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The cost of solar power

Post in 'The Green Room' started by begreen, Jul 7, 2010.

  1. Jags

    Jags Moderate Moderator Staff Member

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    I finally had a little time to review some of the links posted previously. Very interesting stuff. And yes, it appears that some prices have come down. As an example - on of the links that BG posted states that you can by a pallet of 30 panels that are 224 watt panels for less than $18,000. Its a start.

    From most sites that I have read, the payback time is still from 14-16 years, but most panels have some sort of warranty to 25 years with a life span expected to be around 30 years. So basically in 30 years you "should" be able to double your investment (this assumes that electric rates hold steady, and we know that ain't gonna happen).

    It is food for thought. I personally think we are on the verge of cost and efficiency breakthroughs on the new panels coming out. I may kick myself, but I think I am still gonna wait a bit. I am betting on the same trends that we have seen with computer pricing or flat screen tv's, etc. The first ones are slow, clunky and expensive. With each generation they get better and less expensive.

    I would love to see the day that Home Depot sells a plug in grid tied 5kw system for 2000 bucks. YEEE HAWW.

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  2. begreen

    begreen Mooderator Staff Member

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    You are probably right. Commercial thin-film solar panel plants are just coming on line now. They are hard to get at this point, but should drop the price by over 50%. The question is when and will there still be the incentives in place to make this major investment feasible. The other side of the coin is by getting them sooner, you stand a better chance of inspiring those young girls so they don't waste that starlight by leaving the lights on when they don't need them.

    We're in a similar position, but my main issue is the lack of an all day clear shot at the sun. That and who knows if I will even be around in 15 years.
  3. Jags

    Jags Moderate Moderator Staff Member

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    Baahaha - your assuming that they pay any attention to me at all. I could haul in a nuke powered submarine, park it in the drive and plug the house into it, and they wouldn't even ask what the big "gray thing" is. :lol:
  4. fossil

    fossil Accidental Moderator Staff Member

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    Actually, they're black...and you'd need to provide a buttload of cooling water to it for it to operate in your driveway. %-P
  5. Jags

    Jags Moderate Moderator Staff Member

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    Will a garden hose work??

    Dang it - I already put my bid in for the used Russian sub on e-bay.
  6. begreen

    begreen Mooderator Staff Member

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    Hope it's diesel or you have a lll-ooo-nnn-ggg 4/0 extension cord.
  7. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    I still want that little baby nuke at the back of the yard. In a little building that looks just like a Central Boiler OWB. I could power the house and a good sized still off of it. Hell I could heat the house by just circulating the cooling water.

    "911 where are you and what is your emergency?"

    "BB Manor and we have a core meltdown in progress."

    "Meet the responders at the end of the driveway."

    "Hell no. I will be half way to Milwaukee by the time they get here. Bye."
  8. Dune

    Dune Minister of Fire

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  9. Delta-T

    Delta-T Minister of Fire

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    BB theres a lil nuke generating station at UMASS Lowell. Its about 25ft diameter and very.....non-descript. If you look at a campus map its labeld "The BRT" (for Big Round Thing), on north campus right near the campus security office..a lil creapy. Might be just what you're looking for.
  10. begreen

    begreen Mooderator Staff Member

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  11. Dune

    Dune Minister of Fire

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    You Sir are most welcome, and thankyou for fixing the link as well.
  12. oldspark

    oldspark Guest

    The MEN link just talks about energy payback not about payback for the cost of unit, am I missing something or is that what you had in mind?
  13. jebatty

    jebatty Minister of Fire

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    Us wood-burners often overlook the fact that burning wood is stored solar power in a high energy, compact package, and perhaps the most efficient and cost-effective thing we can do is move towards 100% space heating from wood while maximizing conservation in use of electricity. On average in the US we use lots more electricity in a typical home that do citizens in other developed countries. Which means we can achieve a lot by conservation and reducing electricity waste without reducing our standard of living.

