I think the point of view Peter shared has more to do with lower sloped North facing or other non-ideal orientations. The proof is in the pudding – just simulate the production and utility bill offset and see if the proposed orientation makes sense financially. We haven’t done any North facing arrays (yet?) but we have a few that are North-West in orientation and they are working as projected.
I think a side question that this poses is whether, for example, it makes sense to install a reverse tilt on a North facing roof or just mount the panels flush and install more of them. My calculations show that the reverse tilt is still a better economical choice but it is no longer as cut and dry as it once was when modules were more expensive. Of course reverse tilt arrays pose structural engineering and aesthetic considerations so we really try to shy away from them. Best, August *From:* RE-wrenches [mailto:[email protected]] *On Behalf Of *jerrysgarage01 *Sent:* Tuesday, July 28, 2015 12:29 AM *To:* RE-wrenches *Subject:* Re: [RE-wrenches] Using the North Facing Roof Wrenches I see this working south of the tropic of cancer but at 1000 watts per meter squared tilted north might work for a month a year but I don't think the tax credits were proposed for poor performance module installations. I see enphase annual readings prove the point. Jerry Sent from my Verizon Wireless 4G LTE smartphone -------- Original message -------- From: Peter Parrish <[email protected]> Date: 07/27/2015 7:21 PM (GMT-10:00) To: 'RE-wrenches' <[email protected]> Subject: [RE-wrenches] Using the North Facing Roof I recently read a short piece that caught me up short, and I quote: “The fast dropping cost of solar, while a huge boon to the adoption of solar PV, has counter-intuitively altered design parameters. No longer is the north-facing roof considered unusable because limited application in less-than optimal orientations can still show a positive net benefit. Arrays are thus designed now with elements or sub-arrays in these locations, increasing overall kW installation while reducing the energy production per capacity installed. This might have been anticipated based on sheer economic analysis from a users perspective, but so long has solar been expensive that these less optimal orientations were never seriously considered.” I doubt that the individual who wrote this piece came to these conclusions him/herself. Does anyone know of a recent article that argued this perspective? Is this an emerging design practice? If so, I’d like to know more about it. - Peter Peter T. Parrish, Ph.D. President, SolarGnosis 1107 Fair Oaks Ave., Suite 351 South Pasadena, CA 91030 (323) 839-6108 [email protected]
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