification. Batteries, for instance, can provide zero-emission operations during short voyages or boost power during peak demand, a process known as peak shaving. This approach is particularly beneficial for shuttle tankers and other specialised vessels that need bursts of additional energy. As battery technology improves, hybrid systems are expected to become more widespread, easing the transition towards full electrification.

The integration of alternative fuels, such as LNG and hydrogen, into electrical systems is also a crucial factor in reducing the carbon footprint of vessels. LNG has become more common in recent years, with ships using LNG engines to generate electrical power. This not only cuts emissions but also improves overall efficiency. Gas turbines and fuel cells, when combined with electrical propulsion, could provide even cleaner energy solutions, further decreasing reliance on conventional fossil fuels.

In addition to environmental benefits, electrical propulsion offers practical advantages. By reducing the space needed for traditional engines and fuel storage, it allows vessels to increase cargo capacity. RINA estimates that this could lead to a 5% increase, depending on ship type and design. Though seemingly modest, this gain can result in significant economic benefits over the vessel's lifetime, especially when paired with operational efficiencies from lower fuel consumption.

Despite its benefits, the shift to electrical propulsion faces challenges. The higher CapEx, particularly when transitioning from heavy fuel oil to LNG and beyond, remains a barrier. Cargo vessels, which operate on tighter margins, may face delays in adopting this technology. However, as environmental regulations intensify and alternative fuel costs fall, the adoption of electrical propulsion is expected to increase incrementally across different vessel types.

The future of ship electrification may also include nuclear power. Small nuclear reactors, already being explored in other industries, could eventually generate electricity for propulsion, though this remains a distant possibility. “The use of electrical propulsion is not only an enabler for alternative fuels but also a crucial element in reducing the maritime industry’s carbon footprint,¨ says Vezzuto, “paving the way for the next generation of cleaner, more efficient ships.”

The transition to fully electrified fleets will undoubtedly be incremental, driven by evolving technologies and growing environmental pressures, Vezzuto concludes. “With the industry’s focus on sustainability and its desire for flexible propulsion systems, we believe significant progress will be made and the adoption of electric propulsion will gain pace in the years to come.”