How Do Solar-Powered Boats Work? 7 Innovative Vessels That Run on Solar

Solar boats can serve ordinary functions for more sustainable transportation.

Greta Thunberg aboard the solar-powered Malizia II.
Greta Thunberg aboard the solar-powered Malizia II.

Finnbarr Webster / Getty Images

When Greta Thunberg crossed the Atlantic in 2019 to address the 2019 UN Climate Action Summit, she sailed aboard the Malizia II, a racing yacht powered by hydro, solar, and sail. The Malizia II raised the international profile of powering boats with renewable, carbon-free energy.

Installing solar panels on the Malizia II and other boats is a challenge. The panels and electronic equipment can be exposed to corrosive saltwater, strong winds, and extreme weather conditions. The panels must conform to the shape of the vessel, but cannot interfere with the work of the crew. Fortunately, these are challenges that many boat owners have overcome. In a growing industry, flexible solar panels capable of being installed on a boat can cost as low as $200. Solar power isn't just for high-end racing yachts.

One of the virtues of a solar-powered boat is its infinite range when paired with lithium-ion batteries on board, which can store the energy produced by the solar panels. Like a sailboat, a solar-powered boat never needs to make refueling stops.

Spurred on by competitions like the Solar Splash (which calls itself “the World Championship of Collegiate Solar Boating”), the Solar Boat Regatta, the Dutch Solar Challenge, and Solar Sport One, engineers and innovators in sustainable transportation have turned solar-powered boats from a novelty item on the sea to vessels that can serve many functions.

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The Malizia II

The Malizia II

Mark Lloyd/Alea / Getty Images

The Malizia II is a 60-foot (18-meter) monohull boat weighing 8 tonnes. It was launched in Monaco in 2015. While it has participated in a number of races and regattas, it is best known for transporting Greta Thunberg to the United Nations Climate Action Summit in 2019. But it was built for racing—capable of speeds of up to 25 knots, it is one of the fastest boats of its class.

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The Solliner

The Solliner is a line of small catamarans meant for day boating, from Green Dream Boats. At 21 feet (6.2 m), it can accommodate up to 10 people in a U-shaped seating area. They are fitted with four solar panels that allow for navigation without the need for an outside energy source. They can sail at up to 12 km/hr. Solliner boats have been seen around the world, such as the one pictured here in Poland. In the United States, they are sold by Infinity Solar Boats.

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The Aditya

The Aditya, the world's first solar-powered ferry.

Samarjitbharat / Wikimedia Commons / CC BY-SA 4.0

The Aditya is India's largest solar boat and the world's first solar-powered ferry. Carrying approximately 1,700 passengers per day, it is 30 times cheaper to run than the diesel ferry it replaced. In 2020, it won the Gustave Trouve Award for Excellence in Electric Boats and Boating, an international award. The Indian state of Kerala, which commissioned the Aditya, plans on replacing the entirety of its diesel fleet with solar ferries. The Aditya is a 20-meter-long catamaran ferry boat made from glass-reinforced plastic with photovoltaic panels on its roof. It seats 75 passengers at a time.

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The Interceptor

The Interceptor sounds like a racing boat, but it is a 24-meter (78 ft) solar-powered barge whose role is to intercept 50 tons of trash a day from Malaysia's rivers—most of it plastic that would otherwise reach the sea. The Malaysian Interceptor is one of a series of Interceptors created by The Ocean Cleanup, the largest effort to remove plastic waste from the oceans, 80% of which stems from 1,000 of the world's rivers. Other Interceptors are (or will be) stationed in Indonesia, the Dominican Republic, and Vietnam.

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MS Tûranor PlanetSolar

The MS Tûranor PlanetSolar sails on the Seine River in Paris, France.

Pascal Le Segretain / Getty Images

A 31-meter catamaran, the MS Tûranor PlanetSolar is the world's largest solar boat and the first to sail around the world. On its round-the-world voyage, it sailed at an average speed of 5 knots—not racing yacht speed, to be sure, but to be expected from a 6-meter-wide scientific research vessel weighing 89,000 kg (nearly 100 tons), 8.5 tons of which are lithium-ion batteries stored in the ship's two hulls. It was launched in 2010.

The 537 square meters of solar panels are sturdy enough to be walked on, and provide electricity stored in 6 blocks of lithium-ion batteries, allowing the Tûranor PlanetSolar to travel over 60,000 km (37,282 m) in 584 days without fuel stops.

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The Ecowave

The Ecowave (Ecowolna) is Russia's first solar-powered catamaran. In 2018 it conducted a scientific expedition to explore the potential for solar-powered trams for the Neva, Oka, and Volga rivers. Launched from St. Petersburg, the Ecowave expedition covered more than 5,000 km (3,106 m) over 90 days, traveling the Black and Caspian Seas as well as major rivers of Russia. The catamaran is 11.6 metres long.

The solar panels cover an area of ​​solar panels is 57 square meters (613 sq ft) and are capable of producing 9 kW of power. Lithium-ion batteries allow the vessel to sail for 20 hours without recharging.

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The Kevin

While apparently no longer plying the waters of the Lot river in France, the Kevin was a solar-powered hotel boat that offered river cruises focused on sustainable river tourism. Calling his converted barge “the first solar boat-hotel of the world,” owner Dominique Renouf launched Kevin in 2011. The vessel was 97 feet (29.50 m) long, equipped with a solar water heater, and able to accommodate 14 overnight passengers in 6 cabins.

Tourist boat on Lake Altaussee in the Austrian Alps.
Solar tourist boat on Lake Altaussee in the Austrian Alps.

4FR / Getty Images

Solar-powered boats can be as humble as tour boats on Turkey's Lake Eğirdir or on Lake Altaussee in the Austrian Alps. Like ferries, tour boats are ideal candidates for solar power, as their regular routes allow for batteries to be sized with enough electricity to power voyages of days when the sun isn't shining.

Solar boats have barely entered the mainstream boating market, but the technology is within the financial reach of most boat owners, as the cost of solar panels has dropped precipitously over the past decade. Any boat with a large-enough surface exposed to the sun can attach solar panels to it, and with a little wiring and (optionally) battery storage, infinite sailing is an increasingly affordable possibility.

View Article Sources
  1. "Largest Solar-Powered Boat Completes Around the World Voyage." Guinness Book of World Records, 2012.