Neoen, the French company behind a plan to triple its renewable energy in Australia, says coal is "technically and economically dead", as falling renewable energy costs eclipse fossil fuels.

Franck Woitiez, the managing director of Neoen's Australian arm, said the company is aiming to increase its clean energy capacity in the country from 1 gigawatts built or approved for construction to as much as 3 GW by 2022.

Neoen's expansion in Australia is only just beginning, its Australian managing director Franck Woitiez says.

"We are working very hard to develop these projects," Mr Woitiez said, adding that the additional 2 GW could involve another $4 billion in investment on top of the $1.8 billion already invested.

Neoen, 15 per cent owned by the French government, has grabbed headlines in the past year as the operator of the Hornsdale Wind Farm north of Adelaide that is also home to the 100-megawatt Tesla battery – then the world's largest such storage plant.