Is there a credible site out there (besides lancaster's energy fun) showing that solar PV are net energy sink with calculations and such?
I need some ammo against local tree huggers and the amount of stuff out there is overwhelming.
M
It would be surprising if there were. PV arrays currently payback their energy costs of production in between 3 and 4 years depending on the technology and how sunny the site. The next generation will pay back even faster. You could shorten the payback time with a concentrator at the risk of shortening the system lifetime. Try
Above is a DoE site answering your question directly. With a guarantee of 20 years operation and a design lifetime of 30 years most PVs should give at least a 4 fold return on the energy needed to manufacture them.
PV can sometimes be useful and competitive for off grid systems.
Where PV falls down is the high initial capital outlay per installed kW and consequent high dollar cost of the electricity that they produce when compared to other alternatives.
Wind turbines seem to do a fair bit better but nimbys don't like them.
Regards, Martin Brown
** Posted from
Rather a Red Queen approach, isn't it? Verdict first, then the trial.
Regardless, Circuit Cellar has been running a series on Steve's PV system that should be relatively unbiased. Starts with the Dec 07 issue and seems to be available on-line through their archives.
-- Rich Webb Norfolk, VA
Dirk
costs of production in between 3 and 4 years
pay back even faster. You could shorten the payback
What I've been hearing for years is that it doesn't make sense, doesn't reduce Co2 level, is a net energy sink and is only really sensible if you have no other option. If you take away the subsidy you're in the red.
Has something changed radically in the last few years?
M
messagenews:85a3$4846a37f$ snipped-for-privacy@news.teranews.com...
energy costs of production in between 3 and 4 years
pay back even faster. You could shorten the payback
other
Yes - PV has been getting cheaper and more efficient. This is not a static technology and there are massive ongoing improvements in productions technologies.
Dirk
Andy writes:
It's not hard to do the calculations yourself:
1) Determine the amount of power that your house uses in a month, for instance , 1000 kwh..... Then determine the peak power necessary for any extended period, such as air conditioning and hot water heater at the same time. 2) Determine the storage capacity of batteries and inverters needed to provide the peak power for the extended time, AND the amount of power for a month, as you determined in step 1. Price them out for , say, 20 years, allowing for replacement when the warranty of each item runs out. 3) From the internet, determine the average FULL-SUNLIGHT hours you have per day in your location. For instance, the sunlight hours in Dallas are approx 5.5 hours of 100% sun per day and 18.5 hours of ZERO sun. This number is needed to determing the joules a panel will put out each day. 4) Determine the number of solar panels you need to generate the total monthly power for the number of full-sunlight hours in your location..... Price these panels at about $6 per watt in full sun. 5) Add up the cost of batteries, inverters, solar panels, wiring, regulators, switches, transfer switches, metering, auto-aiming (if you have a tracker to maximize the ful sun hours), enclosure, tools, and any required permits.There you have the cost of a solar system that will replace what you are using now.
Now, compare your monthly power bill from the grid to the cost of the equipment you had to buy....... Assume that you may have to replace any of the system components when the warranty period runs out.
That's all there is to it. If you can't do the above, you won't understand the answers which you read from others who have done it. .. and what approximations they made or assumptions they used..... AND whether or not they forgot something.
For instance, each time I have done it, I found that if I just put the money that I would spend on buying the solar equipment in the bank, just the INTEREST on that money would pay my power bill from the grid..... Of course, your results will depend on your life style and where you live.
If, you plan to reduce your energy needs to significantly less than you are using on the grid, getting rid of stuff like elec air conditioning and heat, no hot water heaters, and minimal lighting at night, you may save a bunch of money....... Still, if you reduced your needs to that level, and stayed on the grid, you would save even more money.....
Remember, it takes more energy to dig, mine, smelt, construct, deliver, and install a solar panel than it will generate over it's useful life.
