hydrogen powered cars

Factual Questions
41

>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?

Sorry, I’m going to have to ask for a cite on this one. Failed panels? Pretty rare, actually I’ve never heard of one. Maintenance? What maintenance? Cleaning? Not much of an issue - the rain takes care of that, at least in this part of the country. I’ve never had a full-scale PV system, but I do own small panels which I’ve experimented with. They’re over 10 years old, and work just as well as when I got them.

The largest (& pretty much only) maintenance factor in solar systems is the battery, which admittedly is expensive & needs to be replaced every 3-7 years, depending on quality, maintenance, etc. but I know of systems 10 years old which are still using the original battery.
The following excerpts are preceded by their respective URLs:

“In general, the PV modules are the longest lived component of a PV system. Top quality modules such as Solarex’s MEGA series are designed to last at least 30 years and carry a 20 year warranty. They are designed to withstand all of the rigors of the environment including arctic cold, desert heat, tropical humidity, winds in excess of 125 mph ((200kph),), and 1 inch (25 mm) hail at terminal velocity.”
http://www.sunwize.com/aboutpv/swaboutpv.html

"PV systems have no moving parts, require virtually no maintenance, and have cells that last for decades. "
Much thanks for the link to the NZ geothermal site.
“How many power generation technologies can you name that people want to put in their backyard?” - Richard Chleboski

42

Hey, what about hydorgen powered cars and putting the fuel cells
at the gas stations (away from the slurpees an shit)?

43

I said I didn’t have a cite, and that it was hearsay. I admitted this in my post, which is why my post had a clearly questioning tone. They can become less effiicient in cases due to opacity changes in the coating material, according to my friend. And according to a few links (which can easily be found on Google), this is at least known.

http://www.nyseia.org/basicsn.htm

And of course, this paper talks a bit about optical loss of encapsulant. If you’ve been in this field for some time, I’m a bit surprised you wouldn’t have this paper handy. Note this is from Sandia Labs, and not from a vendor or an advocacy group:

http://www.sandia.gov/pv/prmking.pdf

They go into a bit on how the transmittance has been found to decrease over time. Comments?

See also the point on series electrical resistance, which, according to Sandia Labs:

(prior link)

The material which coats the cells can age, become brittle, crack, or discolour. I’ve seen “burnt-out” panels before. It happens when they are in practical use, day in and day out.

Maintenance of the very expensive batteries and of tracking systems (servos, gears, etc.) Especially in very hot environments. Also, voltage inverters aren’t the most reliable beasts, especially the 220V 50Hz ones. ( :frowning: )

A very light film of adherent dust does reduce the energy transmitted. Ever leave a car out and let the rain clean it? It doesn’t look nearly as clean, or reflective, as after a wash. Same with windows on your house. Over time, chemicals from photochemical smog and other organic materials (as well as some inorganics) build up on the glass. And rain isn’t going to clean it. This is really something any homeowner is familiar with, and not rocket science.

But how do you verify this? Did you meter the light hitting them independently, and their resulting VA’s when you bought them? I mean, without being argumentative here, what is your criteria for “just as well”?

I’m not knocking their reliability overall, and even the Sandia Labs paper I linked above has very good things to say about their performance. Damn good things, in fact, which I freely admit. But let’s not give them magical performance and reliability atributes which they do not possess.

44

I’ve also heard it said that a PV array does not generate any net energy. In other words, more energy is expended manufacturing a PV cell than what you get out of it over an average lifetime. Don’t have any data to back it up, however…

45

No, it’s not true. Energy Payback: Clean Energy from PV

46

Hydrogen is used to store energy* and move it around. People seem to keep forgetting this - think of hydrogen not as a fuel, but a battery.

There are other batteries, but fuel cells can offer charging times of a few seconds and ~ 1,000Wh/kg compared to 120 Wh/kg for a Nickel-Zinc battery. And dont forget the Vanadium redox battery.

So to produce the hydrogen for cars, it is either coal or nuclear (or nuculer as GWB calls it).

*I know oil is a solar battery - but that is a different timescale.

