Using weighted technology similar to old grandfather clocks, Port Kembla-based Green Gravity is preparing a pilot project in a disused coal mine shaft behind Wollongong.
Power is generated in similar ways to any hydroelectric scheme.
During the day, solar energy lifts the weight and, at night, lowered to generate power.
There are over 1000,000 legacy mines across Australia and a twelve-metre prototype has been built at Port Kembla.