A recent study from Berkeley Lab suggests that switching some U.S. ships from internal combustion engines to electric power could become cost-effective by 2035 and could significantly cut greenhouse gas emissions.
This shift could play a big role in reducing the impact of the shipping industry, which contributes about 3% of U.S. transportation emissions.
The study, led by energy policy researcher Won Young Park, was published in Nature Energy.
Electrifying ships is harder than electrifying cars, largely because ships are expensive, built to last decades, and cover long distances carrying heavy loads.
But advances in battery technology have improved battery life and reduced costs, making electric vehicles more feasible.
Park’s team decided to test whether this could also work for ships, especially if they could focus on shorter trips and avoid the need for extra-large batteries to power very long journeys.
The study looked at 6,323 U.S.-flagged ships under 1,000 gross tons, which mainly includes passenger ships and tugboats.
Using tracking data, the team studied trip lengths and patterns, finding that if just 1% of the longest trips were excluded, the remaining trips could be electrified with batteries that are two-thirds smaller than would otherwise be needed.
For passenger ships, they found the batteries could be reduced by up to 85% in size.
The researchers analyzed how much emissions could be reduced based on three possible scenarios for how clean the electrical grid could be. In the most aggressive scenario—95% decarbonization by 2035—they estimated that retrofitting these ships could cut CO2 emissions by up to 73%. Even with less drastic grid improvements, they found emissions reductions could still be significant.
They also calculated whether switching to battery power could save money. For ships with internal combustion engines, the costs include fuel, maintenance, and the social costs of CO2 and pollution.
For electric ships, they looked at battery and charging costs, maintenance, charging infrastructure, and the battery’s “second life” value, or what it’s worth when its performance decreases for primary use.
Under the aggressive decarbonization scenario, they found that electrifying up to 85% of these ships could be cost-effective by 2035, covering 99% of the ships’ annual trips.
The researchers noted that most of the energy needed to charge these ships could be supplied by just 20 key U.S. ports, including New York–New Jersey, New Orleans, and Houston. Focusing on these ports for charging infrastructure would make electrification more practical and efficient.
“This study offers an essential starting point for understanding how battery-electric shipping could work,” said Park.
“It also provides a basis for future research and policy decisions, helping us figure out the best locations for electrification based on ship activity and grid conditions.” By strategically electrifying ships, the study shows a clear path to both cost savings and a cleaner shipping industry in the near future.
Source: Lawrence Berkeley National Laboratory.
