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Making Electricity, Our Photovoltaic System

Discussion in 'Miscellany' started by beaucamera, Apr 5, 2007.

  1. We decided to install a photovoltaic system at the end of last year, but it didn't get installed until last week. I don't know how many of the rest of you have gone through this process.

    In northern California we get electric power from PG&E. There's a tiered rate system. The lowest rates are $0.11/Kwh. Once you use more electricity than the base level, you pay a higher rate. 101-130% of the base rate is $.12/Kwh, 131-200% of the base rate is $0.22/Kwh and 201-300% of the base rate is $.32/Kwh. I don't know about you, but it seems like all the gadgets and electronic toys we have really expand our use of electricity.

    Our system consists of 10 Sanyo 205 solar panels, designed to produce 1.81 KW. It's small relatively speaking, but it was the only pure play we had to collect the sun's rays without shading effects. The roof we placed the panels on faces south.

    Our site wasn't condusive to ground placement so we ended up with this configuration from Ready Solar, a start up based in Portola Valley, California. Ready Solar supplied the panels, inverter and frame(patent pending). The installation was done by RA Tech Solar from Gilroy, California. Mark Thompson from RA Tech Solar is a really experienced guy and we were lucky to have him on the job. Shake and tile roofs aren't easy to do and he had to make frame modifications on the fly, something he did with ease. We liked this design because the panel supports don't show. This was especially important because the roof the panels are located on are in the front of our home.

    Now that everything is installed and the permit signed off, we have to wait for PGE to install a new meter to record the output. Once they do this, we'll sell the electricity produced back to PG&E. We expect the system to reduce our electricity costs by at least one-third, eliminating higher usage costs.

    It's going to be a fun experiment and perhaps we'll make a small dent in the global warming crisis.

    aka beaucamera

    Mark Thompson from RA Tech Solar installing the last panel on the Ready Solar frame.
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    Another view of the array.
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    The completed system.
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    Last edited by a moderator: Apr 6, 2007
  2. gadgetguy11


    Nov 16, 2005
    That is a very interesting project! 1.81kW will be a good savings each month. I was blown away by your utility rates!! Our highest rate in KY is 0.05 for residential (that is 5 cents per kwh!), Industries pay much less, usually 0.035 (3 1/2 cents per kwh!). Coal is cheap, and coal is used to power the generators. 5 cents translates into a monthly bill averaging $125 with 2) AC units, landscape lighting, etc/ for a 3,500 sq feet house.

    Good luck with your photovoltaic system! Sounds like a very intelligent investment. Beautiful landscaping, by the way!
  3. That's cool Virigina, but I have to admit that I'm more taken with your nice flowers!
  4. Yes, John, electricity is expensive here. Be glad your rates are as low as they are! It's interesting to learn what others pay.

    The solar companies told us electric utility rates have gone up here about 5%/year for the last couple of years. (Can't verify this though). Have your rates risen too?

    aka beaucamera

    P.S. We put this front patio in about two years ago. It's the only area where we have a "formal" garden. The deer, rabbits, and gophers abound and challenge serious gardening so most of the rest of our yard is native.
  5. I'm with you on this, Daniel. Solar panels are ugly, but I think we did the best we could with this installation.

    Boy, I love these Spring flowers too.

    aka beaucamera
  6. Way to go Virginia. I agree.. solar panels are ugly......... but so's a DEAD planet!

    You did good girl............!!

    I hope you are well! :biggrin:

  7. gadgetguy11


    Nov 16, 2005

    Electricity rates have not gone up because the energy source (coal) has not changed in value. This is supposedly the lowest, or 2nd lowest cost of electricity in the nation, according to the utility company. We lowered our consumption dramatically using compact fluorescent lamps throughout the house, a 2-stage ultra high efficient 21 Seer 3.5 / 5-ton A/C unit for the 1st floor that replaced a 13 Seer energy hog, similar change for the 2nd floor, set-back t-stats, more insulation, etc.

    The problem with doing that at 5 cents per kwh, is that you get the satisfaction that you are doing the right thing, so you do it. BUT, the cost of the energy saving devices (especially compact fluorescent bulbs) is higher than the net savings in most cases.

    Here is an interesting result: Manufacturing bottom line profit, hence "productivity" appears higher in this area, than in other areas due to the lower electricity cost. It makes a huge difference to the bottom line. That is one of the reasons Toyota built the Camry plant here, and built a truck plant in not-so-distant Evansville, IN. Honda is just North, in Marysville, IN, Ford has 2 plants in Louisville, 1hr 15min from here.

