New analysis suggests state governments are investing enough in solar and wind power to render the Turnbull government’s energy policy near-useless.

Energy analysts RepuTex say the combined effect of state renewable energy targets means the proposed National Energy Guarantee (NEG) will not have much to do.

Queensland is aiming for 50 per cent renewables by 2030, Victoria is aiming for 40 per cent by 2025 and South Australia is well on the way to meeting its 50 per cent target.

The state targets mean modelling from the government's Energy Security Board (ESB) has a high baseline against which to measure the impact of the NEG.

The ESB’s modelling has found that the electricity sector will cut its emissions by 19 per cent by 2030 without the NEG.

But RepuTex's modelling finds that when existing state renewable energy targets are incorporated, emissions from the electricity sector will actually drop 29 per cent.

Australia has committed under the Paris Agreement to cut overall emissions by 26-28 per cent on 2005 levels by 2030

RepuTex says the NEG risks being “immaterial” to the market.

“Unless the target is more ambitious than where emissions are projected to be without the NEG, there is little need for the administrative complexity of the scheme,” RepuTex associate research director Bret Harper said.

State targets have already driven investment in renewables so much that three times more new generation will be added to the system by mid-2018 than the ESB predicted.

“The arms race between the states for renewable investment is well under way, with or without the NEG,” Mr Harper said.

State targets are on track to remain the dominant signal for new generation, unless the NEG imposes even deeper emissions cuts.

Malcolm Turnbull says the Liberals’ win in South Australia is an endorsement of the federal government's energy policy.

The Prime Minister says outgoing Premier Jay Weatherill was the most vocal opponent of the federal government's National Energy Guarantee.

“Jay Weatherill said this was a referendum on energy policy,” Mr Turnbull said on Sunday.

“The people have spoken and spoken in favour of our policies which is to support affordable and reliable energy to ensure that we can meet our Paris commitment, and at the same time ensure that we can keep the lights on and indeed afford to keep the lights on.”