You are right of course that it takes more energy to split water than you get recombining it. 2nd law or something like that. Maybe the reason we see it differently has to do with our current methodology of energy production. Where I live, I see numerous large PV installations and small and large wind generators everyday. I appreciate how unusual that is. But it's easy to see, that as fast as Boulder County is moving to the new power economy, in a short time, 5-10 years or less, there will be a plethora of excess, but intermittent energy. What will we do when we have excess intermittent energy? Turn off the wind generators? I don't think so, I think we'll find ways to store the energy.

Now if you make some reasonable assumptions about fuel cell and electric motor efficiency gains as several others have noted, and onboard HP storage technology, I think it looks very different.

One other point is that carbon neutral really isn't a good enough goal to prevent a bleak future. Maybe if we ALL could go neutral right away but there will always be CO2 producing activities. Methane, at 8-20 times the greenhouse effect is another very difficult to deal with problem. o some of us have to get to carbon negative asap. Biofuels recycle it at best. An offshore wind generator producing H2 is neutral and I bet there's some interesting chemistry that could be applied to move it even farther towards negative.

While, according to my definition, natural gas may only be a store of energy, it is more of a matter of semantics, because, in reality, natural gas does occur on this planet as a “source” of quite a bit of energy, even if it is a limited source. I stand corrected.

Hydrogen is not an energy source. Hydrogen is not an energy source. Hydrogen is not an energy source.

It is a medium. It is most analogous to electricity.

As a medium Hydrogen has some serious storage and distribution issues. In my personal opinion, the reason it gets so much publicity is that moving to this economy would allow existing petrol distributors to maintain control over the distribution. While it currently has some advantages over electricity for long-distance transport, it seems insane to build an entire new storage and distribution system for it when we already have an electricity distribution system. You may have seen it, but here's a super critical look at the “Hydrogen Hoax” http://www.thenewatlantis.com/publications/the-…

One thing I would contend with in the article, is that I think it confuses the point to state that neither natural gas nor hydrogen are energy sources. The comments on this page support that we do not need to create a link in people's mind that oil (or any fossil fuel) is at all like hydrogen.

I have to admit that my comment, “The only way that hydrogen can become truly worthwhile is if someone comes up with a way to create it from renewable energy sources, i.e. wind/solar, and store it is a form compact enough that it is comparable to current battery technology”, does not fully encapsulate what I intended to communicate.

As you have probably gathered, I usually cannot spend the amount of time on these blog posts to get them to the level of sophistication that I would like. Unfortunately, I do not have the time nor resources, nor is it my function, to spend 40 hours a weeks writing feature-length-and-quality articles.

The purposes of this type of blog, and this type of blog post, is to highlight current events relevant to our subject matter, and to comment on them as best we can.

I will say that my true intent has been made clear in my response to the various comments.

I have to admit that you do make some valid points, and as I mentioned, hydrogen will have its place. It simply will not be a major player.

Once again, you point out the reason quite elegantly: “Clean water is not a technical problem at all. It is an energy and wealth problem.”

The bottom line: the era of cheap energy is quickly coming to a close. Even the oil companies freely admit to that! That being the case, it simply makes no sense to loose energy by converting it from natural gas into hydrogen. It makes even less sense to waste energy to convert salt water into clean water into hydrogen FOR THE SOLE PURPOSE OF ENERGY STORAGE!

Clean water made from salt water will be much more valuable for drinking than for energy storage, and this is one case where the price and energy cost doesn't really matter: people will die without water. money is no object. People will get along just fine if they use something other than hydrogen to store their energy.

BOTTOM LINE: As far as I know, it takes more energy to “produce” hydrogen than you ultimately get out of the process. In a era of diminishing returns from fossil fuels, it doesn't pay to waste energy in this manner, for most purposes.

(ps–The new fuel cell technology is certainly a potential game-changer, but only if it doesn't run on hydrogen, IMO.)

I'm pretty puzzled that you think my examples of renewable produced H2 and storage confirm your statements. They don't, they contradict them.

You said
“The only way that hydrogen can become truly worthwhile is if someone comes up with a way to create it from renewable energy sources, i.e. wind/solar, and store it is a form compact enough that it is comparable to current battery technology”.

and I showed you references that current technology is available off the self and in common use to produce it. (For instance, use a wind generator to power a standard industrial H2 generator.) The other reference was about storage. This stuff exists already. So it seems that No, you didn't hit the nail on the head at all.

As for where the H2 comes from? Granted, the previous administration got all hot and bothered about the new H2 economy when someone told them that H2 comes from natural gas. But that was just a red herring.

I spent several years as a reverse osmosis desalination technician. Clean water is not a technical problem at all. It is an energy and wealth problem. Clean water is available anywhere there is water, energy, and some money. H2 electrolysis machines need cleaner water than tap so they incorporate reverse osmosis in the box. If you have the energy and wealth to produce H2, clean water is not an obstacle at all.

The practical scenario is an offshore wind generator that has built into its base a standard reverse osmosis machine to derive pure water from the seawater and feed it into a standard H2 generator. There is plenty of no carbon energy and plenty of water. You don't need to recapture the water from the tailpipe, the Earth will recycle it as it has almost forever. Storage is in undersea bags anchored to the seafloor and transportation is also easy (see Hindenburg reference).

There is lots of technology in the works to improve the efficiencies, but right now it's not economically competitive with the status quo. The much hyped Bloom Box may actually be one of them. There's a reference on the site to using the same technology to produce H2. The assumption would of course be that it would provide a major efficiency gain. But that's not really relevant. Higher efficiency will be a natural market mechanism when we address the actual problem which is the political and social problem of the cost of CO2.

BTW, I think the Bloom Box may very well be a game changer for land transportation. Combining its efficiency gains with high pressure storage, and then using the alluded to H2 production technology may very well provide for quite practical H2 powered HEVs using the SOFC instead of an ICE. The Bloom Box's efficiency gain means that a vehicle would need less stored energy (H2) reducing the pressure and volume of the storage container (and costs of manufacturing and compression). So actually, H2 may be the fuel of the future after all. We'll see.

So what about hydrogen? The energy it takes to liberate the hydrogen from its molecular form –H2O, primarily–is exactly the same amount of energy it will yield when ignited, in combination with oxygen, to provide power. On top of that, you need to store it (no mean feat), transport it and supply it. This energy equation makes it very different from fossil fuels, which have a much better “ROI” in this regard.

The only thing that would make it worth doing, in terms of net energy benefit (or even green benefit, in consideration of the energy used to produce it) is a process that, as you suggest, liberated the hydrogen by using a renewable source. Some form of solar/wind/water could certainly do this, since for H2O you just need a direct current source, as used to power that desktop kit. By extension, perhaps wind power could be used to drive compressors for the containment system as well. But that begs the question as to whether or not the extraction of hydrogen is truly a more widely usable energy source than the types used to power the extraction. Since hydrogen is mostly talked about for propulsion–and as a substitute for fossil fuels–perhaps it would be easier to focus on improving rechargeable batteries (which could also be replenished off a green power grid). Batteries are an established technology; we know how to use them in cars; they produce zero emissions (though we'd need to account for end-of-life handling). Unless there's a niche market I'm missing, where batteries fear to tread, I think your analysis holds, at least as a way to power vehicles.