Andy in Eureka, Texas
You calculations essentially tell someone only whether solar is cheaper for them vs. buying grid power. While this is very useful, it wasn't what the O.P. was after -- whether or not solar panels were a neat energy sink. Indeed, given how regulated the energy business is with taxes and subsidies for various technologies, there's pretty much zero correlation between the two.
BTW, for the cost of getting energy off the grid, you also need to include any losses due to grid power outages. While in many places outrages are rare enough this is essentially $0, people out in the country a bit often have frequent and long enough outages that losing, e.g., some of your frozen food isn't uncommon -- we've probably lose ~$100/year this way. Sooner or later most people at least get a cheap (~$500 or less) generator to compensate for this -- about 1 in 3 people out here seem to have them.
(This has nothing to do with solar vs. grid power, but there was a news story just last week about a lady who'd spent her life in an iron lung who died when the grid power failed and the family was unable to get their backup generator started. Quite sad...)
The department of energy doesn't agree with you here...
---Joel
This is established fact?
Still, the point of PV would be to reduce CO2 emissions as quickly as possible, the sooner the better.
It would seem to me that by installing PV you "create" a big CO2 spike and than work on gradually reducing it for 20 years or so hopefully eventually even creating some surplus or better said "surminus".
M
Just vote Democrat and everyone will feel good ;-)
...Jim Thompson
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"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...
Gore really would be better at getting people to "feel good" with gas at $10/gallon than McCain could, I think... McCain would proably just tell you to suck it up and that our gas is still cheaper than most country's, whereas Core will have some pictures of cute little penguins that he'll remind you we're "saving..."
Careful...that document's
From that document: "Purifying and crystallizing the silicon are the most energy- intensive parts of the solar cell manufacturing process."
James Arthur
Certainly a significant point. It emphasizes how in general it's difficult to do a "big picture" comparison between energy production techniques: Is pure silicon available as "scrap" with the energy used to purify it already "charged' to some other "budget?' Or does it need to be included? For coal production, was there already an operating mine that struck a vein of coal and hence could be cheaply coverted over to coal production with all the initial costs charged to the original mine? Or are the exploration costs directly accountable to energy production? With something like hydropower, rivers have been damed and re-routed for centuries, which makes some more attractive and some less attractive for hydropower production, even though the original intend was often to control flooding and provide irrigation.
I believe that most people are in agreement that if somehow all existing cars and the infrastructure to create and deliver gasoline suddenly disappeared in the blink of an eye, the likelihood that the replacement cars and infrastructure would be anything like what we have today is quite slim.
I'm still thinking eventually we'll just be building more nuclear power plants and the 'day to day' car of the majority will be electric.
---Joel
How will a solar system do when it's cloudy for a week or two? Or when the panels are covered with snow?
John
How many solar panels would survive a hailstorm, tornado or hurricane? What happens with all the chemical waste from making solar cells?
-- http://improve-usenet.org/index.html If you have broadband, your ISP may have a NNTP news server included in your account: http://www.usenettools.net/ISP.htm Sporadic E is the Earth\'s aluminum foil beanie for the \'global warming\' sheep.
Well, if you're grid-tied, and the LLP (loss of load probability -- this is the term the solar guys use) for solar is independent of that of the power grid (approximately true), then the total LLP is just the product of the LLP of each one, i.e., pretty small.
Note that for snow you're supposed to go out and brush'em off. :-) Maybe add windshield wipers? :-)
For non-grid-tied systems, it's a question of whether you just want batteries as a backup or a generator as well. In general a diesel generator is the cheaper option, for very low LLPS... I recall reading some report on Austrialian telco repeaters in the Outback where initially they used all solar
I've used PV design software that lets you play with all these variables. It's somewhat more sophisticated than you might guess: They have a database of weather data for a number of years (many decades in the largest cities) and -- knowing the time of year and your position on the planet -- can calculate a pretty good statistical model of how much energy a PV system of a given size will produce on average and what the standard deviations are. From there, it's straightforward to size battery systems to get the LLP down to whatever point you're willing to pay for, based on when you want to cry "uncle" and just add a generator to the system.
