There are some serious advantages to owning and driving an electric car, including:
- Convenience – you don’t go to the gasoline station and you don’t make individual payments for fuel. You plug in to a wall socket at home, which if you can operate a toaster you can do easily. The utility company of course bills you, monthly with all the other electricity you use.
- Fuel Costs. About 2 cents per mile for electricity compared to about 10 cents per mile for gasoline.
- Emissions. If everyone’s tail pipe was mounted in the center of the steering wheel, everyone would drive electric cars. If they did, everyplace would smell better. Never mind CO2 and global warming.
- CO2 and Global Warming. Ok, we should probably mind it. Oh the planet will be fine, and it will inevitably cure itself of greenhouse gases. But a very small adjustment in our weather can have fairly devastating consequences for us as individuals.
- Driving Pleasure. Yep. They’re more fun to drive. They accelerate better. They accelerate more smoothly. They are much quieter. They’re more fun to drive.
So where does all this magic come from? Well, it isn’t precisely magic. The electric motor actually predates the Otto cycle internal combustion engine and it was always simply more efficient at converting energy to forward motion. No, you can’t run your car on water by hydrolysis. You can’t hook a generator to the motor and make it make its own electricity. You can’t put solar cells on your car to extend the range signficantly. And you can’t use a windmill either. The physical laws of the universe still hold true and the ones pertaining to the conservation of energy hold particularly true.
But the electric drive train is just more efficient than the internal combustion engine. Not a little bit more efficient, about 5-8 times MORE efficient. And all good things about electric cars derive from that.
There are any manner of claims regarding efficiency of both electric motors and Otto cycle engines. And there are hundreds of ways to calculate it. I like to reduce it to the basics – energy into the car, miles driven out of the car. In this way, individual cummulative losses, while interesting, don’t drive us into heroic technical discussions.
To talk about energy input, we have to pick apples or oranges and do both sides with our selection.
Let’s talk about the energy in a gallon of gasoline. This should be pretty simple, but actually it isn’t. I’ve seen numbers all over the place. The reason for this is that gasoline is all over the place. There are actually a LOT of different formulations of gasoline. But the most common type you can buy at the pump today is termed REFORMULATED GASOLINE.
Basically, to reduce emissions, the government requires the gasoline to be OXYGENATED to achieve better combustion of the carbon and thereby reduce the PARTICULATES (soot/smoke) emitted from the tailpipe. Has nothing to do with CO2 but it does have to do with the aesthetics of SMOG in our cities and the smell of emissions.
They originally required an additive termed MTBE. Methyl Tertiary Butyl Ether. This is actually a combination of methanol and isobutylene more conventionally used to dissolve gall stones. But it was an excellent oxygenator for gasoline. Unfortunately, it turns out to be a deadly carcinogen that accumulates in groundwater and resides there essentially forever. This is probably THE classic case of government acting to reduce environmental impact, and instead increasing it, all the while requiring EVERYONE to participate, up to the point where they discovered they are wrong. In which case, they declare the whole episode a SECRET.
That’s correct. They very actively don’t want you to know about MTBE or that MTBE every existed. This in fact IS a conspiracy – a kind of conspiracy of embarassment. In any event, they have emitted their own emissions of the ridiculous notion of using ETHANOL as an ALTERNATIVE FUEL. It takes about 3 gallons of gasoline worth of energy to make a gallon of ethanol. I make whiskey in my garage remember.
But they have quietly replaced the MTBE with ethanol as an oxygenator. It takes a lot of it. And so the ethanol as fuel ruse. It’s a fuel additive and an economically and environmentally expensive one. But it will oxygenate gasoline, and it almost eliminates fuel line freezing and water in the tank. It’s much better than MTBE.
In any event, as best I can tell, the energy content of a gallon of 5.7% ethanol/gasoline, termed reformulated gasoline, is right at 111,836 British Thermal Units (btu) per gallon.
Lets talk about electricity. Electricity is commonly measured in voltage, amperage, and wattage. A volt can be thought of as a pressure, a difference in potential. An ampere is a measurement of the flow of electrons through a conductor. An ohm is a measure of the resistance of the conductor to current flow. A formula, ohms law, defines all three of these in relation to each other.
