How efficient is a car powered by petroleum?
I am doing a project in class and for the life of me I cannot find any information. My project is about how efficient is a wind/battery powered car and now I have to find wind efficiency vs. petroleum efficiency. Please help!
April 1st, 2010 at 2:13 pm
Efficiency of that type is difficult to compare, because they’re two entirely different systems. One runs off of stored electrical energy from the general power grid, which is powered by whatever form of electrical generation available… one is powered by burning a refined ("cracked") product of raw crude oil (petroleum).
A better comparison might be to look at gasoline vs. ethanol engines.
Modern electric vehicles are extremely well engineered. Look at the Tesla Motors website below. Their cars are roughly equivalent to standard automobiles in terms of range (but still shorter) between "fill ups," and are admittedly slower to "fill up" but you can just drive it home, plug it into the same socket that your large appliances (like a washing machine or clothes dryer) go into, wake up the next morning and drive all day without a thought. So it’s very cheap. As far as street "fun" performance, the Tesla Roadster is the fastest accelerating production sports car in the world (so not one of these one-off cars that they try to set records with, but a real car that people can buy). Nothing else even comes close, because of the nature of the energy curve of an electric motor versus gasoline engine. And *way* better than hybrids. Hybrids suck all around, in performance and efficiency at the same time.
But, if you try to compare "fuel" side by side (like I said, kind of hard to do), a gasoline engine get out only about 30% of the energy actually available in the fuel (and often no better than 20%). The rest is just gone mostly as waste heat and exhaust gases that serve no useful purpose, along with the creation of various particulate matter. Electric batteries on the other hand, as far as the "what you get out" of what you put into the battery when running the motor, is instead about 80% useful versus 20% waste. So in that sense, it’s more efficient. By a lot.
Some people who own electric cars that are actually useful around the city these days spend a few thousand dollars up-front to install solar panels in their yards… then they just use those panels (modern ones can last for decades) to charge their cars "for free."
April 1st, 2010 at 2:13 pm
If I’m not mistaken the best petrol cars today have an engine efficiency of around 40%. A little more is probably lost in mechanical systems in the rest of the car.