Remember that first boat-ride in a hand-oared small vessel that slowly took you into the river, and gave you a glimpse of the bank you could have only had from the middle of the water, and filled you with extraordinary joy. Boat-rides are almost always worth it. The hand-oared rides, where you could hear the parting of water, in the company of fresh wind and picturesque view, are increasingly rare, especially at major tourist attractions where the fleet is dominated by diesel-powered boats.

These vessels, when they began replacing traditional boats long ago, presented two great benefits of saving time and human energy. Diesel engine could carry riders deep into the water in no time, lending them the thrill of speed. The boatman  had no need to exert his muscles and could take home more money than he probably could have with his craft earlier.

The diesel drive, however, also took away much of the original pleasures of a boat-ride. Remember complaining of the stink and smoke from the engine in a voice that had to be raised abnormally high to go over the rattle of the engine and understood by the person sitting next to you. And if you have tried using your smartphone to capture a video of the historical ghats in Varanasi, Chitrakoot or some other place, from your boat, the most noticeable and irritating voice in your video probably was that of the diesel engine.

So, when boatmen started experimenting with solar/battery-powered boats, it felt riders could have the best of both worlds: the speed of diesel-engine boat but without its smoke, stench, vibration, and the noise. The transition, however, wasn’t going to be easy: heavy, rigid solar panels mounted on top of boats with weighty traditional lead acid batteries required heavy capital investment but came with technological limitations. Panels faced damage from the strong and wet winds on the river while design flaws limited efficient utilization of the power generated.

Given the immense attraction of boat rides at tourist destinations across the country and the charm of the new technology, experiments on marrying the alternative energy with boats have been underway at many places.

In one such experiment, in 2016, an e-boat project was launched at Varanasi by a local NGO, in association with boatmen. These boats were to run on lead-acid batteries, charged by the grid electricity at a centralized charging point. The advantages over diesel-powered boats were apparent: it did not emit heat, noise, fuel, and lubricant residue. In short, it didn’t contaminate a tourist’s experience with unpleasant sound, sight or smell. And yet, it remained unpopular among the boatmen. The cost of obtaining and the drudgery of transporting four lead-acid batteries weighing more than 200 kg to the nearby grid electricity charging station were hard for boatmen to accept. Longer charging hours, lesser energy density, and large space that these batteries occupied made them unattractive.

A consultation with boatmen and other stakeholders helped TERI identify the problem: a lasting, reliable supply to trolling motor via a lightweight fast-charging battery was essential to operate such a boat; and an economically-sustainable business model was needed to keep boatmen’s interest alive in this intervention.

TERI set out to solve the problem. The solution had to be technologically effective while being economically sustainable. It devised a hybrid solar-powered model, which involves the use of just one lithium-ion battery weighing not more than 30 kg for each boat. These storages have much higher capacity, cycle life, lesser weight, fast charging rate and high energy density in comparison to lead-acid batteries. These batteries are charged at a centralized hybrid solar charging station, located on the bank of the river.

Under the TERI’s intervention, traditional boats are retrofitted with a trolling motor. Boatmen can rent batteries and recharge these at hybrid solar charging station operated and managed by the boatmen association. The business model involves renting batteries by boatmen who don’t have to bear any capital cost. The expenditure of retrofitting and those associated with the charging centre are financed by the Corporate Social Responsibility (CSR) fund mobilized by TERI. A local energy entrepreneur, selected by TERI, oversees installation of trolling motors and lithium battery in the boat along with the required after-sales services.

Under the model, a lithium-ion battery has the option to be charged by both solar and grid power.  The battery, which takes about 2–3 hours to charge, is attached to a trolling motor connected to a propeller, which pushes the boat backwards or forward. A single charge lasts two and a half hours, enough for a boat to complete two trips on a 10–12 km stretch. 

To make the business model work, TERI needed partners who could provide financial and technological support. TERI approached and convinced Indus Towers, a passive telecommunication infrastructure provider, to come onboard. Indus agreed to support the project using their CSR fund. With support from Indus, installation of eight hybrid solar charging units (solar+grid), to supply power to 50 battery-powered boats, in Varanasi and Chitrakoot, has been made possible. Commissioning of 10 more such battery-powered boats and two hybrid solar charging stations at Chitrakoot are also underway.

In comparison to the traditional hand-oared boat, the initial investment for a battery-powered boat is certainly higher. But compared to boats run by diesel engine there is not much difference in capital investment. And once the initial hurdle is crossed, it is possible to earn much more in a cost-effective, drudgery-free, and environment-friendly manner. Given such advantages, boatmen in Varanasi and Chitrakoot have started shifting to battery-powered boats.

The shift also raises the possibility of a return to those quiet, pleasant rides for tourists where one could enjoy the company of their loved ones or just their own self on a boat surrounded by fresh winds.

Mr Kishor Choudhary is the Team Lead of the project and Mr Jitendra Tiwari  is the technical brain behind this model.