I am going solar

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by usbseawolf2000, Feb 16, 2015.

  1. mrbigh

    mrbigh Prius Absolutum Dominium

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    Ja!!!! I ha
    I had been there, not to long in the past.....
     
  2. macman408

    macman408 Electron Guidance Counselor

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    My heat is natural gas, but I'm thinking that maybe I'll have to use as much electricity as I can to burn through my accumulated credits (plus the newly-increased 'minimum monthly charge') before the end-of-the-year electric bill arrives. There's an electric heater in the bedroom I've never used, guess I can turn that on. Maybe plug in a hairdryer or two elsewhere in the house to keep the heat distributed. ;) As it is, I have enough surplus credit that I think I could pay for 4 months of normal electric use - without my solar panels generating another watt. And I only have 2 months left to do it in!

    Of course, if the electric company hadn't decided to up their minimum charge, I probably would've been more interested in conservation than getting my credit's worth... But if they're gonna go to great lengths to screw us, I'm happy to return the favor...
     
  3. Jan Treur

    Jan Treur Active Member

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    You could consider to buy a heat pump. This multiplies the input kWh by a factor 3 or more (compared to an electric heater), so you will not pay much for gas anymore.
     
    #323 Jan Treur, Oct 22, 2015
    Last edited: Oct 22, 2015
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  4. Zythryn

    Zythryn Senior Member

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    So at the end of the year they don't pay you if you have credit left?
    If not, and if they don't carry that credit over to next year, please don't waste electricity.

    Instead, use the same electricity, but during peak times (if you really feel you need your pound of flesh).
     
  5. macman408

    macman408 Electron Guidance Counselor

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    They'll pay you about 3.5¢/kWh of surplus. But they charge around 20¢/kWh for what you use. It's doubly complicated because I signed up for the Time Of Use billing, so I earn credits during peak hours at a rate of 36¢ (or 24¢ on near-peak), and then use up my credits at the off-peak rate of 16.6¢. The net effect is that I can use almost twice as much electricity as I produce for no additional cost, because of the price differences between when I produce it and when I consume it.

    That credit has no bearing on whether they actually pay me, though - if my total bill is less than $120 for the year (including any negative amount), then I pay them nothing beyond the $10/month minimum charge I've been paying every month. Completely separately from that credit calculation, if my total kWh is negative, they'll pay me the 3.5¢ - that's the only way they'll pay me. A rough estimate is that best case, I'd probably net about $3 or $4 from that.

    And I don't plan on wasting any electricity - but I might try to shift more of my energy use from natural gas to electricity, since I'm paying for the electricity anyway. (They're the gas company too.)

    If I were feeling really vindictive, I'd wait for one of their quasi-power-emergency days where they're asking people to avoid using electricity, and then turn on my air conditioner right at like 5 PM as the sun is starting to go down and solar output around the state is dropping, AND power consumption is rising as people return home. (Google "duck curve" from the California ISO to see what the utilities are afraid of.) I'm not quite that pissed off at them yet, but I'm close. Currently, they're trying to end net metering so that those of us with an excess of power in the summer (which is presumably when they need the most power, given that it coincides with the highest rates on their time-of-use programs) can't carry that forward to use in the winter - instead, they'd give us the piddly 3.5¢ rebate in the summer so that they can charge us 20¢ in the winter. They also want solar customers to pay an extra monthly fee based on their peak usage - a tactic that is usually on very large industrial customers, because their sudden load changes can actually make a big difference. And also, those industrial customers usually pay about half what residential customers pay per kWh. :mad: </rant>
     
  6. mrbigh

    mrbigh Prius Absolutum Dominium

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    That is F**k-up
     
  7. Zythryn

    Zythryn Senior Member

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    Sweet setup!
    Out in MN if you elect to go with net metering and TOU you only get wholesale price credit for any excess electricity regardless of the time of day.
    A number of utilities have also started charging extra fees for solar customers. Luckily the public utilities commission has ruled one Utility's fees illegal and are in the process of making a state wide ruling.

    We've been watching the duck curve and future estimates for it pretty closely. It is odd how in California, it may be that utilities will start pushing EVs to charge during the afternoon lull for grid stability.
     
  8. randyb359

    randyb359 Member

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    I just had Solar panels installed. They are going to set up the monitoring tomorrow. It is a small system 3.6 kw/ That should be enough to provide almost all of the electricity I use.
     
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  9. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Do you have a good orientation? Which panels and inverter type did you get?
     
  10. randyb359

    randyb359 Member

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    The panels are only a couple degrees off of due south. I got LG 300w panels and Enphase 250w microinverters.
     