    In 2008 the average US home used 920 kwh/month. About 1/3 of that is for HVAC, 1/3 for kitchen and laundry, and 1/3 for lighting and electronics. Reducing a/c use might be the biggest single thing that can be done to reduce electric use. For us, switching to CFL's, turning off lights when not necessary, and turning off computers and all electronics with power strips reduced electric usage by 25%. Cost of doing this was near $0. Our average non-summer use, which includes supplemental electric heat, electric cook stove and oven, electric clothes dryer, and electric hot water heater, is right around 600 kwh, not great but down quite a lot from the past. That goes up in June-August when we need to run a dehumidifier in the basement.

    Average home kwh use in Germany, Australia and most other developed countries is around 450-500 kwh, or about 1/2 of US average. Which brings to mind the thought of setting 500 kwh/month as our new goal for electric usage.
  14. Dune

    Dune Minister of Fire

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    Just trying to dispel a rather persistant myth that the cost (in energy) to produce a panel is more than the panel will create in it's lifetime.

    To be sure, solar electric will not work for everyone, a thorough investigation of it's utility is certainly needed before embarking upon such a large investment.
  15. jharkin

    jharkin Minister of Fire

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    All this discussion makes me more and more want to look into going solar myself....

    The only thing holding me back is the payback. We are young, just bought the house, don't have a ton of equity and have little ones on the way soon. I'd have to finance it and really cant justify taking on the extra debt unless the payback is going to be under 10 years.

    But with the rate the cost is coming down, 30% tax cut, and MA state credits maybe its only a couple years more before we reach that <10 yr payback?


    -Jeremy
  16. jharkin

    jharkin Minister of Fire

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    Have you guys seen this:

    http://homewind.net/windestimator.html


    I plugged in some very general numbers and its spitting out an estimate of 4 years to break even for a 50% capacity system with all the credits & financing the remainder.
    Note I'm in eastern MA, and our average yearly usage is ~8000 kWh at $0.17 rate.

    Curious if somebody who has soar could plug in your numbers and let us know if this calculator came close to your acutals....
  17. begreen

    begreen Mooderator Staff Member

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    When I put in a high quality stove, heat pump, refrigerator, washer, etc. it was not all about payback because I can't predict the future. But sure enough, my electrical and water rates went up and the increased efficiency started paying back quicker. I figured I stood a better chance of getting a return than putting the money into wall street. That was in 2006 and I've never regretted the decision.

    There are other reasons besides payback for investing in alternative energy. For one, you are building future industries that are going to be a necessity going forward. There is also the increased value to the property, this is permanent infrastructure. Another reason is by installing a system, you become a spokesperson for alternative energy development. This influences your neighbors, friends and most importantly young people. They are always the most curious and appreciative when seeing adults that are willing to invest in their futures.
  18. jharkin

    jharkin Minister of Fire

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    I did some rough figuring.

    We use 8000-9000 kWh a year. A couple different estimator tools spit out ~3.5kW to get me around 50% production. That I assume is under ideal conditions. My actual situation is less than ideal - the best spot I have for an array is on the roof of the garage, that has about 240 ft2 of 12/12 pitch roof that faces roughly southwest. There is one tree off to the east side that partially shades it up till 10am or so.

    So I figure I have space to put up about 2.5kW of panels that will give me maybe 75% of ideal production. I could do a split and put panels on both the garage and the main house, but I hesitate because the main house has more tree shading, and for aesthetics I don't want the panels out front (trying to maintain the antique colonial look).

    I ran the figures through 2 calculators.



    http://homewind.net/windestimator.html
    For a 2.5kW array its estimating 22k gross install cost and 12k net after federal, state and MA rebates. I put an assumption of financing 80% of the net so its predicting 2500 out of pocket year one and then 2-3 years to break even. It's seems to be very optimistic, using ideal conditions and accounting for Mass soalr carve out SREC credits to make it cash positive.

    Subtracting out the SRECs the break even point is 6 years. Figuring I realistically will probably only produce ~70% of what the calculator assumes puts that at more like 10.



    http://mercator.nrel.gov/imby
    Using 2.5 kw at my actual values of 45deg tilt and 245 azimuth, it is predicting typical annual production of 2400 kWh. Using only federal tax incentives it spits out a payback of 32 years.



