Can Solar Energy Reduce High Electricity Costs in California's Central Valley?

[Pengwuino]

So I was looking at my parent's power bill today because they've been complaining the bill is so high. I looked and as I knew for years, we get killed when we go pass what PG&E calls "300% over baseline". We live in the central valley in California where temperatures get to be up to 110 and that 300% over baseline rate is $.40/kwh. I want to try to convince my parents to install a small system at the house to at least reduce how much we're in that ridiculously priced tier. During the worst, we go something like 800kwh per month into that $.40/kwh tier. I want to convince them to get a small system that will supplement the power off the grid and I figure at this ridiculous rate, the return on investment has to be fairly quick. So I have a few questions for hte people in the know around here

1) Where can I find data on the actual usable energy that is received on average at a particular point in the US?

2) How much can they expect to pay upon installation per kw generation? And given say, a 2kw system, how much can they expect to generate in a given day (considering its not sunny all day!)? I was thinking about doing the real nitty gritty physics on this and I realized there's a crazy number of variables to consider such as how long the sun is up, the angling of the roof, the fact that in winter I highly doubt we even get near the 200%-300% of baseline rate. I'm going ot ask PG&E for some detailed records of our usage... hopefully they have them.

 

[JaWiB]

Start here: http://rredc.nrel.gov/solar/old_data/nsrdb/redbook/atlas/ It shouldn't be too hard to get some kind of estimate from that

As for costs, you'll have to look into the kind of incentives available. (http://www.gosolarcalifornia.ca.gov/csi/index.php)

 

[lisab]

Have they done other "little" things, like upgrading their insulation and windows?

 

[CRGreathouse]

Have they done other "little" things, like upgrading their insulation and windows?

+1. If the insulation isn't up to par, this has much better cost/benefit than solar, even with incentives. Of course it also pairs well with solar...

 

[Pengwuino]

The windows were upgraded to triple pane years ago. I think the insulation might be a problem though. I think this house is from the 50s. The main problem is the air conditioner I'm sure. I wonder if there's anything I can install to measure how much power the a/c takes. I have the coolest little meter you plug inline with anything you want that plugs into a wall and it tracks its power usage, but the a/c goes directly into the house wiring so it doesn't help :(.

 

[JaWiB]

If you know the voltage, you just need a current transformer :)

 

[Vanadium 50]

You will be shocked by how much solar costs. The solar panels are not the driving factor: the problem is that you get a couple of volts DC some of the time, when what you want is 110V AC all of the time. Getting from one to the other takes quite a lot of hardware and work by electricians.

The cheapest thing to do is often to immediately sell the power back to the power company rather than trying to use it yourself.

 

[Andre]

The http://library.thinkquest.org/20331/types/solar/problems.html.

My brother in law had this installed while I was there this month:

To the right are solar heat exchangers to heat water boilers, to the left are 16 solar electric panels. The lattitude of the building is about http://www.panoramio.com/photo/28211862, so you can do your calculations and he was told that the installation would be good for an average of 3000 watt, the legal maximum for private grants in France.

As soon as the installation was operational, a week or so ago, we observed the indicator giving a maximum momentarily yield of 1950W indicated on a bright day at noon, and about 400W maximum on a very dim rainy day. He was not very satisfied with that.

The heat exchangers meanwhile heated the warm water reservoirs to around 70C.

 

[Chi Meson]

I would encourage looking into thermal panels before PV panels. Since hot water can be 1/3 to half of your electric use excuding a/c , the payback is much quicker. The technology is more basic so the installation and maintenance is easier.

Considerations: is there a south-sloping roof? What is the pitch? Rule of thumb: it should be due south +/- 10 degrees, and the pitch should be your latitude +10 degrees.

