conklinc wrote:Since you know so much about it Smurf, do youwhat are the issues, if any, with the leftover by products after extracting hydrogen from natural gas? I mean, hey, it can't be good! has to be some bad stuff remaining, like CARBON!
Natural gas, CH4, is comprised mostly of hydrogen and the rest is carbon. So if the hydrogen is being extracted then that sure does leave carbon. I don't know in what form (C, CO, CO2 or something else) the carbon ends up, but it is certainly a by-product.
The real issue is this however.
Suppose that a significant number of cars in California (or anywhere else) start using hydrogen as a fuel. That hydrogen then has to be produced by some means be it from natural gas or from water.
But producing hydrogen from water, is really just producing hydrogen from electricity so far as resource use is concerned. It's the electricity, not the water, which is the primary input of significance (well, it is unless you're in the middle of the desert and have a heap of solar panels that are otherwise unused).
In California as in most places, the "cheap" sources of electricity generation run constantly (or are fully used at other times in the case of hydro) and there is little if any ability to increase output from existing plants. That's hydro, nuclear etc and in most places (not California) coal. So any increase in power generation necessarily comes from the marginal sources of supply - natural gas, oil etc.
So it's really a question of burning gas at a power station versus turning the gas itself into hydrogen. Unless you have a 100% renewable electricity supply, and can increase renewable output so as to produce the hydrogen, hydrogen "from water" is really just a means of turning fossil fuel generated electricity into a flammable gas that can power an engine. Potentially useful if we run short of oil, but it's by no means a "clean" or renewable energy source.
Production of hydrogen from natural gas is roughly 80% efficient. That is, only about 20% of the energy in the natural gas is lost during the conversion. In contrast, generating electricity from gas is 15 - 60% efficient (typically in the mid-30's) and converting that electricity into hydrogen is also quite inefficient.
In short, if we're going to use fossil fuels to generate the electricity then to the extent that we're going to produce hydrogen, it makes far more sense to do it directly from natural gas rather than by means of first turning the fuel into electricity.
For the record, there was a commercial scale electrolysis plant in operation in Hobart from 1956 to the mid-1980's. Originally using 100% hydro-electricity in an era when Australia had no natural gas production, it made a lot of sense back in the 1950's to build it. But the emergence of the Australian natural gas industry (1969) plus the ending of the 100% hydro era in Tasmania doomed the electrolysis plant economically. The last year of full production was 1974 after which it ceased to be financially viable unless the electricity was basically free.
It limped along operating intermittently until finally closing in 1985, with the Hydro essentially giving any surplus power they had to the plant (they were basically just trying to keep people employed in a factory rather than letting the dams spill over). It ran for about 20 weeks in 1975 (a wet year), 10 weeks in 1976 (also quite wet), 5 weeks in 1977, 6 weeks in 1978 and then for a total of about 9 weeks over the following 7 years until final closure in 1985. The only reason it survived at all after 1974 was that it was already built and was running on free power. Once it became necessary to spend money on maintenance, it just wasn't viable to continue and so that was it - game over.
The hydrogen produced at this plant was used to produce fertilizer. It was quite a big operation in its' heyday, with most of the fertilizer being shipped interstate, but it just couldn't compete against production based on natural gas and that's despite the efforts of the power supplier (which did not itself own the plant) to keep it in business.
I don't have a precise figure, but the vast majority of commercial hydrogen production globally is from natural gas. Electrolysis just isn't financially viable, or sensible in terms of resource use, unless you have either a very cheap source of renewable electricity (realistically that would be hydro) and/or don't have access to natural gas.