Well, we just had 30 Solar Power panels installed on our roof

[mitchtv]

As near as I can figure we are generating up to 40KW hrs /day. Does anyone know if that is good?

[Selatius]

1. That's sufficient for home use, I believe. Then I'd have to ask, how many KW/hrs. do you use a day?

If you generate more power than you use, that's a good thing. You have a bank of batteries to store the extra juice? Or is it pumped back into the grid with a deal with the power company that they'd buy the energy you are putting back in?

[mitchtv]

8. Yes, it goes to the Grid SCE buys it

I'm sorry , I have never been able to understand my bill as there are at least 3 different rates I [ay each month,

[ColbertWatcher]

2. I found this...

...http://hypertextbook.com/facts/2003/BoiLu.shtml

[msongs]

4. according to this link avg house uses about 25kwh per day nt

[ColbertWatcher]

7. I guess that depends on where you live...

...in the desert (like Nevada, New Mexico, etc) with air conditioning going most of the day, perhaps more?

[mitchtv]

15. Palm Springs area

I believe it's second only to Death Valley. Last year it was ove 100 at 2am

[ColbertWatcher]

20. Wow. That's hot. n/t

[kristopher]

18. Actually, no.

In low humidity areas like the desert cooling is accomplished with "swamp coolers". These are basically large fans that draw air through a dampened air filter. It is unlike a conventional air conditioner in that it doesn't use a compressor, which is the main power draw in an AC unit. Works great, too.

[mitchtv]

37. We generally do without in temps that the swamp works well in..

Some of the newer houses have both, ours not. There have been more and more humid days and monsoon temps in the last couple ofyears when swamps are no good, nore are they of value over 105 which is normal most of the summer. It will take a while to recover from this rather large hit we took for this (no new car)Maybe in 3 or four years.

[kristopher]

38. As they say

It isn't the heat, it's the humidity. My experience with swamp coolers is that they work GREAT at high temperatures, it is the humidity that negates their effectiveness. I lived in New Mexico for several years where the climate is arid and hitting the hundred plus mark is pretty routine. I never had a complaint.
On the other hand, maybe I'm just easy to please.

[keep_it_real]

3. Kool; sounds good to me.

[whistle]

5. It's good if you are using about 1000KW hrs. per month and can feed

...the excess into the grid, but what happens when your use jumps over 1200KW hrs. per month? Also, 30 panels had to cost something substantial, so the breakeven point will be determined by the cost per KW hrs in your area over the life of those panels

[mitchtv]

11. My understanding from neighbors with similar systems

is you only need assistance from the grid in the summer whe the AC is on. Our average bill in summer is $350 and we run AC only in the PM til midnight and only to 80 degrees. Payoff may never happen, but SCE is very high and will only get higher,

[druidity33]

29. opposite here

My best solar gains come in summer here in Massachusetts. During the winter i get some power when the panels aren't covered with snow. We also heat with solar hot water (evacuated tubes).

Last year i spent a total of $302 in electricity... that's for the year. We too are tied to the grid and "sell" our excess, though at the "producer" rate. Of course we pay for it at the "consumer" rate (in other words, we pay 10x more for it than what we get paid for it... urgh)

Good luck! And do look into swamp coolers, they rock!



edited for early morning spelling...

[roody]

17. The breakeven point is NOW! The satisfaction of using

clean power is pure joy!

[midnight]

6. That is so cool... How big is each panel? What co. did you

get your panels from?

[mitchtv]

9. they look abour 3X4

Solar Power is the brand installed by a co called Gen Self

[blue sky at night]

10. this is so cool, but....

you have to give some more information, like how much did it cost, where do you live, does it tear up the roof, etc. This is stuff we all need to become aware of.

WAy To GO!

[mitchtv]

13. @40K with 14K rebate + several K off taxes(when that comes up)

It took 3 days here in the desert. The roof looks ok . We were concerned about that too the gave us two tiles they removed , but it can be years before it rains again, so we will have our AC guy check it out when he comes to service it next month. On potential problem.. Pidgeons are investigating to mov underneath. so already we have a maintenance issue, And have called the installer.

[MercutioATC]

19. I don't know if this would work, but a possible pigeon solution:

They make clear plastic "spike strips" to discourage birds from landing on balcony railings, etc., where flocking birds are a problem. The "spikes" are plastic and about an inch long, so you're not impaling the birds or anything...just encouraging them to seek greener pastures.

Maybe some of these laid at the gaps between the roof and the panels would help.

[Zachstar]

22. 40k is pretty expensive

I have been talking to the parents about the idea. However, With the fact that many of these are coming from China (Where the process is coming into question for pollution) And the extremely high cost... Well I just think it will have to wait.

20k for an average roof to be covered with panels that last 20 years and have multiple layers to draw in different parts of the spectrum and then it will be considered.

[roody]

31. My system cost me less than 10K after tax credits

and rebates. I have not paid for electricity for 7 years. This is the year for great tax credits. I am planning my solar hot water system and thermal heating. I want in on these up front rebates (CA.).