With gas prices the way they are today, you're spending a lot for a gasoline or diesel generator to make you a kWh, though -- somewhere around $0.70! Still, easily worth it if you have to run it for a day or two compared to losing a hundred bucks or more of frozen foods.
---Joel
Rather few, I expect, but that doesn't seem to stop people in your neck of the woods from using it quite extensively to heat their pools, does it?
Shipped to China, of course. :-) (Seriously, though, if the cells in question came from scrap silicon from the semicondcutor industry, the waste gets disposed with all the same waste used to make Pentiums or whatever.)
I am somewhat myopic here -- in (inland) Oregon and much of the surrounding area, the weather is quite mild and there's a fair amount of sun. The way things are today, it's unlikely you'd ever make any money putting up PV panels (although with all the bizarre regulation in California it just might be a money maker there!), but the independence from the grid is personally worth something (not that I actually *have* a PV system, mind you). I've made the analogy before that if I have an extra, say, $20k to blow on a house, I feel I get much more benefit out of sticking up a PV system than, say, adding another small bedroom; other people would certainly spend the money differently.
---Joel
energy costs of production in between 3 and 4 years
pay back even faster. You could shorten the payback
It doesn't make any *economic* sense if you have the option to buy cheaper mains electricity, but it does provide a net energy gain over the inputs to manufacture provided that the array lasts 3-4 years in service. So PV is not a net energy sink it gives 4-6x net lifetime gain.
Germany has a wierd system where the grid has to buy back PV electricity at some punitive rate which distorts the market and means it is rather too popular there.
For that you want bio-ethanol from corn. It requires such high inputs of energy intensive nitrogenous fertiliser, fuel to run the tractors and combine harvesters, followed by fermentation and distillation that by the time you account for all the inputs it is a marginal gain at best. And in years with a poor harvest it a net loss. But US grain farmers have powerful well paid lobbyists so logic doesn't enter into it.
Converting food grade corn into ethanol fuel is very dodgy on ethical grounds. Unless that is you think it is right that the poor should starve.
The economics are still not good for PV yet. Although as oil gets progressively more expensive that will gradually change - at least in countries that get a decent amount of sunshine.
Simpler hot water systems are cheaper and have been popular in some countries like Japan since the mid 1990's.
The new generation PV have higher efficiency and/or lower cost to manufacture. And with economies of scale it will improve.
Regards, Martin Brown
** Posted from
Shouldn't be that difficult--as a start, just ask the wafer suppliers what their power bills are, and divide by m^2 of product they ship.
It needs to be included. For PV to make the big time, we'll need LOTS more silicon surface area in solar cells than we've ever had in chips, and so they'll account for most of the refining energy.
Thin film cells use less material--that could save a bunch of the manufacturing energy.
That would be fun. (I like electric cars!) An electric with a super- clean 10 KW auxiliary generator is my ideal so far. Unlimited range, twice the efficiency.
James Arthur
Well, such a calculation probably serves to demonstrate that if you took PV technology at its current levels of efficiency and economies of scale, it isn't competitive. But if you want to talk about large scale adoption of PV, it isn't entirely unreasonable to assume that the PV cells will be more efficient and economies of scale would be higher.
That's the whole thing with alternative energy... it's relatively unlikely that someone discovers such a phoenomenal breakthrough that overnight any given technology becomes an obvious choice vs. what's already established, but by funding some small degree of basic research and experimentation (granted, we can argue all day about what some "small degree" of funds constitutes), over time alternative energy does become more and more attractive.
Personally I'd be happy to have a nuclear reactor in my backyard if it meant I'd get cheap electricity: I'm convinced their safety already well exceeds the "likelihood of dying in a car crash on the way to work" threshold.
---Joel
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