The world’s richest people are pouring money into two startups that have developed different techniques for storing energy—one of the biggest bottlenecks in the widespread adoption of renewable-energy. The investors, which include Bill Gates, Jeff Bezos, and Mark Zuckerberg, have all invested through a $1 billion fund that aims to provide “patient capital” to startups. That means the fund is willing to forgo returns on investment for up to 20 years to give the scientists and engineers at startups a reasonable lead time to develop their world-changing technologies.