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Here are some sites you might be interested in:

http://howardhallfarm.com/freewatt.html
http://www.infiniacorp.com/
http://www.mrsolar.com/
http://www.dodsbir.net/selections/abs071/osdabs071.htm
http://www.stirling-tech.com/

You might want to also contact the Honda Motor Company, as they mass produce the engine type you are interested in (they use them in their Hybrids).

Making a blanket statement as you did tends to result in severe cases of "Foot in Mouth" disease. FYI a 50watt 12v PV panel requires a minimum of 8ga wire to connect to the busbar while a 200watt panel requires at least (4)0 wire (quad aught) to handle the amperage it can easily output and most PV panels over the 150watt rating are configured for 24v output.

Now depending on what the OP wants to do with the PV system is going to determine what he needs. If it's simply lighting for a shed, then the issue is even simpler. Get a small PV powered light unit (Brinkman/Others) from the local Home Improvement Center or order it online and use it to light the shed. If it's anything more then lighting, then you need to consider appropriate wire gauge to minimize voltage drops, Purchasing of DC rated switches (standard household switches aren't safe due to arcing).

In regards to the 120/240 AC voltages, you're actually better off putting the Inverters near the batteries and running standard house wiring because of safety factors. We're damn familiar with AC power and there's plenty of standards to follow when working with it. PV systems with high amp DC circuits are very dangerous Common Automotive Batteries can output in excess of 1200A when the posts are shorted, so you damn well better protect those batteries.

Right now the best solution would be to head over to Mr Solar where you can find plenty of PV related equipment and kits for numerous projects.

You bring up an interesting point... If solar power (and other renewable energy sources) are truly as cheap and effective as supporters say they are, then why aren't we using them?

This comment not directed at parent - it's to the world in general: Just shut up and do it already!

If it works so well, why aren't you already paying $0 for your energy bills?!? Here: BUY SOME! Install them, and then (and only then), come back to slashdot and tell us how well they work, and how you don't pay anything for electricity anymore!

I understand our concern about the larger issue of how "everyone else" gets their energy. The discussion about large-scale renewable energy sources is an important and worthy conversation. But what better way to further that goal than to be an example of how this can succeed by just doing it for yourself?

I'm going to price out some solar panels for my house and see if I can make this work right now. In fact, if it *does* work out, maybe I'll look into buying a patch of land and installing a bunch of solar panels and selling the energy. But here's my concern: I'm not the first person to have thought of this. And solar panels aren't exactly a new invention. So why don't we see a bunch of little, private wind and/or solar energy farms? Is it because it doesn't work on a small scale, but does work on a larger scale? I don't buy that - the relationship between the amount of energy collected and the most significant resource that solar energy collection requires (land) is perfectly linear: One 10x10 solar panel optimally collects x KW/h of energy. y 10x10 solar panels optimally collect x*y KW/h of energy. If it's going to work on a large scale, it *must* necessarily also work on all smaller scales.

Like I said, I'm going to look into doing it for myself, but my suspicion is that the reason we're not all already doing this is because it just doesn't work.

1 Kw Panel = 1825 Kwh/year (5 hrs a day * 365)

5*216 1080 watts Panel Costs $5,000
http://www.mrsolar.com/page/MSOS/PROD/wattsort/Sharp216/SESSION_ID/c929b4a648a683c8ffe01940cca4d17f

15 TW/year (http://en.wikipedia.org/wiki/Energy_use_in_the_United_States)

15 000 000 000 kW IN 15 TW

8,219,179 Kw needed

$ 41,095,895,000 Total Cost
$13,675,129,000,000 US GDP

Much less then 10%

Solar Thermal on the other hand

http://en.wikipedia.org/wiki/Cloncurry_solar_power_station

$1.03 per KWH

$ 15,450,000,000 Total Cost to build
$13,675,129,000,000 US GDP

Much less then 10% and has storage for night time

Care to dispute my figures.

I agree this could be provided cheaper, but you underestimated the solar power requirements by a long shot.

