Solar Power Craze on Wall St. Propels Start-Up - NYTimes.com

Or both (substantive and sustainable solar success and another "irrational exuberance" case study)

"Depending on whom you talk to, the rise of SolarCity and similar companies is either a sure sign that solar power is finally having its day or that yet another mania has gripped the markets. Two other companies, SunPower and SunEdison, have also exploded in value. In all, an estimated $13 billion was invested in solar projects in 2013, a tenfold increase since 2007, according to GTM Research, which tracks the industry."

Solar Power Craze on Wall St. Propels Start-Up - NYTimes.com