If not, then consider ground mount or have it installed with those ugly frames that hold the panels away from the roof surface

And what is the coldest temp you get? If it only freezes a couple of times, then you have the option of putting in-line solar collecting tubes that omit the whole heat exchange fluid/pump/extra storage tank business. You would need to be sure that the tubes are bypassed and drained until the freezing season is over. Where I live, that is one third of the year, so it was not an option.

 

[Chi Meson]

The http://library.thinkquest.org/20331/types/solar/problems.html.

My brother in law had this installed while I was there this month:

To the right are solar heat exchangers to heat water boilers, to the left are 16 solar electric panels. The lattitude of the building is about 43 degrees north, so you can do your calculations and he was told that the installation would be good for an average of 3000 watt, the legal maximum for private grants in France.

As soon as the installation was operational, a week or so ago, we observed the indicator giving a maximum momentarily yield of 1950W indicated on a bright day at noon, and about 400W maximum on a very dim rainy day. He was not very satisfied with that.

The heat exchangers meanwhile heated the warm water reservoirs to around 70C.

If there is a single bad/sub-par panel in the works, or if there is any shadow at all on ay of the panels, PV yield will drop. This is my guess for the poor performance. I personally am still waiting for the right moment before I install PV on my perfectly-situated, south-facing garage roof.

 

[Andre]

If there is a single bad/sub-par panel in the works, or if there is any shadow at all on ay of the panels, PV yield will drop. This is my guess for the poor performance. I personally am still waiting for the right moment before I install PV on my perfectly-situated, south-facing garage roof.

No shadow there, but we have no insight in the proper condition and installment of course. I'll check on that.

 

[mheslep]

You will be shocked by how much solar costs. The solar panels are not the driving factor: the problem is that you get a couple of volts DC some of the time, when what you want is 110V AC all of the time. Getting from one to the other takes quite a lot of hardware and work by electricians.

Apparently installation is about 20% of the total cost. The hardware including Solar Modules, Batteries, Inverters and Controllers makeup the other 80%.
http://www.solarbuzz.com/solarindices.htm

 

[Ivan Seeking]

The cheapest thing to do is often to immediately sell the power back to the power company rather than trying to use it yourself.

That is by far the best way to do things. In the past, this wasn't possible as the power companies were not required to buy the power back, or they only paid a small percentage of what they charge you for the same power, but this seems to be changing quickly. California is probably the best of all States in this regard. Given a local smart-grid and a fair sales price for the power, it is just plain silly to isolate the power for your private use. It creates a lot of complications and expense for no reason. Also, this way the owner doesn't need to become an electrical engineer. It becomes transparent.

Pengwuino, I would definitely look into government programs and private funding. I know that there are or were companies in California that finance the up-front cost of the solar panels, and allow the owner to make monthly payments that ideally are [on the average] lower than the cost of your existing power bill. And there have been tons of government money for this sort of thing, esp in California, for a very long time now.

It would be very easy to do some checking locally to see what your expected yields would be, per unit area of panel. You live in a prime location for solar. If anything, you guys get plenty of sun! I have not been a fan of pv except in the areas that are great for solar, like the Sacramento valley.

If you can estimate the duty cycle of the a/c, you could make a reasonable estimate of the demand for power, based on the nameplate ratings. You might also be able to find the phase angle of the unit and calculate the active and reactive power, based on an inductive [noninvasive] current measurement at the a/c control box, or at a dedicated circuit breaker.

 

[Pengwuino]

I would encourage looking into thermal panels before PV panels. Since hot water can be 1/3 to half of your electric use excuding a/c , the payback is much quicker. The technology is more basic so the installation and maintenance is easier.

Considerations: is there a south-sloping roof? What is the pitch? Rule of thumb: it should be due south +/- 10 degrees, and the pitch should be your latitude +10 degrees.

If not, then consider ground mount or have it installed with those ugly frames that hold the panels away from the roof surface

And what is the coldest temp you get? If it only freezes a couple of times, then you have the option of putting in-line solar collecting tubes that omit the whole heat exchange fluid/pump/extra storage tank business. You would need to be sure that the tubes are bypassed and drained until the freezing season is over. Where I live, that is one third of the year, so it was not an option.