The solar panel suggested in your link is an 18-watt ($175) solar panel, and is inadequate to charge the 60-Ah battery included with the Xantrex Xpower 1500 Powerpack. A complete charge would take several days of full sun.

The Lenovo & Dell packages include a 110-watt solar panel, which sells for about $6-700 dollars at Real Goods or Mr. Solar.

For $1500, you could by a decent laptop for $1000, and then assemble your fun $300 solar/battery kit.

Let's try this with some more accurate numbers.

180 Watt Solar Panels ($880 each)

That's 8,888 180 Watt panels to get to 1.6MW peak.

Total cost for the panels: $7,821,440. Now, let's say for spending that much money google is able to negotiate a modest 5% discount to bring the cost per panel with discount down to: $7,430,368.

I'm going to stick with the above assumption that wiring and converters at this level will come in around 20% of the cost. Which is $1,486,073.

Now let's assume they can get the whole thing installed at a price of $500 per panel on average. That's $4,444,400.

There, my total cost for installation is now: $13,360,441.

It's hard to estimate how many watts per day one of the 180 watt panels will produce because it depends a lot on local weather patterns and how they're positioned. But over a 24hour/365 day period I'm going to go ahead and assume an average hourly production ballpark figure of 25 watts per panel. So that's 25 watts x 8,888 panels: 222.2KW hours. Multiply it by 8,760 hours in a year: 1,946,472 KW hours/year.

The best I could find for electric rates is Sacramento at $0.111/kwh.

At that rate, google will save $216,058/year.

Solar panels last much longer than 15 years. Here's a company that claims a lifespan of 30+ years and they have a 25 year warranty. Here's a guy who talks about a 21 year old panel still producing at near it's peak rating.

From personal experience I can say many older panels lose some efficiency and after 12-15 years their output drops to ~80% of the their original peak output. But let's assume the gradual loss of output will coincide with a gradual increase in the grid power price, offsetting each other.

So let's say a 30 year life, $216,058/year comes to $6,481,740. Subtract that from the installation costs and you get: $-6,878,701. Not nearly the $120M loss you estimate.

Now, if prices did, in fact, quadruple (which over a 30 year period isn't only unheard of, but likely) the numbers get ever closer to a net of zero. Not to mention the publicity google gains from this and the mitigation of risk by not leaving themselves susceptable to rising energy prices. And who knows, the panels may last 40 years.

Either way, it's not the giant boondoggle you make it out to be.

Some of your estimates are just plain wrong.

175 Watt panel for $810/each
If I can buy that, I'm sure Google can get a cheaper price.

Most PV panels are warrantied for 25 years. That is, they are gauranteed to produce >90% rated peak power for 25 years. Typical total lifespan is about 40 years (with output dropping to ~80% peak).

PV systems require virtually no maintenance. Think window washers. 100 service people? that's just silly. maybe 1 person full-time, more likely contracted as needed a couple times a year.

at least do a little research on your numbers ;-)

Your prices are way off for PV panels. It didn't take me more than 60 seconds to find . Quantities of 12x panels that peak at 175W, $810 each. About $4.63 per watt (peak) Google will be purchasing in larger volumes than this and will no doubt get a much better price. But at this price point, the PV panels alone would be about $139M for a 30MW peak production array.

Google will realize tax writeoffs for the whole thing, a one-time tax credit (or perhaps they will find a way to make the tax credit apply at a lower amount over multiple years), and above and beyond that they will see significantly reduced site power bills.

The next thing they need to be looking at is average power consumption per employee and find more efficient ways to work. Putting a PC on every desk is wasteful. One fat LTSP server per department (or for multiple departments!) and a thin client on every desk would be more than enough for most people. I did this at another shop a few years ago and it worked great. It's a real shame that most people are stuck in a rut and won't try a new way of doing things .

OK it's not a new way of doing things. The idea itself is really very old. But the technology has caught up with the idea, and it's now a very workable idea, unlike the old X terminal toasters of the early 1990's running on 10Mbps ethernet with lousy graphics chipsets and poor performance, with a couple of dozen people sharing a SPARCstation 5 (not enough machine for one person, let along 12).

I keep wondering where he got the solar system for only 3k.

