Solar energy????

[Kristinsgrandpa]

New Low Cost Solar Panels Ready for Mass Production
Colorado's State Univ.'s panels will cost less than $1 per watt.

Compiled By Adrienne Selko   
Sept. 10, 2007 -- Colorado State University's method for manufacturing low-cost, high-efficiency solar panels is nearing mass production. AVA Solar Inc. will start production by the end of next year on the technology developed by mechanical engineering Professor W.S. Sampath at Colorado State. The new 200-megawatt factory is expected to employ up to 500 people. Based on the average household usage, 200 megawatts will power 40,000 U.S. homes.


Produced at less than $1 per watt, the panels will dramatically reduce the cost of generating solar electricity and could power homes and businesses around the globe with clean energy for roughly the same cost as traditionally generated electricity.

Sampath has developed a continuous, automated manufacturing process for solar panels using glass coating with a cadmium telluride thin film instead of the standard high-cost crystalline silicon. Because the process produces high efficiency devices (ranging from 11% to 13%) at a very high rate and yield, it can be done much more cheaply than with existing technologies. The cost to the consumer could be as low as $2 per watt, about half the current cost of solar panels. In addition, this solar technology need not be tied to a grid, so it can be affordably installed and operated in nearly any location.

The process is a low waste process with less than 2% of the materials used in production needing to be recycled. It also makes better use of raw materials since the process converts solar energy into electricity more efficiently. Cadmium telluride solar panels require 100 times less semiconductor material than high-cost crystalline silicon panels.

"This technology offers a significant improvement in capital and labor productivity and overall manufacturing efficiency," said Sampath, director of Colorado State's Materials Engineering Laboratory.

Sampath has spent the past 16 years perfecting the technology. In that time, annual global sales of photovoltaic technology have grown to approximately 2 gigawatts or two billion watts -- roughly a $6 billion industry. Demand has increased nearly 40% a year for each of the past five years -- a trend that analysts and industry experts expect to continue.

By 2010, solar cell manufacturing is expected to be a $25 billion-plus industry.

This info came from this website 9-10-2007

http://www.industryweek.com/ReadArticle.aspx?ArticleID=14932&SectionID=4


Ed

[Lin]

Just saw a website that offered refurbished 190 watt Sanyo solar panels for $1.2/watt, that about $228/panel.  They said they have a 3 year warranty too.  Only one catch--you have to buy a container of 400.

[kysteve]

Lin,  $90,000.00 would buy a lot of fuel, even at the predicted 7.00 a gallon rate....lol......

[Lin]

Right, but you would be generating 750 kwh/day.  In California, from what I understand, the utility company would be buying most of that at the top tier rate.

[Sean]

Right, but you would be generating 750 kwh/day.

I think you've made a math error.  Or you've moved California closer to the equator.

400 190-watt panels is 76 kilowatts.  That's the maximum or "peak" output under ideal conditions, meaning ~35° lattitude, cloudless, hazeless sky, aimed directly at the sun, and in ~70°F weather.

Real-world output of such a bank, at an optimum but fixed inclination, would average perhaps 300-350 kWh per day.  At wholesale utility rates (what they have to pay you in those quantities), that's ~$30 or so per day, when it's sunny.  Not counting your other installation costs, you'll pay back the $91,000 in about 3,000 sunny days, or roughly 10 years, give or take.  Of course, the panels only have a three-year warranty, so extend that 10-year number by 20%-30% for routine maintenance and replacement of defective panels, etc.

FWIW.

-Sean
http://ourodyssey.blogspot.com

[Kiwi55]

A slightly different but very happy reason for solar...

I hang out in the desert for 2 weeks at a time (Burningman and other events) and for most of my bus-years had a propane fridge onboard.  It couldn't handle the really hot days, driving with the propane on was discomforting, and levelling the bus to keep it working was a giant hassle. 

So after 5 years of this, I went to a cool (no pun) refrigerator website and found a list of the efficiency of all the 110vac fridges out there:
http://www.energystar.gov/index.cfm?fuseaction=refrig.display_products_html
and selected the most efficient fridge I could find, a Summit (no longer made BTW) that was actually bigger inside but smaller outside than my current propane fridge.

I made the change and was quite happy.  I bought a cheap chinese 2KW pure sine inverter from Ebay and wired it permanently to the fridge so that the fridge's thermostat switch hooked into the inverter's off-on switch.  Even though the fridge only draws something like 117 watts when running, starting the compressor requires the full 2KW inverter rating or it just won't work.  (I found this out the hard way by purchasing a 1KW trace inverter that didn't have a chance of starting the compressor!)
Anyway, with the inverter dedicated to the fridge in this way,  the fridge goes on and off as needed but the inverter is never idling and wasting power when the fridge is off... it's off too.

I have four T-125's for my house batteries and this is enough to carry the fridge for about a day and a half, maybe two, then I either have to plug in to shore or run the gene.

Just recently I decided to go solar. The cheap way... There are always solar panels available used, usually thru ebay or craigslist, for around $3 per advertised watt.  Because they are used, they are often less actual capacity than their rating but usable nonetheless, and also considering that mounted flat to a bus roof, they're never going to put out as much power as a set of panels correctly aimed directly at the sun... so I figured getting twice as much wattage as I calculated I'd need would probably do the trick, and this seems to be right on the target.   
  So I bought three 80 watt panels and a cheap Manson 3 stage charge controller, stuck em on the roof and wheeee... no more necessity to plug in or run the gene!!  At least in the desert the three panels produce 130 watts total on average during the day, and this almost perfectly matches the power that gets used considering the fridge, lighting, and occasional bathroom fan, etc.  By morning the batteries are down to 11.75 volts and by end of day they are back charged up on float.  I'm going to stick a 4th panel up soon to make sure I have capacity enough on not-so-ideal days, and also to offset the power my heater fan draws on those occasional nasty cold desert nights.

