Energy Secretary Ed Davey will escalate the increasingly bitter battle within the coalition over green measures by backing calls for a target on cutting energy sector emissions by 2030.
He will pile pressure on Chancellor George Osborne and "blind" Tory sceptics to accept the move by declaring there was "a strong case" for including the measure in the forthcoming Energy Bill.
Liberal Democrats are expected to enshrine a tough target into party policy when they debate a motion highly-critical of Mr Osborne's failure to pursue green growth policies at their party conference.
Mr Davey will use his speech to the Brighton gathering to launch a tirade against the party's coalition partner and effectively align himself with Labour leader Ed Miliband, who joined calls for a target last week.
Liberal Democrats are seething that potential investors in clean energy technology in the UK are being put off because of what they see as an ideologically-driven reluctance of the Treasury to swing behind the sector.
The battle exploded in the summer when Mr Davey succeeded in seeing off Tory calls for significant cuts to onshore wind farm subsidies but at the price of support for gas up to and beyond 2030 and not just as a back up to renewables.
It sparked a backlash from the Government's own climate advisers who said mixed messages were damaging investment in low-carbon technologies such as nuclear and renewables and called for a fixed target to avoid a "dash for gas".
Mr Davey will say that opponents are putting at risk the growth equivalent of building 20 Olympic stadiums every year until 2020 and billions in private investment that would cover the "vast bulk" of the costs.
To restore investor confidence he wants to include a commitment in the Energy Bill to a 2030 target for reducing emissions from the energy sector - with the exact figure placed in secondary legislation to allow flexibility.
The Committee on Climate Change said the maximum carbon dioxide level should be placed at around 50g/kWh - with the conference set to adopt a wider range of between 50-100g/kWh.