Alistair Darling will announce £500m of further investment in green initiatives in an attempt to shore up low carbon industries hit by the recession.
The Chancellor is expected to announce the cash and other low energy measures in Wednesday's Budget, in what officials expect to help secure tens of thousands of jobs.
Mr Darling will effectively double a £500m "green stimulus" announced in the Pre-Budget Report, although he is expected to dramatically downgrade his economic forecasts from that statement in November.
The Tories claimed he would admit to the longest UK recession since the Second World War.
There are predictions too of future tax rises and curbs in public spending to bring down borrowing, which has soared as part of the Government's recession-fighting strategy.
According to The Times, Mr Darling will herald £15bn of Whitehall efficiency cuts as he further reduces the growth of spending in future years.
But ministers are keen to ensure that green technologies emerge from the downturn in good shape.
Money will go into energy efficiency measures and support for energy technologies to ensure investment is not lost from the UK and projects already in development are not held up.
Officials believe the UK's low carbon sector can grow by almost a half, £150bn and employing 1.3 million people, by 2015.
Mr Darling sought to boost confidence in the economy amid expectations of one of the bleakest Budget statements in decades, with Shadow chancellor George Osborne saying it would be a "dramatic moment" and urged Mr Darling to scrap the Government's "unrealistic" future spending plans.
