I have been on the internet trying to find out what the "true cost" of an electric car is and have not been able to find a single study that would have scored a "C" in one of my Engineering Economy classes. Have you found the same thing? That is the point of this blog.
When I taught Decision Theory in graduate school, I used to stress that all decisions are between alternatives and the biggest error that people make in decisions is failure to have "all" the alternatives on the table. That is just for beginners. I did not find any studies that considered the cost per mile of a "used" car. Further, I did not find any studies that took into account the "salvage" value of the electric car after the study period. Per the Wall Street Journal, the prices for used electric cars is in the tank. That is because the life expectancy of the battery is far less than that of a gas engine and is very expensive to replace. The other thing is how to deal with the "free" money from the government that applies to electric cars. It is like having your neighbor give you $7,500 as a gift to buy an electric car and we all know that can not go on for ever.
It starts to get a little more technical from this point on. In my classes, my students had to structure their economic decisions on the basis of "present worth". Adding dollars from different time periods is just like adding apples and oranges. To add money or costs, all the figures have to be adjusted to the same date, "present worth". The electric car might cost $30,000 today and its used value in 10 years might be $10,000, but you can't just subtract the $10,000 from the $30,000 and call $20,000 your cost for the 10 year study period. You wouldn't loan a friend $10,000 today and expect him to only pay back the original $10,000 10 years later? I think you can follow this one.
The other thing that you see in the numbers is the cost of electricity in KWH and the assumption that an electric car can go 100 miles on 20KWH. For starters, a Horse Power is equal to .75KW. That means that 20KW is equal to 26.7 Horse Power and a full charge at 20KWH means your car can put out 26.7 Horse Power for one hour at full 100% efficiency and we all know that is impossible. All these numbers need to be adjusted for efficiency and they never take into account the fact that a used battery is not as efficient as a new one. Interesting isn't it? Further, they never take into account the need for a heater or air conditioning in the electric car. How would you like to have to wait in a cold car in Detroit for 30 minutes for your kid to get out of basketball practice or do the same thing in Las Vegas waiting for school to be out? Think of the heat given off by a 100 watt light bulb? How many of those do you think you would need in Detroit? 7.5 of those is equal to a Horse Power and you only have 53.4 of those that are good for 30 minutes.
The studies that I have seen do not have a clear starting point when it comes to efficiency. To give you an idea how it works, check this example. Most claim that they can recharge your battery in an hour and you can then drive 100 miles. Given that the battery needs 20KWH of electricity and the charging efficiency is 90%, you will need to pay for and provide 22.2 KWH in one hour. Most homes have 220 volt power service rated at between 100 and 200 amps. I am sure that you have no idea what your home system is rated for. It is going to take more than an extension cord to handle the amount of amps that are going to be needed to recharge the electric car battery. Would you believe that it will draw 100.9 amps? If it were on a 110 volt circuit it would draw twice that. Look at your main switch box and tell me how many 100 and 200 amp circuit breakers there are in there? None! If your system works at all, you are going to have a brown out every time you try to charge your battery and it gets worse as time goes on. They don't tell you that do they?
How about the efficiency from the battery to the motor? That is not 100% either. My guess is that it is about 95%. That means your electric car does not have 26.7 Horse Power, it is more like only 25.4 Horse Power. I have a kids 4 wheeler in my garage that has more power than that. What kind of load do you think you could haul for that 100 miles? Remember that you only have that 25.4 Horse Power for "one" hour and it is going to take you at least 2 hours to go that 100 miles. That means you will only have 12,7 Horse Power to keep your electric car up to 50 mph. Can your electric car do that?
This blog is getting a little long, but now I am sure that you can get out your calculator, engineering books and interest tables an figure out if the electric car is really a good deal or not. It is not going to stop global warming nor is it going to save the world as claimed.
When I taught Decision Theory in graduate school, I used to stress that all decisions are between alternatives and the biggest error that people make in decisions is failure to have "all" the alternatives on the table. That is just for beginners. I did not find any studies that considered the cost per mile of a "used" car. Further, I did not find any studies that took into account the "salvage" value of the electric car after the study period. Per the Wall Street Journal, the prices for used electric cars is in the tank. That is because the life expectancy of the battery is far less than that of a gas engine and is very expensive to replace. The other thing is how to deal with the "free" money from the government that applies to electric cars. It is like having your neighbor give you $7,500 as a gift to buy an electric car and we all know that can not go on for ever.
It starts to get a little more technical from this point on. In my classes, my students had to structure their economic decisions on the basis of "present worth". Adding dollars from different time periods is just like adding apples and oranges. To add money or costs, all the figures have to be adjusted to the same date, "present worth". The electric car might cost $30,000 today and its used value in 10 years might be $10,000, but you can't just subtract the $10,000 from the $30,000 and call $20,000 your cost for the 10 year study period. You wouldn't loan a friend $10,000 today and expect him to only pay back the original $10,000 10 years later? I think you can follow this one.
The other thing that you see in the numbers is the cost of electricity in KWH and the assumption that an electric car can go 100 miles on 20KWH. For starters, a Horse Power is equal to .75KW. That means that 20KW is equal to 26.7 Horse Power and a full charge at 20KWH means your car can put out 26.7 Horse Power for one hour at full 100% efficiency and we all know that is impossible. All these numbers need to be adjusted for efficiency and they never take into account the fact that a used battery is not as efficient as a new one. Interesting isn't it? Further, they never take into account the need for a heater or air conditioning in the electric car. How would you like to have to wait in a cold car in Detroit for 30 minutes for your kid to get out of basketball practice or do the same thing in Las Vegas waiting for school to be out? Think of the heat given off by a 100 watt light bulb? How many of those do you think you would need in Detroit? 7.5 of those is equal to a Horse Power and you only have 53.4 of those that are good for 30 minutes.
The studies that I have seen do not have a clear starting point when it comes to efficiency. To give you an idea how it works, check this example. Most claim that they can recharge your battery in an hour and you can then drive 100 miles. Given that the battery needs 20KWH of electricity and the charging efficiency is 90%, you will need to pay for and provide 22.2 KWH in one hour. Most homes have 220 volt power service rated at between 100 and 200 amps. I am sure that you have no idea what your home system is rated for. It is going to take more than an extension cord to handle the amount of amps that are going to be needed to recharge the electric car battery. Would you believe that it will draw 100.9 amps? If it were on a 110 volt circuit it would draw twice that. Look at your main switch box and tell me how many 100 and 200 amp circuit breakers there are in there? None! If your system works at all, you are going to have a brown out every time you try to charge your battery and it gets worse as time goes on. They don't tell you that do they?
How about the efficiency from the battery to the motor? That is not 100% either. My guess is that it is about 95%. That means your electric car does not have 26.7 Horse Power, it is more like only 25.4 Horse Power. I have a kids 4 wheeler in my garage that has more power than that. What kind of load do you think you could haul for that 100 miles? Remember that you only have that 25.4 Horse Power for "one" hour and it is going to take you at least 2 hours to go that 100 miles. That means you will only have 12,7 Horse Power to keep your electric car up to 50 mph. Can your electric car do that?
This blog is getting a little long, but now I am sure that you can get out your calculator, engineering books and interest tables an figure out if the electric car is really a good deal or not. It is not going to stop global warming nor is it going to save the world as claimed.