We do have a south sloping roof, not sure about the pitch though. We only get freezing temperatures a few times a year. Though that sounds like a lot of maintenance for my parents to handle.

I wonder how these businesses work where they actually generate power to sell directly to the utility. I noticed PG&E's wholesale purchasing rate was $0.09/kwh so I am just wondering if businesses like that just have economies of scale working that much in their favor...

 

[Pengwuino]

That is by far the best way to do things. In the past, this wasn't possible as the power companies were not required to buy the power back, or they only paid a small percentage of what they charge you for the same power, but this seems to be changing quickly. California is probably the best of all States in this regard. Given a local smart-grid and a fair sales price for the power, it is just plain silly to isolate the power for your private use. It creates a lot of complications and expense for no reason.

Pengwuino, I would definitely look into government programs and private funding. I know that there are or were companies in California that finance the up-front cost of the solar panels, and allow the owner to make monthly payments that ideally are [on the average] lower than the cost of your existing power bill. And there have been tons of government money for this sort of thing, esp in California, for a very long time now.

It would be very easy to do some checking locally to see what your expected yields would be, per unit area of panel. You live in a prime location for solar. If anything, you guys get plenty of sun!

I don't understand why it makes sense to sell back to the utility. We pay $0.40/kwh at that highest bracket and they wouldn't pay us that for the power we sell back. Just to make sure, we're looking for something supplementary to alleviate how many kwh we go into this $0.40 tier, not completely (or even nearly) replace our dependence on PG&E.

I can't imagine you have to go either 100% PG&E or 100% solar... that would suck.

 

[Ivan Seeking]

I don't understand why it makes sense to sell back to the utility. We pay $0.40/kwh at that highest bracket and they wouldn't pay us that for the power we sell back. Just to make sure, we're looking for something supplementary to alleviate how many kwh we go into this $0.40 tier, not completely (or even nearly) replace our dependence on PG&E.


I can't imagine you have to go either 100% PG&E or 100% solar... that would suck.

In solar friendly areas [wrt the power companies], which presumably includes your area, you use smart metering. To whatever extent you are producing power, your meter slows or even reverses direction. So the net value is what shows up on your bill. If you buy a system having an average output that exceeds your average power demand, you would get a check in the mail each month, not a bill.

The advantage is that you don't have to isolate your power sources. And you don't have to worry about batteries [a huge pain in the butt, dangerous, and expensive]. Best of all, you always use or sell 100% of the power you produce. Dedicated systems can be quite lossy. And you don't always need all of the power your produce. It is a timing issue between demand and supply. Net metering solves all of these problems. In effect, the grid becomes your battery system.

 

[Pengwuino]

In solar friendly areas [wrt the power companies], which presumably includes your area, you use smart metering. To whatever extent you are producing power, your meter slows or even reverses direction. So the net value is what shows up on your bill. If you buy a system having an average output that exceeds your avererage power demand, you would get a check in the mail each month, not a bill.

We use way too much power for that and wouldn't want to buy a system that big. I just want to take a slice out of that $0.40 tier come summer time. Just to lower their bill.

 

[Ivan Seeking]

btw, I had a bunch of late edits in my last two posts.

 

[Ivan Seeking]

We use way too much power for that and wouldn't want to buy a system that big. I just want to take a slice out of that $0.40 tier come summer time. Just to lower their bill.

AFAIK, if it is available in your area, net metering is by far the safest, least expensive, and easiest way to go. Try to do this yourself and dedicate a system, and you will quickly begin to see the practical problems. That is shade-tree mechanic level stuff.

You need to think like an economist and not an engineer!

 

[Pengwuino]

AFAIK, if it is available in your area, net metering is by far the safest, least expensive, and easiest way to go.

You need to think like an economist and not an engineer!

