# The Naked Scientists Forum

### Author Topic: What percentage of eneergy is used to convert a gallon of gas to electrical ener  (Read 1520 times)

#### Joe L. Ogan

• Sr. Member
• Posts: 476
##### What percentage of eneergy is used to convert a gallon of gas to electrical ener
« on: 28/07/2013 21:55:18 »
What percentage of energy is used to convert a gallon of gas to electrical energy?  Thanks for comments.  Joe L. Ogan

#### RD

• Neilep Level Member
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##### Re: What percentage of eneergy is used to convert a gallon of gas to electrical ener
« Reply #1 on: 28/07/2013 23:03:58 »
It's a two-stage process : converting the chemical energy to kinetic, i.e. making the engine move,
then converting that motion into electricity.

The first stage has an efficiency of "25% to 30%" , the second stage at around 90%.

30% of 90% is 27% , ( i.e. majority of the chemical energy in the fuel wasted as heat and sound ).
« Last Edit: 28/07/2013 23:14:16 by RD »

#### syhprum

• Neilep Level Member
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##### Re: What percentage of eneergy is used to convert a gallon of gas to electrical ener
« Reply #2 on: 29/07/2013 22:07:57 »
The overall efficiency of petrol powered IC engines tends to be about 30% but large Diesel engines such as used in ships can achieve 55%

#### Pumblechook

• Hero Member
• Posts: 569
##### Re: What percentage of eneergy is used to convert a gallon of gas to electrical ener
« Reply #3 on: 05/09/2013 00:03:43 »
Slightly meaningless calculation as calorific value is a notional figure.  It comes down to economics.  If fuel A has a low calorific value and cheap it may make more sense to it rather than use fuel B which has much higher calorific value but a lot more expensive.

#### The Naked Scientists Forum

##### Re: What percentage of eneergy is used to convert a gallon of gas to electrical ener
« Reply #3 on: 05/09/2013 00:03:43 »