People, including the so-called experts, seem to be overlooking a central concept! A battery does not MAKE any electricity, it merely stores it. However much energy or work or power you want to get OUT of a battery, must first get put INTO the battery! In other words, batteries are not FUEL like petroleum or natural gas or coal. They actually have no fuel at all, and are instead STORAGE devices. Hydrogen is actually much the same, as there is no existing supply of hydrogen gas; it must be produced, such as by the electrolysis of water (which requires electricity again, very similar to the battery situation). Where promotional displays show the "simplicity" of plugging the car into house electricity, they neglect to note just how much electricity that car is going to suck out of the house wiring!
We MUST therefore add in the consideration of the "household electricity" that regularly has to get put INTO the batteries! This is noting that vehicles powered by batteries or by hydrogen do NOT actually have any "fuel" on board in a conventional sense. In both cases, OTHER energy sources (specifically electricity) is simply "stored" in the batteries or in the Hydrogen. There is actually such a small amount of storage possible that even Hydrogen-powered vehicles should be thought of as "being essentially weird batteries!"
Point: To get a specific amount of "motive power" from a vehicle, an even larger amount of (electrical) energy had to be used to either charge the batteries or to separate the Hydrogen from water. THERE is where a big hurdle is!
Most people also don't realize the amount of electricity that is needed. I happen to own a golf cart and its charger. After an 18-hole round, it fully charges in around 8 hours. Doesn't sound bad! It draws 9 amps of electricity at 120 volts, or around 1080 watts of electricity. It is true that a kitchen toaster draws more, at around 1500 watts, but imagine a toaster running for eight hours straight! And that is just for a few miles of traveling on a golf course at rather low speeds. Getting the picture?
By the way, people who do not own golf carts do not realize this, but in charging at 1080 watts for 8 hours, I use around 8.7 kWh for a round of golf. Even at ten-cent electricity, that 5-mile drive at low speed around a golf course costs close to a dollar! I realize that a golf-cart, and especially an older one like mine, is not the most efficient of electric vehicles. Still, to see that just to travel a total of 15 miles at the 5 mph of a golf cart, requires around $3 of electricity, I have to say I see a $3 gallon of gasoline a LOT more convenient (and cheap)!
So these comments are based on the realistic expectation of getting the electricity from conventional sources. People who have never done the math often insist that they will buy a few solar cells to provide the electricity or put up a windmill. Admirable thoughts, to be sure. But look at the numbers below, regarding the massive amounts of electricity needed to replace just a single gallon of gasoline! Have you ever seen your electric meter spinning wildly when your central air conditioner kicks in? Imagine that happening constantly for a ten-hour period, just to replace a single gallon of gasoline. And anyone thinks they are going to get THAT MUCH electricity from a few solar cells or a backyard windmill? Interesting! It is logical that the public is not yet familiar with this stuff, but shouldn't the politicians who spend billions of our tax dollars on this stuff know more of the facts? Each Congressman and Senator has a staff of around 400 people (all of whom we pay for); doesn't it seem reasonable that we should expect that at least ONE of all those people would actually look into facts before spending fortunes of our taxpayer money? Shouldn't the people who are actually designing and building them be aware that there is no logical future, except for a brief time as a novelty? Who is doing the thinking? (Sorry for the philosophical tangent, but I never like it when the American public is mislead, which seems to happen all the time these days!) Of course, those companies expect to make many millions of dollars in profits if just the government decides to give them a billion for research! They have great incentive to tremendously exaggerate the facts!
One watt-hour is equal to about 3.412 Btus, so this 450 Btus is the same as around 130 watt-hours, or, for a 14-volt automotive battery, around 10 ampere-hours of actual usable power. The 130 watt-hours is also equal to around 0.18 horsepower for an hour. Now, this might sound like a lot, but remember that the 14,000 Btu in the pound of coal resulted in this 450 Btu that is actually usable in a car, only about 3% overall efficiency! And the other 97% of that energy when the coal was burned all went toward heating that contributes to global warming! Not nearly as attractive as the EV salespeople say!
