Malcolm Turnbull has rejected efforts to “dumb down” the energy debate into renewables versus coal, and says the government’s new investment framework will encourage “all of the above”.

A day after a significant incursion by Tony Abbott into the energy debate – with the former prime minister arguing the government should not support renewables and should instead prioritise coal-fired energy for grid security – Turnbull said the energy debate had seen too much ideology and “not enough competence”.

“It isn’t an issue of renewables versus coal,” Turnbull told reporters in Brisbane.

“A lot of people try to dumb this down into something like that. It is a question of all of the above. All of these technologies have a role to play, whether it is coal, whether it is gas, whether it is wind, whether it is solar, storage is critically important.

“You have to keep the lights on and people have to be able to afford to pay the bills when they are on,” he said.

Turnbull’s comments followed a threat by Abbott to cross the floor if the government attempted to legislate a new clean energy target to replace the renewable energy target after 2020, a stance supported by backbenchers Craig Kelly and George Christensen.

The government is attempting to finalise a new investment framework for energy and is contemplating a clean energy target, which was recommended by the chief scientist Alan Finkel in a review of the national electricity market.

It is already clear that the government will not adopt the specific target modelled by Finkel, which had a threshold which would not allow coal to get certificates – but it is possible the government could pursue a modified clean energy mechanism.

The government has also been telegraphing rule changes to the national electricity market as part of its energy policy process.

The Australian Energy Market Operator wants a “day ahead” market, which allows better planning to ensure sufficient quantities of dispatchable energy are available in the system – and there is also talk around the government of a shift to a capacity market, which exists in Western Australia.

Turnbull flagged rule changes to the national electricity market in a radio interview on Thursday. “There is a lot of change being made as a result of the Finkel review recommendations and there will be more to come.

“The rules do need upgrading,” he said.

Despite the internal disagreements, the Coalition has been united in its efforts to pressure AGL to keep the Liddell coal-fired power plant operating for longer.

AGL has given notice of its plans to shut the plant in 2022.

Turnbull and the energy minister, Josh Frydenberg, have met with AGL chief Andy Vesey and asked him to consider keeping the plant open beyond 2022, or sell it to someone who will.

The deputy prime minister, Barnaby Joyce, has been particularly strong in calling for AGL to sell the asset, which it bought from the New South Wales state government.

On the Thursday, the Business Council of Australia chief, Jennifer Westacott, defended AGL.

“They have made it very clear, what the cost of keeping that plant is – $160m a year leading up to 2022, they have made it clear that it is unviable beyond that and you have to remember that only 1% of coal-fired power stations stay open passed this 50-year life that they have across the world,” she told ABC radio.

The business chief said certainty on energy policy was needed after years of policy mismash.

“We are in this position because we have had a decade of terrible policy. We have had failed starts on a carbon pricing scheme. We have had a mismatched of poorly designed green schemes and renewable schemes.

“We have had states putting moratoriums on gas supplies, which has really restricted gas. Now we have capacity coming out of the system as these players age. What I would like to have a debate on is, what do we need to do to fix it? And it won’t be one scheme, one project.”