I am! We have newly installed smartass-meters . I'm still extremely confused. What's wrong with having a small system that just supplements your power draw from the grid? Even in winter i don't think we'd ever have a net production in power (or well... ok, maybe not THAT small of a system). So during summer, we'd see a decrease in the top tier and in the winter, maybe we'd sell some back... but most importantly is decreasing that top tier in the summer time.

 

[Ivan Seeking]

Do this the wrong way, and you will probably just lose money, and you parents would be justified in their skepticism.

 

[Ivan Seeking]

I am! We have newly installed smartass-meters . I'm still extremely confused. What's wrong with having a small system that just supplements your power draw from the grid? Even in winter i don't think we'd ever have a net production in power (or well... ok, maybe not THAT small of a system). So during summer, we'd see a decrease in the top tier and in the winter, maybe we'd sell some back... but most importantly is decreasing that top tier in the summer time.

How is that different from smart metering? That is how smart [net] metering works.

Otherwise, you have to dedicate loads to the panels, which becomes problematic.

 

[Pengwuino]

How is that different from smart metering? That is how smart metering works.

Otherwise, you have to dedicate loads to the panels, which becomes problamatic.

So... is that good? Smart metering that is. I think I'm extremely confused here.

Doesn't the system hook directly into your houses wiring? And when the power load is too much for the panels, it takes the rest from the grid? And if you aren't using all the power the panels are producing, it feeds back to PG&E?

 

[Ivan Seeking]

So... is that good? Smart metering that is. I think I'm extremely confused here.

Yeah, I'm a little confused about your confusion.

Doesn't the system hook directly into your houses wiring? And when the power load is too much for the panels, it takes the rest from the grid? And if you aren't using all the power the panels are producing, it feeds back to PG&E?

Yes. And your meter responds accordingly.

By "the system" I assume that you mean your net metering system? If not, then that [net metering] is what you need to do what you want to do. You can't just tie into the existing system and expect it to happen all by itself. You need the proper equipment - and it all has to be legal!

 

[Pengwuino]

Yeah, I'm a little confused about your confusion.



Yes. And your meter responds accordingly.

By "the system" I assume that you mean your net metering system? If not, then that [net metering] is what you need to do what you want to do. You can't just tie into the existing system and expect it to happen all by itself.

Ah! There's the problem. By system I meant the solar panel system. So I want to consider a small array of solar panels to just try to offset some of the ugly $0.40/kwh useage we have during the summer.

 

[Ivan Seeking]

Ah! There's the problem. By system I meant the solar panel system. So I want to consider a small array of solar panels to just try to offset some of the ugly $0.40/kwh useage we have during the summer.

And I'm telling you what it takes to make that happen at a profit [and without killing someone like a line worker with PGE]. Again, if you don't do things the right way, you will just lose money and would be better off not to even mess with it.

 

[Pengwuino]

And I'm telling you what it takes to make that happen at a profit.

Have smart meters?

 

[Ivan Seeking]

The system has to be designed properly and legal. You can do this even if the power company won't allow you to sell power back, if only to reduce your own bill. But you can't just rig something like this on your own. Not only does the inverter have to be in phase and voltage matched with the power company supply, you also have to be protected against backfeeding the lines in the event of a power failure, which could kill a PGE worker. This all has to meet the national electrical code standards and be approved for use by an inspector.

If you try to buy panels that are too small, you won't recapture the cost of the installation in a reasonable period of time... if ever.

The only other way to do this is to go with a dedicated or partially dedicated system, which can get really complicated and expensive, or become impractical from a supply-demand perspective - thus significantly offsetting or reversing any financial gains.

 

[Pengwuino]

OHHH No no no no no, I'm not actually putting it in, we'll get an actual solar installation company to do it! I'm just wondering if it's profitable. I know PG&E has installed smart meters here and they do buy power back, but I just want to make sure that it makes sense to buy a small solar panel system simply to help offset our power consumption from PG&E during summer when the bill just skyrockets. We'd still anticipate a bill every month... just not an $800 bill!