This is for the situation for batteries. Current technologies regarding producing Hydrogen and then recovering it are actually worse, although they are expected to get comparable to the battery situation some day.
In contrast, a gallon of gasoline has around 126,000 Btu of energy in it, of which a modern car converts around 21% into motive power, so there results around 26,000 Btu of motive power. POINT: Around 60 pounds of coal (with 840,000 Btu of chemical energy in it) must actually get burned to provide the electricity such that a battery-powered car can do the equivalent to a single gallon of gasoline! (60 * 450 = 27,000) (This is a VERY "losing proposition"!)
That amount of electricity that needs to go INTO the batteries in the car (to be equivalent to that ONE gallon of gasoline) is therefore the 1100 Btu per pound of coal divided by that 3.412 times 60 pounds, or around 20,000 watt-hours of electricity. That is a LOT of electricity! Say you will have 10 hours at night for the batteries to recharge. That means that you would have to have 2,000 watts of power constantly being used and feeding the batteries. For the 14 volt circuitry of standard batteries, that would mean that around 140 amperes of charging electricity would constantly be needed. (NOT the 6 amperes of a good battery charger!) (This huge charging current might actually cause the batteries to explode, unless they are a special and more expensive Deep-Discharge type of battery!) (Batteries in golf-carts are generally wired in series to reduce the amount of current needed.)
Even the house wiring involved might be in question! We are talking about a REALLY impressive battery charger, of course, akin to 25 conventional battery chargers used together, which requires that 1820 / 3.412 * 60 or about 32,000 watt-hours of input electricity. Over our ten hours, we are therefore talking about needing 3,200 watts of electricity constantly coming in to supply your battery charger. Your house electrical service is sufficient for this need, but standard house wiring would not be. If at 120 volts, a constant 30 amperes of house electricity would be needed, where normal house circuits are either 15 amp or 20 amp if heavy duty. This probably means you would need the specialized wiring like was installed for your air conditioner, which uses roughly the same amount of electricity, through a special 240 volt wiring made especially for the air conditioner. This means you need around 15 amperes of input power to provide that 3,200 watts at 240 volts, or about 30 amps if it is 120 volts. Herein could be a problem, because most houses were built with 100-ampere electrical service If the A/C is running and this battery charger and some other electrical devices, you might get close to the full capacity of the house wiring! The existing house wiring, and even the transformers up on the utility poles, are barely big enough and could overheat at that constant heavy ten-hour load!
We can use a golf-cart for comparison. Even there, a LOT of electricity is needed to recharge it after a round! Where a normal battery charger can charge at 6 amperes (at 14 volts) for around 80 watts, the charger I got with my golf cart charges at the rate of around 800 watts, ten times as much. During an overnight re-charge of 12 hours, that is around 10,000 watt-hours or 10 kWh of electricity that was provided for the batteries. For a golf-cart that can generate around 4 horsepower, if it is actually running for around two hours of the three hours of a round of golf, that uses up 4 * 746 * 2 or 5900 watt-hours or 5.9 kWh, which is realistically what the efficiency of the batteries, motor and gear train are capable of providing. Golf carts need special "deep-discharge" batteries because they tend to be so tapped out from such a round. Note that the cart only travels maybe 4 miles total, and at just a few miles per hour, and it still needs around 10 kWh (or, we will soon see, a dollar's worth) of electricity) to do that. Now, consider if you want that golf-cart to be far heavier, and to move much faster and much farther. See where that 32 kWh we discussed above is actually very realistic? They don't make gasoline-powered golf-carts, but they would use up around 1/3 gallon of gasoline, or again about a dollar's worth today) for a round of golf.
We haven't even yet considered the cost of all that electricity! When you think about a constant 10-hour long consumption of about as much electricity as your central air conditioner uses, you probably start to get the picture. But say you are in some wonderful location where electricity is still only 10 cents per kilowatt-hour. We are needing to use up 32 kilowatt-hours (to equal the vehicle performance of a single gallon of gasoline, remember), so that is 32 * 10 or $3.20 of electricity added to your house electric bill, for the equivalent to ONE gallon of gasoline! It does not initially APPEAR to cost anything, and the car merrily scoots around on its battery power. But if and when an owner realizes that they also have to spend at least $3.20 in extra electricity for each gallon of gas not used, much of the financial argument goes away!