One volt is the amount of energy required to move one ampere of current through one ohm of resistance.
If you kept the resistance of the conductor at 1 ohm, but increased the voltage to 2 volts, you would get 2 amperes of current. If you then dropped the resistance from 1 ohm to 1/2 ohm, you would have 4 amperes from the same two volts. Their definition is pretty much defined by their relationship.
The basis is actually the number of electrons flowing, like water in a hose. Turn up the pressure, more water comes out. Make the hose bigger (lower resistance) more water comes out. Take away the pressure (voltage) no water. The flow of water is caused by the water pressure and limited by the resistance of the hose to flow.
If we want to measure power, we do so in watts. A watt is defined as 1 ampere of current at one volt of potential.
If we had 1 ampere of current at a 1 volt potential, and we let that run for 60 minutes, we would have consumed a WATT/HOUR or wH of electricity.
To the electric service in our homes, it is typically delivered at 120 volts. And it is measured in kilowatt hours (kWh.). A kilowatt hour is simply a thousand watt hours. And so 120 volts, at a current flow rate of 8.33 amps, for one hour, is equivalent to a kilowatt hour or kWh.
You may have seen a light bulb marked 100 watts. That is how much power it would consume in one hour. And so the typical 100 watt light bulb requires a current of 0.8333 amps at 120 vac.
If you run the bulb for 10 hours, you have consumed 1 kWh of electricity. In Southeast Missouri, they have just raised the summer price of electricity from 7.2 to 8.3 cents per kWh. So you can run a 100 watt bulb for 10 hours for about 8.3 cents on your utility bill. It’s actually remarkably inexpensive when you consider the advantage of having a light.
To convert the energy in a gallon of gasoline, we know that the formula for converting BTUs to kWh is:
1 kWh =3412.3 BTU
1 gallon of gasoline = 111,836 btu = 11,836 / 3412.3 = 32.77 kWh
The government, without ever actually designing a car themselves, have mandated that those who DO manufacture automobiles will achieve a fleet average of 27.5 mpg by 2011.
Barrack Obama has increased those demands to 27.3 mpg. (I know, but we are currently in the Alice and Wonderland world of Barrack-speak, where up is down, down is up, and taxes not paid are actually expenditures out of the pockets of taxpayers. You’ll get used to it after awhile. I think a lot of people actually LIKE it.)
But what kind of mileage do we actually get NOW from internal combustion cars. Well, the latest year where I have all matching figures is 2007. In that year, we had some 255 million cars, and we drove 3,029,822,000,000 miles burning 142,354,380,000 gallons of gasoline = 21.28 mpg
So we can do a kind of a neat thing here, and simply divide the number of kWh in a gallon of gasoline by the number of miles we drive per gallon of gasoline to get the number of kWh per mile or miles per kWh.
1 gallon = 32.77 kWh / 21.28 = 1.54 kWh per mile.
If you like the mileage of a new car better than actual mileage of our existing fleet, we can do it again.
1 gallon = 32.77 kWh / 27.3 = 1.20 kWh per mile.
This is sort of macro. We put gasoline in one end, we get miles out the other, and we know the energy usage per mile in kWh. We don’t care what the efficiency of the engine is, what the losses are in the transmission, or in the wheels. We just have an energy per mile calculation here.
ELECTRIC CARS AND BATTERY STORAGE
The problem with electric cars is that batteries are not nearly as good at storing energy as gasoline is. With 475 lbs of the very latest Lithium Ion Iron Phospate batteries, comprising 64 cells of 3.6 fully charged volts and 90 amp hours each, I can store about 20.736 kWh of electrical energy. Worse, I can’t really use all of it. I can only use about 80% of that (16.588 kWh) before I begin to damage the batteries.
Worse, there are some losses in putting the electricity into the batteries. I use an advanced power factor charger that is about 95% efficient. So I have to use about 17.461 kWh of electricity from the wall to replace that 16.588 kWh of electricity.
That’s the discouraging equivalent of about 0.5 gallons of gasoline. Yes, the entire range of my car is based on its ability to store the usable energy in one half of a gallon of gasoline.
The good news is that it uses an average of 225 wH of electricity per mile from the batteries, or 236 wH of electricity from the wall per mile. That’s right I get over 4 miles per kWhr.
