http://www.wolframalpha.com/input/?i=1+hour+*+100km%2Fh+%2F+...
There are huge variations in how much vehicles consume on a per-passenger basis. And there's no reason that alternative energy / electric must approach the energy density of petroleum - that assumption only holds if you're assuming that a vehicle must carry all of its power with it (and many existing ones don't.) Looks at catenary-powered buses commonly in use in many metro areas - low energy consumption per passenger, off-vehicle power source. I'm not saying they're a solution, but just that you can't get to a good new solution by assuming it has to look like the current dominant option.
But do we really need to go 60 mph? Vehicles seem to be optimized for less-common use cases (e.g. 5 people in the car traveling 60 mph) instead of their more common uses (e.g. one person commuting at 30-40 mph). I, for one, would like to see smaller vehicles - NOT SmartCars and the like but an actual rethinking of the car that would be optimized for the single person commute.
If the chart on the website is to be believed, gasoline is second only to diesel in terms of energy density of viable fuel sources.
The power consumption of a vehicle has little to do with gasoline, though there is an important consideration for efficiency in terms of converting the fuel to linear motion (internal combustion engine and drivetrain).
Vehicles powered by any method are incredibly power consuming. Your average vehicle weighs more than 10x the weight of a single passenger, or in many cases 10x the weight of 2 pax.
Public transportation (impractical in the suburbs), or self-navigating vehicles (more practical) would seem to be a key in reducing the vehicle:occupant weight ratio and increasing overall efficiency.
Misleading industry puff piece. The question isn't how much would it take but rather how much does it take.
Petrochemical / coal, fossil fuels in general are already generating our power at increasing cost in terms of the raw materials, processing (more difficult processing of oil sands, frakking, etc.)
Give me modern nuclear combined with alternatives like increasingly cheap solar.
Of course, at this moment the US government is mulling tariffs on chinese solar panels since they are too cheap. Evidently the free market is awesome except when it results in cheap products that threaten an established industry.
Er...
I'm talking about the fundamental difference between a battery of any variety (chemical, flywheel, etc.) and petrochemical energy sources.
The article compares energy density of gasoline and other energy sources with "electric". It's a poor comparison. These are different categories. One is an energy source which is also a storage medium (single use), the other is a pure storage medium.
China actively and heavily subsidizes its solar industry. That is hardly the result of a free market.
I'd say the same for modern nuclear.
[1]http://en.wikipedia.org/wiki/Internal_combustion_engine#Ener...
Given those rough figures, even when powered by oil stations battery-powered cars can theoretically be more efficient at using oil than a car with an ICE.
[1]http://en.wikipedia.org/wiki/Oil_power_plant#Heat_into_mecha...
[2] http://en.wikipedia.org/wiki/Electric_car#Energy_efficiency
If we assume the transmission lines are 98% efficient, the charger is 95% efficient and the battery is 90% efficient, the motor controller is 95% efficient, and the motor is 95% efficient (drive efficiency of 90% instead of 80% of the parent quote)...
0.33 * 0.98 * 0.95 * 0.90 * 0.95 * 0.95 = 25% efficient, with efficiency numbers somewhere between "best case" and "optimistic". ICE in an efficient car is competitive with that. A hybrid will beat that.
[0] How Stuff Works estimate: http://auto.howstuffworks.com/fuel-efficiency/alternative-fu...
[1] Nobody knows for sure what the transmission line (including step-up and step-down transformers) is in actual practice. Note the Wikipedia article says "efficiency" several times, but never pins an estimate onto it: http://en.wikipedia.org/wiki/Electric_power_transmission
click
"Yup."
As others pointed out, you have to divide by about 5 to 7 to account for the losses in going from gas to available power at the wheels. Even then, gas wins against batteries by about a factor of two. And batteries are only getting better very slowly.
On the other hand, the cost per mile for an electric car is less than half the cost per mile for a gas powered vehicle. And the car is actually simpler.
The economics will favor electric cars soon because of this. The car won't be able to go 300 miles in one trip though. But If we have charging infrastructure in enough places, almost all trips can be satisfied with 100 mile range or less.
For a big road trip, you'll just rent a gas car, similar to how today you rent a U-Haul truck for that odd occasion where you have to move a huge pile of stuff.
The original article isn't interesting. You may as well say that your mouse has enough energy to recharge your iphone for 10 years, provided we found a way to convert the mass into energy.
