It isn’t expected that ” . . . an eco-roof to increase photovoltaic efficiency significantly, but the benefit would increase eco-roofs’ (sic) value nonetheless.” And how does that follow?

It is interesting too the problems associated with becoming “green.” While it is doubtful that there is the 50 to 90 degree heat differential at the top of Portland buildings. If so, it would seem that photovoltaic cells may be very inefficient. Then combine them with the eco-roof which itself would cause the ambient temperature to increase. Never mind that an eco-roof is not inexpensive to install as it brings with it the issue of roof design.

And there are those who want to paint every roof white. “White reflective roofs are used in hot climates because they reflect the sun’s rays before they can heat up a building.” Are we talking about Portland as being in a hot climate? Really?

In the end I wonder what is gained?

“White roofs, eco-roofs and solar panels are all positives in terms of climate change and reducing our carbon footprint,” Klesch said. “When those combine, there’s even more of a positive return.” Wishful thinking.

It is not clear that any of these, or a combination thereof, will produce a net reduction in the carbon footprint. And, if so, at what cost? Empirical data is absent.

A Perspective