How much gasoline does it take to charge an iPhone?

Of all the pressing energy questions facing the world today, probably the most perplexing is the problem of providing enough energy to power the roughly 78 million iPhones that exist in the world today (OK, not really, but it’s up there). Energy researchers can breathe a sigh of relief however, as ExxonMobile Vice President Bill Colton has provided the solution to this issue. In a blog post on his company’s website, Colton is quoted saying that one gallon of gasoline packs enough energy to fully charge an iPhone daily for 20 years. With one simple statement Colton has put to ease all the Angry Birds addicts out there that were worried about being able to maintain their high scores.

In an effort to prove that gasoline is going to remain the main source of energy for the world by the year 2040, Colton uses this factoid to enlighten the masses to the fact that petrol is the lightest and most energy dense fuel in the world. While it’s obvious that the iPhone doesn’t use gasoline as a power source, Colton is talking about the energy potential in the fossil fuel.

By doing some simple math using ExxonMobil’s numbers, and assuming that an iPhone user is charging the device once a day, it takes 0.018 ounces of gasoline every 24 hours to keep the device powered constantly. This comes out to just one drop of gas a day. Pretty amazing, especially when you do some additional calculations to figure the monetary cost of the gasoline as opposed to the price of charging the devices using electricity. By multiplying .018 by 78 million, then dividing that number by 128 (the number of ounces in a gallon) we end up with a figure of 10,968.75 gallons of gas that would be needed each and every day to power all of those devices, assuming they are all still operating.

Multiply that by $3.50 for a gallon of gasoline, a reasonable cost here in the US, it would cost the world roughly $38,388 in gasoline daily. This figure is actually less that it costs for a consumer to charge their iPhone using electricity. It costs roughly half-a-cent to charge a mobile phone each day at home. Multiplying that number by the same 78 million iPhones then dividing by 100, and we find that the daily electricity cost is around $39,000.

Of course, this still doesn’t solve the fact that gasoline is a non-renewable energy source, and the fact that gasoline can’t be used to charge an iPhone (unless you use a generator and then there are whole sheets of efficiency figures we would have throw into the mix). Math aside, the post from ExxonMobil is nothing more than a PR effort to make the public feel better about spending money on the consumption of natural resources, thus putting money into its pockets.