 

[Ivan Seeking]

OHHH No no no no no, I'm not actually putting it in, we'll get an actual solar installation company to do it! I'm just wondering if it's profitable. I know PG&E has installed smart meters here and they do buy power back, but I just want to make sure that it makes sense to buy a small solar panel system simply to help offset our power consumption from PG&E during summer when the bill just skyrockets. We'd still anticipate a bill every month... just not an $800 bill!

You need to determine the typical output per sq meter for your area based on real examples, the cost per unit area for the pv panels, the cost of power from PGE, the cost of the installation per sq meter of panel [including all PGE-related work], the life of the panels, and from that determine the minimum sized system that is profitable. There is some minimum size below which you will never see the pay back. Generally, you are looking at 10-15 years for a good or ideal system. Once you get into 20 and 30 year return cycles, you are into the life of the panel, and its a net zero gain.

I can tell you that I was looking to put in low-head hydro on my property. Just to get feedback protection, I needed to buy a $10,000 switch. How long would it take to pay for just the switch with my 5KW hydro, at 12 cents per KWHr?

 

[Chi Meson]

We do have a south sloping roof, not sure about the pitch though. We only get freezing temperatures a few times a year. Though that sounds like a lot of maintenance for my parents to handle.

The maintenance for the in line tubes is bar far the least maintenance for any system, whether thermal or PV. Here's the link for the tubes I was http://www.sunmaxxsolar.com/evacuated-tube-solar-collectors.php".

If there is a regular month when all the freezing occurs, then the tubes should be left drained during that time. The procedure would be no more than turning two valve levers and opening a drain. To get it back on line, close the drain, and turn the two levers again.

Pets are much more laborious than that.

 

[Ivan Seeking]

Something else, you may find that geothermal heat pumps or a/c units can compete with solar, in your area. I don't know the track record of these systems yet [just happen to be revisiting that issue lately] but in principle they can improve the efficiency [not really, but effectively so] of your a/c unit by I think about 200% [according to the sales info...]. They do this by using the relatively cool Earth on your property as a heat sink, rather than using an air-cooled condenser. By doing this, your ac unit has do less work for the same cooling capacity.

I would bet that these systems are at least competitive with solar, if not more. I don't yet know if they have delivered as promised, but they have been around long enough now to evaluate their success.

 

[Pengwuino]

You need to determine the typical output per sq meter for your area based on real examples, the cost per unit area for the pv panels, the cost of power from PGE, the cost of the installation per sq meter of panel [including all PGE-related work], the life of the panels, and from that determine the minimum sized system that is profitable. There is some minimum size below which you will never see the pay back. Generally, you are looking at 10-15 years for a good or ideal system. Once you get into 20 and 30 year return cycles, you are into the life of the panel, and its a net zero gain.

I can tell you that I was looking to put in low-head hydro on my property. Just to get feedback protection, I needed to buy a $10,000 switch. How long would it take to pay for just the switch with my 5KW hydro, at 12 cents per KWHr?

I think we'd end up having to get someone out here to figure everything out but I bet the prospects are good considering our steep roof, ridiculous costs to buy power, incentives, and the fact that I think Fresno is an hours drive from the Sun.

One thing I wonder, on a separate but related issue, is how do people make businesses out of selling solar power? I saw PG&E's contract rates at about $.10/kwh for solar power. Do you just get huge economy of scale cost reductions? I suppose it's a question of whether or not the installation costs scale linearly with the power output...

 

[Ivan Seeking]

I think we'd end up having to get someone out here to figure everything out but I bet the prospects are good considering our steep roof, ridiculous costs to buy power, incentives, and the fact that I think Fresno is an hours drive from the Sun.