An aside- when I put these up on the roof I wasn't keen on putting more holes in the roof for wires, so instead I butted them up against my roof air conditioners, ran the cables up under the AC/s, in to them and up "high" under the cowling where there's no chance of rain or water, punched them through into the cool air duct, where inside the bus I could then route them wherever.  It worked out really well.

Anyway, just thought I'd report a successful  solar installation that is extremely practical and definitely better than "useful for an occasional light or fan", and didn't break the bank.  $700 for the three panels, $60 for the controller, (not necessarily part of the solar cost, but $200 for the dedicated inverter and $600 for the fridge), and ten bucks worth of mounting hardware, and I have a fridge that doesn't need levelling, keeps cold even on the hottest days, and runs on energy that doesn't come from some sort of fuel tank.. 

One more thing to note- every watt that the panels see coming from the sun, even if not converted to electricity, is a watt that doesn't hit the roof of the bus.  I noticed immediately the difference inside on a hot sunny day- the bus was quite a bit cooler than it's ever been.  Makes sense... three panels 2 x 4 ft is almost 3 meters of free shade- that's almost 3KW not getting absorbed by the bus roof!!

Any chance you can post a diagram of how you wired the inverter to the fridge?.
I must be missing something, but when the fridge shuts the inverter off doesnt the fridge loose all ower? How then does the fridge thermostat (which has no power) trip the inverter back on. This seems like the perfect solution for me, I just cant envision the wiring.
Thanks...Paul

[Lin]

Sean,
    Yeah, I know I was on the optimistic side, but since we live in the desert, overcast days are not an issue.  I thought that one might be getting over 40 cents/kwh, but that was just a guess.  Anyway, I expect that rates will be going up steadily so the payback period would be pushed closer each time.  Solar panels, I think, have proven to have a life span of at least 20 years. This is obviously all hypothetical, I doubt that the county would allow it on my property anyway, and SoCalEd might have something to say about it too.  There was a guy in Santa Cruz that put in such a large system the PG&E refused to let him hook it up saying they would have to upgrade there lines to accept his power.  He took them to court and won, but he was one of those people to whom money is not an issue. 

[Sean]

[snipped]

Any chance you can post a diagram of how you wired the inverter to the fridge?.

Folks, let's snip our quotes.  There was no need to repost Gary's entire message in this reply -- we can all go back and re-read it if needed.  Just the relevant line or two would have been sufficient.  Some of us are subscribing to this thread in email -- I had to re-read Gary's entire message just to get to your question.

I must be missing something, but when the fridge shuts the inverter off doesnt the fridge loose all ower? How then does the fridge thermostat (which has no power) trip the inverter back on. ...

Not to step on Gary's toes, but as long as I am typing, I'll answer the question (but leave it to Gary to post his diagram, if he's made one).

The thermostat is a simple on/off (meaning SPST) switch -- it does not require any power of its own to run.  You simply remove the thermostat from the original circuit, connecting the two wires thus disconnected directly to each other, thereby "bypassing" the switch.  You now wire the switch instead either to where the inverter's on/off switch was (if any), or into one of the battery connections to the inverter.  If the latter, you need to be sure the thermostat switch is rated for the full current draw of the inverter, or else use the thermostat to operate a relay of appropriate rating to turn the inverter on and off.  From Gary's post I surmise that his inverter had an on/off switch and he simply replaced it with the thermostat in the fridge.

HTH,

-Sean
http://ourodyssey.blogspot.com

[Sean]

...  I thought that one might be getting over 40 cents/kwh, but that was just a guess.

$0.10 per kWh is more typical, FYI.

...  Solar panels ... have a life span of at least 20 years. This is obviously all hypothetical, I doubt that the county would allow it on my property anyway, and SoCalEd might have something to say about it too. 

Well, we're getting a bit far afield from buses (but there will be some bus-related content later in my post, Richard, I promise!), but as long as we're talking about it:  The numbers I tossed out earlier are, indeed, hypothetical, because we've left out big chunks of the installation costs, including the 76 kilowatt, grid-tie inverter system -- well into the tens of thousands of dollars.  We also left out the tax credits and incentives for installation of alternative energy systems, which then offsets some of that cost.

That said, if you do want to put in a large (or even small) solar system, don't worry too much about county objections.  State law in California heavily favors installation of solar, and, while the city or county may make you jump through a certain number of hoops, they generally can not prohibit such systems outright.  I remember a case a few years ago in the bay area where someone with a solar installation on his roof was able to force a neighbor to cut down or prune a 100+ year old tree, which was also legally protected, because the solar legislation trumped both the neighbor's property rights and the tree protection provisions.  FWIW.

As long as I've mentioned tax credits (bus content here), I should point out that they are available to bus conversions as well if that happens to be your primary residence.  In our case it is, and we were able to submit the entire cost of our solar panel installation last year on our taxes for the alternative energy credit. Also, we bought the panels in Arizona to begin with, where the state sales tax is waived on solar panels.  YMMV, etc.

-Sean
http://ourodyssey.blogspot.com