You are encouraged to do research to confirm what is described above. It is all true. Did you notice the "worst part" of what is described above? I'm not even talking about the fact that you would wind up paying for at least $3.20 of house electricity to replace each $3 gallon of gasoline! In refining a gallon of gasoline, yes, significant energy is used up, although I have never been able to get a reliable figure. But certainly well under 840,000 Btu of refining energy is required to form the gallon (126,000 Btu) of gasoline. Replace all cars with battery-powered vehicles, and we then would NEED to burn 60 pounds of coal or use 840,000 Btu of coal (or nuclear) chemical energy to produce the equivalent effect of every gallon of gasoline. This is worse, regarding resource energy wastage, than the vehicles that are currently on the roads! (Yes, the energy is used up in a distant place, and maybe it seems possible to be able to be ignored, but that is still a really bad idea!) And virtually everything that does not contribute to the "motive power" winds up as wasted heat energy.
When those 60 pounds of coal were burned to create the needed electricity to duplicate the benefits of one gallon of gasoline, carbon dioxide is also released into the atmosphere. The coal is around 75% of bituminous coal, or 45 pounds of that. It is fairly simple to determine the amount of carbon dioxide that is created when it is oxidized. The amounts of carbon and oxygen have to be in a molal relationship of one to two. That means the weight relationship has to be 12 (the atomic weight of carbon) to (12 + 16 + 16 or 44) (the atomic weight of the molecule of CO2. This means that 44/12 or 3.67 times the weight of carbon dioxide is created, or in this case, 165 pounds, of carbon-dioxide would get released in this process. When a gallon of gasoline is burned in an automobile, it is less. A gallon of gasoline weights around 6 pounds, and it is about 83% carbon. That means that it contains nearly exactly 5 pounds of carbon in the gallon. Again using the 3.67 multiplier, we can see that only around 18 pounds of carbon-dioxide is released.
This means that global warming then would occur around 7 times as fast as now! (840,000 / 126,000 [heat]) or (165 / 18 [CO2]). If millions of people started driving battery-powered or Hydrogen-powered vehicles, it would therefore be a far WORSE environmental disaster than now, causing global warming to become even faster than it already is!
Isn't that something?
Something that is promoted as attractive as battery-powered cars, or Hydrogen-powered vehicles, being the worst imaginable long-term effect on the climate? It is because the people who want to SELL such things never emphasize such "downsides" and politicians will jump on board anything that the public sees as "interesting"! So our government will certainly pour billions of our dollars into research on battery-powered vehicles (and then Hydrogen-powered vehicles), but it will eventually be seen as a VERY bad idea. I hope you saw why the same reasoning applies to Hydrogen, as the electricity needed to dissociate water to provide the Hydrogen has the same source!
It does not appear that reporters yet know enough to ask about how long the battery charging takes or how much electricity is needed.
Yes, battery technology figures to continue to improve in the future. So do Fuel-Cells, especially since our Government is spending many billions of our tax dollars to finance that research! But since batteries (or Fuel-cells) do not actually HAVE any power of their own, you really wind up dealing with the issue of how many hundred amperes of electricity you can charge the batteries with. In upcoming years, it seems certain that the proponents who keep insisting on battery-powered cars will move to higher voltage batteries, mostly so they can avoid having to use inch-thick wires to charge them! So 100-volt or even 1000-volt batteries may be presented as some "breakthrough" in the future. But it won't reduce the load on your house wiring system or on your pocketbook! It would only be to simplify a minor problem regarding the thickness of needed wires.
But the people who intend to sell millions of such vehicles must already be aware that owners will not enjoy paying an extra $3.20 or more in electricity to replace every $3 gallon of gasoline, especially when it also (indirectly) causes such massive increases in atmospheric heating, carbon-dioxide, global warming, pollution, etc. Yes, early owners will not know of such things, but they are certainly going to quickly find out! How could millions of such vehicles then ever get sold? People talk, especially when they have complaints! It seems a real mystery.
