Brace yourself: electric vehicles will overtake petroleum ones

By MUNGAI KIHANYA

The Sunday Nation

Nairobi,

19 January 2025

There are two major concerns that have curtailed the mass adoption of electric vehicles: range anxiety and ownership cost. Range anxiety is the unfounded worry people have about how far they can travel before needing to recharge the vehicle. Most electric vehicles today can drive for about 500km on one charge while most motorists never drive more than 200km in day – ever!

Cost of ownership has two components: purchase and operation. The purchase cost of electric vehicles is still much higher than that of normal engine vehicles – it is about double. But the running cost is a tiny fraction – less than 10 per cent!

Now, one litre of petrol contains about 34 million joules of energy (34MJ). So, at the current price of Sh176/L in Nairobi, the unit energy cost of petrol comes to about Sh5/MJ. In comparison, one kilowatt-hour (kWh) of electricity costs about Sh29 and it is equivalent to 3.6MJ of energy. This works to about Sh8/MJ. How comes then that running an electric vehicle is cheaper than operating a conventional petrol engine?

The answer is in the efficiency of converting energy into useful work. Petroleum engines are horrible at this! Most the energy in the fuel goes to waste as heat leaving only about 25 per cent available for useful work. Electric motors are very good at it; the convert over 80pc into work.

This, together with the fact that petroleum engines need to remain idling when not in use for short periods, makes electric machines a lot more cost effective than petroleum ones. Let me illustrate with a real case. My neighbour has a petrol-powered fence trimming machine. It consumes about 350ml of petrol to do one hour of trimming. At the current price of fuel, this comes to about Sh61/h.

I have a similar machine but mine is the rechargeable electric type. It has a 2Ah-20V-battery that is enough to operate for about 60 to 90 minutes. 2Ah at 20V works to 40Wh which is equivalent to 0.04kWh. At the current electricity price of Sh29 per kWh, this comes to just over one shilling for one hour of work.

Yes. One shilling of electricity does the same work as Sh61 of petrol! Surprisingly, it cost me Sh15,000 to buy the electric trimmer while the petrol-powered ones go for Sh20,000. I highly suspect the same trend will extend to the vehicle sector and in due course, electric vehicle will become cheaper to buy than petroleum ones. It’s just a matter of time!