    Then going back to the first calculator and de-rated the estimated utility saving by 20% to represent the more realistic 2400kWh/yr production. I get paybacks of

    10 years without SRECs
    3 years with SRECs

    I'm still unsure about this calculator - for one it assume a tax deductible loan, whereas I dont have the equity to borrow against - and the annual utility saving seem very optimistic. It must be accounting for time of use net metering or something.


    Defiantly interesting, but it still seems hard to justify something with a 10year payback that I'd be forced to take out a personal loan to finance. Maybe in 5~10 years when Ive got the home equity to borrow against..... By then hopefully the cost will come down even more.


    -Jeremy
  19. sullystull

    sullystull Feeling the Heat

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    Here's a pic of a job that was just completed in Morgantown, WV (home of West Virginia University). The (3rd party) book store decided to install what is probably the largest private solar array in the state--52 panels. So, for those of you with kids, send 'em to WVU to help reduce the payback time on this system.

    Attached Files:

  20. GaryGary

    GaryGary Feeling the Heat

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    Hi,
    I installed my own grid tie system, and ran into no problems. I still qualified for all the rebates that are offered in Montana.

    The system is 2150 watts.
    Total cost before rebates $9959 ($4.63 per watt)
    Cost after rebates $6471 ($3.01 per watt)
    I did not really look around a lot for the best deals -- I think that one could probably do somewhat better than this.

    PVWatts says the system will generate 3073 KWH per year, or about $300 saving at our current rates. So far, its ahead of the PVWatts prediction.
    So, right now its a $300/$6471 = 4.6% return on the investment.
    The return is tax free, and its protected against electricity rate increases.
    I don't think that's so bad -- and, the system was a lot of fun to put in -- I learned a lot :)

    I don't think the simple payback calcs are of much use -- how do you know what electricity will cost in 10 years?

    The system uses the new Enphase micro inverters with one inverter on each panel. It was very straightforward to install.
    The permit people and the utility people were all cooperative -- I did not detect any negative attitude toward DIY systems at all.

    This is all described in mind numbing detail here: http://www.builditsolar.com/Projects/PV/EnphasePV/Main.htm

    You can see a live report on the system output (courtesy of Enphase) here:
    http://www.builditsolar.com/Projects/PV/EnphasePV/RealTime.htm
    If its nighttime, it won't be doing much :)

    The economics page on the project is kind of interesting from the point of view of how the return from PV compares to some of the other energy projects we have done -- in a word its pitiful -- I guess the message is do the other stuff first, then do PV.

    Gary
  21. begreen

    begreen Mooderator Staff Member

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    Thanks for the links Gary. I have been looking at the Enphase vs central inverter solution. One concern is the failure rate of these units. When I investigated about a year ago, there was a report where engineers took them apart and were concerned about the cheap capacitors used. Even sitting on a shelf the capacitors would fail in about 5 years, but behind a hot panel, the rate was much higher. Now that we are seriously looking into a system I started looking at Enphase again and find that there is little data out of the field on these units. Some websites are reporting that they have been forced by Enphase to pull the results of their testing.

    Have you heard anything about this? It concerns me because I have a shading issue and would like this to work, but locally we have seen inverter failures on a few Enphase installations, though Enphase appears to be claiming no field failures. (That seems almost impossible.) I just want the facts so that I can make a good decision. Can you shed more light on this product's successes and problems out in the field (not Enphase's own reports)? I'm also curious why Enphase was chosen for this location. There doesn't appear to be a tree in sight. Was it Enphase sponsored?

    As an alternative we are looking at the Solar Magic product from National Semiconductors. Do you have any experience with this product? I like staying with the DC system, it allows us to use WA state made Silicon Energy panels, but also am finding it hard to get user field reports on this product.

    http://peswiki.com/index.php/Talk:Directory:Micro-Inverter_System_by_Enphase_Energy
    http://www.wind-sun.com/ForumVB/showthread.php?t=5117
  22. GaryGary

    GaryGary Feeling the Heat

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    Hi,
    I had not seen that before.
    My system has been fine -- no failures of any kind.

