Software billionaire Mike Cannon-Brookes’ private company Grok Ventures, the biggest shareholder in AGL Energy, has given a provisional thumbs-down to the appointment of director Patricia McKenzie as chairman, calling for “independent, fresh thinking” to set the coal power giant on a path to low-carbon energy.

The news of Ms McKenzie’s new role comes less than a week after ex-Tabcorp chairman Paula Dwyer was set to be appointed as chair, and is part of a broader leadership overhaul that includes the addition of seasoned renewable energy leader Miles George as a director and CFO Damien Nicks as acting CEO.