In the mid-seventies, at the height of the "energy crisis," Klaus started working in solar thermal systems engineering. He co-founded Alten Corporation, a San Francisco Bay Area solar engineering and hardware manufacturing firm.

The Alten solar collectors were based on an economically priced copper-tube, aluminum-fin design for which Klaus held a patent. Over the next decade, Alten Corporation produced some $30 Mill. worth of solar collectors for third-party financed installations.

Klaus also taught several solar engineering classes at local colleges and Stanford University.

Klaus Heinemann authored a textbook on solar engineering "Thermal Applications of Solar Energy" (no longer in print) and wrote/licensed a number of computer simulation programs for solar engineering applications.