[RE-wrenches] kWh performance warranties (was volcanos)

[Joel Davidson]

Allan,
The volcanos string evolved into a discussion about contractors' system performance warranties as compared to equipment nameplate warranties. I find it interesting that solar module manufacturers warranty power output levels for 20 to 25 years, but inverter and charge controller manufacturers do not warrant the level of efficiency that their equipment will operate.
Joel Davidson
  ----- Original Message ----- 
  From: Allan Sindelar 
  To: RE-wrenches 
  Sent: Wednesday, April 28, 2010 10:06 PM
  Subject: Re: [RE-wrenches] kWh performance warranties (was volcanos)


  Joel,
  Your link has nothing to do with the kWh performance warranties being discussed, so I'm confused. The warranty referenced simply says that "The insurers will indemnify for any reduction in power loss from CNPV's warranted, 90% guaranteed energy output in the first 10 years and 80% in the following 15 years. Additionally the insurance also covers expenses which might become necessary when recovering the formerly certified energy output." That's a standard module performance warranty, with the indemnification being based on whether it meets 80/90% of  nameplate rating; it has nothing to do with overall guaranteed system performance.
  What am I missing here?
  Allan


  <![endif]--> 
  Allan Sindelar
  Allan at positiveenergysolar.com
  NABCEP Certified Photovoltaic Installer
  EE98J Journeyman Electrician
  Positive Energy, Inc.
  3201 Calle Marie
  Santa Fe, New Mexico 87507
  505 424-1112
  www.positiveenergysolar.com



  Joel Davidson wrote: 
    kW and/or kWh performance warranties are what some customers want and are willing to pay for and what some PV companies provide successfully. Many wrenches guarantee their systems' DC and even AC nameplate rating. For several years PowerLight, now owned by SunPower, entered into kWh contracts with its customers. Their success was based on good system design, performance modeling, installation, monitoring, and service. I observed (not insider information) their systems performing 4% to 6% better than PVWatts estimates. Basically, they did what all smart contractors do: under-promise and over-deliver.

    Here's the latest news about performance guarantees. See http://globalsolartechnology.com/index.php?option=com_content&task=view&id=5388&Itemid=9

    Small companies can provide the same customer confidence without performance warranties. Give your prospective customer a list of satisfied customers who have been monitoring their systems. Let your customers tell your prospects that your systems deliver what you promised (estimated). Then tell your prospect that they can save money by not buying a performance warranty.

    Joel Davidson
      ----- Original Message ----- 
      From: Jeff Yago 
      To: RE-wrenches 
      Sent: Monday, April 26, 2010 7:02 PM
      Subject: Re: [RE-wrenches] Volcanos, reduced solar production and kWh performance warranties


      I would never contract for a guarantee minimum performance for a very simple reason - weather!

      I think the only reasonable guarantee is to state the "nameplate" output of the array provided under test conditions, and make it clear that  air temperature, clearness factor, dust, cloud cover, and out of tolerance utility grid events will all reduce system performance from this perfect lab value.  Since you cannot control any of these affects on system performance, there has to be a reasonable expectation of system performance for you and your client. 

      Why do doctors and hospitals have you sign a disclaimer before they render service?  How about accountants, mechanics, engineers, stock brokers, and dentists,   Yes, you can sue for gross negelence, but how many will sign a statement that guarantees their work will have a specific outcome.  Odds are, the small print in the document you sign will point out that there are too many unknowns beyond their control that could reduce the hoped for outcome and if you want a guarantee, -  buy life insurance - you die - they pay -guaranteed.

      Jeff Yago
  

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