47

Man, all that work & my post doesn’t show up…I don’t want to post all that again…
Anthracite, you made some good points, and I responded, but since my post ended up in limbo, I’ll do a condensed recap…

  1. Yes, there is slight degradation, and yes, contaminents will accumulate on the cells…but this is a very small amount, and the practical amount of energy harvested isn’t significantly affected. Around here, there aren’t many trackers, folks just put them on their roofs. Compared to other technologies, solar is very low-maintenance, though I didn’t intent to imply any magical properties.

  2. I never said I was in the field, but I worked with someone who was & got the chance to learn a lot about PVs, as well as see some in the field.

I also wrote a long paragraph about how most people won’t realize the potential benefits of solar & wind because it takes a certain kind of person to tinker. I’m really rather pissed now that my post disappeared, and I’ll be sure to copy posts to the clipboard from now on before I submit replies so I won’t have to go through this again. Damn the internet, damn it to heck.

Oh yeah…UV beats the crap out of everything - it’s the leading cause of wear & tear on hang gliders & sails, as well as just about everything that sits in the sunlight & doesn’t move.

Dammit all…

48

That’s the energy density of pure hydrogen, isn’t it? I think the numbers would be comparable if you include the weight of the hydrogen tank. Anyone got an estimate?

49

Yeah, I wrote a multi-page treatise on coal once for someone that the SDMB ate, and I just said “fuckit” and didn’t want to re-write it. I normally write in Notepad first, then C&P. Too much wasted effort, otherwise. Hell, even the UnaBoard has dropped a post of mine once in a (great) while - which really pisses me off, since it’s my own freaking Board…

I think the difference is we’re looking at it from different ends - I’m looking at it from the MW-level utility installation, and there are going to be different pluses and minuses than from the residential/individual/kW-level, like you say.

50

I must tell you about a geologist friend of mine who spends at least 9 months a year in the Australian outback looking for various minerals and stuff on behalf of energy and mining companies. His 4 wheel drive workhorse has this fantastic solar panel and refrigerator setup which Mick has owned since 1991 apparently. The solar setup that is - the 4wd vehicles are owned by the companies he works for. The refrigerator utilises a solar panel which sits on the roof of the cabin. Also, the solar panel feeds a current into the car battery as well so that it never goes flat. It has proven to be an absolute godsend for Mick. The refrigerator also catches humidity from the internal cooling and provides 3 liters of fresh water a day for Mick. All in all, a magnificent setup for a working geologist in the field. He could have a complete engine breakdown but that solar panel will keep him in water, and radio contact no matter where he is. It powers the GPS as well. It effectively makes his work almost totally self contained in terms of safety.

51

I dont think so.

Someone might check these with the Rubber Book.
H2: 30 kWh/kg
Natural gas: 9.3 kWh/kg
Oil: 11.6 kWh/kg
Gasoline: 12.3 kWh/kg
Lead-acid battery: 35-50 Wh/kg
Coal: ~ 5 kWh/kg
Hydrogen fuel cell: 1 kWh/kg
Methanol fuel cell: ?
Zn-Ni battery: 120 Wh/kg
LPG: 15 kWh/kg

The point remains, it doesnt matter what battery you have, you still have to charge it up. So when the oil runs out in 50-100 years we use newcula.

52

…or coal.

53

You lost me here. You describe “true” hybrids as electric cars, right? As opposed to regular old internal combustion cars. Well, the current hybrids are… well… a hybrid of those two systems, hence, a real “hybrid”, right?

Or do you mean that a true hybrid is a car run on electric motors or generated by electricity? I guess if that’s the case, I’m just nitpicking your terminology - since the combining of two systems is a hybrid, and it’s not really correct to say one hybrid is a “true” hybrid and one isn’t - at least in this context.

54

Anthracite, I agree completely, in my limbo post I mentioned that solar was more practical for home & community use. I don’t think the technology is quite ready for large power supply installations, though if solar got half of the subsidies oil did, there’d be solar shingles on everyone’s roof. Imagine if you will, shingles which last 50 years and produce clean, dependable energy while keeping raindrops off your head…

I also wanted to point out that solar & wind power are complementary technologies, and IMHO should be used together whenever possible. In the winter, when less power is available to the PVs because of the lower angle of the sun’s rays, the wind is usually stronger…and a small increase in wind speed means a huge increase in available power. If it’s raining out, and the sun is obscured by clouds, the wind’s usually blowing. Also, a large part of the expense of solar is the batteries, inverters, etc. which are the same parts needed by a wind system…you can add wind capability for a fraction of the cost of an entire wind power system.

