Renewell Energy
They are repurposing oil and gas wells into the lowest cost, greenest, and most flexible energy storage in North America.

Location
United States
Extended description
There are over 2 million inactive oil and gas wells in North America. Regulations vary, but in all cases owners are required to remediate them, a collective cost of over $280B. Renewell Energy is creating an energy storage device that can be used in place of remediation, allowing a huge impending expense to massively deploy gravity-based energy storage at a very low added cost. Renewell's solution will build the greenest, most flexible, and largest distributed energy storage network currently feasible. With a potential of over 40 GWhs at $62/kWh, Renewell can deliver the storage necessary for wind and solar to experience uninhibited market share growth.
http://renewellenergy.comRelated industries
Energy
Sustainability