Economically viable hydrogen power a fallacy?

Factual Questions
1

Is it reasonable to assume that the energy in required to split a water molecule into hydrogen and oxygen (electrolyze) would be theoretically equal to the energy out when you use hydrogen as a fuel by recombining it with oxygen? Aren’t we dealing with basic laws of physics here or is there some loophole that I’m missing.

And is it also reasonable to assume that the splitting and recombining operations would have some level of inefficiency that would render the energy needed to make hydrogen greater than the energy you would get when you use it as a fuel?

If these two assumptions are correct then it’s hard for me to see how hydrogen alone could ever be used as a replacement for fossil fuels.

About the only advantage of hydrogen that I can see is its use as an energy storage medium, not unlike a battery where it takes more energy to charge than the battery can release.

Following this line of thinking, the key to hydrogen use would be a source of cheap power that does not have any of the current environmental/political problems of fossil fuel and can be used on a massive scale. Fission power is the only one on the table that appears remotely capable of meeting these requirements. Maybe solar power.

Economically viable hydrogen could then be produced despite a net energy loss because the energy to make it is essentially free.

So before anyone gets excited about hydrogen don’t we need to obtain the holy grail of cheapo environmentally friendly energy first?

Or am I all wet on this?

2

You’ve got a good handle on it. Still there are other ways to use hydrogen. Hydrocarbon fuels can be used in some fuel cells.

3

One potential advantage is that the energy to split the water molecules can be expended in centralized hydrogen plants, rather than in tens of millions of mobile internal combustion engines, with widely varying levels of efficiency and emissions.

The central plant can be designed and run for optimum efficiency and emission control, so even if the plant has to use fossil fuel it would still be a gain compared to what we have now. Then again, you have a lot more options in fueling a stationary plant…at least at design time you can decide between coal, natural gas, or petroleum.

I promise I’ve heard this basic theory from a reputable broadcast source, but have not found a link despite diligent googling. I’ll keep looking and come back with it when I can.

4

What I have read leads me to similar conslusions, cloudbase. I’m not very optimistic about hydrogen powered vehicles, but I believe fuel cells could be viable for home use. Units like this may be a solution to remove home customers from the power grids, which are still dependent largely on fossil fuels to generate electricity.

5

An article in Wired new issue, How Hydrogen Can Save America, suggests using nuclear power as the way to manufacture the hydrogen. Well, along with renewables. So first we have all this cheap energy and… Um, if we had all that cheap energy, would we have as big a problem in the first place? Wouldn’t we have more electric cars, then? And what about…?

Never mind. This is Wired. It doesn’t have to make sense.

6

What about extracting hydrogen from methane? My understanding is that electrolysis is not very efficient but that there are other methods (perhaps using a catalyst) for extracting hydrogen from methane which yield more energy than they consume. Of course, one could simply burn the methane, but I don’t know how that compares, environmentally speaking, with hydrogen.

I got into an argument once with a guy at a party who claimed his father had invented a car which ran on water. He told me his father made it work, drove it around a bit, and then disassembled it because it was “too dangerous.” I tried to explain that, as far as I knew, you’d need at least as much energy to split water into hydrogen and oxygen as you’d get from burning it but he just got defensive and angry at that point. I gave up. The fight against ignorance sure has a long way to go…

7

Even if we had really cheap electricity, you need a way to use it for transportation.
The main problem with electric cars right now is not the energy they consume, but the fact that with current batteries you get terrible range, especially if its cold out and you want to run a heater, or you want to run the air conditioner when it is hot.

Hydrogen Fuel cells act like a really energy dense battery, allowing you to generate enough electricity to get a range comparable to gasoline cars, with the only outputs being water vapor, and what ever is produced at the power plant the makes the hydrogen.

8

Let’s look at it like this…
even with new discoveries of oil and natural gas, the reserves of fossil fuel will begin to diminish in this century, and become scarce by the end of it.
There are still vast reserves of coal and oilshale which will take their place for a while, as they become economical to mine once again. But even these lower grade fossil fuels will run out or become too low grade to repay the energy expended in mining.
So Hydrogen (probably in fuel cell technology), and perhaps bio-alcohol will have to take the place of fossil fuels-
we might as well start using them now, and keep the fossil fuels for the petrochemical industry.
You have to find the energy for the manufacture of H2 from somewhere though- it is essentially a form of energy storage.