But not a salesman. Also, you really need to see proof of the average annual output per unit area of panel, for your area. Keep in mind also that your installation cost will not vary linearly with the size of the installation. It will be more of a step-wise function at the low end, with a minimum cost no matter how big the installation.

One thing I wonder, on a separate but related issue, is how do people make businesses out of selling solar power?

Who says they do? AFAIK, solar is only now competitive at the user level for solar-friendly areas. If there are any examples of commercial production sites that are competitive, they were surely funded with grant money that doesn't have to be paid back.

 

[Pengwuino]

But not a salesman. Also, you really need to see proof of the average annual output per unit area of panel, for your area. Keep in mind also that your installation cost will not vary linearly with the size of the installation. It will be more of a step-wise function at the low end, with a minimum cost no matter how big the installation.

Aha! Thats where the fisicist in me comes out! I was thinking of figuring out the equipment needed to put a small single panel up on the roof and monitor the actual intensity that we can get throughout the day. Step 2: Extrapolate. Step 3: Profit! Or not.

Who says they do? AFAIK, solar is only now competitive at the user level for solar-friendly areas. If there are any examples of commercial production sites that are competitive, they were surely funded with grant money that doesn't have to be paid back.

Pff, I thought I smelt something fishy. I was thinking the only way it would make sense is if the costs of expanding from say, a 100kW to a 200kW system were mainly in the panels and possibly meant economies of scale were important. I really don't know how the costs of running these things are spread out equipment wise.

 

[Ivan Seeking]

Aha! Thats where the fisicist in me comes out! I was thinking of figuring out the equipment needed to put a small single panel up on the roof and monitor the actual intensity that we can get throughout the day. Step 2: Extrapolate. Step 3: Profit! Or not.

You really have to be careful at the low end. That's where the initial costs can kill the whole deal. Size does matter... even in California.

Pff, I thought I smelt something fishy. I was thinking the only way it would make sense is if the costs of expanding from say, a 100kW to a 200kW system were mainly in the panels and possibly meant economies of scale were important. I really don't know how the costs of running these things are spread out equipment wise.

You do get the economy of scale, but this only goes so far, and then you run into distribution costs.

What example did you have in mind?

 

[Ivan Seeking]

I would bet that you could safely use {$10K <= cost}, as a starting point for the electrical system needed to make it PGE safe...not including the cost of the electrician. As I said, this was my out-of-pocket cost for one switch that I was required to buy - independent of the size of my alternative power source. Phase and voltage concerns were still my problem [and cost].

Then again, with all of the emphasis on solar in your state, the minimum size issue might have improved siginficantly. Maybe it won't be that bad anymore.

 

[mugaliens]

How is that different from smart metering? That is how smart [net] metering works.

Otherwise, you have to dedicate loads to the panels, which becomes problematic.

My uncle runs a smart meter which records both gain and loss from his solar power panels, as well as the net, for which he is either billed or paid. Spring and Fall he makes money. In winter he looses a little bit, and during the summer it's a bit more, although his design (he designed and built his home) covets an insulated basement and R-50 walls with an R-75 ceiling. He's done some additional improvements since then involving aluminized mylar reflectors, so I think that while the insulation factors remain the same, the amount of heat entering the home during the summer has been cut by about 75%, while the amount of heat gained during the winter has increased several hundred percent. Even though he lives in Michigan, I don't think he even has a heating bill anymore. I do know he installed a thermal-salt storage system which leverages what he collects during sunny days to take care of those cold winter nights and cloudy days. It's a phase-change system, not a molten system. His only complaint is that after a few years "things grow and get nasty" in his words, but as the salt solution just sits there and is totally enclosed, he really doesn't care.

I asked him once why he didn't simply go with a water system and he told me that much less grows in the salt than would in the water, and the chemicals used to treat the water would be very expensive, while the brine of the salt keeps most things at bay without having to treat anything.