Unfortunately, modern science and technology probably cannot provide those solutions that people will expect and need. At some point, the public will finally realize that the petroleum and natural gas that we are using up at wild rates really DID take hundreds of millions of years to form, collecting and storing the Sun's energy from all those years in those fuels. We are currently using up those fossil fuels at nearly a MILLION TIMES as fast as Nature can replace them!
In case you are not familiar with the numbers, each year, we Americans use up over 20,000,000,000,000 cubic feet of natural gas, just for energy (and even more gets used to make plastic materials such as garbage bags). We Americans also use up over 1,800,000,000,000 pounds of petroleum every year. (I guess I could be generous and use the smaller number of 280,000,000,000 gallons, or 7,000,000,000 barrels of crude oil.) Of course, we also use up massive amounts of petroleum to make nearly everything that is plastic, along with countless other products! I have to think that, 30 years from now, when the world has virtually no petroleum or natural gas left, people will be astounded that WE were so stupid as to make disposable plastic wrappers for every single product, which all immediately gets thrown away! WE are not going to come across as very intelligent, just 30 years from now!
Yes, America has a lot of coal, the largest known supplies anywhere in the world! So we might have the chance to maintain industry and business, as long as we are all willing to deal with the coal-fired factories, trains, and home furnaces. But there does NOT figure to be anything to replace the oil and gas that we are merrily using up (as though we have infinite sources).
Actually, I suspect that the ONLY real hope of vehicles beyond around 20 years from now is that they somehow run on coal! NOT like the early Stanley Steamer cars, but something sophisticated. Maybe some pyrolyzation process rather than actual burning. But all research is now in batteries and hydrogen, as they have captured the public's and Congress' interest. And in using up at least 1/5 of America's food crop production to provide corn to be converted into Methanol, an even more stupid idea! I really think that some day, research into somehow using coal as vehicle fuel will become necessary!
In a peculiar aspect of God's sense of humor (I think), even though we humans do not have the self-restraint to control or stop Global Warming, and as people will certainly be killing each other for the very last barrels of oil, the "forever supplies" of those fuels are all going to run out within just one or two decades. The politicians will actually be saved from having to make such "hard decisions" (which might reduce the profits of their friends who run the giant companies). Instead, they will have to face far worse decisions, as to how to keep people from freezing in winter, and how to finance farm production to feed everyone, without any fuels or chemical fertilizers! And how to deal with food shortages and far higher food prices in grocery stores directly resulting from these peculiar directions of driving the American future.
In only ten years, it seems possible that a gallon of gasoline might cost $100 or even $1000. How much driving do you expect to do then?
The "Ethanol adventuare" of using 1/5 of the total farm crop production of 2006 for conversion to Ethanol, which provided only around 2% of the vehicle fuels we used in 2006, is simply endangering our near-term food supplies. News reports are already (April 2007) discussing higher milk, bread, beef, and many other food prices in our grocery stores, as a result of the massive focus on producing Ethanol. But some weather problem is bound to occur. Where we used to have massive over-production of nearly all crops, our government has planted the seeds of a true food-supply disaster, which could happen any year now. In 2008, it is expected that the amount of America's total crop production which will go to making Ethanol will be 1/3 of everything grown! It is as if we are totally crazy, or that we do not even give any thought to what might be a consequence next week or next month or next year! It really is amazing!
The specific point of this Essay, though, is smaller! It is merely to show that the Battery-powered or Hybrid cars and Hydrogen-powered vehicles that all Americans are already pinning their futures on, are certainly going to fall far short of expectations, because of a simple and basic assumption which happens to be wrong! The Hydrogen or the electricity to charge batteries is NOT a natural resource but instead has to be somehow made, and in both cases, they are energy intensive processes. Isaac Newton described the Conservation of Energy. Whatever amount of energy you have to start with, you cannot end up with more than that, and in fact, due to many losses, you ALWAYS wind up with less than you started with, with the other part generally becoming wasted heat energy.