Mr Solar wants $840 for 175 watts. For 1.2kw, you'd need 7 of them, or almost $6k.
He may be a tad expensive, but within reason

Add another 3k in for the inverter and other gear to hook it into your power system.

Mr Solar wants nearly 10k for a 1.4kw system.

Well, I don't really trust this site, but they're number 2 on google, $5k for a 2.4kw system, but they're advertising a $4k cash rebate and $2k california credit.

Solar doesn't work well for everyone. A few things...

not everyone has a conveniently South facing roof, which greatly adds to the expense and/or efficiency.

There are significant variations in solar's potential between different areas of the country: http://www.mrsolar.com/faq/insol/usa.htm

Batteries aren't a problem if you use a solar charger.

Oh, and as far as towers / antennas go, I bet many parks already have cell towers for safety reasons. Why can't they just use those?

At 1.5 watts per SQ foot, covering an area of the roof with solar panels will only net you 12 amps per 1000 sq feet of home @ 120V. Consider that most homes have 200 amp power panels. 1000 sq feet of panels costs $62,000. Saving $100/month, the panels would exceed their life expectancy before making back the raw cost.

The average price for a 1,000 sq foot house in my area is around $80,000.

Consider that in areas further south, power production goes up more than 50%, which makes the panels a much beter deal. Add in maintenance and repairs, and it makes no sense to install solar panels here.

One solution would be to rig an old ~200MHz laptop up with two of the usb/wireless/fry-skimmer-antennas and put it on top of your hill. One could point to the source, the other home. Then the issue would be power. You mentioned solar, which would be pretty cool. Place the laptop in a weather-proof box, shaded by the solar panel, with the the two antennas sticking up and yay, access!

Some links to help:

Solar Laptop
http://www.mrsolar.com/
Home-built
Radioactive Network

Please email me if you get something like this working, I'd love to set one up for my parents.

My question to you is about how much did it cost to setup this type of a system. I setup a solar power system using a solar battery charger, a 12 volt battery, and power inverter for my shed. The total cost was about 100 bucks.

I would love to have some stuff in my house moved off the main power, but cannot justify cost of equipment over the cost of using the power company.

Are there places out there where you are getting the equipment for reasonable prices? Is this a homebuilt system, or did you buy one.

Looking at a few systems such as Mr Solar small systems start around 5k.

Just curious about what you did...

Thanks.

We have solar water heaters to preheat the water which enters the hot water heater. It's not very high tech, and it sure ain't tech-sexy, but it does what I think you want.

Check your power bill to see how much gas/electricity you use each month, and compare that to the ratings on your hot water heater, dishwasher, clothes washer, dryer, and home heating/cooling system. Those five items use a large percentage of your energy, don't they? Preheating the water entering your water heater will reduce the energy necessary to heat your water to a good temperature. (The energy to heat something is proportional to the difference between the initial and final temperatures; q=hA(Ti-Tf) for convection.) BTW, you might want to turn down the output temperature of your hot water heater to the temperature your dishwasher needs for the hot cycle. That is the hottest almost anybody needs any water in their homes, and heating the water above the "dishwasher temperature" is a waste of energy.

Don't get me wrong, I like electricity from the sun, but it isn't the only way to harness the sun. And I don't think it is the most efficient. Alas, I can't find any examples of solar power conversion efficiencies in my Thermodynamics or Heat Transfer textbooks, so I can't compare numbers. You might want to check out Mr. Solar for some more ideas.

Good luck.

Louis Wu

Louis Wu

Thinking is one of hardest types of work.

They've been selling solar cells for laptops for a long time -- this is nothing new, but still interesting to look at for those didn't know these things existed.

MrSolar also has some laptop solar panels available -- kind of pricey, and he was a bit of a Y2k nut. Wanted to boost his sales, I guess.

Patrick

They've been selling solar cells for laptops for a long time -- this is nothing new, but still interesting to look at for those didn't know these things existed.

MrSolar also has some laptop solar panels available -- kind of pricey, and he was a bit of a Y2k nut. Wanted to boost his sales, I guess.

Patrick