This solar ferry in India runs on $2.60 a day

Inland of the port of Kochi, on the Arabian Sea in southern India, a 40km long inland lake/waterway separates the towns of Vaikom and Thavanakkadavu. 

The distance between them is only 2.5km as the fish swims, but considerably longer going around the waterway via land. So for the hundreds of commuters that go from town to town each day a ferry makes a lot of sense.

The Aditya, India’s first solar ferry, makes even more sense and is a runaway success after being in operation for just over two years:

  • 22 trips per day (15 minutes each)
  • 75 people/trip, 1650 people/day (580,000/year)
  • 72.8 kWh of energy consumed/day (3.3kWh/trip)
  • 58% State of Charge (SOC) at end of day
  • ₹ 179 (rupees) grid charging cost per day 2.60 US$ (to top up batteries not charged by solar)
  • 58,000 litres of diesel saved
  • ₹ 4,612,000 – 65,000 US$ annual savings


The Aditya is a catamaran, 20 metres long, 7 metres wide, covered by 140 square metres (1,500 sq ft) of solar panels – about one side of a tennis court. It was built by NavAlt Solar and Electric Boats, an Indian-French venture which also makes solar electric cruise boats. The India government provided financial and resource assistance.

The solar panels are rated at 20 kW and connect to two 20kW electric motors and lithium-ion batteries with 50kWh capacity. About 700 kg (1,500 lbs) of battery. The boat runs at about 5.5 knots, but sometimes races along at 7 and a half. The two motors operate under separate systems so that the ferry can reach shore if one is disabled.

One of the advantages of electric motors over diesel in this type of heavy application is that efficiency doesn’t drop with load, so the electric motors can operate at 50% load and in emergencies at 100%.

The Aditya is monitored and upgraded remotely

Here’s another cool thing. All of the Aditya’s operating data is transmitted to the NavAlt Solar for remote monitoring. Trouble shooting, and upgrades can also be done remotely, as if a computer is plugged in on the boat. It also means that anyone can see where the boat is and when it will arrive. Check out the link:

The project has been so successful that the Kochi Water Metro is adopting boats with electric engines in place of fossil fuel-run engines. There are also strong recommendations that the government add solar and electric boats under India’s Faster Adoption and Manufacture of Electric Vehicles (FAME) policy.

Sandith Thandasherry, founder and CEO of NavAlt, said “The electric vehicles (EVs) currently on road were added using the incentives of the FAME policy. Solar boats derive more than 75 per cent of their energy from the sun and the rest from the grid, which makes them cleaner.

2 thoughts on “This solar ferry in India runs on $2.60 a day

  • August 16, 2020 at 12:05 am

    Indian designs will always cost effective.


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