SO, when you are all excited about going to a car dealership to buy a battery-powered electric car, or a Hydrogen-powered fuel-cell vehicle (or a Hybrid), try to remember these things! The salesperson is not going to tell them to you!
The advertising presentation of the popular Hybrid cars is rather misleading. Their performance is not what American drivers have come to expect from all the hype, and their consumption of electricity (and therefore increases in electric bills) comes as a great surprise to owners. Fortunately, they can still just buy gasoline, and drive an under-powered car, to avoid looking like having gotten "took!" Not even counting the fact that automotive batteries tend to only last a few years, so owners have THAT cost to look forward to as well.
Another stupid-brilliant idea is manufacturing and selling vehicles that will only run on what is called E-85, meaning 85% Ethanol fuel. Again, if there were unlimited supplies of Ethanol, that might make sense. But when America uses up one-fifth of all its farm crop production to provide only around 2% of the amount of fuel that American drivers use up each year, it indicates scary thinking, or lack thereof. By the time the auto manufacturers fully perfect cars that they will be able to sell to run on E-85, and by the time there are enough service stations that even carry E-85 for such drivers, it is certain that some overwhelming crisis will occur (probably in a weather problem and severe shortages of food for Americans), where sanity might again briefly appear and the massive effort toward Ethanol will very suddenly end. For the few people who may wind up buying E-85 vehicles, they will merely wind up having something that might someday go into a museum, something like what happened to the Edsel automobile!
It is really sad that even supposed Regulatory Agencies of the Government have participated in this hype. A car that has a conventional engine, is likely to get the gas mileage that has long been known, somewhat UNDER what the EPA estimates say! But regarding Hybrids, they seem to have just considered the battery-powered miles to be "free" (because no gasoline is used) and they have listed some Hybrids as having 60 miles per gallon fuel efficiency. That is technically true, if you totally ignore the cost of all that electricity needed as calculated above! If they wanted to go even farther, they could set up a really short test procedure where ONLY the batteries were even used, and then they could let the manufacturers advertise "1000 MPG" or "1,000,000 MPG" or more! The person's home electric bill would go off the charts, but they do not seem to see any reason to consider that expense!
Unfortunately, they clearly have done the common "spin" that spokespeople seem to all use today to deceive the public. THAT is really sad. Especially since this particular product actually can probably provide pretty decent performance. Why is it always seen as necessary to be deceptive today?
Using information from their own web-site:
First, there is a small-print, very faint, and very hard to read Disclaimer at the bottom of their web-pages that notes that their vehicles have not yet passed government safety testing, and they say that their specifications might change as a result of that. (By the way, since they have not yet passed government safety tests, they are not yet street legal in any State and could therefore not yet be licensed!)
However that information can be mathematically Integrated to determine the actual acceleration, when one also knows the vehicle weight. The web-site gives the vehicle total weight as being 2,500 pounds.
We can first calculate some more things that DO agree with their claims, to show that at least those claims are credible. Let's consider their vehicle top speed. The streamlined shape of the vehicle certainly has a Coefficient of Drag of around 0.3. The total frontal area of the vehicle is around 18 square feet. The claim is that the top speed is 120 mph, which is the same as 176 feet/second. We can simply calculate the total aerodynamic drag from this information (and the average density of air (around one slug mass per 420 cubic feet). It is 0.3 * 18 * 1762 / 420 or around 398 pounds of aerodynamic drag. There is also tire drag which is around another 45 pounds for that vehicle weight. The total vehicle drag is therefore around 443 pounds (at that speed). If we just multiply this drag force by the velocity (176) and divide by 550 to convert it to horsepower, we get 142 actual horsepower as being needed. Given that they indicate that their motor efficiency is around 85% to 90%, and there are mechanical efficiencies of the tires and wheels, this is in fairly good agreement with the roughly 180 horsepower claimed available from their graph at 13,000 rpm (times that efficiency factor). This confirms that the expected top speed is likely to be around what they claim. Fine here.
