Fads Come and Go — is the Electric Car a Fad?
Written by Dr. Klaus L.E. Kaiser
Fads come and go, but sometimes they stay around and, after a while, everyone wonders how the world ever lived before. The question here is whether electric cars are just another fad or are they the beginning of a whole new way of doing things, such as going to the beach, or grocery shopping.
In order to get a handle on that question, let’s look at some critical information.
First, consider the amount of a typical gas tank’s worth of electric energy. Let’s say your car has a tank of 50 L (approximately 15 US gallons) gasoline. The energy equivalency is 33.4 kWh (kiloWatt-hours) per gallon of gasoline. Therefore, if your car had batteries and an electric motor only and everything else being equal, you would need a battery system with a storage capacity of approximately 10 times the number of kWh of the number of liters of gasoline; therefore 500 kWh of electric energy storage.
The internal combustion engine (ICE) has a lower efficiency of energy (fuel to usable power) conversion than an electric motor (EM); roughly 27% compared to 80% for the EM. In other words, the ratio of stored power to usable power for the EM is approximately three times that of the ICE. Therefore, in calculating the effective cost of running an electric car this also needs to be considered.
Cost of Electricity
Nationwide, the average residential cost of electric power is in the order of 12.5 cent/kWh, prior to additional costs. Adding those additional costs would bring it to somewhere in the $0.15 to $0.20 range per kWh, depending on other conditions such as “cost of delivery”, taxes and so forth. With that, to “fill up” your electric car with 500 kWh of electricity would cost about $90 on average.
Using a price of $4/gallon, the cost of the equivalent energy in the form of gasoline would actually be less; namely $60.
Cost of Vehicles
Next, let’s consider the cost of an electric-power-only vehicle (EV). Until now, the cost of EVs is well above the average car price. Let’s just say that the average car (all costs included) has a price of $25,000. You certainly have to shell out more for any EV; in fact quite a bit more, sort of like $100,000. A large part (50%?) of that amount is due to the cost of the batteries. Batteries are the real weak point of the EV craze.
Energy Storage Capacity
Energy storage is another critical point. Batteries, being chemical systems, just can’t compete with gasoline. Even the best batteries have an energy density of only 1/40 of that of common gasoline or diesel fuel. Therefore, even the combustion engine’s lower efficiency is negligible in terms of those carbon fuels’ energy storage capacity in comparison to any battery system of equal weight.
Durability and Cost of Batteries
Of course, batteries for EVs must be rechargeable and, primarily for weight reasons, they are lithium-ion batteries (LIBs). You find LIBs in many modern electronic devices such as cell phones, cameras, tablets and the like. These gadgets are using micro-circuits with extremely low energy needs to function quite well for many years.
If you have used such a device for a few years you likely will have noticed a decline in battery performance. Not only are they slowly losing power even when not used, perhaps they even develop a “memory lock” despite (or because of?) regularly being recharged to “top them up.” In short, after a while, they need to be replaced. That’s when the cost hits home; I just had to replace one for a cordless telephone at a surprising $30.
Don’t expect any different “sticker shock” for your EV battery replacement when needed.
Recharging EV Batteries
Companies selling EVs, like Tesla, have come up with novel incentives. Currently Tesla offers free electricity recharge at their stations. Of course, that will last only for a while. But more importantly, even at a charging rate of 120 kW, it’s not an “instantaneous refill” as you would get with gasoline. Even at its super-quick charging stations you have enough spare time to go shopping for a while, i.e. 30 minutes. Other commercial outfits only have chargers delivering 10 kW (using 40 amperes at 250V) where it takes more like 6 hours to “fill-up.”
While Tesla claims a recharge time of 20 min with supercharging it would only give you a 50% recharge under such conditions. Their web site also says that an 80% level (of battery capacity) recharge will take 40 min and a 100% recharge 75 minutes. They also offer a complete (?) battery exchange in less than two minutes at an unstated cost. Having seen one of their cars stripped down to the batteries which cover the entire frame, I wonder how that is done.
With a fully charged 60 kWh (approximate energy equivalent to 2 gallons gasoline) battery as in the Tesla model S with a curb weight of 4,700 lbs, the company claims a range of 230 miles (temperature dependent) at highway speed. That’s unless you use the air conditioner, go uphill and downhill, turn on the headlights, or drive at a temperature less than 55 F. Quite telling is that their interactive web site does not even allow you to calculate a range limit at temperatures below freezing. Presumably, nobody needs to drive their car in winter.
Putting it All Together
When putting it all together, i.e., the purchase price plus the costs associated with depreciation, battery deterioration and operation of any EV are still much higher than that of any car with a combustion engine. Combined with the range and temperature limitations, EVs are more like expensive toys.
When you count in the time (your time) and frequency of recharging and limited range to go just a couple of hundred miles, even in warm California, it ought to be clear that EVs are not a wise investment, certainly not in colder climes or at this time and, more likely, if ever. Perhaps Tesla’s recent stock price action reflects such recognition.
But if you have money to burn…