I don’t know. I only have values for it on a mass basis memorized, which is why I specified mass. The person who made the original post needs to calrify what they were saying.
If you want to say I’m wrong, why not just look it up and do the math yourself? Or is this going to be like that home thermostat thread, where everyone made assertions, but I was the only one who bothered to do the math? And then no one gave a shit? :rolleyes:
How much does a liter of liquid hydrogen weigh? At 70.8 kg/m3, so that gives us:
70.8 kg/m3 * 1m3 / 1000l = 0.0708 kg/l
So, at 120 MJ/kg NCV, we have:
120*0.0708 = 8.496 MJ of energy per liter.
Gasoline weighs about 0.685 kg/l. So, at 44 MJ/lg NCV, we get:
44*0.685 = 30.13 MJ of energy per liter.
So, on the volumetric basis, it’s about 28% the energy density.
So on a mass basis I’m right, and on an volumetric basis I’m not.
Ah hell, doesn’t matter. And if we want to quantify it… there’s approximately four times more hydrogen in 1 gallon of gasoline than in 1 gallon of liquid hydrogen.
I didn’t know this but it looks like Crafter_Man is right. Using Anthracite’s number for density of gasoline, and assuming gasoline is C[sub]8[/sub]H[sub]18[/sub], there is 0.11 kg of hydrogen in a liter of gasoline. Pure liquid hydrogen is only 0.07 kg/l. Similarly, there’s more hydrogen in natural gas or propane than the same volume of pure hydrogen gas.
The reason is fairly clear for gas; gas is mostly empty space filled up by fast-moving molecules. It’s the number of molecules that determine volume, not the size of each molecule. Liquid is more tightly packed but still, large molecules take up only slightly more volume than small molecules. A two-atom molecule occupies less than twice the volume of a single atom.
Popular distribution of the fuel cell is not going to provide America with “Free” energy. All it will do is remove our dependance from oil.
Fuel cells, as we have them today, run on pure hydrogen, from a tank, which was purchased from a company that produces industrial gasses. This is because fuel cells of today, are still in the research phase.
Second Generation Fuel cells may incorporate a recovery method whereby water in their exhaust will be collected, and electrolized(sp) into hydrogen. They could use solar cells to provide current for this process. These are still research devices, though.
Third generation and fourth generation research devices will have better systems to be sure.
The commercial variety is not there, though. There are not any Fuel Cell powered vehicles that are commercially available. When commercial fuel cells become available, they will be different than the ones we are using today. A situation similiar to crafter-man’s idea will be prevalent.
Energy companies will spring to existence, built on the foundations of the oil companies. These will produce, not gasoline, but a compound like gasoline - with may hydrogen molecules - in a carbon oxygen chain. Fuel cells will then strip these hydrogen atoms off the chain, and use them to power the vehicle. Most likely they will stip the oxygen molecules off as well to release water in the air. Remaining oxygen molecules will probably be reacted with the remaining carbon molecules to form CO2 which will be vented out of the fuel cell. Energy companies will still have to synthesize this fuel probably from water. And considering that they set the price for fuels anyway, they will be able to demand what they want for it, just as oil companies do now.
lets see, the op is talking about hydrogen for fuel cell cars. you are talking about powering homes…
seeing as you are a global energy corporation…
what i meant by free (and you all knew this already) is the energy itself is free. obviously a huge windmill or a geothermal plant or the freaking hoover dam isnt free. come on. but compared to burning coal and oil, they are.
everyone knows a dam uses gravity to make water spin turbines… gravity costs us nothing to make, we cant run out of gravity, and it is going to rain forever most likely. the only problem i see with this is most anywhere you can put a dam in the US has probably been taken or ruled out for one reason or another.
solar panels arent cheap, but once again, you cant run out of sunlight, or rather we wont ever run out of sunlight, sure there are cloudy days but eventually clouds go away and solar panels produce electricity. the sunlight is free, it doesnt go away, etc etc.
windmills can be placed in tons of places… all of the panhandle and west texas is windy from what ive experienced, its also a huge massive black hole. there is nothing out there but flat uninhabited ground, putting windmills up wouldnt hurt anyone, maybe getting the power to them would be a challenge considering there isnt much out there, but still. wind is free, you are not burning anything to make wind.
my point (duh) was that there are a few ways of generating energy out there that do not require directly consuming a natural resource. earth will always be warm on the inside, the wind will always blow, and there will always be sunlight. we however will run out of natural resources.
im not doubting your 10 year engineering degree or your l33t m4th sk!11z but come on, both of you knew what i meant.