Let's look at their acceleration claim, of zero-to-sixty in around four seconds (which is impressively fast). They certainly did that demonstration in what they call first gear, which has a total gear ratio (and therefore torque multiplication) of 14.3. It is easy to see from this ratio that the motor would be turning at close to its maximum revs at 60 mph, so first gear might have been provided simply to be able to show off with this impressive zero-to-sixty acceleration. In any case, they provide a torque curve for their motor, which suggests that it would produce an average of around 160 ft-lbs of torque through this whole sequence. Multiplying this by the total gear ratio gives around 2300 ft-lb of torque, which becomes around 1900 pounds of thrust after considering the various mechanical losses. We have the aerodynamic drag of around 40 pounds average and the tire drag of another 40 pounds to subtract, so we have around 1820 net pounds of thrust available for acceleration. We divide this by the vehicle weight of 2500 pounds to get 0.73 to get the g-force acceleration. This is roughly 16 mph/second acceleration, or around four seconds to get from zero to sixty. This confirms that in their first gear, the acceleration they describe is realistic.
There is actually another factor involved here, regarding a flywheel effect of the motor rotor itself having to accelerate as well. Without knowing the Rotational Inertia (I) of that armature and rotor, it is not possible to calculate the reduction which must occur in this vehicle acceleration, but it must certainly be slightly less than calculated above. In other words, slightly over 4 seconds for zero-to-sixty is then realistic.
The acceleration claim also tells us something else about the Tesla! It has absolutely nothing to do with the matters at hand here, but it still seems worth noting. The acceleration they describe, of zero-to-sixty-in-around-four-seconds, means that the average acceleration is therefore around 0.73G (as indicated above.) On a dry and clean roadway, the best static coefficient of friction is around 1.0. This means that the 1820 pounds of thrust for acceleration must necessarily require roughly that amount of weight on the driving wheels, or around 1800 pounds. If one axle of a 2,500 pound car has 1,800 pounds on it, the other axle has only 700 pounds. This would be an incredibly dangerous vehicle to drive on any curvy roads, if it has that extreme of a weight-distribution. For an actual Licensed highway vehicle, it could not possibly pass road safety tests with such an extreme weight-distribution. Maybe it will be modified before any get onto the road. Which also would mean that the acceleration performance would necessarily have to be slightly less. (It is interesting all the things that Physics can tell us about any mechanism!) (They might also have used extremely sticky tires for such runs, where less vehicle weight would then have to be on the driving axle.)
So the actual mechanical performance of their car is impressive. Again, much of that is because it is a rather small car that is very aerodynamic. Still, impressive.
If we do a drag analysis for 60 mph (similar to the 120 mph calculations shown above), we can see that the total vehicle drag is around 100 pounds aero plus 45 pounds tires or 145 pounds total. As above, this calculates to 23 horsepower being constantly needed. To drive 100 miles at that (constant) speed takes 1.66 hours, or 38.7 horsepower-hours of energy. This is the same as around 29 kilowatt-hours of energy. However, getting electricity out of batteries is not a perfectly efficient process, and they acknowledge that their motor ranges from 90% to 80% efficient. To charge this amount in a two hour period therefore requires charging at a rate of over 15,000 watts. Their charger circuits cannot have perfect efficiency so certainly around 18,000 watts of household electricity would be needed.
If this were simply "plugged in" to a standard outlet, it would require 160 amperes at 110 volts! But standard household outlets are only rated at 15 amperes and even heavy duty ones are only rated at 20 amperes! They are talking about so much electricity that at least 6 or 8 standard outlets would be needed to provide enough power! In fact, the very special wiring that was put in your house for your central air conditioner might not be enough to provide the 80 amperes at 220 volts that would apparently be needed to charge a Tesla in the two hours as described.
In this area, their promotion is extremely misleading. It cannot simply be plugged in as they imply. Very heavy duty special house wiring is required to be able to do that massive charging.
