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I used the numbers from solarbuzz.com. http://solarbuzz.com/ Cost of a panel right now is $5.20 per peak Watt. For more facts, also see http://www.solarbuzz.com/Consumer/FastFacts.htm.

So I did some numbers. My electric bill is about $40/mo from PG&E. I use about 353KWh/month.

I figured that there are about 6 effective peak hours of generation per day. That is, I get about 12 hours, but if you average it all hour, it's like I get peak sun for 6 hours (Solarbuzz says 5.5) in my area.

Okay, so that means for each $5.20 I spend, I get 6 WH per day. Since I use 11.8KWH/day, that means I need about 2000 peak watts of generation. That means I'd have to spend about $10K on cells (not including tax, and solarbuzz says the PV array is only half the cost of the system). At $40/month, that means it will take me 20 years to get my money back (really, double this), hopefully my cost of new lead-acid batteries every 4 years or so won't turn that 20 years into never.

And that's in sunny California, if I chop down the trees that shade my house and keep it cool. Oh, and I don't even have A/C!

So, what did I do wrong? Where's the magic of solar power here? Sounds like I'd have to take a huge bath to go solar.

Were just referring to ROI on energy put in?

Yeah, we periodically hear of the big breakthrough that will reduce the cost of PV cells. This has been happening for decades, but PV sales are still overwhelmingly conventional silicon (and may be getting more expensive now that PV production has exhausted the surplus Si byproduct feed from fabs.) So don't be credulous about the latest claim; judging by history it will very likely go nowhere.

Nuclear has gotten a lot of money from the government, but then nuclear has provided a lot in return to the government, like bombs and nuclear propulsion for warships and subs.

Uranium is quite a bit more abundant than is often depicted; remember that at today's U price the cost of the natural uranium itself is a very small part of the cost of nuclear energy, so its price could go up a lot without significant impact. When and if that happens, we can build powerplants with improved breeding to extend the resource even more.

If you can dispute that, please provide a reference for your pesonal residential grid electric supplier you use -a URL is fine- and what the contract terms are

This is the Chicago are; we're supplied by ComEd. Residential rates are 8.75 cents/kWh (plus a fixed service fee of $7.13/month). There are also taxes, IIRC, but I don't remember what they are.

According to this page, PV electricity is still about 30 cents/kWh in the sunniest locations. Chicago is far from the sunniest location; let's say 50 cents/kWh here. So solar is not competitive with grid power for my by about a factor of five.

Best case is thus 6 hour * 1.2 kW/m^2 * 10 m^2 * 0.15 efficiency = 11 kWh per day. If you would consume this energy in one hour yould thus can run your car with 11kW, or 15 horsepower.

Then I want to see the KWH cost of solar when you are done. Average in the US is about $.075 KWH or so.

Solar power costs are closely tracked on Solar Buzz and the average industrial cost is 20c/kWh. Those plants are commercial enterprises operating at a sustainable profit.

New solar power plant designs from Australia (google for Big Dish ANU) have gotten the costs down as low as 12c/kWh, all inclusive. It's still not as cheap as coal but it's definitely competitive.

I hate to correct you on costs per watt: currently is between $3.50 and $5.30 per watt, dependind if you buy 1 module or 100,000 modules.

Current prices of photovoltaic cell modules is always tracked at a nice website, http://www.solarbuzz.com/Moduleprices.htm.

Half the cost (55%+) of a solar cell installation is dc->ac conversion & associated electronics. this development does not help that cost, unfortunately...

--Kevin

--> Shameless Plug: I'm looking for a Sr. Software Engineer Job in Northwest suburbs of Chicago, Perl, C, some Java & C#, 14 yrs. experience; Laid off due to merger. kevin@justanyone.com--

Astropower went bankrupt in February and was bought by GE's PV division in March.

Linky

Linky

FYI, here's a small primer on how large scale generation works: first there is a generation source, producing low (5-20 kV) voltage electricity, which is then 'stepped up' by a transformer to above 100 kV over alternating current. This is then sent through power wires to a substation which then 'steps down' the current to residential levels (there may be multiple transformers up and down).

The big difference is PV is distributed . This means a far more efficient, redundant, and secure grid. But it also mean less grid stress, because more power is generated locally. For example, normally my power comes from my roof (distance 20 ft). Sometimes some of my power comes from my neighbor (dis. 500 ft). Occasionally some my power comes from the shopping mall (distance 3 miles). When the insolation is low some of my power is imported from 2 states away (600 miles). Say the weighted average distance my power travels is 1 mile (down the same wires it would have before). Now compare that to the centralized infrastructure we currently use which 90% of the time its traveling 600 miles! Transmission efficiency is improved and grid utilization is reduced.

