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Since my electric company pays me for any excess power I generate, the only thing I have going against me is the up front cost is higher... (capital investment) And in the area I am planning on moving too, they don't pay you for the excess power but you get carryover credits. Since the summer is a lot of sun and the winter not so much, you can bank your credits in the summer to get you through the winter. You could still go too big though. Granted, in both of these states you have a max KWH that you are allowed to get a permit for as a residential home owner. And at least where I am at, I will hit that limit before I over generate power. But that is just my case. Your results may be different.
Otherwise, your comments are spot on. They do make electric "dumps" for excess power generated, but that is hardly a good idea.
Let me take this to an extreme to make the point. If you leave a PV panel out in the sun not hooked up to any load, it will degrade.
Do you have a reference to substantiate your statement? I can't find anything to that effect.
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Originally Posted by DCforever
I'd suggest your second set of comments on undersized systems is a reason for a homeowner to adopt my approach of replacing before panel failure.
But how do you predict panel failure on a product that seems like it will never wear out because the decay rate is so tiny, and which is really only vulnerable to physical damage?
Here's an interesting article that confirms my personal experience, in which a privately owned thirty-year-old rooftop PV panel was checked for performance in 2010, and found to still be delivering electricity within factory specs, as confirmed by Raju Yenamandra, the North American head of sales and marketing for SolarWorld, the current owner of the old Arco Solar factory in California.
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"Your module is still performing to factory specifications — or perhaps a little better. That’s very good. We usually tell people to anticipate a performance degradation of 0.27% per year.”
When I told Yenamandra that the PV module’s serial number is 256387, he informed me that it was manufactured in 1979, during the very early years of Arco’s PV manufacturing history.
Joel Davidson, the PV dealer who sold me my solar panel, now lives in California. When I called him up, he was happy to reminisce about the early days of PV.
..... It should be good for a few more decades of service
.....
My old module shows no signs of browning, electrical corrosion, or water intrusion. It certainly looks as if it’s ready to perform for another decade or two.
“A PV cell is a rock that makes electricity,” said Davidson. “Unless something corrodes the electrical contacts, it will still keep working.”
As panels become more efficient you'll be able to increase the system output by just swapping out panels.
Sorry, this still makes no sense to me. If your current system is already exceeding your needs, why would you want to spend money to swap out a working panel for a newer, higher output panel? Sure, if you had a limited area to place your panels and needed to increase output, you would do this. But most people who want to increase output of rooftop systems simply add more panels to what they already have.
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Originally Posted by DCforever
My guess is the PV installer will track their customers and encourage them to make economically beneficial upgrades. As long as the simple payback stays in the 3-5 year time frame, I don't think it would be a major stumbling block. PV owners are not run of the mill consumers. They are receptive to economic arguments.
OK, but you still have not presented a viable economic argument to do so.
They do make electric "dumps" for excess power generated, but that is hardly a good idea.
But as this commenter says, dumps are used to protect battery banks against overcharging, and are only used on systems which have mechanical momentum, such as wind and hydro power. PV systems have no such momentum. Turn them off and they're off.
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Re: pv dump load to water heater on midnite solar classic?
When talking about solar, this type of load would be considered an 'opportunity load' rather than a 'dump load'. Dump loads are used when the wattage must go somewhere, used in generators like wind and water. Solar can just 'not produce' and it's happy.
We have had an 1800 sq.ft. two bedroom, two bath off-grid house for 15 years.
It is 1.5 kw with battery storage. The house is rented out as a vacation rental. It has all the modern ammenities...with our average nightly rental of $225.
Total cost of the system is in the neighborhood of $30,000. NO tax breaks in Washington state.
The most important thing is to start conserving energy before sizing a solar system. The best money you can spend is conservation of electricity. LED lightbulbs, barrier strips on never off appliances, and of course, right choice for fuels. Electricity is really expensive and inefficient for things that require heating elements.
Solar works on small scale. Don't recommend it for a industrial society!!! Solar is really expensive....hope your not doing this to save money.
We have had an 1800 sq.ft. two bedroom, two bath off-grid house for 15 years.
It is 1.5 kw with battery storage. The house is rented out as a vacation rental. It has all the modern ammenities...with our average nightly rental of $225.
Total cost of the system is in the neighborhood of $30,000. NO tax breaks in Washington state.
Hmmmm. This information seems out of date. Solar panel prices have dropped drastically in recent years, more than 80% since 2008 alone, and $1-1.25/watt has become pretty much an everyday price today from major dealers. Checking Amazon just now, I found a listing for a 1.5 kw panel set (6 - monocrystelline 250w panels) for $1,799. Installed prices for complete system, of course, are more expensive but can be found in many places for $3-5/w.
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Solar works on small scale. Don't recommend it for a industrial society!!! Solar is really expensive....hope your not doing this to save money.
Actually, solar energy is already cheaper than grid power in some areas, and it's still going down in price. Hundreds of thousands of Americans have already installed residential solar systems in order to save money.
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More American homes than ever before — nearly 31,000 — had solar panels installed on their roofs in the third quarter of 2013, the Solar Energy Industries Association announced Tuesday. Combined with utility scale projects, the U.S. gained a total of 930 megawatts of photovoltaic solar capacity, a 35 percent gain from the previous year. And we’re set to nearly double that amount.
.....
The increase was lead by large projects, but residential installations, which increased by 49 percent from 2012, showed the most rapid growth.
..... By the end of 2013, SEIA predicts, the total of individual solar projects in the U.S. may reach 400,000, accounting for over 10 gigawatts of power capacity.
Your specific situation in Washington State is pretty much the worst case for the US... you live in an area with almost the lowest solar energy potential in the country, other than Alaska... your grid power there, courtesy of the Columbia River hydro electric plants is among the cheapest in the country...and the state offers no tax breaks. It's better almost everywhere else.
IMHO - It makes more sense to me to collect solar heat and leave the electricity to the experts. This is really relevant in places served by the TVA and BPA.
"509" is the area code for Eastern Washington, not quite as cloudy and rainy as some may be picturing. Our system, in Southern Oregon on the east side of the Cascades at about 4,400', averages about 6 hours of sunlight a day (and that is just taking the generated kWh and dividing by the number of days, so that is WITH system losses).
Because we are on a grid-tie tariff program (which is very generous) we don't have battery storage. The one thing I have been watching, and will think about upgrading to, is the potential next generation of inverters which will allow the system to be used when the grid is down. Currently a grid failure takes the inverter off-line and even if you could be generating power, you aren't.
As far as maintenance - in the summer we have to hose the panels off when they get dusty, maybe once or twice. We get out there about 6 times a year to change the tilt of the panels to adjust for season. That is it.
Last edited by PNW-type-gal; 05-17-2014 at 10:26 AM..
Reason: typos, typos. Eeeek.
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