Charging EVs with home plug points, public charge points, fast-chargers
Decades of conditioning from using petrol and diesel vehicles have shaped our refuelling behaviour — largely driving till the tank is almost empty, and filling up at a petrol station.
Today, with advances in battery technology, we are beginning the transition to electric vehicles (EVs). Today, the cost of electricity to drive an EV is about a tenth of the cost of petrol for a similar vehicle. But talk of fast-chargers, range anxiety and other unknowns have served to needlessly confuse the public. To garner the environmental, economic and strategic benefits of this opportunity, we have to change our refuelling behaviour patterns. There is a multi-layered approach to EV refuelling or charging the battery. They are home plug-points, public charge-points, and public fast-chargers.
For the moment, let us confine ourselves to electric two- and three- wheelers and cars. Intra-city driving is the dominant use today. We typically drive around 10-40km/day. Hence, there is no need to go to a petrol pump daily. Similarly, most EVs will not require “empty to full” charging every day. Look at how we charge mobile phones. We generally do this overnight and sometimes when they are not in use during the day: we don’t go to a shop. We do not normally wait for the battery to empty.
EV charging will be similar to mobile charging, but with more wheels, bigger batteries and chargers. In countries leading the EV transition, the battery is usually filled up overnight, using home plug points. This is the first layer of the charging infrastructure, and is already in use in India.
Inexpensive public charge-points form the next layer of the charging infrastructure. Since many flats in India do not have designated parking for vehicles, a number of public charge-points, amounting to 25-50% of the number of EVs must be set up. Facilities that already have designated parking such as societies, offices, bazaars, educational institutions and shopping malls are suitable locations. Public charge-points can be used for overnight charging and for a fill-up during the day. These are adequate for two- and three-wheeler EVs for intra-city needs.
Occasionally, public fast-chargers will be used to provide a quick fill-up, address range anxiety and meet the requirements of longer trips. A smaller number of these are needed as the third layer.
In India, home plug-points and public charge-points can supply upto 3.3 units/hour to EVs, or range per hour of charging of up to 20kms for cars and 100kms for two-wheelers. Both utilise chargers within the EV. Public fast-chargers are 7.5 to 15 times faster than charge-points. However, electricity supplied by fast-chargers will be more expensive per unit than that from charge-points. This is because the higher capital cost of fast-chargers must be recovered through the tariff or subsidies.
At present, ultra-fast-chargers are rare in India. Electricity from ultra-fast-chargers will be even more expensive. Home charging will be the least expensive, since it has little to no capital requirements. Swappable battery infrastructure has recently been announced for two-wheelers but this will likely be confined to high density areas.
Recently, a popular electric car was driven from Delhi into the mountains of Himachal. The advertised range for this car with full battery is around 300 km. It required five hours, and almost 80% of full battery, to travel 120 km from Chandigarh towards Shimla. The range was reduced since the car had to climb 1,500 metres. Therefore, inter-city car travel must be carefully planned: EVs can be competitive with petrol vehicles in the plains, but one must slow down in the hills to conserve range. Such ventures are of great benefit in raising public awareness.
Intra-city travel should be our primary focus, until sufficient range is available in EVs. That will happen in three to five years. Today EV range is sufficient for intra-city use, and speeds are competitive with petrol vehicles in the hills and plains. Meanwhile, charging infrastructure should continue to be built with an emphasis on home plug-points, public charge-points and strategically placed public fast-chargers.
Rajan Kapur is senior vice-president, IEEE Smart Village, a humanitarian seed fund and incubator
Surender Mohan, chairman, Rise Up Foundation Mandi; Bharat Singh Rajpurohit, dean, Infra and Services, IIT Mandi; and Bharti Ramola, member, Integrated Mountain Initiative, gave inputs
The views expressed are personal