At this point in the process you are prudent to minimize your effort while showing a desire to give the client some ballpark numbers. As long as they don't want you to dial in a large swimming pool pumping system or a machine/auto shop, start with 2 Wp/sqft, 40 kW and decide what you want to charge them for $/Wp. If you have a clean, unobstructed 4,000 sqft of roof space and not overly long wiring runs you could bid less than $7.00/Wp. Better to submit a "not to exceed" than to come back with an unpleasant surprise.
Good luck. - Peter Peter T. Parrish, Ph.D., President California Solar Engineering, Inc. 820 Cynthia Ave., Los Angeles, CA 90065 Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885 CA Lic. 854779, NABCEP Cert. 031806-26 [email protected] -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Luke Christy Sent: Saturday, May 09, 2009 10:50 AM To: RE-wrenches Subject: [RE-wrenches] PV Estimate for Vaporware Building Wrenches, We have been asked for a cost estimate for a grid-tied PV system sized to offset the electrical consumption of a building that is still in the design phase. The building in question will be a elementary/high school for a small community in southern Colorado. The only information available is that it will be ~20,000 square ft, and will be going for LEED Gold certification. Heating will be either via a ground-source heat pump or gas-fired boiler+solar thermal feeding radiant floors. Obviously the final choice of those two options greatly affects electrical consumption of the building, but that aside, how are people dealing with this sort of estimate process?...ie: when the building itself is still vaporware. Is there a reasonable way to come up with a ballpark W/ft² value when one is dealing with a host of unknowns? Any techniques you've used to deal with these extremely amorphous requests for costs? Thanks in advance for your input. -Luke Christy Luke Christy NABCEP™ Certified PV Installer Solar Gain Services, LLC Center, CO _______________________________________________ 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 _______________________________________________ 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