So let’s compare:
Internal combustion car to be developed in 2011 = 1200 wH per mile.
Electric car built by whiskey drinker in garage in 2008 = 236 wH per mile.
Any way you cut it, the electric car is over five times as efficient as the internal combustion engine automobile. Cost per mile?
1 gallon = $2.00 = 27.3 mpg = 7.32 cents per mile.
1 kWh = $0.082 = 4.24 miles = 1.93 cents per mile.
If you drive the national average of 40 miles per day:
1 day = $2.93 in gasoline or $0.77 for electricity
1 week = $20.51 gasoline or $5.39 for electricity
1 month = $87.90 gasoline or $23.10 for electricity
And that’s using a mythical gasoline car that hasn’t been manufactured yet, as mandated by a government that doesn’t know anything about making cars.
I don’t know anything about making cars either. But you can see the video of mine running.
ALL benefits from electric cars have their basis in this matter of effiiency. Electric drive plants in cars are simply more technically elegant, and MUCH more efficient than internal combustion engines, coal fired engines, wood fired engines, and all other known technologies.
When I step on the accelerator of my Porsche eSpeedster, it makes a sound a bit reminiscent of the Warp Drive sound on Star Trek as the Enterprise accelerated through space.
When I step on the accelerator of my Escalade, it sounds a lot like Uncle Jedd’s truck in The Beverly Hillbillies.
Whose show do you want to be on?
WHERE DOES HE GET ALL THESE NUMBERS?
I’d love to tell you that I make them all up. And my detractors would love to tell you that too. Dealing with numerical statistics is a bit like trying to choke a rattlesnake with both of you covered in Wesson Oil – it gets slippery and most people do it badly.
But we traditionally look to goverment studies to compile and present unbiased statistical data. While we all know there are some problems with that assumption, it is a bit better than simply copying what others are saying in forums on the Internet. I call that “typing yourself smart with a keyboard.”
And so in using any number, I like to trace it back to some published, refereed, study subject to public comment from informed individuals. For the purposes of this discussion, I found the U.S. Department of Energy, Energy Information Administration to be the best source regarding energy production, pricing, and consumption. For vehicle, driver, and driving statistics, the best work seems to be done by the U.S. Department of Transportation, National Highway Traffic Safety Administration.
These numbers change! Between the filming of the video, and writing the blog, there are minor inconsistencies in my numbers. Those are generally time zone related. If you talk about 2009 numbers, they are of course different from 2007 numbers or 2008 numbers. When comparing two values, you may only have both for 2007, because one of them isn’t published yet for 2008.
I have gone to some trouble to compile individual links to individual tables in many cases providing you access to the sources as they are published. The gasoline use and pricing, world oil prices, etc. are usually updated monthly or even weekly. In this way, you can go to the table at any time, and get the CURRENT data for YOUR uses.
U.S. Department of Energy – Energy Information Administration
World Crude Oil Prices
Retail Gasoline Prices
Weekly Gas Prices
Daily Gasoline Consumption
Finished barrels per day x 1000 x 42 = gallons
CO2 IN POUNDS PER GALLON GASOLINE 19.564
Annual Retail Sales of Electricity to Consumers
Average Retail Price Electricity
Electricity Generation by Fuel Source
Average Monthly Electricity Consumption
Total CO2 Emissions by Energy Source
CO2 Output from Electricity 1.341 lbs per kWh and declining . Coal only – 2.095 lbs per kWh
Reformulated Gasoline – 5.71% ethanol = 111,836 btu
Convert gallons to kWh. 3412.3 btu per kWh
111,836 / 3412.3 = 32.77 kWhr.
National Highway Traffic Safety Administration
2007 Registered Vehicles 255,747,983
2007 Licensed Drivers 205,741,845
2007 Vehicle Miles Travelled 3,029,822,000,000
2007 Daily Gasoline Consumption = 390,012,000 gallons
2007 Average MPG across 255,747,983 vehicles travelling 3,029,822,000,000 miles burning 142,354,380,000 gallons = 21.28 mpg
Average miles driven per driver each year 14,726
Average miles driven per driver per day 40.34.