For the 'grid' is a misnomer - its NOT a two-way street

And that the EROEI is quite different when you consider solar taking the major power role.

We've already shown it to have a better EROEI than fossil fuels, even when favoring the fossil fuels with less stringent EROEI calculations (i.e. not counting embodied energy of equipment). If PV has a EROEI of 15 (minimum), and since the fuel/sun is a free resource, its energy output can replicate itself by x^15. Hardly a problem

There are a lot of responses to this, and there are a lot of sub-topics here, so I'm just going to sum up a few points on this issue.

There are a several mechanisms to consider in asking weather (sorry, pun intended) a shift away from current energy sources to wind power would reduce global warming.

1. The original post says:
"the amount of power being extracted from the atmosphere would be more than the increase in greenhouse gas atmospheric energy forcing since 1600."
So there's the issue of how much power is subtracted from the atmosphere by wind power, compared to how much (if any) is added or subtracted by other means of generating power.

2. There's the matter of how much power is added to the atmosphere by using the electricity, a la the parent post claiming :
"Almost all the electricity used today is CONVERTED TO HEAT!"
Again, this should be compared in relation to other sources of power.

3. There are completely separate issues from how much power is directly added or subtracted from the atmosphere, ie, carbon dioxide emissions leading to a greenhouse effect, thereby increasing the heat retention of the atmosphere.

Let's take a quick look at the physical accuracy of these claims.

1. Is it even clear that turbines are subtracting heat from the atmosphere? They slow down the wind. Net, over the course of years, the total amount of wind on earth probably isn't changing much (you don't hear much about the global wind epidemic, however people in Florida might feel about things right now), so the wind is probably being converted into heat when it expends itself in friction. So turbines probably do reduce heat by some amount, because some of the wind that goes by them doesn't just get converted into heat, some gets converted into electricity. This can't be said for other most major sources of power today, particularly fossil fuels and nuclear. Where these don't subtract heat, they actually release huge amounts of heat. 2. Where the power came from probably has very little net effect on consumer habits for power usage, so this argument is probably irrelevant.

3. Wind power does not contribute to any warming effects I know of, where evidence for the greenhouse effect is mounting. Nuclear doesn't contribute here (even fusion would not significantly change the composition of the atmosphere), but fossil fuels are generally considered to be the major cause of the greenhouse effect.

Now let's guess if these are relevant:

1. The amount of heat subtracted from the atmosphere by turbines should be equal to the amount of power they generate. (Yes, this power comes back out as heat when the electricity is used, but remember, we're comparing the net effect vs. other forms of power, and we're assuming the usage is the same for all forms, so we're comparing the generation side). According to this, in 1999 the world used about 377 quadrillion BTU of electricity. Assuming we switch all that power to wind, there are complications regarding storage inefficiencies, but I think these would all cancel out anyway. (Producing 43% more total energy to make up for 70% lost in conversion & storage would take more heat out of the atmosphere, but in that case it actually would put more heat back in through usage than other forms of generation that don't need to go through the conversions and storage.) So how much global cooling does a sync of 4*10^15 BTU provide us? Would it make a dent in atmospheric temperature? Check this math, but 4*10^15 BTU is about 1.8*10^14 watt-hours. According to the equations here, (and their assumptions about the specific heat capacity of the atmosphere) that's about 1.13 degrees Kelvin per year, or about 2 degrees Fahrenheit. Zounds, that's enough to take us into global cooling! NASA estimates for global warming are closer to

Um, solar panels do in fact last that 20-30 years.

From the second PDF: "Energy payback estimates for rooftop PV systems are 4, 3, 2, and 1 years: 4 years for systems using current multicrystalline-silicon PV modules, 3 years for current thin-film modules, 2 years for anticipated multicrystalline modules, and 1 year for anticipated thin-film modules (see Figure 1).With energy paybacks of 1 to 4 years and assumed life expectancies of 30 years, 87% to 97% of the energy that PV systems generate won't be plagued by pollution, greenhouse gases, and depletion of resources. ... Based on models and real data, the idea that PV cannot pay back its energy investment is simply a myth. Indeed, researchers Dones and Frischknecht found that PV-systems fabrication and fossil-fuel energy production have similar energy payback periods (including costs for mining, transportation, refining, and construction)."

Future versions of PV may of course payback their embodied energy in even shorter times.

And nothing meant personally by this, but perhaps you might ask why you have been misinformed on such a crucial issue? Perhaps somebody stands to make money by keeping you in the dark?

PV panels will win in the end (barring another breakthrough like cold fusion). Standard arguments against PV and rebuttals:

Doesn't making solar panels pollute? Not so true now, and if we don't solve the pollution problem for all manufacturing, nuclear power, solar space satellites, or any other energy source will still bury us in waste from consumer goods produced using that energy. So zero emissions manufacturing and recycling needs to be solved in any case.

