EnergyAustralia is expected to announce big upgrades for its Mt Piper coal power generator in NSW.

Reports say the company has a plan to help stabilise the east coast power grid and secure the plant's future for another 24 years.

With about 87 per cent of power produced in NSW coming from black coal, EnergyAustralia has been looking at energy recovery options for the Mt Piper plant.

It wants to generate an additional 30 MW of electricity by burning non-recyclable plastics and other refuse.

It is also working on plans to build a rail coal unloader for the generator, giving it more options on where to source fuel.

Mt Piper supplies up to 15 per cent of NSW’s electricity and has an operating life until 2043.

The company’s commitment to the future of Mt Piper throws more uncertainty on the older 1480-MW Yallourn generator – which is the most carbon-intensive generator left in the National Electricity Market (NEM).

EnergyAustralia has faced speculation that it wants to close Yallourn late next decade, ahead of its current 2032 shutdown date.

An official announcement is expected this week.