Wind farms have become fairly common in advanced Countries. In Denmark, one large windmill is built after issuing 800 or so shares, the number of households that can be provided with power from a village machine. These shares, and up to 10m2 of solar panels providing hot water and electricity are purchased by middle-aged couples to ensure free energy in their retirement. Most connect to the grid, and buy or sell energy as they have the need, or have surplus energy. They provide for their old age.
Solar panels as hot water provided to insulated tanks, or as electrical generators, are becoming routine fixtures in modern societies; again, surplus electricity is sold to the local grid, and surplus heat is dumped into hot water systems.
Deep drill-holes, sited over areas of volcanic heat or where the earths crust is thin, convert water into steam for use in the heating of buildings, or in powering steam turbines for electrical production.