A few years back he had a problem with his solar panels during the summer, as simply turning them off would cause the water to boil, so he had to drain them in the Spring and refill them in the Fall, but from what I understand, he has since built a "summer shunt" in which they're simply routed to an outside radiator, which keeps the system below boiling point. It's passive, so no electricity is used, and he still taps the system for hot water. During the winter he does drain the external radiator cycle, but not until around November. He starts using it again around April.

 

[Ivan Seeking]

Just out of curiosity, I checked on one scenario to see how it works out at today’s prices.

I am seeing a price of about $400 for 75 watts, for solar panels.
http://www.affordable-solar.com/bp-solar-bp-375J-75-watt-solar-panel.htm

If we want to run a 1000 watt auxiliary air conditioner unit that is isolated from PGE, we probably want to allow for at least a 50% fudge factor [0.707 multiplier against the output capacity of the panels, to allow for the angle of the sun] so that the unit will function through a good part of the day, so figure 1500 watts. This requires 20, 4x2 [ft] panels, at about $8000, and having a footprint of about 160 square feet.

Add the ac unit for about $500, so $8500, plus the installation of the panels. Assume that you do all of the work at a very low cost; so we’ll say $9000. [technically, you still need a $500 inverter]

At 40c/KW-Hr, and generously assuming that we get operation 8 hrs a day in the summer, it would take about 2800 summer days [maybe 28 years or so] to pay for the installation. Assuming that you can get 4 hrs of power per day in the late spring and early fall, maybe one could double the annual yield and see a profit in 14 years. In the winter you probably couldn’t generate the power required to run the a/c unit, but you might run a 500 watt heater for part of the day. So you might see payback in a little over ten years or so. But the 8 hour per day number is likely way too optimistic using a 50% overcapacity, even in your area.

This is where the grid is handy. You can use everything that you produce. It functions as an infinitely variable load. But to do that, you probably need to tack another $10K onto your installation price, so now we are looking at 20 years to break even. The way to improve that number is to put in more panels. .

 

[mheslep]

Just out of curiosity, I checked on one scenario to see how it works out at today’s prices.

I am seeing a price of about $400 for 75 watts, for solar panels.
http://www.affordable-solar.com/bp-solar-bp-375J-75-watt-solar-panel.htm

Not that it effects your narrative aside from payback time, but that's fairly old and expensive technology at $5.3 per Watt (and made Beyond Petroleum). Here's a newer example at $3 per Watt, same website, different make:
http://www.affordable-solar.com/sharp-ND-U224C1-224-watt-solar-panel.htm
which will also require 30% less area and mounting infrastructure for the same total power installed.

 

[Ivan Seeking]

Not that it effects your narrative aside from payback time, but that's fairly old and expensive technology at $5.3 per Watt (and made Beyond Petroleum). Here's a newer example at $3 per Watt, same website, different make:
http://www.affordable-solar.com/sharp-ND-U224C1-224-watt-solar-panel.htm
which will also require 30% less area and mounting infrastructure for the same total power installed.

Interesting, I checked the top three google hits, which were all landing at ~ the same price.
http://www.google.com/search?source...=UTF-8&rlz=1T4DGUS_enUS313US313&q=solar+panel

The 8 hours per day is likely about 20% too high for a 50% overcapacity, but the price drop is encouraging to see.

 

[mugaliens]

(sigh) Install IR reflectives in your attick then open a window when it gets hot.

What's this four hundred dollar stuff? Marketing hype? Someone in the business is definitely stringing you along!

Try $40. Yes - "fourty."

 

[Ivan Seeking]

(sigh) Install IR reflectives in your attick then open a window when it gets hot.

I've seen it 125 degrees F at the north end of the Sacramento Valley [same valley where Pengwuino lives]. 110-degree days are common. IR reflectors and open windows won't cut it.

I remember it being 80-90 degrees at midnight, many times.

 

[Pengwuino]

I've seen it 125 degrees F at the north end of the Sacramento Valley [same valley where Pengwuino lives]. 110-degree days are common. IR reflectors and open windows won't cut it.

