In the last couple of years, the transportation industry in India has been adopting renewable energy in a big way. For airlines as well as railways, solar power has become a preferred option. And now, the waterways are taking to it as well. Solar powered e-boats on the Ganga in Varanasi, launched by Prime Minister Narendra Modi, made news recently.

India’s very first ferry powered by solar energy, to be deployed in the backwaters of Alappuzha by the Kerala State Water Transport Department, is another case in point. It will also be the country’s largest commercially operated solar-powered mode of transport.

How it took shape

The 75-seater passenger ferry is being built by NavAlt, a Kochi joint venture firm, in collaboration with a French company at Aroor in Alappuzha district. Construction is almost complete. The battery and motor console, which have undergone testing, have been flown in from France. In all likelihood, the ferry will hit the waters by the end of June.

Working on 40 kilo watt propulsive power, the 20-metre by 7-metre ferry, with a maximum cruising speed of 7.5 knots, is capable of plying the waters for five to six hours on a normal sunny day. It will have an alternative power system for emergencies and its battery will be charged by plugging on to a normal electric circuit at the end of the day’s journey. According to Sandith Thandasherry, the brain behind the innovation, it will be India’s largest boat equipped with lithium battery storage.

The Kerala State Water Transport Department plans to operate the boat on the 2.5 km Vaikkom-Thavanakkadavu route. The crew will be trained to handle the boat, as the operating system is different from that of conventional diesel-powered ones.

For Thandasherry, the idea to integrate solar energy into the marine sector began in 2009. It was in that year that the former IIT Madras graduate and his team began experimenting with pleasure boats. This won them a place in the Limca Book of Records for the fastest solar boat in India. However, there were odds as well, since some experiments, like the application in existing fishing boats, failed to materialise.

Finally, they realised that the best application of solar in boats is in passenger transportation. Since there were no solar ferries in India, this was a challenge. Eventually, a joint venture with AltEn came about and the aim was to make a winning combination that had not only the technology but also the expertise to build cost-effective solar ferries.

Engineering challenge

Thandasherry, who is also a marine architect, admits there were various challenges that confronted them when they began building the ferry. “The biggest was to manage the boat’s weight control," he told "Since the project has a strong technical committee to review the design and construction with experts in class, composites, Naval architecture and from ANERT and Kerala University, on many occasions, their suggestions for increasing the safety margin would lead to heavier structures, whereas our aim was to compensate this weight increase by choosing lighter materials in other areas.”

Since it runs on solar, the boat has been eligible for subsidy from the Union Ministry of New and Renewable Energy. ANERT, the ministry's nodal agency in Kerala, is a member of the technical committee of this project. They have promised to procure a 50% subsidy instead of the 30% that is normally obtained, because this is a unique project and the first of its kind in India, said Sandith.

Conventional versus solar

Unlike conventional ferries that ply on diesel-powered engines and at times, petrol, Out Boat Motor, a solar ferry, runs on electrical propulsion powered by energy from sun (mostly) and stored energy from a grid (as back-up in cloudy and rainy conditions).

Apart from using clean energy, solar boats are significantly better than their conventional counterparts since they do not pollute water, do not release harmful emissions, are very silent and comfortable for passengers, have low vibrations, do not emit the smell of diesel or petrol and have a lower cost of ownership. The initial cost is high, but the operating cost is low. In fact it is touted to be the world’s cheapest solar-powered boat once built, according to construction cost per passenger.

While the solar ferry costs Rs 17 million (about $2,50,000) to construct, an ordinary boat with the same safety standards and amenities would cost Rs 15 million. Additionally, the cost of diesel for operating a conventional boat is around Rs 3 million.

"The ferry launch will prove that we can avoid all the problems of a conventional ferry and make it cheaper," Thandasherry said. "It will be an attractive option in all locations where passenger water transport exists. Furthermore, it will open up new locations where diesel boats cannot run because of noise and pollution, such as dam sites, ecologically sensitive areas, drinking water sources and so on.”

Other state governments have also shown an interest in using solar power for their water tourism industry. The company has already made a 20-seater solar-powered boat for a tourism operator in Bhatinda, Punjab. Thandasherry said they are also in talks with Maharashtra Tourism Development Corporation. In West Bengal, the state transport department has already visited the company's client to get details on a similar project, he said.

He is hopeful that soon most states will initiate such projects. Even houseboats could be solar-powered if their conventional shape is tweaked to make the boat lighter and to accommodate solar panels, Thandasherry said.

Need for an Indian make

Recently, a pleasure boat that runs on solar energy and is of Chinese make was launched for tourism in Andhra Pradesh. “There are a couple of boat builders in India, apart from some manufacturers in Europe, America and Asia, who can construct such boats, since these are easier to make and the technology is simple," Thandasherry said. "However, it does not make sense to import them from abroad when there are options here. The only reason could be that it is cheaper, but may be of poor quality. Otherwise, for the size of the product, the shipment cost and custom duty do not justify it to be imported. Normally, boats are designed for a period of 20 years, but ones such as these might not be."

According to Ajith Gopi, Programme Officer, Solar Photovoltaic Projects, ANERT, solar ferries have done well in European countries. They are more popular in Scandinavian countries such as Norway, Sweden and Denmark.

“It’s better we develop solar boats based on our end use in India," Gopi told "The exact load requirement based on the type of boat, available area for photovoltaic module integration, autonomy and placement of battery bank etc. are the key factors to be looked into while designing them."

If crystalline photovoltaic modules are used in the boat, one has to be very careful, taking factors such as the wind into consideration at the design stage. “On the roof of the ferry, if the solar module is blended, the wind cannot influence due to the solar integration," Gopi said. "If you have the solar array erected on the boat separately, it will take the wind with it and influence the boat, so these are the factors that need to be kept in mind while developing a solar boat."

Gopi said that there are technologies that allow them to integrate the photovoltaic module on the roof with a thin film, as is done in developed countries. "In India, the need of the hour is using optimum technology and considering the end use of the consumer, be it ferries or fishing boats,” he said.

This article first appeared in India Climate Dialogue.