In the early 2000s, solar PV presentations typically focused on environmental benefits, energy independence / security, and hip technology to impress neighbors. Electric bill savings projections were usually back-of-the-napkin estimates meant to support the non-financial motivations for going solar.
OnGrid founder Andy Black began selling solar in 2001. He noticed that between the high electric rates in Northern California and government incentives, going solar could be a great decision on financial grounds alone. Andy had his proof after more research and working out the math in a very elaborate spreadsheet. Using conservative assumptions, the rate of return for a solar investment was often over 10%.
Andy wanted to share what he learned with other solar professionals, and began offering workshops on solar financial modeling in 2004. He was often pointing to his spreadsheet to illustrate concepts, and students inevitably asked for copies. Andy embraced the opportunity, and made the OnGrid Tool spreadsheet available to the industry in 2005.
Since 2005, OnGrid has continuously improved the OnGrid Tool. It's now web-integrated, with a supporting Visual Basic framework for advanced functionality (geek speak). Several hundred solar companies subscribe to it today.