The impact of the renewable energy target on parts of Tasmanian industry has been grossly exaggerated, a left-wing think tank believes.
Four large energy-intensive Tasmanian companies claim the RET costs them $20 million a year, ripping $200 million from the state over 10 years.
The claims have got Tasmanian senator Jacqui Lambie fighting for the target to be scaled back and talking to other crossbenchers about a plan to include existing hydropower and solar schemes in the RET.
The proposal would remove the need for significant investment in renewable energy to meet the target.
But The Australian Institute says claims by the four companies are "gross exaggerations" and the real figure is closer to $8.5 million a year.
The think tank says the RET brings in $125 million to the state, without taking into account jobs and lower electricity prices.
"Claims made against the RET by industry are not free of self-interest," institute senior economist Matt Grudnoff said.
The government wants to slash the target of 41,000 gigawatt hours to about 27,000, claiming that figure will represent 27 per cent of energy use by 2020 instead of bipartisan level of 20 per cent.
Crossbench senators wrote to Prime Minister Tony Abbott outlining their plan to include existing hydro and solar, after major party talks failed.
The Australian Greens want no change to the target and 100 per cent of energy from renewables as soon as possible.
Greens leader Christine Milne plans to meet Senator Lambie, hoping to persuade her to retain the target.
Senator Milne fears her Tasmanian colleague has been misled by industry about the impact of the RET.