The 40% number is NOT a peeer-reviewed number.
Most studies have it around 17%, and in my own experience,
I think that number is closer to reality.
And frankly, if roof joists can't hold solar, it means. the roof
needs a replacement anyway. And with higher wind and more
extreme weather from climate change .. that is important to know.
There have been some studies in the hurricane-prone southeastern
USA, that show roofs get damaged less during high-wind and
hurricanes that have solar water heating and/or photovoltaics.
Happy New Year all. Regards, Scott
Scott Sklar
President
The Stella Group, Ltd.
706 North Ivy Street, Arlington, VA 22201
VA Phone: 703-522-1195 (3049 direct)
The Stella Group, Ltd.. is a global strategic technology optimization owner's rep firm for
clean energy users and companies, with a focus on system standardization,
modularity and web-enabled diagnostics. Scott Sklar is an Adjunct Professor at
The George Washington University teaching three unique interdisciplinary
sustainable energy courses, and an Affiliated Professor with CATIE, an
international graduate university in Costa Rica offering graduate degrees
on sustainability. Sklar is the Sustainable Energy Director at GWU's Environment
and Energy Management Institute (EEMI).