Travel times cut nearly in half, sharply reduced emissions, and satisfied passengers. The pilot project with an electric hydrofoil boat in Stockholm’s public transport system, financed by the Swedish Transport Administration, shows strong socio-economic profitability.

Maritime transport is the most emission-intensive mode of transport per passenger-kilometer, despite accounting for only a small share of total travel. It is both more energy-intensive than buses and rail transport and still heavily dependent on fossil fuels. Many Swedish archipelago ferries are several decades old and run on older diesel engines that emit large amounts of carbon dioxide, nitrogen oxides, and sulfur. Today, however, other options exist. Modern hydrofoil technology lifts the hull out of the water, enables efficient electric propulsion, and almost completely eliminates both wake and noise.

In a project financed by the Swedish Transport Administration, electric boat manufacturer Candela, in collaboration with Region Stockholm, has therefore developed the fully electric hydrofoil boat Candela P-12, with capacity for 25 passengers. During 2024 and 2025 it was tested under the name Nova in regular SL service on Route 89 between Ekerö and Stockholm.

The results from the project’s final report show that the hydrofoil boat outperforms conventional ferry traffic in every respect. Energy consumption fell by 66 percent and carbon dioxide emissions by more than 90 percent compared with diesel. Ridership increased by 22.5 percent, and 95 percent of passengers were very satisfied. A major reason for this was, of course, that travel time was almost halved.

“The hydrofoil boat uses the same amount of energy when traveling at eight knots as it does at 25 knots. So why go slowly when you can go fast? Since the boat doesn’t create any wake, we were granted an exemption by the County Administrative Board to operate at higher speeds,” says Brigitte Junker at Candela.

The boat is also quieter than conventional ferries, especially at the dock, where no engine noise is produced. At a speed of 25 knots, the measured noise level corresponds to the sound of a modern passenger car driving at around 45 km/h.

“It’s gratifying that the results turned out as well as they did and that passengers were so positive,” says Tobias Carlsson at Region Stockholm.

“The hydrofoil boat also represents a change in scale compared with the existing fleet. Instead of operating large vessels with few passengers for much of the year, smaller and more fully utilized boats could be used. That said, I don’t think one should lock into a single size. Different routes and times require different vessels. Larger electrified hydrofoil boats are also on their way to the market.”

As part of the project, Region Stockholm also conducted a socio-economic analysis in which the current setup on Route 89 (two large conventional vessels) was replaced with six smaller electric hydrofoil boats of the type tested. The results show that the hydrofoil alternative delivers significant socio-economic benefits through shorter travel times, higher service frequency, and reduced emissions. Overall, the net present value amounts to approximately SEK 119 million over the vessels’ lifetime, indicating that the measure is socio-economically profitable.

“On this route, which runs relatively close to the city with a large catchment area, the calculations show that it would be economically justifiable to introduce fast electrified vessels,” says Tobias Carlsson.

Despite this, it is not a given. Fossil-free public transport on water is not yet the norm in Sweden. A study by KTH and Vattenbussen, which examined the innovation capacity of public transport, showed a few years ago that the “socio-technical system” behind it struggles to break established patterns. Entrenched regulations, planning processes, and models simply have difficulty accommodating unconventional modes of transport and innovative solutions.

“I think introducing fully electric hydrofoil boats is a no-brainer, especially in a city like Stockholm that is surrounded by water. The infrastructure is already in place,” says Brigitte Junker.

“Candela’s boats have received a great deal of international attention and are already in use in several parts of the world. It would be a bit embarrassing if they weren’t seen in Stockholm because of cumbersome regulations. I’m not saying all boats should be small hydrofoil boats, but we need a fleet of them that can operate on multiple routes.”