ADITYA – 150 Days of Service; and Surprise!

From the day of inauguration on 12th Jan to yesterday (12th Jun) ADITYA completed 150 days in service. In this period, along with demonstrating some of the unique characteristics of a solar ferry, it also dispelled some of the myths propagated by the nay-sayers. The unique features that were showcased successfully based on feedback from people were:

  • “the boat is silent” – a favourite one for passengers. Because it was the case, music and TV for entertainment was added to fill the silence!
  • “there is no smell of diesel”. The nauseating smell is totally missing in this boat.
  • “no vibrations”. Along with the silence this is responsible for passengers not realising whether the boat started moving from shore.
  • “refreshing” – a favourite from the crew. Unlike the exposure to noise and smoke in diesel ferry that make the crew tired after duty hours, here they are not tired.
  • “unbelievable low cost of operation” – from the client. Against normal daily fuel bill of 6,500 ₹ and additional 500 ₹ for maintenance (lubes, filter and engine overhaul), the daily cost for ADITYA is just ₹ 163.

Some of the myths that was propagated by the opponents of the solar ferry project were as follows:

  • “The boat will not be able to move with 75 people on board with solar power (with less than 20 kW)”. Coming from a self-declared expert on propulsion (was teaching the subject in a leading university), it provided the credibility. But sadly after IRS trials and successful trial run in Vaikom with 75 people on the first day destroyed the myth as well as credibility of the “expert”.
  • “The battery will drain in two hours on a cloudy day. In between the boat will stop and drift to Thannermukam bund and a whole lot of imagined horror.” Unfortunately for the “expert” we had some cloudy days and the service continued without being affected on any day and destroyed that myth.
  • “The wind in Vaikom-Thavanakkadavu route is very strong and it will capsize the boat.” Sadly the “expert” forgot boat stability basics that catamaran boats are more stable than single hulled ones. During strong windy days the service continued without any issues, thus dispelling the myth.
  • “The currents in Vaikom-Thavanakkadavu route is very strong and boat will not be able to propel and will drift to Thannermukkam bund.” There were days with strong current flow but none caused any deviation in our regular path. So another myth busted.
  • “During monsoon and heavy rainy day the boat will not able to do any service.” It has been two weeks since the heavy rains started. On many days the contribution from sun is very low, even as low as 10.5 kWh (sunny days is 65 kWh), yet the service was not affected. This was the last straw of hope for the non-believers, sadly that myth also gone. To put in perspective ADITYA was to be designed for sunny days with reduced trips on rainy/cloudy days, but with higher efficiency in design, even on rainy/cloudy days with some support from grid charging during breaks, the trips are largely unaffected.

I wonder what will be the new myth that will be propagated. Maybe a black-swan event!


The OPEX or operating expense is a crucial factor that makes a public transport sustainable. In a subsidised public transportation, especially water, if the OPEX is high it will kill the transport system (refer the sister concern on roads, KSRTC). CAPEX can be funded by some schemes, so the key for sustainability is low OPEX.

In this context if one sees the daily revenue from operating a ferry it is about 6000 ₹ by charging 4 ₹ for a 2.5 km travel across the lake. The daily fuel expenses is higher than this – 100 litres per day is about 6500 ₹. In addition the lubes, filter and engine overhaul takes it to almost 7000 ₹ per day. In comparison the daily OPEX of a solar ferry is only 163 ₹. This is the cost of power from grid at 7.5 ₹/unit. In the last 150 days there was no maintenance work done on the motors or batteries apart from checking done by our team for understanding the system performance.

In both cases there is additional cost of salary of staff which would be about 3000 ₹ daily. ADITYA model is a perfect solution to make public water transport sustainable.

Although 100 litres per day savings that is achieved by ADITYA does not seem much, but in a year (350 days) it is 29 tonnes (0.832 g/cc). This goes a long way in reducing our dependence on imported crude oil and save foreign exchange.

As responsible people we must be aware and concerned of pollution, but in reality, no one cares unless there is economic rationale. The savings in diesel translates to about 90 tonnes (2.67 tonnes/1000 litres of diesel) of CO2 emission reduction every year.

This is a very interesting comparison. For each trip that carries 75 people for 2.5 km and 22 trips in a day, a total of 1650 people travel. The daily OPEX for a diesel ferry is 7000 ₹ that yields a cost per passenger-km of 170 paisa. For 2.5 km it is 4.25 ₹, slightly more than the ticket charge of 4 ₹ (hence the small loss).

For ADITYA with daily OPEX of 163 ₹ the cost per pax km is a ridiculously low figure of 4 paisa. For 2.5 km it is 1 ₹. Hence 4 ₹ for tickets is making profits even for a subsidised ticket. The only issue for the government would be public demanding ticket prices to be lowered to 1 ₹ in light of this information.

This is the part that solves the issue of economics for taking care of the planet. Although initial cost of ADITYA is slightly higher (20%) the difference in cost is taken care in two years of OPEX (yearly savings is about 24 lakh ₹). In the 7th and 14th year the batteries will be replaced at around 25 lakhs costing (at todays price, which is expected to be reduced as lithium adoption increase in EV). In its total life cycle of twenty years solar ferry saves enough money to buy another two solar ferries.

Note that the difference in pricing is in a situation without benefit of scale. Hence, when we are building the 50th boat of ADITYA-like the price is likely to be same as diesel ferry. This again assumes that government is not keen to give similar incentives offered to electric vehicles on road under the FAME scheme (that is another post) despite better eco-friendly characteristics. We are optimistic that better sense will prevail though.

A surprise!

Although monsoon days are not good for solar production on average, there are some days when it comes up with surprises. These are the days when the air is clear of dust (low scattering) and solar panels are clean. Earlier from a 9 kW panel (for propulsion on each side), we could get about 6-6.5 kW power, in some sunny days during monsoon the production reached 9.3 kW power – a record. After all, monsoon also gives nice surprises for solar power.


Now we are focussing on ADITYA version 2.0 with lot of advanced features and higher performance. Here performance is defined as higher speed or range or combination of both. Our aim is to increase performance by at least 25%. There are at least 20 key areas of improvement in design to make a boat that is better for the passenger, operators, and world at large. Time for R&D!

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