Clean Tech

Battery swap for cost slash: The buzz stops here

M. Ramesh | Updated on: Sep 25, 2019
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Raising the density of e-buses wherever possible will reduce the cost of operations

There lived a finance wizard, the story goes, who came up with the right answer to any problem his subordinates took to him. Only, each time a ticklish problem was posed to him, he would open the drawer of his desk, take a peek and come up with the perfect solution.

When he died, his eager juniors opened the drawer to find out what gave the wizard the answers. They found a piece of paper bearing the three fundamental principles of accountancy — “Debit the receiver, credit the giver; debit what comes in, credit what goes out, debit all expenses and losses, credit all incomes and gains.”

The point of this parable is, obviously, the importance of fundamentals. To bring in an e-mobility revolution in India, it is necessary to not lose sight of one of the basics of economics — scale drives down costs.

Going by the tenders for e-buses, India is expected to see 5,600 electric buses in the next 18 months in about 65 cities. And that is only the beginning. Prof HM Shivanand Swamy of CEPT University, Ahmedabad, says that if the government and industry play the cards right, there could be 20,000-30,000 e-buses in India in the next 5-7 years. However, for a country as large as India, even that is not quite enough.

Buses for the masses

It is fairly well understood that e-buses will lead the e-mobility revolution in India. Two-wheelers and three-wheelers “will go e” quite early on, but buses are those that will move the masses.

Personal transportation, cars and SUVs will take time to go electric.

The time of e-buses has come. Studies have shown that e-buses are more economical than diesel buses, on ‘total cost of ownership’ basis. For sure, they cost a bomb — for example, a BYD (Chinese) bus costs ₹1.6 crore — but it is well worth it because your running costs are low. Because e-buses cost twice as much as the diesel-powered, interest and depreciation costs are correspondingly double, but all other costs such as fuel and maintenance are far less.

Here are some illustrative numbers. In Bengaluru, an AC diesel bus will incur a cost of ₹85 a km; an e-bus will need ₹20 less. For non-AC buses, the numbers are ₹55 and ₹40. Another estimate, made by Prof Swamy, seems to be less generous to e-buses. In a 2018 paper on Financing of e-Buses, he estimates the typical costs of diesel and electric AC buses at ₹68 and ₹61, respectively. But the variance in estimates is understandable because the cost-per-km of e-buses depends upon a number of factors, but mainly the density of buses per route and choice of technology. Indeed, the number of buses you put on a route and the passenger load, in a way, determine the choice of technology. You see a good example in the operations of Ashok Leyland in Ahmedabad. The bus maker has deployed 50 buses in the city; 18 of them on a high-traffic route and the rest spread over several routes across the city. These 18 are in battery-swapping mode, while the rest are charged at one of the several charging stations on the routes.

Thanks to the higher frequency of buses, Sun Mobility, Ashok Leyland’s partner, is able to run a battery-swap service for the buses. (Sun Mobility is a start-up co-founded by Chetan Maini, who kicked off e-mobility in India two decades ago by bringing in the two-seater Rewa cars, which business was later sold to the Mahindras.) Because the buses do a quick run on the route and come back to that point, the battery could be downsized. Yuvraj Sarda, Head-Strategy, Sun Mobility, tells BusinessLine that swapping enabled the battery to be downsized from 350 kWhr to 64 kWhr, reducing weight and making more room for passengers. It takes less than three minutes to pull out the drained battery and put in a fully-charged one.

And because you can charge up the batteries at leisure, you don’t have to build a series of fast charging points, which are costly. A ‘fast’ charging station that will fully energise a battery in four hours costs ₹20 lakh. If you want to charge much faster (oh, you can, but you will lose energy in the process and shrink battery life), it will cost you more. The lesson from this, therefore, is to raise the density of e-buses wherever possible, so that swapping, rather than charging, is possible. This will bring down the cost of operations.

Safety awareness

The e-bus is a new animal. Sure, there are half a million of them in the world today, but more than nine out of ten are in China alone. Therefore, for the rest of the world, the e-bus is still an unknown commodity.

The question is, how safe is it? A scary point is that the bus has 650 V DC motor — anything above 60 V DC is fatal to touch. And, batteries could catch fire.

Karthick Atmanathan, who heads the electric mobility division of Ashok Leyland, recalled while speaking at a conference in Chennai recently that he bumped into a fire department official in a restaurant and realised that the man did not quite know how to handle Li-ion battery fire. A burning battery, Atmanathan said, even if dunked in a tank of water, will resume its burning after it is taken out. Ashok Leyland’s buses have several layers of protection, such as auto switch-off in case of overheating or an accident. A spokesman of the company says e-buses are safer than diesel buses — only you have to learn how to handle things during emergencies.

As the country moves towards e-buses, awareness on safety needs to be built, lest a freak accident derails the whole movement.

Published on September 25, 2019

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