Seeing this article prompted me to pen this down.
Somehow people still confuse that solar panels are kept on electric boats to reduce the cost of power or offset the fossil fuel source in the grid. That is because they think electric boats as electric trains (since KMRL!). Unlike electric trains, electric boats are not connected to the grid when energy is consumed (while moving). Hence solar panels on boat serve the purpose of reducing the battery size and thereby economics works better. It is not relevant in projects where CAPEX and economics is not a concern. That seems to be the case in KMRL since the public is yet to get hold of the economic feasibility of operation of the boat and CAPEX has almost doubled with specs changes.
With regards to comparing with Aditya, it is true that KMRL boats are planning to run at 8 knots in electric mode as opposed to 6 knots for Aditya (max speed of 7.5 knots). These boats are going to be air-conditioned as well. Binary thinking of either all or none is the blindspot here. The cost of power from solar panels is cheaper (whether to run propulsion or air-con) than grid energy stored in batteries or power from genset on board. Large shore installation definitely counterbalances the fossil fuel source in the grid. The most effective for that is to have one single large plant and feed to the grid rather than multiple small plants.
Incidentally, the largest solar boat in India is under construction. This is a 25 m catamaran with 100 passenger capacity that is the fully air-conditioned and maximum speed of 7.5 knots. It has a 24 kW solar plant to maximise the use of energy from the sun and keep battery size small.
This paper was written to open such minds, but my effort failed for KMRL. Let’s us hope future projects do not make the same mistake. https://www.researchgate.net/publication/340514257_Solar_Panels-On_Boat_or_Shore
Another point raised in the article is comparing aluminium with steel. There is no doubt that aluminium is a far better material than steel for boats. However, it should be compared with GRP in terms of benefit. Both are equally light and gives a good performance. The only disadvantage for GRP was the cost of recycling although the initial cost and maintenance are much lower. However, one added element missed out is the fact that if the choice is is aluminium then the marine grade plates and extrusions will be imported (mostly Australia) compared to domestic manufacturing for GRP. Again, if aatmanirbahratha is not there in the equation, it would not matter either.
A very important point, all the while swept under the carpet, is the ticket pricing of water metro ferries. With CAPEX five times a typical ferry boat operated by SWTD and OPEX higher as well, it is no doubt that to manage the costs the tickets rates will be much higher. Water Metro ferries can position itself as faster than normal ferries with 8 knots compared to 6 knots and airconditioned but then Vega 120 operated by SWTD is airconditioned as well as much higher speeds of 12 knots. This means Vega 120 ticket pricing will be the upper bound in the perception game. At its ticket price, OPEX will be managed but CAPEX will never be. This game will be very interesting in the days to come. Such choices are made by people who do not have skin-in-the-game, which is to pay back the loans that they sign up for!