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How many gallons of gasoline would it take to charge an iPhone?

exxonmobilperspectives.com

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Re: How many gallons of gasoline would it take to charge an iPhone?

#51

Post by Tichy »

jbooth wrote: post #45
Tichy wrote: post #40

Earlier quoted context omitted.

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 fo…

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.

Re: How many gallons of gasoline would it take to charge an iPhone?

#52

Post by calloc »

GFischer wrote: post #39
revelation wrote: post #15

Earlier quoted context omitted.

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. http://www.aftermarketleads.com/2011/12/maruti-alto-delivers... I suspect the problem is partly American attitude towards small cars. Japanese, Europeans and South…

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).

Re: How many gallons of gasoline would it take to charge an iPhone?

#53

Post by rdtsc »

henrikschroder wrote: post #18
rdtsc wrote: post #10

> And energy density is one of the key factors behind the reliability 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 ?

> Per mass hydrogen is pretty attractive. 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. :-)

I understand that. Not saying we should use it. Only highlighting that for some domains a different type of energy density can be used.

Re: How many gallons of gasoline would it take to charge an iPhone?

#54

Post by waivej »

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?

Re: How many gallons of gasoline would it take to charge an iPhone?

#55

Post by rdtsc »

teamonkey wrote: post #38
grecy wrote: post #11

They neglected to mention that even modern internal combustion engines can only capture about 18%-20% of that energy.[1] [1] http://en.wikipedia.org/wiki/Internal_combustion_engine#Ener...

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. [1] http://en.wikipedia.org/wiki/Oil_power_plant#Heat_into_mecha... [2] http://en.wikipedia.org/wiki/Electric_car#Energy_efficiency

However does the efficiency offset the inefficiency (physical and economic) to store enough electricity to make it feasible.

Re: How many gallons of gasoline would it take to charge an iPhone?

#56

Post by Adaptive »

soren_dahl wrote: post #13
Adaptive wrote: post #6

We don't mine batteries from the ground. 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…

"We don't mine batteries from the ground" Er...

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.

Re: How many gallons of gasoline would it take to charge an iPhone?

#57

Post by GFischer »

calloc wrote: post #52
GFischer wrote: post #39

Earlier quoted context omitted.

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. http://www.aftermarketleads.com/2011/12/maruti-alto-delivers... I suspect the problem is partly American attitude towards small cars. Japanese, Europeans and South…

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…

Sorry, it's even worse, I picked the gallon figures off the Internet because I was lazy. Thanks for the correction and calling me out.

It seems the Twingo figure was in UK mpg, so US mpg would be closer to 40 mpg (US).

Same for the Maruti figure, it would actually be 50 to 60 mpg (US).

From what I read, both are still way more efficient than your average American car.

I'd like to get an Accent, but they're close to 30.000 dollars after (humungous) taxes here in Uruguay.

Re: How many gallons of gasoline would it take to charge an iPhone?

#58

Post by gvb »

teamonkey wrote: post #38
grecy wrote: post #11

They neglected to mention that even modern internal combustion engines can only capture about 18%-20% of that energy.[1] [1] http://en.wikipedia.org/wiki/Internal_combustion_engine#Ener...

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. [1] http://en.wikipedia.org/wiki/Oil_power_plant#Heat_into_mecha... [2] http://en.wikipedia.org/wiki/Electric_car#Energy_efficiency

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.

[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

[2] http://en.wikipedia.org/wiki/Lithium-ion_battery

Re: How many gallons of gasoline would it take to charge an iPhone?

#59

Post by Adaptive »

tkahn6 wrote: post #25
Adaptive wrote: post #6

We don't mine batteries from the ground. 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…

> Evidently the free market is awesome except when it results in cheap products that threaten an established industry. China actively and heavily subsidizes its solar industry. That is hardly the result of a free market.

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.

I'd say the same for modern nuclear.

Re: How many gallons of gasoline would it take to charge an iPhone?

#60

Post by drcube »

herge wrote: post #42
drcube wrote: post #24

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 ma…

How many times more efficient is a gas power plant than the average use of a car?

Wikipedia says: "Even when aided with turbochargers and stock efficiency aids, most engines retain an average efficiency of about 18%-20%."

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."

http://en.wikipedia.org/wiki/Fossil_fuel_power_plant

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