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Thanks for saving me the trouble of tracking down sources. The claim was inartfully stated at best. However, it all ends up going back to your definition of "

Thanks for saving me the trouble of tracking down sources. The claim was inartfully stated at best. However, it all ends up going back to your definition of "net positive". I read "net positive" as getting more out than you put in during the refining process. Neither gasoline nor hydrogen from water is a net positive by this basis. If you extend the "net positive" test to the extraction and refining process, then you have to include the process to make the electricity for hydrogen-from-water or it's not a fair comparison. I can't dig up electricity. In this case both processes are net positives if the comparison is even.

saalweachter 13y ago
I wouldn't go that far. First, to be honest, I don't trust the initial claim. I couldn't find a source for the 3.5 to 7 kWh figure, and their are a lot of ways it could be wrong or misleading. Firstly, you don't refine gasoline in a vacuum; when you refine a barrel of oil, you get roughly 45 gallons of refined petroleum products, including about 19 gallons of gasoline. Are they assigning the full cost to the gasoline, dividing it by volume, or by energy cost? And 3.5 vs 7.5 is a full factor of two. What is the average cost? Even taking the energy cost as gospel, it still tells you a heckuva lot more about the vehicles than the fuel. ICEs peak at about 30% efficiency, so you ought to be able to apply a solid 12 kWh from a gallon of gas to making cars go. If the fifty miles you can push a particular electric car on 7.5 kWh is more than your typical car, that's hardly the fuel's fault. And indeed: the current record for fuel efficiency is 209 mpg. So it's duplicitous to say that electricity is more efficient for running cars than gasoline, or claim gasoline is somehow energy negative. We get so much energy from gasoline we can be extraordinarily wasteful in how we use it.

saalweachter 13y ago

I wouldn't go that far. First, to be honest, I don't trust the initial claim. I couldn't find a source for the 3.5 to 7 kWh figure, and their are a lot of ways it could be wrong or misleading. Firstly, you don't refine gasoline in a vacuum; when you refine a barrel of oil, you get roughly 45 gallons of refined petroleum products, including about 19 gallons of gasoline. Are they assigning the full cost to the gasoline, dividing it by volume, or by energy cost? And 3.5 vs 7.5 is a full factor of two. What is the average cost? Even taking the energy cost as gospel, it still tells you a heckuva lot more about the vehicles than the fuel. ICEs peak at about 30% efficiency, so you ought to be able to apply a solid 12 kWh from a gallon of gas to making cars go. If the fifty miles you can push a particular electric car on 7.5 kWh is more than your typical car, that's hardly the fuel's fault. And indeed: the current record for fuel efficiency is 209 mpg. So it's duplicitous to say that electricity is more efficient for running cars than gasoline, or claim gasoline is somehow energy negative. We get so much energy from gasoline we can be extraordinarily wasteful in how we use it.