Cutting Loose from the Grid Rocky Mountain Institute warns that cheap storage is the real threat to utility companies.

Rocky Mountain Institute issued a report claiming that the real long-term threat to regulated utilities lies in the falling cost of energy storage systems. Driven by the growing popularity of hybrid and fully-electric cars and delivery fleets, efficient batteries are growing cheaper. That process will accelerate rapidly as Tesla and Panasonic carry through plans to build the world’s largest battery factory somewhere in the American Southwest.

When solar homeowners can afford to store their own electricity in a  big, cheap battery bank, they’ll no longer need the grid, RMI argues. In less than 20 years, if electricity prices continue to rise, consumers will begin to leave the grid in droves, just as cell phone owners have cut loose from land lines over the past decade.

In a blog post titled “Caveat Investor,” RMI this week warned financial markets not to depend on the long-term stability of utilities that don’t change with the times.