Aditya (boat)


Aditya is a solar-powered ferry operating between Vaikom and Thavanakkadavu in the Indian state of Kerala. The boat was inaugurated by Kerala Chief Minister Pinarayi Vijayan and Union Minister for Power and Renewable Energy Piyush Goyal on 12 January 2017 at 5 pm.
It is India's first solar-powered ferry and was the largest such vessel until Indra (boat) was launched in 2023.
The boat was designed and built by Navalt Solar and Electric Boats, Kochi — a joint venture between Navgathi Marine Design and Constructions, Alternative Energies and EVE Systems.

Development and background

  • Initiated by the Kerala State Water Transport Department to reduce fuel costs and emissions.
  • Construction began in 2016 at Navalt's Kochi facility and was completed the same year for about ₹2 crore.
  • Launched on 9 November 2016 and commissioned on 12 January 2017.
  • A Public Interest Litigation filed on 20 June 2016 had claimed a solar ferry would be “impossible to operate”, but the project's success disproved this and later won multiple international awards.

Design and construction

  • Type: Catamaran passenger ferry
  • Dimensions: 21 m × 7 m × 1.75 m
  • Displacement: 23 tonnes
  • Material: GRP hull / aluminium superstructure
  • Registry: Kodungallur Port under Kerala Ports
  • Classification: Built to Indian Register of Shipping rules for inland vessels
The hull was developed using extensive CFD analysis by Navgathi and AltEn to optimise hydrodynamics. Construction and testing were witnessed by the Technical Committee, IRS surveyor and Kerala Port Surveyor on 16 November 2016 at Aroor backwaters.

Technical features

  • Solar array: 140 m2 roof panels rated 20 kW
  • Propulsion: 2 × 20 kW permanent-magnet motors
  • Performance: 7.5 kn max; 5.5 kn cruise
  • Battery: 50 kWh lithium-ion + 9.6 kWh gel backup; 700 kg total
  • Average power use: ~20 kW
  • Operating cycle: ≈ 22 trips/day
  • Charging: 32 A shore charger overnight
  • Monitoring: Real-time telemetry to Navalt servers for diagnostics and remote software updates

Safety features

  • Catamaran design ensures superior stability; can safely carry 200 passengers while meeting IMO stability standards.
  • DNV-class approved propulsion batteries minimise thermal runaway risk.
  • Multi-level safety system includes:
  • * Warning for approaching temperature/voltage limits
  • * Slowdown command when limits are reached
  • * Automatic shutdown to prevent damage
  • Independent dual propulsion trains allow safe return to shore in case of failure.
  • Built under IRS inland vessel rules ensuring redundancy and safety compliance.

Tests and trials

  • Optimisation trials: 13–14 November 2016 – software fine-tuning with French experts.
  • Builder trials: 15 November 2016 – system validation.
  • IRS and Technical Committee trials: 16 November 2016 – maximum speed 7.4 kn @ 90% power; redundancy verified.
  • Client trials: 25 November 2016 – attended by Transport Minister A. K. Saseendran and officials; performance approved.
  • Site trials: Full-day Vaikom–Thavanakkadavu route, 22 trips completed successfully.

Operational performance

Since entering service in January 2017, Aditya has continuously operated between Vaikom and Thavanakkadavu.
Performance highlights :
  • 3.1 lakh litres of diesel saved
  • ₹2.6 crore+ fuel cost savings
  • 30 lakh+ passengers carried
  • 740 tonnes+ of CO₂ avoided
  • Average CO₂ reduction: ≈85 tonnes per year
  • OPEX ≈ US$79/month
  • Operational breakeven achieved in 2019
  • First battery replacement completed in 2024

Energy and efficiency statistics

Average annual CO₂ saving ≈84.8 tonnes.

Initial operation data

  • First 60 days – 73.3 kWh/day, SOC 65%, grid charge ₹124
  • 150 days – 73.7 kWh/day, SOC 60%, grid charge ₹163
  • 1 year – 72.8 kWh/day, SOC 58%, grid charge ₹179
  • OPEX savings ≈₹25 lakh in Year 1

Tender specifications

  • Estimated daily energy need: 110 kWh
  • Solar generation: ≈80 kWh/day
  • Battery support: 50 kWh capacity
  • One trip ≈5 kWh → 22 trips/day = 1,650 passengers
  • Operation window: 07:00–19:00 with optimised breaks
  • Cloudy-day charging via 32 A shore charger adds ≈21 kWh in 3 hours

Awards and recognition

Winner – The 1st Gussies Electric Boat Awards – *Best Electric Ferry in the World*Solar Impulse Foundation – Efficient Solution Label

Legacy and broader impact

  • Aditya's success led KSWTD to plan conversion of all 48 diesel ferries to solar-electric systems.
  • As of 2025, Navalt Solar and Electric Boats has 73 projects worldwide – 35 vessels in operation and 38 under construction.
  • Geographic distribution: 68 in India, plus one each in Canada, Israel, Maldives and Seychelles.
  • By sector: Tourism 43, Passenger Transport 19, Fishing 6, Vehicle Transport 2, Workboats 2.
  • Navalt continues to expand with new models including Indra, Barracuda, Srav, Marsel and Destiny, and the Greenship modular platform for defence and commercial applications.