Big users bankroll new power to offset carbon footprint

Mining giant BHP is using wind farms and solar to offset its carbon footprint. (Marion Rae/AAP PHOTOS)

Supermarkets, tech giants and mining heavyweights are increasingly buying into wind and solar farms to offset emissions and attract climate-savvy customers.

For two decades, Australia's Renewable Energy Target (RET) has created an obligation for big buyers of electricity from the grid to use more renewable sources.