[madokie]

33. I wish I was a little bit younger so as to take on the extra upfront costs

In seven years we'll be paying, at todays rate and useage, about 7 grand for our electric. We're total electric except'n for wood pellet heat.

[FREEWILL56]

24. There are places you can go to read more on these things like:

www.homepower.com/home or http://www.solar-electric.com/
The magazine offers a free pdf download for a free sample copy.
On the 2nd link there is general info here as well as a store to check out the stuff and the prices involved, plus a forum you can go to.

[wtmusic]

12. Fantastic Mitch...what'd they set you back? nt

[mitchtv]

14. post above yours

[roody]

16. I only use 7 KW a day.

9 panels generate it.

[kristopher]

21. Average home use in US is considered 1000kWh/month

This analysis is based on that. You can do it specific to your energy use if you look at your bills and total your annual usuage. It isn't that complicated if you just sit down for a few minutes and noodle it. I mean, not knowing what you are paying per kWh is like not knowing what you are paying per gallon for gasoline.

Your electricity is probably around $0.12 a kWh (delivered) so if you produce 40kWh/day that's $4.80 a day. If your end of the price was $26,000 and you paid cash then the payback (not counting the lost earnings on your $26,000) is 14.8 years - longer if you financed the purchase.

I'm happy you like your system, but I think it is important when making a purchase like this that people consider the full cost. Above I pointed out the fact that the payback didn't include lost earnings on the $26,000. Depositing that amount for 15 years @ 6% yields accrued interest of $37,945. Add to that your original %26000 in principle and the actual cost of your system is $63,945 over 15 years. I used 15 years because that is the payback with no interest. Most analysis would be based on 20 years.

Again, using 1000 kWh/monthas average use and producing 40kWh/day, if you deposit the monthly the money you don't spend on electricity ($120/mo) plus the value of the excess 7kWh/day ($25.55/mo) you sell back to the utility, then at the end of 15 years @ 6% you will have accumulated $26.344 in principle and $16,395 in interest. Subtract that total of $42,739 from the $63,945 and your actual cost for the joy of owning your own system is $21,216.

I recommend to people that if they want to support clean energy (please do) the best use of their money is to contact their utility and sign up for the Green Energy Program. They are offered virtually everywhere and you will produce much more Green Bang for your energy dollar.

[FREEWILL56]

23. Nice try, but in most cases it won't be as you say.

There are other variables you fail to account for such as rebate programs and normal rate increases over that same period of time not to mention the fact that you are guessing at most of the figures.

[Zachstar]

25. Ok well lets keep this simple.

I aint spending 40k for a solar set.

[kristopher]

27. You could take it and invest in a portfolio of renewables.

Money costs are one of their biggest expenses.

[FREEWILL56]

35. I didn't ask you to and I don't care if you do.

I certainly was not speaking to you so anything else you have to volunteer to me?

[kristopher]

26. The rebate is taken into consideration

The system was 40K with a 14K rebate. Sure, I'm estimating, but what's your point? In the first place I suggested the OP check their utility bill and use the actual numbers for accuracy.

Second, I suspect I'm pretty close. The point is to demonstrate what a basic analysis looks like as most people really have no idea. As to the cost of electricity being too low, that would depend on where it is now for the OP. I pay just under $0.10 kWh delivered and would expect the average over the next 15 years to be somewhere around $0.12 kWh.

Also, frankly, it ticks me off when the good nature and good intentions of people are taken advantage of by people who could care less about the problem of climate change. It's one thing if you know the costs and what alternatives are available to help meet the purchasers goals (presumed to be avoiding high cost of electricity and helping the fight against GW), it is entirely another when their worries and good intentions are used to manipulate them.

[FREEWILL56]

36. My point is that you did not say this was only one possibly

estimated scenario and many do not have rebates available to them. You may pay $.10/kwh, but there are a few that are less and the majority with much higher costs as yours is low compared to nationally. Many pay even more during peak usage hours. The average you site to be possibly $.12/kwh in 15yrs may remotely apply to you and at best that is a pure guess on inflation and the greedy nature of many utilities.
As to your last comment, I do hope that wasn't aimed at me just for having a point that shows it's more variable than you site. I do have some pvs and would like more when the monies allow, so I am not antirenewable, but I also recognize that all of my electric needs will not be met with solar as it will be impossible at this point with today's technology given my location, orientation to the southern sky, and amount of physical area that can be used by me for that purpose.

[kristopher]

39. WTF are you talking about?

What I laid out is a standard basic analysis with a caveat that it should be adjusted to mitchtv's situation; I wasn't writing a dissertation. It was obvious that if the OP doesn't even know the price/kWh for the electricity he is displacing then he certainly hasn't done even a rudimentary analysis of the economics behind his purchase. If he wants a complete, fully fleshed out analysis he can use the basic template I provided and do it himself.

I think it is safe to say that most people have never seen a payback analysis done properly. Research shows that the lay public has a huge blind spot regarding energy costs - especially electricity, it is a black box commodity. Like mitchtv, they tend to look at their aggregate spending instead of per unit prices. What passes for a proper analysis is often no more in-depth than "can I afford the payments." And even if they do an in/out payback calculation they neglect to include the opportunity costs (interest in this case) of their outlay.