    The page describing my system gets a lot of reads a day, so I'd guess that if people were actually having much trouble I'd have gotten a few emails, but have not gotten any.
    I've actually found the Enphase support people to be very knowledgeable and helpful -- maybe worth just giving them a call and asking if they have a response to these arguments.

    You might also check with Guy M. -- he put quite a bit of work into selecting his Enphase system, and I think he keeps up on things more than I. He had an article on his system in Home Power a month ago. His website is:
    http://www.arttec.net/SolarPower/index.htm

    One reason that I settled on Enphase beyond the usual set of reasons is that if I had used a single larger inverter, it would have had to be out in the weather, and they are not rated to operate at the kind of low temps we get here. The Enphase inverters are rated down to -40F.

    I understand the comment about paying someone to come out and replace a single inverter being a negative, but I have to say that for my system it would take me less than 10 minutes to do it myself -- there is really nothing to it.

    I have also come to like the online reporting system they have. You can go there and get a PV panel by PV panel report on how things are going. Every inverter reports its status regularly, and if any of them are having a problem, Enphase automatically sends you an email. Without this, I could see myself having a system with reduced output just because I'm not that good about checking that things are working. It is a little spooky getting an email from your inverter :)


    I don't mean to say that these guys are not sincere or that they may not have a point, but it reminds me a little of the time before I bought my Prius -- there were a number of people saying that there was no way the battery pack could last and that it would cost $10K to get it replaced. They made what sounded like good cases for their arguments, and it nearly kept me from buying the Prius. Well, the Prius is now at 97K miles -- no problems, and by my math its saved me $9000 in gasoline over my my old Subaru Outback. Its just hard to pick out the valid arguments from the bad ones, and for any new product there will be people who are very skeptical.


    I guess one indicator might be that Enphase seems to be doing well, and that there are other companies coming out with similar products.

    If you find any more data on this, I'd appreciate an email.

    Gary
  23. jharkin

    jharkin Minister of Fire

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    I agree with you on all points begreen. For the same reason Ive also done new energy star Fridge &dishwasher; in the last year and am looking into replacing my basement dehumidifier with a higher efficiency unit for same reason.

    My concern about payback on PV is because I don't have the cash. I'd need to finance it and cant risk loosing the house if one of us gets laid off and the return wont offset the payments. Its the ONLY thing holding me back.

    Heck for fun I even printed out a chart and did sun surveys. My garage it turns out is a no go. The front of the house looks doable. The angle is not great (SW) but from Feb-Oct I get at least 6hr of sun. June Ive got a full 10hr. Dec is only about 3hr, but I could stretch to 4~4.5 if I took down a couple pine trees.
  24. btuser

    btuser Minister of Fire

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    I've found a couple calculators online and for 50% PV replacement it would cost me about $32,000. 100% would be about $64,000. My electric bill is about $200/month. After incentives I'd be looking at 25k for 50% of my power, and the break-even for cash is 12 years.

    To put it in perspective, $24,000 is a car loan. A car that needs gas, insurance, inspection, registration, repairs, and detailing after somebody scratches the door.

    $24,000 in the bank or on the roof.........$24,000 making $1200/yr minimum that comes to 5%......... STOP IT! I HAVE TOO MANY PROJECTS!!!!!!
  25. GaryGary

    GaryGary Feeling the Heat

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    Hi,
    I don't want to seem like cheer leader for Enphase systems, but one advantage they do have is that you can start small and grow as spare cash allows.
    You can literally start with one PV panel and one microinverter for less than $1000. You can then add panels easily as time and cash allow.
    There are several places that sell these "starter" systems -- WholeSaleSolar.com is one of them.

    But, I'm not sure how the rebate programs handle repeated small additions?

    And (at least where we are) you would need to through the whole permitting process for the first small system -- plus installation of the net meter by the utility. I suspect that after that you could probably get away with adding panels without further permiting-- but that may depend on where you live.

    Gary

    Gary

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