From generally known evidence regarding charging batteries extremely fast like that, the internal structure of the battery often suffers and the battery lifetime might therefore suffer. They don't mention what the cost of replacing their battery pack is, but it certainly would be expensive. A moderately similar experimental electric car recently shown to the press has such an exotic battery pack that replacing it would cost over $300,000! Obviously, the Tesla battery pack is not that exotic or expensive, but it clearly would be a significant expense if and when it needs to be replaced.
A Tesla spokesperson was on TV talking about this after the above text was written. The battery pack would apparently currently cost around $9,000 to replace, but she pointed out that battery technology is constantly improving and that cost might drop. She also said that the battery pack lifetime is currently at least two years. It was refreshing to see an honest and open answer to such a question.
Similarly, as discussed much earlier about battery-powered vehicles, the COST of that electricity can be significant. Using Tesla's numbers and this analysis, we are talking about needing to charge around 29 kWh actually into the batteries (in those two hours, after that 100-mile drive). And that due to the efficiencies of chargers, this necessarily requires at least 35 kWh of actual house electricity. If electricity is charged at conventional rates of around 10 cents per kWh, this is around $3.50 for the electricity for that hundred miles. Granted that this is less than the cost of gasoline in any vehicle to go that distance, but it is still considerably more (around triple) what they claim the electricity cost would be.
Therefore, the Tesla, which is being promoted as being TOTALLY green, in reality causes at least four times as much carbon dioxide to be sent into the atmosphere than if it simply had a gasoline engine in it! Otherwise, it seems to be a rather attractive idea! Impressive acceleration and top speed and decent range. Only the immensity of the charging process, and the consequences of that are such terrible necessary requirements. Like discussed above, NO battery-powered vehicle has any of its own energy, and it requires to get all that energy from some different power source, in this case, house electricity. Even if Tesla is right that electric power companies would give tremendous rate reductions for the electricity because it was nearly all used at night, that cannot stop the requirement that the (remote) electric powerplant necessarily has to cause the release of that 240 pounds of carbon dioxide into the atmosphere from the coal burned.
By the way, many of the advantages of the Tesla have to do with its tiny size and very aerodynamic shape. Any car that had a more conventional size and shape would require a far, far bigger motor and far, far more electricity and battery size and capacity. If that car had a similar horsepower gasoline engine in it, the acceleration and top speed would be comparable, and the gas mileage would be impressive. The two main differences would be that the range would be easily 500 miles (with maybe an 8 gallon gas tank) and that the weight of the vehicle would be more engine instead of the same total weight of batteries.
The Tesla information is very vague about its battery system. Obviously, they are protective about their own unique advances. But we have calculated here that to charge at the rate they describe, there must be around 15,000 watts of charging that is done. Their literature mentions that their charger works at 70 amperes. This seems to imply that their batteries must be a series battery pack, because these numbers imply an effective battery voltage of around 200 volts. Such a high voltage (instead of conventional cars 12-volt batteries) makes a lot of sense in permitting far thinner wires to be used inside the car and in the charger and connectors, although even 70 amperes requires fairly stout wiring.
I suspect that you will NEVER see any reference to a Tesla being driven at night (because all those light bulbs use up a LOT of electrical power which is therefore taken away from being available for the electric motor); nor being driven with the (included) air conditioning operating. Automotive air conditioning normally takes around 6 horsepower, so the 23 required horsepower for that 60 mph highway driving would become 29 horsepower. This would both reduce the range by 25% and increase the charging time by 30% (as well as increasing the carbon dioxide given off at that distant electric powerplant by another 30%).
I realize that there are many optimistic people who simply say that the detriment of burning coal (which currently provides around 51% of all the electricity used in the US) could be eliminated by CHOOSING to use nuclear powered powerplant electricity instead. First, you don't have any way of deciding where your electricity is made, but second, few people seem to realize that the US already mined essentially all of its Uranium some years ago, and all of the 39 Uranium mines in the US have been closed and completely shut down for some years as a result. We import virtually all the Uranium used in American powerplants! No one seems to know that! (Only a very small percentage is actually from US sources, and that happens to be from the decommissioning of nuclear weapons, for just a few percent.)