55

Flying_Monk, being a pedant here, but the OP was about powering cars. I would love to see solar shingles on houses though.

And any excuse for me to link to what will be the worlds tallest structure. A solar chimney, 3,300 ft ( 1 km ) high that can power 200,000 homes.

56

Senorbeef: I mean that the Insight, technically, can function without the electric system. It’s got a standard gasoline motor coupled with a transmission & drive system, with the electric drive & charging, regenerative brakes etc. basically riding piggyback.

A true hybrid, in my personal view of design, is accomplished by utilizing the best characteristics of the respective technologies synergetically to achieve maximum efficiency & reliability. My basic example is a well-known ideal among people interested in hybrid cars. Gas & electric technologies are a natural match, ignored for almost a century due in part to the cooperation between big auto & big oil. However, though the Insight may not be a “pure” hybrid in the strictest sense, there are some people who’ve managed to squeeze over 80 mpg on highway trips from them. That’s pretty darn good, and if they tried going the ideal path (and you know that Honda could, if they put their minds to it) it’s a pretty sure bet you could get at least 100 mpg out of a 4-person hatchback a little larger than the Insight. Food for thought: Honda’s 1983 Civic CRX got 67 mpg on the highway. That’s using a regular gasoline engine.

57

I’d like to clarify my last post: a hybrid system like the one I described as “ideal” is known as a “series” hybrid. If the Insight was capable of being driven using only the electric motor, it would be called a “parallel” hybrid. This has the capability of great efficiency, compared to the Insight’s motor-assist system, because when a car is travelling at 60 mph on the highway it uses very little power, perhaps less than 10. (I’ve read figures of 15 hp for a regular car, in print somewhere in the mid-eighties. I think under 10 is a good guess, given the Insight has low rolling resistance & a drag coefficient of only .25, but it’s not exactly an educated one. It may even be as little as 5.) You can supply that power with just the electric system, at great efficiency - and the principle applies for lower speeds, as well - but if acceleration is needed, so the the gas engine, and the lag time necessary to restart it & the the power to the wheels means using just the electric is more suited to highway-type constant-speed driving.
I really think the Insight could be easily converted, and new advances in lithium-ion polymer cell technology is going to accentuate the electric system’s capabilities to a great degree.

58

Ok, just got back to the board, haven’t checked posts in a while.

Sam, remember that I am not suggesting that you can power a vehicle on solar power. I am suggesting that you can electrolysize water to provide hydrogen for a fuel cell using solar power. It is a huge difference. Anyone can see that a few solar cells will provide enough power to do this to a quantity of water over a period of time. The exact requirements for a system like this can be computed, and it doesn’t take an engineering degree to do this, just some basic chemistry.

My point though is that it will never be done commercially. Because, energy producing companies do not want this to happen, they want to be in control, pulling the reigns of the energy market, and making money.

But, since you will not even give me this much credit without seeing a cite for an experimental variety of this fuel cell - reformer, I will find one, because I remember reading about it last year.

Now to do some googling.

59

Ok here is a cite, all-be-it a not very good site, of the scenario that I proposed. I will look for some better ones as time permits.

http://www.nmsea.org/Demonstration_Equipment/Fuel_Cell_Exhibits.htm

60

Here is another cite that suggests that water can be electrolisized into Hydrogen and Oxygen using solar power:

http://www.virtualtechnologiesltd.com/FAQs/FAQ-Fuel_Cells-Virtual_Technologies.htm

Here is a copy of the text in question:

Hydrogen can either be reformed from fossil fuels (i.e., natural
gas, propane, etc.) or, the system can be coupled to a
renewable energy source to generate hydrogen through
electrolysis of water. (Solar panels or wind generators are
required to produce the electricity for electrolysis.)

But it will take some very savvy individuals to marry the technology together. Not savvy in the sense of how to do this, but savvy in the sense of how to keep the energy companies from squashing his or her business.

Ok that is about all I am doing now, I will search for some better cites later today