EV = Electric Vehicle

ICV = Internal Combustion Vehicle

Which is more efficient? Let’s take a quick look…

In 2014, Toyota announced a new, more efficient internal combustion engine, which they claim has acheived a thermal efficiency of 38%. Impressive? Reasonably so. Internal combustion engines have an inherent problem, and that is energy loss. In 2007, Melody L. Baglione of the University of Michigan found that vehicle system demands comprise a total of 24.6% of the energy consumption of an ICV. That puts average energy loss in the ballpark of 70-80%.

So for Toyota to develop an engine with an efficiency rating of 38%, that is pretty impressive. For an internal combustion engine, at least. But here is the catch: Mitsubishi’s i-MiEV, along with many other EVs, had reached an overall efficiency rating of 79% – two years prior!

As you can see, efficiency isn’t the strong point of combustion engines. Large amounts of energy are lost before they can even be used, and the little bit that does come through doesn’t really do anything that an EV can’t do with the same amount of energy. I decided to do my own digging on this one…

It turns out that the energy density of petrol is 9.5kWh/l. Ten liters of fuel equates to only a wee bit more than battery pack in the soon-to-be discontinued Tesla Model S 90 (95kWh in petrol compared to 90kWh in the Model S 90). OK, so what now? Keep in mind that 75.4% of this energy is lost in conversion. The average internal combustion engine will leave you with 23.37kWh of actual, usable energy. Almost every electric car in production has a battery capacity of at least 24kWh, and that will carry you the same distance as 95kWh of energy in a petrol engine.

Some people advocate for a charging system that is familiar to the masses – by making it like a fuel station. The first question I have for them is “Why?”.

Fuel stations require a special stop to refuel. Charging stations can be placed anywhere with a suitable supply of electricity. These stations are either free or significantly cheaper than petrol, and they are almost all conveniently located near cafe’s, supermarkets, shopping centers, or CBDs.

For New Zealand charging locations, see the Chargenet Map. If you are a Tesla driver, you probably already know about Tesla’s enormous charging network that covers Europe, the United States, southern Canada, eastern China, parts of Australia, and is starting to be installed in New Zealand. You can also use the Open Charge Map to find charging stations anywhere in the world.

You generally cannot fuel up your petrol or diesel-powered car at home, either. This is a luxury available only to EV drivers. Most EVs can charge from a 10A power outlet (albeit very slowly), a 16A caravan socket, or you can install a dedicated circuit to charge your car at much higher currents.

How long does it take you to charge an EV? Not long at all. You get home, plug it in, and leave it. Come back in the morning and you’re ready to go. It is advisable if you are travelling in rush hour traffic that you only charge to 90%, so you can make the most of the car’s regenerative braking. This means money saved (the cost seems to average about $5 per week here in New Zealand), time saved (no more petrol stations), and, because time and money are two of our most precious resources, a huge amount of stress taken out of your everyday life!

How long does it take you to refuel a petrol or diesel vehicle? Depending on where you live, it can be over two hours. You have to drive to the station (not everybody is lucky enough to have a petrol station on the way out of town), if it is busy, then you have to queue. You finally get to the pump, open the fuel flap, remove the filler cap, insert the nozzle, and start pumping petrol. Can take a few minutes to do this, too. Then you have to go into the store and recite your pump number to the attendant. They then find the pump on the computer system, recite the cost to you, and send it through to the EFTPOS machine for you to pay. Once you have payed, you get back in your car, and drive out of the station, and have to negotiate your way back onto the road to continue your journey home (or wherever it is you are going).

Let’s take a look at pollution, shall we? The simplest way to discuss pollution from vehicles is give you the option of two sealed rooms – one has a petrol-powered V8 Holden Commodore sitting in it. The other has a Tesla Model S sitting in it, powered on. You will be locked in this room for 6 hours, and both rooms are about the size of a single garage. You cannot switch either car off, either.

Few people would want to be locked in a sealed, confined space with something that consumes the precious oxygen they need to breath and replaces it with toxic gases now, would they. For example, the room with that dreamy Commodore will quickly fill up with Carbon Dioxide, Mono Nitrogen oxids, water vapour, particulate matter, and heat.

Meanwhile, the room with the Tesla will fill up with, well, nothing harmful really.

Many people don’t even think about these things when they spurn electric vehicles – they simply get defensive and ignore the entire oil industry as they proclaim how terrible electric cars are for the environment! Or they start babbling about things like Lithium mining, which for the record, doesn’t actually exist…