"I bet they're going to talk about the total amount of energy in a gallon of gas, without mentioning anything about how that's translated to electrity, and how much of the energy is lost in the process"
What do you expect? The author wrote the study for Exxon Mobil.
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.
Well how much energy is lost? 50%? 80%? Assuming it is 50%, then the answer would be you could charge the iPhone for 10 years instead of 20 years. Still interesting.
Overwhelmingly most of it. Most generators run on diesel and not gasoline, and I gave up trying to figure gallons per KwH after a few minutes of googling. But you're talking about converting heat to mechanical energy with a ton of lossage, and then mechanical to electricity with a ton more lossage.
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.
But the way to turn fuel into energy already exists, even if it is inefficient. OK, you could also burn my mouse, but it would probably be even less efficient...
I still think it makes a strong point for telecommuting.
Key takeaway: Vehicles powered by petroleum fuels are incredibly power consuming. Driving a car a single hour on a highway consumes as much energy as an iPhone does in about 46 years.
All vehicles are incredibly power consuming (compared to iPods) and there are basic limits to improving this. If you want a vehicle that is large enough to hold a human and can push air out of the way at 60 mph, it's going to take a lot of energy. Driving habits, aerodynamics, and size can change this usage by a factor of order unity, but they can't do it by orders of magnitude. Thus, alternative energy sources must approach the energy density of petroleum if they are to be competitive.
Thinking like this is what prevents real innovation. All of these statements seem to be common sense, but they're all individually false when you dig below the surface.
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.
> Thinking like this is what prevents real innovation.
On the contrary, thinking like this is what spurs real innovation.
Look how many comments in this thread are about trivial changes like cutting the size of cars by half, or doubling fuel mileage, or cutting speeds in half. Likewise, think how many people assume you can make an appreciable change in global warming by recycling a bit more, driving a bit less, or buying the right brand of milk. What these all have in common is that they seem much easier to implement and, crucially, they make you feel like you're doing something.
In fact, we need major innovations. The point of my back-of-the-envelope argument isn't to assume that new solutions look like old ones. (I mean, I take it as obvious that, e.g., if we have ways to wireless beam energy to moving cars then this is an awesome solution and brilliantly defeats my argument.) The point of the argument is that you can't make minor changes; they have to be ambitious.
What I mainly took issue with was the conclusion: "Thus, alternative energy sources must approach the energy density of petroleum if they are to be competitive."
That seems utterly faulty to me, as I pointed out - there are multiple ways to solve the problem, none of which would necessarily require increasing the energy density of alternative power sources. All you have to do is reduce the amount of energy that needs to be stored in the vehicle, either by reducing use or required range between charges.
My bad, poor choice of words. Of course it is not the fact that it is fueled by petroleum that contributes most to the five+ orders of magnitude in difference in power consumption.
> If you want a vehicle that is large enough to hold a human and can push air out of the way at 60 mph
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.
They're called bicycles, motorcycles, buses, and trains. The first two give up protection from the elements, the second two give up independence. Keeping both the constraints nets you a single-person car-like device with say a 30hp motor - somewhat more efficient, but not enough to drive adoption.
Gasoline (and energy in general) just isn't expensive enough for any of the alternatives to be taken seriously (infrastructure-wise) anywhere but dense urban areas.
My commute is mostly highway, at 65 Mph. The most common use case for my vehicle is thus very different from yours. Your vehicle would add extra time to my commute, and would not be useful for me in any situations where I am travelling long distance (120 km/h is the norm in Europe, that is about 75 Mph) I want to go faster, I don't want my trip to take even longer.
I suppose this depends on where you live, but going above 60mph is normal usage for me. In fact, a minimum speed limit of 45mph on freeways is fairly common (unless you can't due to traffic, of course).
On the other hand, I've never been able to drive above 45 mph on my normal commute, I'm only able to do so when I go on holidays.
Some cities are just not planned for cars (European cities like Vienna for example, where you cannot enter the downtown, or some South American cities like Montevideo).
I used to have a Maruti car and it was plenty for 99% of the time, and I'd buy a low-range electric/hydrogen/whatever car if it was cheap and offered me a better mileage equivalent.
Fuel economy can only improve by a factor of order unity (typically, less than 2) by changing speeds. And as I said, vehicle size is also incapable of reaching the orders of magnitude needed.
When visiting family in SC and FL I usually gag when I see people driving around (even running errands) in golf carts. Maybe I should give them a high-five instead.
No, people need to realize that cars weighing in at 3+ tons with capacity for 5+ passengers to transport a single person to work are not viable. Because the "give us something we can hotswap for oil" attitude is obviously going nowhere.
My current car weighs 0.8 tons and has a 50 miles per gallon consumption (Renault Twingo), and the one I had before weighed 0.7 tons and could archieve up to 115 miles per gallon (according to an article) though something like 60 or 70 mpg was more normal.
I suspect the problem is partly American attitude towards small cars. Japanese, Europeans and South Americans have much more efficient cars for daily commute.
You really need to specify whether that 50 miles per gallon is in US or UK gallons ...
US gallon is 3.78 Liters, UK gallon is 4.54 Liters.
