[RE-wrenches] Volcanos, reduced solar production and kWh performance warr...

Mon Apr 26 18:30:29 PDT 2010

Pat,

At what point (kW or cost) does a weather station with online monitoring make sense? 
I like to put a weather station on all commercial PV systems and upscale residential systems unless the client does not want it or will not pay for it. I like to measure irradiance, wind speed and direction, ambient and cell temperature (and rainfall if the customer will pay for it). Then I have the system call me automatically when performance is not as expected. I also like to put CTs on the grid to make sure utility input is correct.

What (or who ) defines "normal weather?"
You don't have to be concerned with weather if your DAS measures actual performance against calculated expected performance. We have early morning fog in southern California, so I set the automatic trouble call for between 10am and 4pm.

Defining expectations for the large (> 1M) installations must be particularly vexing - what constitutes normal or expected downtime due to mechanical failure becomes key to structuring PPA's.
I write into the service contract that we will respond to customer or automatic trouble calls 48 or 72 hours during weekdays (not weekends) and during regular business hours (8to5). I have had only one client who wanted me to wear a pager. I told him that (1) PV systems are reliable, (2) if his system was not powering emergency or life support loads, and (3) he would have to pay my hourly rate 24/7 if he wanted me on call 24/7. He quickly changed his mind about how important his PV system was.

Joel Davidson

  ----- Original Message ----- 
  From: SOLARPRO at aol.com 
  To: re-wrenches at lists.re-wrenches.org 
  Sent: Monday, April 26, 2010 7:57 AM
  Subject: Re: [RE-wrenches] Volcanos,reduced solar production and kWh performance warr...

  Marco:

  At what point (kW or cost) does a weather station with online monitoring make sense?  
  What (or who ) defines "normal weather?"
  Defining expectations for the large (> 1M) installations must be particularly vexing - what constitutes normal or expected downtime due to mechanical failure becomes key to structuring PPA's.
  If making a warranty on kWh production must be part of a contract, a number of concerns must be tackled in the way it is written, especially with regard to the value of compensation.  Maybe funds could be awarded for over production or applied as a credit against lower than expected kWh. 

  Pat Redgate
  Ameco

  In a message dated 4/26/2010 4:38:43 A.M. Pacific Daylight Time, solar1online at charter.net writes:

    Hi Marco,

    I hope this query does not divert response to your original question.

    How is the situation of the reduced performance due to the volcano (or other "acts of God" or the like) approached in the Power Purchase contract? Perhaps this could be titled "Reduced Solar Production As a Result of Reduced Solar Input". 

    TIA,

    Bill Loesch
    Solar 1 - Saint Louis Solar

    PS As I remember, the last time I bought a new vehicle, back in the Dark Ages, the auto manufacturer's warranty deferred to the tire maker's warranty (for tires), etc. Any similarity?

      ----- Original Message ----- 
      From: Marco Mangelsdorf 
      To: 'RE-wrenches' 
      Sent: Sunday, April 25, 2010 10:02 PM
      Subject: [RE-wrenches] Volcanos,reduced solar production and kWh performance warranties

      This thread brings up a very timely issue that I’m dealing with right now with PV Power Purchase Providers.  As an integrator providing turnkey PV systems of X kW, I’m being asked to contractually agree to a minimum performance warranty for said PV systems.  I am EXTREMELY uncomfortable to any such clause in any contract that I would sign.  I have strong confidence in my PV design capabilities  and engineering support and in my professional crew to install a top-quality PV system.  I have a lot less confidence in an inverter manufacturer being able to get to a site on a Hawaiian island in the middle of the Pacific in a super timely fashion as the lost PV kWhs rack up.  And as I mentioned in a previous post today, we have an active volcano here that’s been spewing since 1983, a volcano that could get a lot worse on any given day.  I’m leaning strongly against agreeing to any such clause.  Way too bad a precedent to set.  Way too much of a liability.

      Anyone else had to deal with this bugger of a performance warranty demand?

      Thanks,

      marco

      ProVision Solar

      Marco:

      Our production schedule has been in tatters - lowered by perhaps 30% because of the rain.... can't plan, can't do.  Then I pay overtime on good days to (try to) catch up.

      We have a number of systems online and I had not thought to actually review and compare from this year to last.  I'll let ya know.

      We'll get a call like - "My bill is higher than last year (edison has a bar graph of monthly consumption for the past 13 months) and I'd like you to look at my system" or My meter is not going backwards, should I call edison?"  The weather is so consistently wet this winter (think Hilo) that we usually just need to ask-

      "Been outside lately?"

      But everywhere is so green and the desert bloom is outrageous.........

      http://www.desertusa.com/wildflo/ca.html 

      Pat Redgate 

      Ameco Solar 

      In a message dated 4/25/2010 12:24:53 P.M. Pacific Daylight Time, marco at pvthawaii.com writes:

        Pat,

        Kicked your butts as far as lower output?  If so, by how much on a percentage basis?

        On the Big Island of Hawaii, we’ve had a very active volcano doing its thing since 1983.  With the normal trade winds, the vog (volcanic smoke + fog) gets blown south past the volcano, around the south tip of the island and then back up along the west side of the island.  Which means that Kona-side residents can be in a yucky vog zone for days and sometimes longer.  Think L.A. on a smoggy summer day.  And as far as percentage decrease in solar output, I really have little accurate clue.

        Marco

        ProVision Solar

        Kicked out butts, in fact.

        Pat Redgate

        Ameco Solar

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