Comment: It could mean solar,

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In reply to comment: Nothing free about this energy (see in situ)

It could mean solar,

It could mean solar, geothermal, hydroelectric, storing a lightning strike, or something using earth's energy from the same wave that syncs our brain waves sync to. Something decentralized and without the cost of fuel means free to me.

Please come join my forum if you're not a trendy and agree with my points of view.