US gallons: 50 MPG = 21.26 km/liter
UK gallons: 50 MPG = 17.70 km/liter
50 MPG (UK) is 41.6 MPG (US).
In my Hyundai Accent (Korean) I get 34 - 36 MPG (US) depending on how I drive it. It is not nearly as efficient as a Renault Twingo or my grandma's Toyota Aigo (awesome little car).
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.
Oil power stations are around 33% efficient[1]. Electric drives have up to 80% efficiency[2].
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.
You also need to account for the transmission line efficiency[1], the charger efficiency (typically 90-95%), and battery efficiency[2] (80-90%).
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.
[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
Since they don't really follow through on the original question: the article implies it will take ~137 micro gallons to charge an iphone. The size of the fuel would be slightly inferior to an M&M [1].
Petroleum is really frickin' energy-dense (leaving aside the fact that unless you're heating something only a small fraction can be turned into useful work).
A mid-range home EV charger peaks out at about 20kW.
By contrast, the energy flux of a gas pump is around 20MW.
Good point. Most homes around here are wired with 200A, 240V power, so a 20kW charger would eat up about half of that.
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.
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. :-)
Yes, bicycles are quite efficient. Not only compared to cars, but interestingly also to animals. While a normal human is quite bad at converting food into motion, the system bicycle+human is comparable to some of the most efficient animals. Now, if they had bicycles as well...
Considering that bicycle + cyclist is roughly an order of magnitude less massive than a car, that sounds about right. Of course, cars are also vastly more efficient at converting fuel into work than humans are.
Calculating the energy density of gasoline versus battery is misleading unless you also include the engine, fuel system, radiator, battery, etc. Sure my truck can hold 120pounds of gasoline but the energy density includes an 800 lb "gasoline to transmission" adapter.
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?
Iphones run on oil too (and coal, gas, nuclear energy, and various renewable fuels). It's just that giant synchronous generators are more efficient than a million internal combustion engines, so they burn the oil at a central location and pipe it to you over wires in the form of electricity.
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.
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."
That's odd, they neglect to mention the true cost of gasoline; both in subsidies used to keep it cheap at the pump, as well as the environmental cost associated with cleaning up their profit-generating mess.
ETA: Point out an oil company's dishonesty, get downvoted. Only on HN.
US pump prices are low because you don't tax it like other countries, that's not a subsidy.
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.
It would be a fair trade, but your whataboutery didn't include the true subsidies (http://en.wikipedia.org/wiki/Energy_subsidies) as well as the much larger environmental cost: CO2 production from burning fossil fuels. It's going to cost a lot to clean that up, and I sincerely doubt that ExxonMobil or their brethren are going to foot that bill.
I read the wikipedia link, it seemed inconclusive. Fossil fuel subsides are less than that of renewables (unless I am reading the article wrong) and that's a 1-1 comparison, fossil fuel must utterly dwarf renewable in terms of revenue.
I'm not saying that big (or small) oil is innocent by any means, personally I believe the problem lies with the political side of it, but certainly I don't think the basics of oil extraction and delivery deserve the rep they currently have.
And on farming, how much carbon do you think farmers released into the atmosphere burning the trees and scrubs that stood in the way of the farmland? Not to mention the damage done to the hydrosphere?
The fact that fossil fuels get any subsidy is obnoxious. They're the entrenched necessary evil that needs to be made obsolete. So of course alternative fuels are subsidized, and should be until they displace fossil fuels.
Farming is most certainly a problem, and I fully understand and agree with the Harper's article -- but it is a straw man in this discussion. I merely pointed out that an article authored by an oil company neglected to include the true cost of their product vs. competitors. And, unless the true cost is realized (most likely in the form of taxes on carbon emissions), fossil fuels will remain the most viable source of energy. It doesn't mean I/we have to accept it, there is a better way.
What "true subsidies" are you referring to? The link you cite to doesn't really mention any. The three biggest fossil fuel subsidies listed are:
Foreign tax credit ($15.3 billion), the Credit for production of non-conventional fuels ($14.1 billion), and the Oil and Gas exploration and development expensing ($7.1 billion).
The first and third are deductions just about every global corporation gets. The second one appears to be subsidizing alternative fuels, not fossil fuels at all.
My god, that website has the most amazingly civil and constructive comments I've ever seen on a blog post. I wonder if they're moderated, or just getting traffic from a very narrow section of people who write well.
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.
Maybe rephrase your question to be clearer, but I'm assuming you mean mining the chemical components of batteries. Not what I was referring to.
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.
Actually, lithium is a very depletable resource just like oil and coal are. Not in the sense that we use it up for energy, but in the sense that if you want to run all cars on lithium batteries there simply isn't enough easily mine-able lithium in the world. In this sense it is valid to say that we mine batteries. The same story goes for most solar panels.
Comparing the energy density of gasoline with the energy density of a charged battery is obviously also valid.
I agree and instead of tariffs I'd rather see the US put some money behind domestic solar. I don't want subsidized goods to kill the domestic mfgrs, but I'd love to see us combine our technical innovations in solar with a full court press to get the industry off the ground.
Wow. Let's try to convince people why it's alright for us to use a fuel we know to destroy the environment in countless ways and imply that it's someone else's job to advance alternative, less harmful alternatives to gasoline.
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.
Energy density of the batteries has been steadily increasing. There's no reason to believe that it will hit a way, so this argument is misleading in that it assumes the density will be constant.
- 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!
> 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.
click
"Yup."