Academic fronts Shorten over RET

A Canberra academic has buttonholed Opposition Leader Bill Shorten, demanding he backs the renewable energy target.

The government wants to adjust the 20 per cent RET target so it matches a decline in energy usage.

Labor is in discussions with the government about a possible compromise.

Matthew Ruffin, a lecturer on sustainable communities at the University of Canberra, interrupted Mr Shorten's press conference on Wednesday to quiz him about Labor's policy stance.

"I hope you don't weaken it," he said, telling him Australia should be moving as quickly as possible to 100 per cent renewable energy.

Mr Shorten told him Labor would not support the government's aim for a "real" 20 per cent target.

"We can assure you on that," he said.

Mr Ruffin later tweeted: "If you cave on the 41,000GWh RET target you will lose all credibility with the electorate. Stand strong."

Earlier on Wednesday, the Australian Solar Council released an open letter to Mr Shorten urging him to support the target and campaign for an increased target for 2030 or 2040.

Chief executive John Grimes said there was no public policy argument for exempting emissions-intensive industries from the RET.

Those industries benefited from both low power prices and the reduction in the wholesale cost of electricity delivered by the target.

"Solar is overwhelmingly popular with voters and we will work with the community to strongly oppose any changes," Mr Grimes said.