You are receiving Wrench list digests. If you are responding to one of the messages in the digest, be sure to replace the subject line with the correct one for the individual message. Thanks. Rather than base a performance guarantee on average annual production and introduce the possibility of disagreements about the weather, power quality knocking inverter offline, and other things beyond your control, I think it's better to stick to the manufacturer's performance guarantees and measure instantaneous production to ensure that the array is performing as expected for the irradiance and temperature on a given day. If one of my customers had a concern about production, I would go out on a clear day with my multimeter, daystar meter, and surface temperature meter. Take the measurements, plug in figures for inverter efficiency, degradation from aging, etc. and compare expected AC watts with actual. This doesn't account for intermittent inverter dropouts that might effect annual production, but it does show whether the array is performing as expected.
Regards, -Hans ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of Joel Davidson Sent: Wednesday, August 05, 2009 11:42 AM To: RE Marketing for home scale RE industry Subject: Re: [RE Marketing] PV system Performance guarantee Each company has its own performance contract. In general, if you monitor the system by internet and it is reasonably close to your shop so you can fix problems quickly, then you should be able to guarantee kWh/month within 5% of the PVWatts conservative estimate with the condition that daily weather is within the normal 30-year climate range. ----- Original Message ----- From: bill roush <mailto:[email protected]> To: RE Marketing for home scale RE industry <mailto:[email protected]> Sent: Wednesday, August 05, 2009 7:42 AM Subject: [RE Marketing] PV system Performance guarantee Anything out there on what is reasonable to ask of a contractor for a Performance Guarantee on a PV system? 5 years/less? Based on what parameters? Same for home, small commercial and larger commercial? -- Best, Bill Roush Heartland Solar Energy Industries Association www.hseia.org Heartland Renewable Energy Society www.heartland-res.org ________________________________ _______________________________________________ Sponsored by Home Power magazine Re-Markets mailing list [email protected] http://lists.re-wrenches.org/listinfo.cgi/re-markets-re-wrenches.org _______________________________________________ List sponsored by Home Power magazine List Address: [email protected] Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
