What's a powerful way to help people use less power at home? Pit them against their neighbors. As founder and president of Opower, Alex Laskey helps utlity companies show customers, right on their utility bills, where their own house sits on the spectrum of neighborhood energy wasters -- and how to beat the game. It seems silly, but the large-scale reductions in energy usage are no joke.

Opower works with more than 80 utilities on three continents, and serves over 15 million customers. Since its launch in 2008, it has cumulatively saved utility customers more than $200 million and 2 terawatt hours (TWh) of energy -- enough to power a city of more than a quarter million people. It's all through a powerful combination of behavioral science, data analytics and good marketing.

In the next twelve months, Opower is on track to save another 1 TWh, equivalent to more than one half the generation of the entire US solar power plant industry in 2011. In May 2016, Opower was bought by Oracle.