Power companies in NSW will have to display the cost of the federal government's carbon tax on bills under a new plan unveiled by the NSW government.

Premier Barry O'Farrell says consumers are entitled to know exactly how much of their bill is paying for the federal government's "disastrous" carbon tax.

He says bills would also display the cost of renewable energy schemes including the solar bonus scheme.

"The public have a right to know how much all these schemes and taxes are adding to their bills," Mr O'Farrell said in a release on Friday.

"NSW Treasury estimates the carbon tax alone will add up to $498 a year to household bills and families should be reminded about this impost every time their bill arrives."