Drop-dead simple energy idea: Gravel on ski lifts

Last week Bill Gates briefly mentioned that he made an investment in an energy storage startup that he called “gravel on ski lifts.” Contributor Michael Kanellos put two and two together and guessed that Gates’ reference was to the startup Energy Cache. . . . . (It has created) a system of buckets on a line that picks up gravel at the bottom of a hill, and moves the gravel to the top of the hill; when the process is reversed, the gravel moves back down the hill and powers a generator to produce energy.

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