    I am thrilled that you put this system in. You are doing the right thing, and hopefully will even save a little money to boot! I have not seen any of these systems in this area - payback would probably be longer than the homeowner's life!
  8. We have had a system like this (2400W of maximum power) in place for nearly 2 1/2 years now. It is hooked to the grid and runs the meter backwards at times! :cool: :smile:



    It took almost a year to get the town's permit to build the trellis structure to support the panels, even though it is not visible from the street and no neighbor was against the project! These people care more about their town small politics than about doing the right thing. The local solar dealer/installer business had to sue them (and win) for them to change their stance and be more open about solar in general... Sheesh!!

    Anyway, our electricity cost has gone down in about half, and the higher the electricity price is, the more we save, since it shaves cost off the top rate. Yes, it will probably take 13-15 years overall to break even, but overall it is the right thing to do.

    The system has already generated about 9000 kWh, in almost 10,000h when the system was active and generating. The 2.4 kW number is the maximum power that the system can handle, but those conditions only happen during the mid-day hours in the summer time. As you can see, the average production is slightly under 1 kW, but that is something. :wink:

    Nowadays, panels deliver 50% more power for the same surface, for a cost about the same. My BIL has just installed a 3600W system for the same price it took us to do 2400W 2 years+ ago. A lot more research and investment is being done in this arena now, in the Silicon Valley investment community in particular. Hopefully, this will mean even better gear soon... but I am not looking to upgrade for another 12 years, unlike my camera! :biggrin:
  9. Chris101


    Feb 2, 2005
    Nice Virginia!!! Wow, you're 21st century all the way!
  10. Gale


    Jan 26, 2005
    Viera Fl
    Very good Virginia.
    This is surely the way to go.
    I save energy in many ways myself. Have for a long time. Including water usage.

    I love your yard and flowers to:>)))) I am very jealous ...
  11. That is very cool.

    So, if there is a power outage, does the system (panels and batteries?) keep the lights on, for at least a time?
  12. gadgetguy11


    Nov 16, 2005
    Wouldn't that depend if the power outage happened when the sun was shining, or at night?
  13. Welcome to the solar world! We have been of grid since 1983, and used to sell the gear before the Inet came along, not having phone lines did us in. It is a different life style off grid, but it is nice to not be depenedent on the power co. The western elec. co. are more in tune to solar customers. Here in the South it would take a year of forms to get through the process. Good Luck, happy for you.
    Last edited by a moderator: Apr 7, 2007
  14. No. This type of system has no storage capacity so all the energy that it produces must be either consumed locally or sent back to the grid right away. When the system detects that the grid is off (i.e. during a power outage), it shuts itself off as a precautionary measure, since there can't be any guarantee that all the energy converted from the sun light could be dissipated otherwise. Granted, this is fairly primitive, and I am sure that future systems will do better.

    In the meantime, systems like TomP is referring to allow to totally be disconnected from the grid, but they are also a lot more complicated and expensive, due to the energy storage requirements. The PV system that Virginia and myself have installed are really meant to complement energy taken from the grid, not replace it...

    In fact, since we are de facto power producers (and the utility company is buying power back from us), we also have a clause in the contract that says that overall we must be net buyers, not net producers: in other words, we can't have a negative electricity bill. This means that it is useless to dimension the system too large, compared to the household consumption.
  15. Ah, thanks for the explanation. In our next house I hope to use solar.

    I am also hoping for advancements in solar panel design and manufacturing to bring the prices down and performance up.
  16. Thanks for piping in here, Philippe.

    Like all technology products, it's hard to know where to jump in. The odd thing happening here in Silicon Valley is that just as interest and investment in solar products is increasing, the rebates available to the consumer are decreasing.

    I've learned so much since I started on this project 7 or 8 months ago. Monitoring systems are pretty primitive so, for now, we're doing that by hand, checking the meter at mid-day and after the sun has gone down. Our inverter, a Zantrex 2.5KW, has an RS232 port that can be used to monitoring, but that's a rather primitive approach.

    When I looked a power backup systems, I learned that the options were expensive and not all that good...........yet.

    Panel technology is moving fast, but concrete roofing tile systems tend to lack the ventilation that helps solar cells dissipate heat, decreasing their efficiency. (BTW, Philippe, your installation seems perfect for heat dissipation!)