A mid-range home EV charger peaks out at about 20kW.
By contrast, the energy flux of a gas pump is around 20MW.
You might be confused because a typical battery in an EV is around 20+kWh, which is why it takes a few hours for the wall charger to charge it!
For comparison, a 20kW load would draw 83A at 240V. A smallish pole mounted utility transformer may supply 20kW.
Of course, none of it detracts from your point that petroleum is very energy dense :)
So a 7.2kW charger is about 2500 times slower than a fast gas pump.
Even slow gas pump (say 10MW), used with a conventional engine (say 20% efficient), compared with a state-of-the-art fast charger (say 200kW) would still be ten times as fast in a miles-per-hour contest.
EVs make up for this somewhat by being able to charge anywhere that has a decent supply of electricity for hours at a time, but it still shows you what they're up against.
Density can actually be per-mass or per-volume. Per mass hydrogen is pretty attractive.
http://en.wikipedia.org/wiki/Energy_density
Now we just need an efficient, safe and clean way to turn gasoline into electricity and problem solved ;-) right ?
A bucket of gasoline contains more hydrogen than a bucket of liquid hydrogen, and you can actually keep the gasoline in the bucket.
Hydrogen is awesome as an energy source if you look at the combustion formula and the per-mass energy density. In all other aspects it's a horrible, horrible, horrible fuel. :-)
If you believe this calculator, it takes 2419kJ to go 20km while cycling. (http://www.tribology-abc.com/calculators/cycling.htm)
A gallon of gas contains about 114,000BTU (http://en.wikipedia.org/wiki/Gasoline_gallon_equivalent). Note that the Exxon diagram is 'per fillup' not per gallon.
So... http://www.wolframalpha.com/input/?i=%281%2F%28%282419kJ%2F2... yields 617MPG while biking.
It's approximate, but good to know that biking is roughly an order of magnitude more efficient than cars.
[Source: Dad, hobby-bicyclist/mechanic]
It's like asking "how much gas does it take to run the LCD screen on my car stereo?", comparing it to how much electricity a mansion uses and concluding that gas is the old fuddy duddy stick in the mud holding back progress.
http://en.wikipedia.org/wiki/IC_engine
Wikipedia again: "Typical thermal efficiency for electrical generators in the industry is around 33% for coal and oil-fired plants, and up to 50% for combined-cycle gas-fired plants."
ETA: Point out an oil company's dishonesty, get downvoted. Only on HN.
Environmental cost? I'll grant you that accidents involving rigs and shipping are spectacular and locally devastating when they happen, but what about the pros of a cheap and relatively easy fuel, it has saved millions of lives.
To give some balance what about farming? Farming has devastated the environment on a global scale. It's subsidised to the teeth too...
"Profit generating mess" is hyperbole, but you can have it since I went for whataboutery.
- oil company predicts oil will still be used in (a lot of) years
- oil company realizes that a) there is an incredible amount of energy in oil and b) the most efficient machines available use only small percentages of that energy
Dumping the remaining energy as heat in a climate-change world. Great!
Obviously, the contribution to global temperature increases due to the literal heat dissipation of engines is extremely, extremely negligible. Petroleum can cause changes to global temperatures through the release of carbon, which changes the Earth's insulation, but no through actual heat.
If you want to get really thorough about extracting all of the energy in a gallon of gasoline, you could power a US household for 7.5 million years.
[1] http://www.wolframalpha.com/input/?i=1+%2F+20+%2F+365+gallon...
Once cars have "iPhone" batteries, gasoline cars will go away. A Nissan Leaf is rated for 3x the energy efficiency of a comparable car. I doubt people will mind giving up gasoline fumes and filling stations. (33khw in gallon of gasoline versus 3.5khw/mile in a Leaf.)
I can pedal a bike at 200W for an hour. Isn't this enough to charge 80 iPhones? How is this a useful comparison?
I think using gasoline is fine for now. I'm not a hard line environmentalist or anything. At the same time I don't get how these companies can justify this kind of propaganda. Yes, it is their duty to their investors to make as much money as possible but it's no secret that one day we won't have enough oil to go around. I don't get it, logic dictates that you'd sell gasoline for the time being but at the same time you'd be pumping huge amounts of money into research and development of alternative technologies. The oil company that brings the best alternative to market first has the most to gain in the long term. Articles like this are so blatantly disingenuous and short sighted it makes me want to puke.