There are certainly other even more optimistic people who simply assume that photovoltaic cells (solar cells or PV) can supply the needed electricity. First, such electricity is only available during the daytime when the sun is shining (and Tesla describes recharging through the night). But people who want to believe that have no clue as to how many PV cells would be needed! We have calculated above that around 18,000 watts of electricity would be needed to do the charging that Tesla describes. In a different energy-related page in this Domain, we present the Physics of PV devices, where around 7 watts per square foot of PV cells is possible during bright sunlight around noon. Even under those perfect conditions (noon, no clouds) around 2600 square feet of PV cells would be required. That web-page presentation describes that it is common that around $150 in total installed cost is involved for each square foot of PV cells. This would mean that around $390,000 worth of solar cell installation would likely be required to provide the amount of electricity the Tesla describes being needed! I suppose that if you can afford a $92,000 electric car, you may also be able to afford $390,000 of solar cells to charge it! But keep in mind that this is for NO CLOUDS and only around noon! Even more solar cells would be required for nearly any real climate!
See the problems? Even though that Tesla can show impressive acceleration and top speed, and decent range, and even though it is such a tiny car that the amount of electricity used is only around three cents per mile (while even at 50 mpg with a small gasoline engine, the gasoline would currently cost around 6 cents per mile), the bottom line regarding why it is even supposed to be desirable is allegedly how GREEN it is. But the reality is that some distant electric powerplant has to pump at least four times as much carbon dioxide into the atmosphere than if the vehicle had simply had a smaller gasoline engine.
The single point for which it is sold is therefore (sadly) totally invalid. It may be fortunate that the only people who will be able to buy a $92,000 car probably have plenty of money available! However, I suppose that most of them will not even be bothered by the need for maybe an extra thousand dollars of specialized heavy duty wiring being installed in their house to be able to charge the Tesla. And their likely lifestyles are such that they will never even notice if their electric bills happen to get a lot higher because of charging their Tesla.
I see it as a wonderful "novelty" for rich people to play with. For the practical reasons presented in this article, it seems inconceivable that "normal" people will ever benefit from such battery-powered vehicles or even use them (except for golf carts and electric wheelchairs).
It would be nice to be able to say that there was any chance whatever that this technology could advance to actually becoming useful some day. But Tesla even notes that they have already accomplished impressive efficiencies of around 90% and 80% at peak use. What a Tesla has is probably about as good as it will ever be able to get. And if it were not for the horrible requirement that some distant electric powerplant has to release massive amounts of carbon dioxide into the atmosphere to be able to charge the Tesla, it actually could be a useful product. But when a product is SOLD and PROMOTED as being totally green, while the actual reality is entirely opposite, it then turns out to be a really terrible idea!
The truly sad thing is that if millions of people could some day drive vehicles that are electric powered like the Tesla, Global Warming would necessary become far worse as a direct result.
The Earth's Rotation as a Source for Energy
Waste Nuclear Power For Making Electricity And Heat?
The Physics of Efficiency In Electric Power Plants
Individual Ways of Reducing Your Energy Usage
Methods of Storing Energy for Later
How Much Energy Comes From the Sun? And Why is there Global Warming?
How does the Sun create so much energy?
Inventions Which Might Help Deal With Coming Energy Catastrophes
An Invention to Efficiently Make Electricity from Solar
Enormous Heating of the Atmosphere by the Alaska Pipeline
Air Conditioning without Huge Electric Bills and without Freon
A Method of Storing Summer Heat to (Nearly) Entirely Heat a House all Winter
An Extremely Highly-Efficient (and Fast, 200.0 mph) Transportation System for People and Products
The Sophisticated Woodstove I Invented in 1973
The Physics of Wood as a Heating Fuel
Why is the North Pole Heating Faster than the rest of the Earth?
A Possible way to greatly reduce Aerodynamic Drag of Airplanes
( http://mb-soft.com/public/index.html )
C Johnson, Physicist, Physics Degree from Univ of Chicago