How are you getting the hydrogen from the windmills, geothermal, or solar sources? From the electricity produced by them. You said, and I quote:
You are the one who came in and made the assertion, with no real explaination, that these were “free” energy sources. So don’t get huffy when someone calls you on it.
And if it’s “free” to get electricity from these sources for hydrogen production, then it should also be as cheap to power your house. The two are connected, actually.
I am a global energy corporation?
No, they are not. What is the levelized annual cost of a wind generating plant, or a solar PV plant, compared to a coal plant? Or how about just the cost per kWh, neglecting construction? Do you know what it is?
Utilizing hydro is not free. It is very cheap, but most all of it is way overcommitted. And it makes up a very small fraction of the US electrical energy suppy. And this fraction will decrease steadily, since not only is hydro output fixed, but Greens are striving hard to tear down dams and to limit their operations.
Utilizing sunlight is not free.
Utilizing wind is not free.
Here, let me provide an example of energy costs, along with friendly Mr. Hyperlinks:
Note the phrase “long term goal”. I’ll use some more l33t m4th to say that that equates to 6 cents/kWh.
From: http://www.awea.org/faq/cost.html
You can figure the rest out yourself. Including what the cost of producing electricity from non-renewable fuels is. It’s a hell of a lot cheaper than these “free” sources. Yes, it’s non-renewable, and even at a much higher cost the renewables are the way to go in many cases. But don’t come in here, assert that they are free, with no other explaination, and then think no one’s going to call you on it. The GQ Forum may have gone to hell in a handbasket, but that doesn’t mean I have to like it.
That’s great if that’s your point. However, that’s not clear at all from your first post.
10-year engineering degree? Wow, what’s that, a PhD++? I wish.
And if algebra is “l33t m4th”, then I think there are larger problems at play here.
Once again, I ask you: What is the levelized annual cost of a solar PV, wind, or geothermal plant? What is the equivalent availability factor of them, and capacity factor? They may be renewable energy, but free they are not. In fact, they will be quite a bit more expensive in practice.
I’d like a cite to a reputable research program working on putting solar cells on cars to convert exhaust water back into hydrogen for power. Because there isn’t NEARLY enough solar flux to power a typical car, even if the solar cells were 100% efficient, and the conversion from water to hydrogen through electrolysis were 100% efficient (it isn’t, and can’t be).
If you want to see how much solar power is available, have a look at the annual [url=http://www.lasersol.com/air_water/sunrayce_99/Sunrayce.htmlSunrayce competitions. These vehicles are huge, flat beds of solar cells, driving extremely light 1-person cars on very tiny low-friction wheels. They can go about 45 mph, they can barely accelerate at all, and the total amount of power they can make wouldn’t run your handheld hair dryer.
This is the absolute state of the art in solar power today.
Because hydrogen(especially liquid hydrogen, as you have to deal with cryogentic materials too) storage and transfer requires higher safety levels than coffee and slurpees. Hydrogen burns, slurpees don’t. Also, you would need a large volume of stored hydrogen to power cars. Coffee only needs a couple gallons to get a store through the day, while with hydrogen you would need hundreds or thousands of gallons a day, requiring a large storage tank, and associated equipment. This type of stuff is expensive, especially considering there is little demand for hydrogen fuel right now.
>Perhaps even the oil tycoons have realized they’re going to run >out of oil someday, and they had better start diversifying.
Oil company executives aren’t stupid…well, some may be, but they’re rich enough to hire all of the geniuses they need. They know the score, and they’re playing the game accordingly. In the 70’s & later they tried to discredit wind & solar, while at the same time they were developing these technologies. BP Amoco is one of the biggest (maybe THE biggest) producers of solar cells today.
