Alternate title: "What question am I asking (really, I have something in mind but I need help phrasing it)."
This is a complex (for me) subject, so it may take me a few tries to get an intelligible question out of this (please bear with me while I herd my neurons to the starting gate ;)).
[ol]
[li]What types of energy/fuel can be used to power vehicles, such as automobiles?[/li]
[li]How much energy does it cost to extract (for example) 1 barrel of petroleum from the earth, transport it to a refinery, and deliver it to a dispensing (gas) station for use?[/li]
[li]What are the energy costs for generating an equivalent amount of energy by other means, and transporting it to a refinery (if required), then on to a dispensing station?[/ol] [/li]
To illustrate what I am getting at, I suspect that an overhead wire system (or functional equivalent – think slot cars!) might be fairly efficient in getting electricity from a power generation facility to the end-user (an electric car, in this case), but the cost of the infrastructure would be prohibitive and you would be limited to going only where the cables went. A hydrogen-power system might have ecological benefits, but no-one seems to consider that while hydrogen is common, using it for fuel is akin to pumping water from the ocean to a high reservoir so you can use it for hydroelectric power (basically, it’s a means of storing energy, not creating it, if I understand correctly).
Similarly, I have heard solar energy touted as a potential source of energy for automotive vehicles, but it seems to me that the amount of sunlight one can expect to fall on a typical automobile is not likely to produce enough energy to move it around a lot unless you had a powerful storage system and a lot of time to let it charge between uses. If you use remote generation sites and transmission lines to get the electricity to a dispensing point (a recharging station for your electric car) is it more or less efficient than (or the same as) any other power generation scheme that relies on the existing power grid to transport electricity from where it’s generated to where it’s needed?
Fossil fuels are a method of storing energy; stored sunlight from millions of years past - that’s why we ‘win’ with them - we don’t have to actually expend energy to do the storing for ourselves.
Even nuclear power from radioactive isotopes is exploiting stored energy - the stored energy of ancient supernovae that fused lighter elements as they blew up.
While you are technically correct Mangetout it seems quite obvious that SSGtBaloo means that hydrogen is simply a means of storing usable energy, not creating it.
While nuclear and fossil fuels are indeed just energy storage devices they are not storing energy that was ever usable to humans. That is a very significant qualification as SSGtBaloo rightly points out. Hydrogen fuel takes electrical or heat energy that humans already have a use for and converts it into another form, with losses, so it can be re-converted into electricity or heat. The entire process yields less human available energy than was available to begin with.
In contrast nuclear fuels are not a form of energy that is usable to human beings until they undergo fission. The energy they contain was never available to humans. The same is true of fossil fuels in that the chemical energy they contain is not usable to us until it is converted into heat. The use of fossil or nuclear fuels in engines yields a lot more human available energy than the system started with.
It seems a shame to have to expand on what I thought was such an obvious and widely known point in order to provoke a discussion on the subject the OP actually wanted to discuss.
Just the cost of getting the fuel, whatever it is, be it petroleum, sunlight, poo-gas, hydrogen, etc., from where it is to the filling (or charging) station.
BTW, usable hydrogen fuel does not exist in significant quantities anywhere on the surface of the Earth. It is always (so I have been told) found in molecules of something else, such as petroleum, water, sugar, and a variety of other substances. Extracting hydrogen from water makes as much sense as reconstructing wood from smoke and ashes – not an efficient proposition unless you have a nearly limitless supply of energy from some other source to power the process to make it.
In a previous thread I said, as the OP here did, that hydrogen is a storage medium, not an energy source, and was told that most hydrogen used today is refined from natural gas, and is not made by splitting water. Thus hydrogen is also a fossil fuel.
Hey! I’ve heard about that, but not nearly enough. How much energy does it take to extract the equivalent of a gallon of gasoline versus how much energy does it take to extract the hydrogen equivalent of a gallon of gas?
:smack: Mutters to self: “Proof read, proof read!”
Err… That should read as follows:How much energy does it take to refine a gallon of gasoline relative to the amount of energy it takes to extract an energy-equivalent amount of hydrogen gas?"
–SSgtBaloo
(You see? I can be intelligible. It just takes a little effort.)
One of the problems which is not typically included in the calculations equally, is “How much does it cost to develop the technology necessary to utilize these forms of energy?” When discussing alternative fuel technologies, people are quick to point out that tons of money needs to be spent on building the infrastructure necessary for the production and distribution of these fuels, but nobody mentions how much money has been spent building up the production and distribution channels for fossil fuels over the centuries (Coal has been used by the Western world since the late 1700s or so, China is reputed to have used it since before Marco Polo showed up demanding take out, oil has been in use since at least the 1800s.).
Hydrogen can be reformed fairly easily from natural gas, the expense of it comes from developing the equipment, and the cost of tooling up for mass production of said equipment, plus the training of personnel in how to use and repair the gear. This is considered a “normal” expense when dealing with fossil fuels, but is considered exceptional when dealing with alternative fuels.
Simply looking at BTU’s, kerosene and diesel come in the highest of liquid fuels.
Some of these issues were discussed in the thread on steam powered cars, but nobody had any real answers as to what the cost of things like gasohol were.