The nation’s energy regulator has warned consumers may be paying more than they should for electricity because major coal and gas generators dominate the market at peak times despite a massive influx of new wind, solar and battery projects over the last two years.

Clare Savage, chairwoman of the Australian Energy Regulator, said a major review of electricity market had revealed several issues, including a worrying concentration of power among traditional generators even as a crowd of renewable players dominate the market during the day.