Isn't PV is expensive? It is cost competitive in many situations right now, and it would be just about everywhere right now if the end user had to pay the true cost of fossil fuels (pollution, militarism, centralization, etc. which would mean the true cost of oil is now over $200 per barrel) And the costs continue to drop -- with no theoretical reason PV panels should ultimately cost much more than glass, shingles, or sheet plastic.

What about producing and storing power in nothern climates? No one says people have to be a purists at the start. Liquid fuels like ethanol or gaseous fuels like hydrogen can be produced in a variety of ways from PV in some centralized facilities and transported by truck or pipelines to be used for about 10% of a northern home's total energy use (mainly winter use) for northern climates which don't get much sun in the winter (as an alternative to solar arrays that are ten times larger to supply all power needs in the least sun winter months). These systems can also be used to cogenerate heat and power. Eventually energy storage techniques will continue to improve (better batteries, better hydrogen storage, PV systems that produce ethanol or other liquid fuels directly) and then even this minimal centralized assistance can be reduced.

Overall, decentralized power will be the future, just like we now have decentralized computing and decentralized printing. There may still be some use for centralized big power plants, despite various social costs of centralization (such as for making aluminum from ore), just the equivalent of the mainframe of today is still useful for big data crunching tasks. Still, as nanotech proliferates (leading up to the StarTrek replicator), decentralized power from PV will be able to handle more and more material production needs (including enabling people to make their own PV solar panels at home as they need them -- and probably enabling them to recycle PV systems locally as well).

So, no need for nukes! Don't underestimate what thirty or so years of continued innovation on PV and materials science and nanotech will produce.

Based on primary energy source, coal-fired capacity represented 43 percent (260,990 megawatts) of the Nation's existing capacity (Figure 1). Gas-fired capacity accounted for 19 percent (117,845 megawatts); nuclear, 14 percent (86,163 megawatts); renewable energy sources,2 1
Inventory of Electric Utility Power Plants in the United States 2000

Photovoltaic Industry Statistics: Market Share

Try alchohol based oxygenates like ethonol.

If I can store power efficiently, then my solar cells need to generate 18 kWh per day, in about 10 hours of nice, bright sunlight. That's 1800 watts at any given time. At $2/watt, that's $3600 for the array (ignore the storage costs for now).

My electric bill for that month was $55.74, so I get payback in a little more than 5 years.

The problem is, I've seen different numbers for panels. Modules for consumers cost $5.85 per watt, these days. And at that rate, my scenerio costs $10,500, and the payoff time is now 15 years. If I invest that money, and get a 7% rate of return on it, I make more money by PAYING my electric bill ($61.25 per month income, $55.74 payout). It's more profitable for me NOT to install the cells.

The numbers quoted in the previous post for cost drop by growth indicate that (I'd love to see how the math for this is done, properly, but my aproximation follows) those $2 cells will cost $.75 in 2010. Excellent!

But the cost of panels is not all CELLS, and has stayed pretty darn stable. In the past three years, panel cost has only come down a few percent. It went UP some months, too. So we can expect the panels to be cheaper, but not by NEARLY that much.

And in the above I've ignored storage inefficiencies, and support hardware and battery costs.

In other words, I don't think the picture is so rosey.

Yes, the link I gave you showed you the maths - indeed to generate *all* the power needed just with solar would require large areas of land. That is why I was suggesting that such scheme should operate in conjunction with other alternatives. You dont need to meet "peak" demand in the way you suggest. Dont forget that there is an area in your home that can be used to generate free power - your roof. You can cover the roof of your home with solar tiles, combined with systems that directly heat water for the house etc.

Zero annual electricity bills for these guys - the tiles make as much electricity as they take from the grid. (ok with gas heating). Check also This link, This link , This link or This link

Do you think that nuclear is a better option? Or cheaper? The UK (and many other countries) has squandered truely huge amounts of money on nuclear, now, it appears, with no positive end result - they are going to be left with a collection of reactor sites that are going to be very expensive to decommission and clean up. If they had invested just a fraction of that money on renewables, we would be burning a heck of a lot less coal/oil/gas now. There are actually parts of the world (ie Chernobyl) that are too radioactive to live, thanks to mistakes/miscalculations made by the nuclear power industry..

And the point is - why bother with nuclear, why take the risk? It is becoming very apparent that alternatives really can deliver cheap electricity, without the same level of pollution and waste. Furthermore, costs of solar cells will drop as volumes increase. Case in point - look at the monitor you are (probably) looking at now - if it is TFT - and think how much the price has decreased in the last few years as manufacturing techniques have improved and volumes increased.. Push the production volumes up, and have every house in the country use solar tiling..