Let me repeat myself, if someone is aware of the full costs and they want to spend their money that way, then more power to them. However, I know for a fact that most people do not know the full costs when they are making very expensive decisions that have societal consequences. That's what I'm most concerned about; the costs to society of inefficient decision making regarding energy.

As to the last comment in my last post, no, that wasn't directed at you as a manipulator. However, your first response seemed to have a bit of "shoot the messenger" to it and it did cross my mind that you MIGHT be trying to validate your purchase decision. IF that's the case, I'm sorry if you feel bad, but it is important to go forward instead of looking back. To that end it is better to be informed and feel bad than live in blissful ignorance, IMO.

[roody]

32. You are assuming that the banks will not be

collapsing and losing our savings. Who makes the green energy? How do they make it? How much is lost in transmission over long distances? Can the satisfaction of paying a green energy bill surpass the joy of having green electricity produced and used at home and receiving a NEGATIVE bill?

[kristopher]

40. Are you a Doomer?

Yes, I'm assuming civilization continues. Lot's of people make green energy. The key to getting the cost down to where it will displace fossils is economy of scale, that's why doing it through the utility is a better way to spend your green dollars than trying to go off the grid.
The question about transmission losses is a good one. It points to the blackbox nature of the grid that I referred to in the post above. Think of the grid like a pool of water. When you buy water (electricity) from this pool, you hook a line into it and it flows under pressure into your home. There are many outflows and inflows connected to this pool, and each one is monitored for the quantity passing through. So if you want to buy water (electricity) from company A, the pool manager keeps a record of your use and sends the money specifically to company A. That doesn't mean you get the actual water (electricity) that company A pumped into the pool, it just means that you are providing specific financial support to company A because you think business practices are better than the other companies pumping into the pool. In this case, company A's business practices are, in fact, a little more expensive; so if they are trying to break into a low bid system, they are at a disadvantage because the other companies aren't willing to incur the expense of the better business practice.
This all means that in the context of making a decision to support how the water (electricity) gets harvested and pumped into the pool, the transmission losses incurred in GETTING TO THE END USER isn't a factor.
the transmission losses are very relevant, however, when the utility is selecting providers of water (electricity) who employ the business practices that people are willing to pay more for.

As to the joy of ownership, that is valued by the individual as what they are willing to pay. I'm just saying it is important that people should actually KNOW what they are paying.

[Pachamama]

28. That's a lot of Juice! How much do you actually need/use per day?

We installed last year a system half that size & production. We use about 12-15Kw hrs a day, however when you take the winter months into account and less production as opposed to the summer months, it all works out to produce what we need year-round. I'm assuming that before you decided to put this system in place, you studied your annual usage and consumption patterns and determined what size system you needed.

A bigger question is since from your profile it indicates your here in California as I am, what rate structure are you on and are you doing "net-metering"? I'm here in Northern California and we use Pacific Gas & Electric (PG&E) and we got to be included on the E7 rate structure which is no longer offered as of the first of the year. It breaks down the day into peak and off-peak hours. If we produce during peak hours 12-6PM and feed the grid, we get credited at $.28 per kwh. If we use the power at off-peak, we get charged $.10 per Kwh. The advantages here of course are the opportunity to really offset your electrical costs. The new rate structure for net-metering is "E6". With that, they have Peak, Off-peak and low-peak. The rates are different too...not quite as good I think of as the E7 rate structure no longer offered, but still pretty good.

I reccommend you look into your rate and metering options to optimize your production and usage.

[jpak]

30. 40 kwh a day is *real* good

and you said you would *never* do this!!!!1111

:thumbsup:

:yourock:

[WhiteTara]

34. what are your panels rated as?

figure that you have 5 hours of full radiant power a day. Add up all the watts that you use per hour (each bulb at 40w-60w etc) multiply the hours that it runs per day and there you have it...your answer.
Lucky you to generate your own power. There is something really wonderful about it....I used to have my own power plant, water and road system and of course heating. There was no electric hum anywhere and the peace that exuded was incalculable.

[roody]

41. Increase the value of your home.

All of us have neglected to mention the huge increase in the value of one's home when it has its own electrical power source.

[kristopher]

43. excellent point. nt

[Not Sure]

42. I don't know if this is an issue in your area

but how resistant to hail are solar panels? Our roof was destroyed one year ago this week by 2-½" hail. I'm not sure anything could survive that and this is the second time in five years the roof has been destroyed. However, if the panels are intended to survive hail storms or the insurance companies insure them at their replacement cost for a fair price, then I'd be interested in looking into this. Our summer electric bills have been as high as $400 per month in the past, but usually hover around $300.

[Finishline42]

44. Solar PV industry standard runs a test for hail

The Solar PV industry standard requires the panels to withstand 3/4" hail at 60 mph.

In my neck of the woods, most of the weather comes out of the west and since most panels would be mounted on a incline facing south, they probably would not be exposed the worse case in a hail storm.

Most panels have 20 to 25 yr warranty on current output.