Originally Posted by melgross
I mean when adding something that gives an impression of being green, but which isn't making much difference.
I'll agree with this, as many companies/architects throw the term 'green' around so much it loses meaning. (And even LEED certification can be gamed in ways that undermine the original intent.) Unfortunately solar generation often gets thrown into this game and people don't know whether it's an honest effort or not. That's the point I'm trying to work against.
From an engineering point of view, PV makes infinite sense: convert the sunlight that is hitting your roof for free into electricity, which you need. As part of the bargain, on flat roofs solar panels even shade the surface that you would otherwise pay to insulate and cool internally from the heat transfer. (You would obviously insulate the roof for other reasons, but in the summer the heat load from the sun wouldn't be as great if they're shaded by panels.)
From an economic point of view the answer, as always, is "it depends". If you live in a cloudy climate your solar harvest will obviously be lower (although not zero). If your construction costs are high, such as on the top of a 60-story building, or an unfavorable roof pitch, that's a strike against. If the panels and inverters are too expensive, as they were in the past, your payback period extends out. But in Silicon Valley most of these concerns are no longer significant concerns. There are few places in the US more appropriate
for solar installations than the sunny regions of California.
The reason I go on about this is it's one of the few topics I think need to be discussed, and more importantly, taken back from those who try to confuse the issue for who-knows-what agenda. Jimmy Carter had panels installed on the White House, and then Reagan had them removed. They were already bought and installed! This is sound economic policy? If people have hesitations against installing solar panels on new construction
(setting aside the more complicated retrofit applications) it's probably because of the perpetuated myth that PV is still uneconomical. Either that, or they simply cannot handle a 15-year investment (and yet many will happily gamble their retirement funds on volatile stock offerings). This perception needs to change.