CANBERRA: Australia's electricity is about to be greened-up big time - but not without a fight first.

Laws to ensure that a fifth of energy comes from renewable sources by 2020 have been tabled in federal parliament.

The policy, which is separate to emissions trading, appears set to be approved because the coalition and the Greens like the idea.

Power prices will rise to pay for the Renewable Energy Target (RET), which will be a huge boon to wind, solar and geothermal power.

But there's a hurdle to be cleared: whether big polluters should be largely exempted from paying for it.

The government wants to grant such exemptions, but says they'll only go ahead if the embattled emissions tradings scheme is opposed by parliament.

The coalition doesn't like this and will move to decouple the two schemes.

"It is pure vandalism for the government to try to hold the renewables sector and their own RET legislation hostage," said coalition environment spokesman Greg Hunt.

The Greens will move to scrap any exemptions to big polluters under the RET.

Renewable energy groups just want the RET passed and have urged politicians to stop playing games with green jobs.

Greenpeace is worried that the target will not really amount to the promised 20 per cent of electricity from renewable sources because solar hot water systems have been included as electricity generators.

Minister Assisting the Minister for Climate Change, Greg Combet, told parliament the RET would mean more green jobs.

"The Renewable Energy Target scheme will accelerate deployment of a range of renewable energy technologies like wind, solar, biomass and geothermal power over the next two decades," Mr Combet said.

He said green energy would quadruple from 9,500 gigawatt hours to 45,000 by 2020 under the RET.

Mr Combet also moved to increase the penalty for electricity generators who don't do their bit under the RET.

The RET will work by forcing electricity retailers to buy a certain amount of their power from green sources. They will pass on the costs to all consumers.

The RET will include a new rebate for solar panels.

Debate on the Renewable Energy (Electricity) Amendment Bill 2009 and related bill was adjourned.