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Crunching the Numbers on a Hydrogen Economy
mattnyc99 writes "In its new cover story, 'The Truth About Hydrogen,' Popular Mechanics magazine takes a close look at how close the United States is to powering its homes, cars and economy with hydrogen — including a calculation of where all the hydrogen would come from to meet President Bush's demands. Interesting that they break down the future of hydropower not by its advantages but by its challenges: production, storage, distribution and use."
Interesting that they break down the future of hydropower not by its advantages
I do not think it means what you think it means.
With a fuel cell in each house, you could essentially generate hydrogen from water and electricity at night when the power plants are idling in inefficient speeds. During the day, you could do the opposite and generate electricity from the hydrogen generated the previous night.
Or you could do what most people do when they want hydrogen, heat a hydrocarbon with steam. It is a hell of a lot cheaper than electrolysis! In fact, most fuel cells use some sort of hydrocarbon reforming to get their hydrogen. Unless you store hydrogen as a liquid, its energy density is just too low for any reasonable fuel tank.
The fixed or stationary energy use, at homes, offices, and factories is not in as much of a crisis as the transportation sector. For electricity generation, there are alternatives like coal (yeah, it is dirty), or nuclear (yeah, most people fear it) or tar sands (yeah, it is expensive to recover) or wind (yeah, it has some problems), solar (yes, it needs high investment). There are problems, but USA is self suffiicient in them, and we wont be held hostage by foreign powers. There is breathing space to develop really good alternatives.
On the other hand, in the transportation sector is in crisis already. So much of personal transportation depends on gasoline and freight depends on diesel and air transportation depends on kerosene. No serious alternatives are emerging and the time is running out on those sectors. Most predictions of peak oil is around now or 2010. Even the most optimistic estimates about the Hydrogen powered cars or biodiesel driven trucks talk about widespread adaptation around 2020.
America is particularly vulnerable to this energy crisis. It is not as densely populated like Europe or Urban India and China. It is not easy to switch USA to use electricity driven public transportation. So much of the economy depends on the high home values of the sprawled cities and the humongous fleets of trucks delivering goods. So much of the infrastructure is built around the idea it is very cheap to transport goods over 100s of miles. And America is not self sufficient in this energy sector. This is a grave crisis.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
Maybe I'm taking you too literally here, but remember that no fuel cell system aimed at the mass market take pure hydrogen as an input, mainly because of it's inherent danger (think Hindenburg).
Instead, they take some other compound, like ammonia or hydrides, from which they extract the hydrogen to power the fuel cell. The advantage is that at no point do you have a large enough quantity of hydrogen to cause an explosion.
So my point is, generating the appropriate "fuel" for a fuel cell isn't as easy as electrolysing water to get it's hydrogen. You'll then want to combine that hydrogen with a carrier, which is what will be injected into your fuel cell. That's the complicated part.
Misleading titles? Inflammatory blurbs? Keep in mind that Slashdot is a tabloid.
Yes, hydrogen is a fuel, but it is not an energy source. It is a fuel you have to put the power into. The phrase "hydrogen economy" is an idiocy at best; a fraud at worst. The economy will be based on whatever source of energy is used to make the the hydrogen. Like, oooooooooooh, gas and coal.
.burn oil and coal. Using hydrogen as a fuel increases coal and oil use until the price of them rises above the cost of energizing hydrogen by other means.
The more things change. . .
Gasoline and diesel have to be refined -- it's not like we find them naturally in the ground.
But the energy is already in the crude (stored solar) and it can be used to power its own refinement. There is a loss of available energy in the process, but a net gain nonetheless.
There is nothing but net loss in hydrogen since any energy that can be extracted from it must be put in it the first place - and the Second Law wins. The current cheapest and quickest way to put energy into hydrogen is to . .
In other words, when hydrogen becomes really, really expensive itself.
KFG
This is mentioned in TFA (second page, heading "SOLID-STATE"). IIRC there are more materials that can do this, collectively they're called metal hydrides. Metal hydride tanks are heavy and expensive: Mercedes built a car with a metal hydride fuel tank about 10 years ago, the tank alone cost $100k.
The temperature needed to release the hydrogen is about 300 deg C.
http://www.hydro.com/en/press_room/news/archive/2
http://business.guardian.co.uk/story/0,3604,94313
They don't just use hydrogen.
http://www.newscientist.com/channel/earth/energy-
They are lucky they live where they do. It's a hot bed of free energy.
$ cat
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I've seen this prediction-of-doom vary from 10 years to 50 years.... projected at various points over the last 30 years. Chances are, you'll be able to see some headline in 2070: "Oil Running Out in 20 Years!!!"
Amazing how you don't graps what "Peak Oil" really is.
At a certain point, production stops increasing, and in fact starts to decline, because not enough new fields can be found to replace the spent ones. (When's the last time you saw a field of Oil pumps in PA?) The price of oil goes up, as the supply goes down -- making currently non-profitable oil reserves and energy sources, theoretically, more profitable.
We will likely never run out of oil, although it will eventually (50 years? 500?) reach the point where it's simply too expensive to get the stuff out of the ground, and we only use biomass-made oil or some other alternative fuel source.
That's because there are no fuel cells aimed at the mass market yet, except alcohol testers, which are anyway not a power source. Hydrogen is not more dangerous than gasoline; it does not concentrate on the ground but escapes high to the sky. You can neither be soaked in hydrogen. It does however have a lower threshold for ignition, but putting things together it is not especially dangerous. Thinking Hindenburg, less than half of crew and passengers actually died. Try find that number in any plane crash with an equivalent amount of flames.
Wish it were like that, but if they contain the energy, hydrides, ammonia or whatever else can also burn. The idea is mostly to increase volumetric energy density, as hydrogen is very light and going around with a 70-MPa cylinder is somewhat unpractical (though not impossible).
Victims of 9/11: <3000. Traffic in the US: >30,000/y
The Hindenburg fire was NOT caused by hydrogen, but rather by a new exterior covering that the Zeppelin company was trying out - a butyl rubber fabric coated with iron oxide and powered aluminum - in other words, a formulation very close to what the Space Shuttle Solid Rocket Boosters use for fuel.
In addition, the skin panels were not electrically bonded to the superstructure of the ship and formed a series of capacitors which were highly charged - when the ship was grounded by the mooring lines, the panels discharged, some through the wet cords binding them to the ship, some by arcing (and thus setting themselves on fire).
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