Hydrogen is a storage technology, not a production one. Unfortunately, fuel cells are still too expensive, but they’ll be in widespread use before too long - probably as home power generators. I don’t think it will be long after that we’ll start seeing them in production cars.
However, there is still a 60% energy loss involved in producing hydrogen from water. It’s easier & cheaper to get it from fossil fuels, chemically.
No one’s said anything about oil company subsidies yet. They make a great difference in the price of electricity. Nuclear is very expensive, as well as dirty. Wind power in particular is experiencing an explosion right now, and technically it’s the cheapest. It’s too bad we let go of our lead in this technology - we had a working turbine producing 1.2 MW in 1941.
Does anyone have any hard data regaring geothermal? From what I understand, it’s nowhere near ready, and may never be.
How come no one’s mentioned biodiesel? The main problem with fossil fuels is that we’re adding the CO2 of plants that died millions of years ago to today’s atmosphere. We could be re-using that CO2, and we’d still be able to drive our SUV’s. Also, we wouldn’t have to drill, or worry how much oil’s left underneath us.
Add this to the fact that biodiesel runs better than regular diesel, and requires no modification to cars or the delivery mechanisms, and it’s obvious that it’s a technology worth investigating. There are already many stations across Europe that serve biodiesel.
There are other factors as well. For instance, solar has a high startup cost, but there are no moving parts. There are solar panels which have been in operation for over 20 years, and they’re still putting out about the same power as when they were new. Solar gets cheaper the longer you use it.
There is enough energy available from wind & solar & alternative sources to meet all of our needs…not wants, mind you, but needs. We waste an incredible amount of energy. Our houses require huge amounts of heat to stay warm in the winter, then we pour lots more energy into them in the summer to move the heat out. There are many houses in this country that utilize thermal mass to lower heating costs & eliminate the need for air conditioning…as BrainGlutton pointed out, our daily living habits our wasteful in other ways…
Hybrid technology is a century old, but we’re only now starting to see hybrid cars on the road, and none of them (yet) are “true” hybrids, more like regular cars with a hybrid drive system attached.
Engineers have known for ages how to build a truly efficient car: design a small matched engine & generator to run at its most efficient speed, and only that speed. Drive the wheels with electric motors, and dump braking energy back into the battery. The powerplant kicks in when the battery is low, or when you’re accelerating & want all the power you can get. We could have an Insight-sized car delivering 125 mpg or more with today’s technology, though it wouldn’t have neck-breaking acceleration.
A few more thoughts to consider…we’re spending god knows how much money on exercise machines every year, devices which purposefully waste energy. Why not consider human power? Generators can easily be attached to exercise bikes to produce 50-100W or more, depending on how hard you want to pedal. God forbid we use bicycles for getting around; they’re only the most efficient form of travel there is.
Sorry for the energy-production talk; it’s necessary when considering hydrogen for cars.
Oh yeah, well there already running them hydrogen buses in California and we all know that California is the leader in energy policies (cars are built especially for California ) so I say so what if you have to put the fuel cells on a different isle from the coffee and stuff.
Solar becomes less efficient the longer you use it, according to my renewables expert friend (no cite offered, so it’s hearsay). And there is a not inconsiderable amount of maintenance, cleaning, and replacement of failed panels. Do you have any sources which show long-term annual costs versus capacity factors and production?
I agree wholeheartedly. I’ve posted in years past here of the results of energy audits I’ve done, and I feel there is a very large amount that can be done through conservation first.
Not hard data, but I don’t know where you get the idea that geothermal isn’t ready to be exploited. Here’s a bit of history on one geothermal plant in New Zealand that’s been in operation for decades. I visited this place several years ago and it is the most amazing collection of piping I’ve ever seen.
There are several other geothermal plants in New Zealand. Wairakei is the oldest, I believe.
Iceland gets something like 16% of its power from geothermal. But it’s an aberration, because it is a small country with a high concentration of geothermal sources.
For the average country, there just aren’t enough geothermal power sources to provide a significant fraction of energy.
