Tea time observations – 9-6-2015

It is interesting that gasoline is not a single chemical. Rather, it is a mixture of hydrocarbons with a lengths between 4 and 12 carbons long. UNLEADED GASOLINE (UNBRANDED) MSDS No. APPC975 Ver. 1. Print Date: 05/19/2003 lists some of the contents as:
BENZENE, CYCLOHEXANE, ETHYLBENZENE, METHYL TERT-BUTYL ETHER, TOLUENE and XYLENE.

Most people do not realize the fantastic energy density contained in a liter of gasoline. (http://www.eia.gov/todayinenergy/detail.cfm?id=9991) EIA states that even gasoline diluted with 10% ethanol still provides about 120000 BTU per gallon (31700 BTU per liter – 9.3 KWH per liter). Compare that to our highest density, publicly-available lithium-ion battery which boasts a mere 0.25 to 0.675 KWH per liter.

Now suppose that there is only a 25% energy conversion efficiency between the gasoline to electricity function.  That still leaves 2.3 KWH per liter of gasoline.

Ok.  So you buy an electric car.  Now you are burning coal (9.8 KWH/Kg) with a conversion efficiency of 33 50 45% (EIA again http://www.eia.gov/tools/faqs/faq.cfm?id=107&t=3) then assume a 40% power transmission loss to heat generated in the power lines.  On top of that, you can only get an 80 to 90% charging efficiency for LiPo batteries and that doesn’t include the loss due to AC power rectification at the point of delivery.

Interesting isn’t it?

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