Fission is the easiest option at the moment, although I personally don’t like the low level risks involved in the generation end or the higher level risks involved in the mining end, fission is definitely a viable option.
No-one has been able to get Fusion to produce an energy surplus yet, and it may be dangerous, but it should be relatively clean, and by midcentury it could be feasible- there is plenty of deuterium in the sea…
Solar power; we get 15000 times the energy from the sun per day than we use, but when you factor in cloud cover, efficiency etc you end up having to cover 3% of the entire land surface of the earth with solar panels in order to get a comfortable lifestyle for every one on Earth (assuming little population growth).
It is also worth utilising as much wave, tidal and deep ocean (see OTEC) power as can be feasibly grabbed, as there will be no more fossil fuel available for hundreds of millions of years once the present reserves are gone.
I am trying to avoid mentioning my favourite energy source, extra terrestrial solar collectors, as they are really a far distant future luxury option… but when we feel the need to use a trillion times our current energy budget, the sun will still be there.

9

In addition to ebaracum42’s point, there’s the advantage that having a dense, environmentally sound energy storage technology gives you – it makes some of the other renewable options more feasible.

Several of the major problems of wind, solar, and wave energy are that it can’t be adjusted depending on demand, there’s few reliable places to put it, and some of those that are are a long ways away from where you want to deliver the power. With something like a fuel cell, you can save up the energy with reasonable efficiency and use it later when demand changes, or transmit it to another location without having to build a wired network.

This seems to be the most sensible way to get extraterrestrial power to earth, so it’s a step along that path. Hydrogen makes the most sense as it’s the least polluting option.

10

eburacum45, I have an article written in the early 1950’s which predicted we’d run out of oil by 1990 or so. Whilst I fully support the search for alternative fuels, I have problems with the whole “We’ll run out of oil in fifty years!” comments. After all, fusion power has been “Just around the corner!” for the past fifty years or so…

11

Yep. A few months ago I heard a talk show host on the radio in Houston saying that hydrogen power was “free energy.” He then went on to say, “What do you think the air you’re breathing right now is made out of?”

12

Well, most environmental activists think oil will run out in thirty years. I reckon we could still have oil around in reasonable amounts in 2100, and lower grade fossil fuels could last a lot longer… in this I think I am more optimistic than most.
However, unlike nearly every other resource, once the fossil fuels are gone, they are gone. So we have to have something else in place, or go back to mediaevalism by 2200.

13

Ah, energy, my favorite topic.

If you read “Hubbert’s Peak” you will know that some geologists predict that the peak of oil production is happening right now. Once all the people in China start driving cars, I’m sure the consumption of oil will be accelerated.

A few of you mentioned “fission” without acknowledging the fact that “fission” is not free. Aside from the obvious problem of nuclear waste, and the fact that nuclear power is not a politically viable option, we only have a limited amount of uranium available - enough to take us to about 2050. (this fact from a governmnet scientist who works on nuclear energy) There are possibilities to use the waste generated by today’s power plants, but the start up time for any new generation of reactors is about 20-30 years. It won’t save us in an unforseen energy crunch.

Any fuel cell needs to get its energy from somewhere. I have heard that output of energy plants will have to double to generate enough hydrogen to replace today’s gasoline needs for transportation. Add future growth in population and well, things may be bleak.

A recent study by a professor at Cornell points out that it will be near impossible to replace fossil energy with renewable resources. http://sharpgary.org/RenewableE.html

Ultimately, most of our energy comes from the sun, even fossil fuel represents the storage of millions of years of solar energy, and we are squandering it within a few hundred years.

Add it all up: increased population with increased energy and food needs, increased oil prices and decreasing supply. Once fossil fuel becomes very expensive, is there really a good replacement? You can’t grow it because we need the land for food, in the future more than ever, and the energy made from crops doesn’t justify the energy costs required in planting, fertilizing, harvesting and processing it.