The UK is setting a target of getting 20% of its power from re-newables by 2020, and a lot of that will be wind-power. There are soon to be huge offsiore wind farms in construction.. And they are not noisy, nor do they upset wildlife - thats basically a myth - same site documents the evidence. The USA has a similar wealth on uneploited wind sites too..

In the UK we could in fact have 200% power needs just from offshore/onshore wind without too much difficulty. What do you do when you have too much power? Turn it into hydrogen for cars. What do you do when you dont have enough power? Burn some hydrogen.. We already have infrastructure to transport gas.

Whose time has come. Put solar windows in all office blocks, and solar tiles (both electric & water heating) in the roofs of all houses, and you go a long way toward solving the energy problems. Even in cooler countries these schemes pay-back after a few years - ie the extra it costs is paid back in electricty savings. In hot contries, a house can (in effect) generate as much electricity as it consumes - in Australia you have Zero annual electricity bills for these guys - the tiles make as much electricity as they take from the grid. (ok with gas heating, but the hot water supply is provided by the sun too). Check also This link, This link , This link or This link.. Want a large scale plant? What about the deserts of the world ?

Combine with Wind power, and other alternatives, and we may get 100% of our energy needs without nuclear, coal, gas.. What do you do when you have excess off-peak power? Turn it into hydrogen for your car!

Read more about it here..

Didn't you read? I just showed you that by covering half my roof with the best solar cells available on the market, I cannot even cover my own electricity needs. What do you suggest, covering the countryside with panels?

I am not saying that solar tiling would always be the *only* source of power - but that if houses did have solar tiling we would save a huge amount of power. Top that up with Wind power, Tidal power, Hydro-electric, then make sure houses use energy saving lightbulbs, are well insulated, etc, and you can have a national energy system wihich needs little or no coal/oil/nuclear.. This is not some sort fantasy - it is already starting to happen. Maybe we shouldnt cover the countryside, but what about the deserts of the world ?

>Such projects are up and running around Europe now, and pay back for themselves in a few years, even comparing to cheap dig it up and burn electricity.

Where, pray tell? Publications to defend your assertions?

Plenty, just Google solar roof tiles estate

Zero annual electricity bills for these guys - the tiles make as much electricity as they take from the grid. (ok with gas heating). Check also This link, This link , This link or This link

I scheme I recall quoted a break-even time of about 5 years - ie, even at todays prices, the houses will pay for the extra cost of solar tiling on the roofs in 5 years in terms of electricity savings - I will have to dig that link out again..

>France is not yet paying fully to *get rid* of the nuclear waste - its shipping the stuff to the UK to reprocess.

Completely wrong. France has a reprocessing plant in La Hague which actually also reprocesses other countries' used fuel. You are mixing it up with the British Sellafield reprocessing plant, which is indeed closing down.

Fair point about la Hague, we have imported reprocessing waste from Europe through the Chunnel, but France does have its own reprocessing plant.

>People are scratching their heads and saying hang on, what do you *do* with plutonium that is going to be radioactive for centuries, and has to be guarded in case some terrorist digs it up to make a dirty bomb..

The solution is well known and widely used: you get your plutonium and you mix it with regular fissible U235 to make a combustible called MOX. Then you feed MOX into nuclear reactors for energy production. The plutonium is degraded into shorter-life elements (mostly Americanium 241) which are less toxic and need to be stored for a few years instead of a few millenia. That's what the French and other Europeans are doing since the 80s. Big bonus: You can also use plutonium coming from disarmed nuclear warheard.

You would not be suprised to learn that Greenpeace do not agree with that. The technique you describe sounds good in theory, but in practice reprocessing still generates unacceptable levels radioactive pollution and waste that is still very difficult to deal in practice. BNFL have had particular problems with liquid waste products that are very expensive to handle and dispose of safely - its the practical details that are the problem. Furthermore

Could it be that the big oil interests have no interest in a cheap efficient environmentally friendly source of power ?

You have to wonder sometimes when good technology is ignored, is there some sort of hidden oil-company aganda ?


And this got labelled informative? Sheesh.

Here you can see a list of solar cell manufacturers - at least two oil companies (BP and Shell) are on it.

Here is a view from the EU about the future of big business in photovoltaics.

Here is an account of Shell's involvement in Fuel Cells and Hydrogen power in general.

Here is an account of some of Shell's involvement with biomass power generation.

Here is an overview.

Still, no doubt these will be dismissed with a "Yes, but apart from the solar cells, the fuel cells, the biomass research, the wind energy, and forestry, what have the oil companies ever done for renewable energy?".