I remember it being 80-90 degrees at midnight, many times.

Yup, its a god awful area to live. Climate-wise, it's actually considered a desert.

 

[Ivan Seeking]

Yup, its a god awful area to live. Climate-wise, it's actually considered a desert.

Remember that terrible heat wave three years ago? At the time, I was working in a plastics plant in the sacramento area, that was running over a million watts of heat inside the plant, which was not climate controlled. I would bet that it was over 130 degrees in there on the worst afternoons.

The hotel a/c was a large, common [freon] system, that failed. So everyone in the hotel lost a/c. People were actually sleeping in the pool on rafts!

 

[Pengwuino]

Remember that terrible heat wave three years ago? At the time, I was working in a plastics plant in the sacramento area, that was running over a million watts of heat inside the plant, which was not climate controlled. I would bet that it was over 130 degrees in there on the worst afternoons.

The hotel a/c was a large, common system, that failed. So everyone in the hotel lost a/c. People were actually sleeping in the pool on rafts!

Yup, our a/c couldn't handle it. I couldn't be upstairs where my computers are until around midnight those days because the monitors wouldn't run at the temperatures the room was at. We had our pool up those days and you'd get out, dry off, and boom, instantly sweating.

 

[Ivan Seeking]

The http://library.thinkquest.org/20331/types/solar/problems.html.

My brother in law had this installed while I was there this month:

To the right are solar heat exchangers to heat water boilers, to the left are 16 solar electric panels. The lattitude of the building is about 43 degrees north, so you can do your calculations and he was told that the installation would be good for an average of 3000 watt, the legal maximum for private grants in France.

As soon as the installation was operational, a week or so ago, we observed the indicator giving a maximum momentarily yield of 1950W indicated on a bright day at noon, and about 400W maximum on a very dim rainy day. He was not very satisfied with that.

The heat exchangers meanwhile heated the warm water reservoirs to around 70C.

What is the electical load being driven by the solars panels? If you don't have a 3000 watt load, you can't produce 3000 watts.

 

[mugaliens]

I've seen it 125 degrees F at the north end of the Sacramento Valley [same valley where Pengwuino lives]. 110-degree days are common. IR reflectors and open windows won't cut it.

I remember it being 80-90 degrees at midnight, many times.

I hear you. I used to live in Vegas, where it sometimes remained above 100 throughought the night, and you're right - active air conditioning is about the only way to go.

 

[mheslep]

Interesting, I checked the top three google hits, which were all landing at ~ the same price.
http://www.google.com/search?source...=UTF-8&rlz=1T4DGUS_enUS313US313&q=solar+panel

I suspect, from indirect observation, that those low power panels come from old inventory which can be moved because there continues to be a market of buyers for the just-one-panel-at-100W, enabled by the internet, in which case $3-400 beats $680/220W every time.

The 8 hours per day is likely about 20% too high for a 50% overcapacity, but the price drop is encouraging to see.

The price could be said to be collapsing in the last couple years:

http://www.technologyreview.com/energy/24498

According to Harry Fleming, the CEO of Acro Energy Technologies in Oakdale, CA, these changes mean that the cost of a typical five-kilowatt rooftop solar system has dropped from $22,000 after state incentives are applied ($40,000 without them) to $16,000 in the last 18 months. Prices are expected to fall to $13,000 by the end of the year ($25,000 without incentives). "This is going to make solar a middle-class product," he says

With incentives that's $2.6/W installed.
Also see this history from some people in the business since the 70's
http://1366tech.com/v2/company-mainmenu-1

 

[mheslep]

Yup, its a god awful area to live. Climate-wise, it's actually considered a desert.

Ouch, that will ding the solar panel efficiency, maybe 15% less than at room temperature. That is, a 5KW array would put out only 4.2KW at 140F panel surface temperature vs 72F.
http://www.solarpower2day.net/images/9t.png