There are some who contend the total solar energy falling on the earth in real time won’t provide all of our food and energy needs in the future. (solar includes wind, photovoltaic, hydro, etc)

14

Hydrogen fueling would require an entire infrastructure for transporting hydrogen as well as many more advances in creating efficient engines. From the Wired article: “Today, power from a fuel cell car engine costs 100 times more than power from its internal combustion counterpart; it’ll take a lot of R&D to reduce that ratio.”

We’re much, much closer to developing economically viable gasoline/electric hybrids; we’re even closer to all-electric engines than we are to a fuel-celled economy. If we get really cheap energy, that’s where it will be used first.

Whether hydrogen is better in the long run is something that can be debated; but it won’t be used in mass numbers before electric is. That problem is just easier to engineer.

15

The good news is that fusion isn’t even dangerous, but the bad news is that there’s no telling how long it’ll take to get it. These are both for the same reason: It’s difficult to get a fusion reaction going, and keep it going. If you shut off a fission reactor, you’ve still got a bunch of radioactive material sitting around and getting hot, but if you shut down a fusion reactor, the reaction stops and you’ve got some perfectly stable deuterium sitting around and cooling rapidly. So you don’t need to worry about an out of control fusion reaction, but it’s also hard to produce an in-control reaction.

16

Are you referring to England or the UK, perhaps? Just curious, because this scenario does not apply to the US…coal is the cheapest fossil fuel that we have, by about a 3:1 margin on a cents/MBtu basis. It does, however, apply to the UK.

17

That is good news- (Btus? how quaint)
I like the idea of Ocean Thermal technology myself- it uses the otherwise empty oceans, produces fresh water…
there must be some drawback, some reason it is slow to develop (probably cost again)

18

I’m sorry, but pure electrics are pretty much a no go at this point. Until someone comes up with a better battery (which like fusion is “just around the corner” :dubious: ), electrics aren’t going to happen. GM’s shelved its electric car program (it seems Ed Begley, Jr. was about the only one to want one) and is dumping all its R&D money into fuel cells. The other carmakers are doing the same, IIRC. (That’s pure electrics, hybrid electrics are a different matter.)

Rusalka, I seriously doubt that the folks who claim solar wouldn’t be enough to supply power needs have a grasp on things. Here’s a federally funded solar plant which if it were expanded to roughly 100 square miles would provide enough power for the US. Also, more and more low-power devices are being designed, so it might one day come to pass that we’ve got an increasing population, but our energy consumption remains flat, or grows at a considerably slower rate. I seem to recall that England was supposed to starve to death sometime back in the 1800s, so take predictions that we’ll run out of this or that soon with a large grain of salt.

19

You are forgetting that renewable sources will have to supply all of the transportation needs of the earth someday, nevermind just replacing fossil fuel fired plants for electric power. All of our food production systems currently require oil. The reason food is so cheap in the U.S. is because of cheap oil.

Sure devices will become more efficient, but it will always take a minimum amount of energy to move a ton of grain 30 miles… or whatever.

See the study cited above, it was published in “Bioscience” a serious journal, for a sobering look at the alternative energy question.

20

Rusalka, I don’t know what the energy consumption of transportation systems vs. electric power consumption is, but if one hundred square miles of conventional solar panels can supply all of the US’s electric needs, then any other energy needs can be satisfied by building more plants of that scale, using geothermal, nuclear, wind, hydro, and anything else that we can think of. Hell, we can even turn a space elevator into a powerline and use it to supply electricity from space based solar cells to the Earth. Not to mention that there might be some uranium in them thar asteroids.

In reading the article you linked to, the biggest hinderence seems to be cost not capability. As our oil reserves dry up, the costs of other things (such as solar produced hydrogen) will begin to come down. The article also doesn’t take into account technological innovation. The US Gov’t (before Clinton cut the funding) was developing an IFR reactor which could use radioactive waste to generate electricity. The waste which an IFR reactor produced was of a vastly lower level of radioactivity than that produced by other reactors. As James Randii once said, “You’ll never go wrong predicting death and destruction.”