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  11. Jan Treur

    Jan Treur Active Member

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    I notice a difference of 50W between maximal power of panel and microinverter. Would it mean that when your panels produce at their max, the microinverters are overloaded and only provide 250W of AC? In my case it is the other way around: I have panels of 265W and 285W and microinverters of 300W. Sometimes the microinverters produce up to 310W, especially when clouds are coming and going.
     
  12. mrbigh

    mrbigh Prius Absolutum Dominium

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    The panels are only a couple degrees off of due south. I got LG 300w panels and Enphase 250w microinverters.
    By rule of thumb, the panels should be a higher wattage due to aging or media degradation, a normal factor.
    These will never provide the same power output after their ten year anniversary.
    If at the beginning of the installation, you are so lucky to have some sort of energy overproduction or peaks for some period of the day, called saturation, the microinverters will smooth the total production and go above the label rating with out any problem.
    Your microinverters are the finest quality available, nor the cheapest.
     
  13. randyb359

    randyb359 Member

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    It is what the installer recommended. They are approved by Solarize Allegheny which was set up by the Heinz foundation to encourage the installation of solar panels so I trust their recommendation. The panels only put out the rated power under ideal conditions so the amount of time they will actually be clipped should be really small. Especially since I live in Pittsburgh which is one of the cloudiest cities.
     
  14. fuzzy1

    fuzzy1 Senior Member

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    That panel rating is not a true maximal power. It is a rating under a specific but very infrequent operating condition. Under other conditions it can produce even more power than that, but the great majority if its life in most installations will be spent producing significantly lower power.

    It is generally not cost effective to use microinverters sized to never 'clip' the panel output. The money difference would generally by better put into larger capacity panels that clip some of the time but are putting out more power in the far more common less-than-ideal conditions. But the circumstances are quite variable depending on the specific site conditions, local weather, and the particular pricing of the components on the day they are purchased.

    The labor cost need to perfectly optimize this complex puzzle is much greater than the value of the components and power being traded off. I.e. it is not worth spending $1000 of labor to analyze and optimize a $500 component-and-power tradeoff.

    The Enphase M215s generally clip at 225 watts, while the M250s clip right at 250 watts. The clipping level may actually be a current limit instead of a power limit, but my system voltage hasn't varied enough to spot the difference.
     
  15. jzchen

    jzchen Senior Member

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    This complexity is exactly why the OP and I went with the Solar Edge optimizer inverter setup. It is supposed to be, at least when I was shopping three years ago, slightly more efficient, and got a slightly higher CA rebate. The higher wattage panels tended to be more efficient, but somehow the micro inverters were not configured to handle such output.


    iPad ?
     
  16. Jan Treur

    Jan Treur Active Member

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    Probably a small difference between maximal power (Wattpeak) of a panel and max Watt of a microinverter will not make much difference in production, as the periods of 'clipping' the panel output will be very rare indeed. But I am wondering whether a 50 Watt difference is not rather big. In my own situation I quite often see periods that my panels produce substantially more than 50 Watt under their Wattpeak. I had a choice to go for 250 W or 300 W microinverters with a rather modest price difference, and I have chosen the 300 Watt inverters. At that time, beginning of 2013, I was not aware of the power optimiser option from Solar Edge. If I would have known that option I might have chosen it, as in that case the capacity of the inverter is for the whole, and then it is easier and less costly to fit it to the overall Wattpeak of your system (although you also have to take into account the capacity of the optimisers).
     
  17. randyb359

    randyb359 Member

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    enphase claims the M250 is good for panels from 210-310 watts. Yesterday they were reporting 256 watts each. Today was a nicer day and they peaked at 242. How do you know if they are actually clipping?
     
  18. jzchen

    jzchen Senior Member

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    Solar Edge has residential optimizers up to 405W, and commercial up to 700W, where two modules are supposed to be tied in series. My 327W panels are connected to the 400W optimizers.

    Power Optimizer | SolarEdge

    I ran across them somehow researching for quite a few months, and luckily it wasn't too late to change. (I was still comparing prices). I must say in our third year output seems a little down...

    MT2L03 ?
     
  19. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Look at the production graph of the system. It should be a bell curve. If the top of the bell is flat, you have clipping.
     
  20. Jan Treur

    Jan Treur Active Member

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    I would be more convinced when they also would have a 300W microinverter in their collection. If that would be the case they might argue differently that the 250 W is good for panels from 210-270 Watt and the 300W for panels from 250-320 Watt. But I think up till now they only have the 215W and 250W microinverters. In their (current) case the 250W option is the best option they can offer for panels in the higher range, so it will be tempting for them to make such statements about 'being good' also for the higher range panels.
     
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