    Inverters convert DC to AC current and also need to be in protected/cool environments.

    Roof top panel systems tend to reduce heat so many user report that they have a cooling effect.

    You can place panels where the exposure isn't ideal, but you'll need a lot more of them just to get production. Many solar companies I found are more than willing to do this. This can increase installation costs and add to problems if you need roofing repairs. This is just a note to the wary, use the sun as your guide. Fortunately we were able to investigate scenarios in winter. That really helped us figure out what approach to follow.

    If you have a solar story to tell, I'm sure many here would like to know how you have fared.

    aka beaucamera
  17. I find this quite interesting. I have a large south-facing roof area that can only be seen from the air. But our electricity rates are much lower here than in California, though higher than in Kentucky, apparently. It might take a long time to recoup an investment.

    Virginia, did you do a calculation of the payback period for your investment?

    And how about cleaning? Don't you have to keep those panels clean for efficiency?
  18. Hi, Jim

    Trying to figure out the economics of this type of investment is a crap shot. The inverters have a life span of about 15 years, the panels, 20-30, or so we've been told. How much you save on your electricity depends on the rate structure of the utility you get service from and how much rates increase in the future.

    If you save $50/month that's about 5%/year on a $12K investment. You are going to buy electricity no matter what so that $600/year you save, you'd be spending anyway and it's taxable. If your tax rate is 25% that means you are actually going to need to generate $750/yr. in income to pay for this electricity. Even with a modest investment like this, it would still take 16 years to break even on your initial investment. If utility rates rise, you'll be ahead of the game sooner. If interest rates rise faster than utility rates, you capital might be better spent in other ways. There's definitely an ecological benefit, but that's difficult to figure into the financial equation.

    The panel efficiency can be decreased by dirt and grim. I've asked the supplier for more information about cleaning. I think most people just hose them down.

    Maybe Philippe will tell us what he does.

    aka beaucamera
  19. Thanks for the information, Virginia. I was afraid it would not be an easy exercise to compute the payback period for your investment - I just wondered if the economics were compelling in your rate environment.

    We bought a hybrid car last November (Toyota Highlander), not because of the potential savings, which are probably nonexistent unless the price of fuel reaches $5/gallon, but because we just liked the performance of the vehicle.

    I'll be interested to hear what Philippe has to say.
  20. In terms of cleaning, just running a hose in a great while (once a year?) is enough. We haven't noticed any degradation in performance. The average output per hour has been steady at just under 1 Kwh around the year, with the maximum output at 2.3 KW during the mid-day hours in the summer, with a total production of perhaps 22-24 Kwh on a sunny summer day, and only 4-6 Kwh on a rainy winter day...

    I think we are on schedule to break-even in the originally estimated 14-15 years, but as rates go up (they never go down, do they?), the actual break-even point might be even a bit lower. Even, if it means replacing parts (inverter at 15y and panels at 20y) later on, it's still worth it. Even, if not saving anything money-wise and assuming everything stops working at the break even point, it is still worth it from an environmental standpoint! :smile:

    However, when we replace parts in a few years, we'll save even more as the efficiency of the inverter and the panel will have increased a lot by then. Heck, it already has by about 50% in the last 3 years, and that was before the big money of Silicon Valley even looked at this as the next "big thing".

    Incidentally, Virginia is right, as the technology becomes more mainstream, its mass scale makes it more interesting to big business and the Silicon Valley money, while it makes less and less sense to have the states (the only rebate we had) and now the feds (is that still true in 2007?) subsidize it to bootstrap the industry. In effect, we have the same timeline for break-even as Virginia (say 15 years), but with a technology far less efficient, which was subsidized by California to make up for the difference. Without the subsidy, it would have taken 22-25 years to break even and the equipment may not even last that long...

    However, remember the energy crisis in California, with rolling black-outs, the Enron rip-offs, etc...? The state thought that promoting solar, with subsidies, was a good way to avoid repeating that crisis, by allowing more little producers to come online, not to mention that they produce the most when it is most needed, i.e. hot! At the same time, not as much capital and time was needed to make a little bit of a difference, compared to building a bunch more new plants. I think it was a good idea, and that action is largely creating the climate (pun intended!) in which the industry can develop and sustain itself. The fact that oil prices have continued to rise since that time gives even more ammunition to the venture capitalists of Silicon Valley to invest in new energies, solar being at the top of the pile.
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