Bill shock, economic upheaval and grid instability will be caused by a proposed exit from coal-fired electricity generation in just eight years, takeover target AGL Energy warns.
"If we transition before the system is ready, reliability will be at risk, costs will inevitable flow on to customers and communities will be impacted," a spokeswoman told AAP on Thursday.
For the past two decades AGL has been committed to decarbonisation, adding more than 2350MW of new generation to the grid, the company said.
