The Hydrogen "Economy"-- Un-Economical, Even Comical
Just a few points of fact for the discussion below:
Fuels are all about generating heating energy and converting that energy for mechanical work. Natural gas has a heating value of about 980 btu/ft3, hydrogen has a very LOW heating value of 290 btu/ft3 or about 1/3rd the value of nat. gas.
Fossil fuels like gasoline and diesel (and coal) have really enormous heating values--much higher than natural gas for instance. Coal is right up there as well. Nothing can compare the energy density of fossil fuels. That's why they fueled the rapid rise of civilization in the past 150 years.
Hydrogen is generated by steam reforming of natural gas in crude oil refineries. Refiners use the hydrogen to bubble through crude and diesel products because the hydrogen reacts with sulfur in those fuels. This is done to comply with governement regulations on these fuels.
Steam reforming of natural gas also makes hydrogen, but it also makes some Carbon Monoxide and Carbon Dioxide for each volume of Hydrogen. The carbon monoxide and carbon dioxide are VENTED to the atmosphere, so 0it's anything BUT "green."
Hydrogen can also be made by using DC current to electrolyze water. But it takes a vast amount of electrical energy to break the H2O bonds. Hydrogen bubbles up from one electrode, Oxygen from the other. The collected hydrogen, dangerously explosive, must be compressed and stored. There is basically ZERO infrastructure for the manufacture, storage or transportation of hydrogen. (On the other hand, there are 100's of thousands of miles of high pressure natural gas pipelines across our country.)
Hydrogen production by electrolysis is only 75% efficient.
Ok, first, if you've already generated electricity by burning fossil fuels (some 70%+ is generated that way depending on ur location), and you distributed that power on the grid, why would you then use that power to electrolyse water to create hydrogen?? You'd only be converting perfectly good electrical energy just to store it as hydrogen. And that's quite expensive: the cost of electricity, the facilities, the energy, the inefficiencies (only 75% efficient) and the cost to compress that gas. And hydrogen has no distribution infrastructure. (Whereas, Electricity and Natural gas have truly ENORMOUS distribution networks- discussed below). Also storing and using hydrogen is risky because, even though it has a low heating value, it's extremely explosive.
William Hoagland, senior project coordinator at the National Renewable Energy Laboratory's hydrogen program, told Time Magazine, ".....why would anyone invest in additional equipment to make hydrogen rather than simply putting the electricity on the grid."
If you're making hydrogen from steam reforming under extreme conditions of heat and pressure, it's very expensive to make, ie., costly. But cost is not a problem for refineries because they use relatively small amounts of H2 to de-sulfurize their products, so it's just a cost of business. If you don't desulfurize, then you have no product--it has to be done.
The only reason that we're even discussing Hydrogen fuels at all is because of the ENORMOUS hype about it's possible use in auto engines BUT, hydrogen has 1/3rd the heating value of natural gas and is VERY expensive on a BTU basis even before distribution (which doesn't even exist). You would probably need a special engine to burn hydrogen as a fuel because it's so low in heating value and so explosive (problem with early detonation in the cylinders?). I don't think that it's possible. Maybe someone could comment on that for me?
Fuel Cell Hype
So people are left to get all excited about using hydrogen in fuel cells in automobiles---using expensive hydrogen gas to convert it to electricity IN THE CAR using a fuel cell. There's enormous HYPE about fuel cells!.
Yes, it could be done, but think about the roundabout way to get there: 1) you generate electricity using mostly fossil fuels, 2) you distribute electricity on existing grids, 3) you convert AC power to DC power to electrolyze water to make Hydrogen, 4) you must compress the Hydrogen for storage, 5) then you must build an entirely new distribution network to get it to consumers, 6) then consumers have to buy a ridiculously expensive fuel cell/electric AUTOMOBILE, 7) then they have to buy a ridiculously expensive fuel (Hydrogen) whose distribution network doesn't exist. If this isn't the definition of insanity, I don't know what is.
The fuel cell process of converting hydrogen back to electricity is only 60% efficient, Or, to put it another way, for every kW of electricity supply, you get 800W for a Battery Electric Vehicle, but only 380W for an Fuel Cell Vehicle – less than half as much. That doesn’t even take into account the fact that 90% of hydrogen is currently generated from fossil fuel sources.
Why not just buy a battery powered electric car and use cheap electricity that is already available and widely distributed----and skip all those other steps and processes???? But even electric battery cars are at least twice the cost of gasoline (or natural gas) fueled cars.
You'd be better off converting your car to CNG (compressed natural gas). Now THAT is a very viable approach especially in the US. Most developed countries have widely distributed natural gas supplies. Natural gas in the US are among the cheapest fuels IN THE WORLD. It's also cheap in Thailand. Thailand uses compressed natural gas widely for vehicle fuels in Bangkok for instance. It's a very cheap fuel there and most cars can be easily equipped to use natural gas without major modifications (they have to add a Nat.Gas tank in the trunk).
Hydrogen is Dangerous
Recently, a chemical plant producing hydrogen in Santa Clara exploded, leaving fuel cell vehicle users in California short of fuel, but just a few days later a refuelling station in Sandvika, Norway also went up in flames. This really brought home the truth that hydrogen can be a dangerously explosive gas..Car fuel tanks are now Kevlar-lined to protect against explosions!! Not exactly a confidence-inspiring tale here.
In summary, hydrogen has specialty use only in refineries and chemical plants, AND NOWHERE ELSE in any kind of economic terms.