Would you be surprised to learn that one of the most significant figures in the history of the solar house was never terribly excited about the prospects for solar heating? I'm referring to MIT engineering professor Hoyt Hottel, who designed and built the first-ever 'active' solar house, in 1939. In the book I call him a "skeptical innovator."
Hottel's MIT Solar House I was a tremendous engineering success, using flat-plate hot-water collectors of his design. It produced as much heat as it needed on an annual basis. A year later, in 1940, he gave an extraordinary speech at Harvard. He complained that other scientists compared the amount of solar energy on an acre of land to a "healthy stream" of oil from a garden hose. He exclaimed: "solar power is not just there for the taking!" A long excerpt from that witty speech is included in The Solar House (pages 101-102).
Here are a few more skeptical tidbits from Hottel which aren't included in the book:
"When we started we had high enthusiasm. But we slowly came to realize that while there were uses of the sun, they were not as promising as we all thought they would be." (1976)
"If you wish to lose the least money, get fifty percent of your heat from the sun. If you wish to lose no money, don't get any." (1976)
Here Hottel is reacting to the times; by the mid-1970s there was considerable public enthusiasm for the solar house concept, but an inexperienced industry to fill the need.
Hottel's campaign of restraint culminated in his article "Cloudy Forecast" in Skeptic magazine (Mar-Apr 1977), where he argued that the government shouldn't subsidize "presently available ideas that are economically shaky" but that they should look for "better ideas." One might note that the predominant 'presently available idea' for solar house heating at that time was Hottel's own: flat-plate collectors with water storage. He also predicted that solar's future would depend upon principles which "remain to be discovered." (And he didn't mean photovoltaics.)
I think a lot of creative people (like the subject of my earlier book, architect Gregory Ain) end up doubting the value of their work in retrospect, especially near the ends of their lives. Hottel was different: he didn't necessarily doubt the importance of his own solar house experiments, but he (seemingly) wanted to prove---from the 1940s to the 1970s---that the active solar house wasn't economically feasible at the time. He clearly took pride in his role as a skeptic, and believed he was making a contribution by broadcasting caution.
I wonder if any other figure in history had such strong record of innovation and impact in a field that they didn't necessarily believe would succeed.
(Note that Daniel Behrman also discussed Hottel's "latter-day role as a Cassandra" in his 1976 book Solar Energy: The Awakening Science.)