AN overhaul of Scotland's energy sector would create tens of thousands more jobs than currently exist in the oil and fossil fuels industry, new research claims.

The report by the Scottish Greens also calls for the Grangemouth refinery and petrochemicals plant to be taken into public ownership with the decommissioning of North Sea oil and gas fields prioritised.

The party said the proposed changes would move Scotland from a dependency on "energy colonialism" to an "energy democracy".

But the Scottish Tories have branded the plans "pure fantasy", claiming they ignore other energy types in favour of preferred industries.

According to the report, Jobs In Scotland's New Economy, renewables and a push for green energy would see 200,000 jobs created by 2035. There are currently 156,000 people employed in fossil fuels.

The Greens say the report uses government and industry assessments to calculate the figure with conservative estimates, while the 'new economy' would also include building on 'green chemistry', home insulation and forestry.

Other policy proposals include creating a publicly-owned renewables company to encourage offshore wind, tidal and wave developments, converting Grangemouth to make and use synthetic gas, launching a national insulation retrofit programme and a large-scale reforesting programme and making available support packages for fossil fuel workers to aid their transition to new sectors.

Scottish Green MSP Alison Johnstone said: "In recent months there have been mass lay-offs in the oil and gas industry. The ongoing insecurity due to the volatile price and finite nature of this resource has devastating consequences for families and communities.

"The only credible and responsible course of action is a managed transition towards sustainable sectors as outlined in this major report.

"We can enhance skills, encourage innovation and increase supply chain opportunities for Scotland’s small and medium-sized businesses. We have the chance to become a world centre of expertise in oil and gas decommissioning, with imminent global demand for such knowledge.

"To make the most of these opportunities we need to reject austerity, prioritise investment and reconsider the billion pounds annual subsidy we give oil and gas multinationals."

But Scottish Conservative energy spokesman Murdo Fraser said: “The plans from the Green party on energy are based on pure fantasy.

“Just like their SNP counterparts the Greens seem to be obsessed with offshore wind, tidal and wave developments while ignoring the benefits of other energy methods.

“Scotland has a workforce experienced in oil and gas extraction and we must use these skills to help exploit our undoubted shale gas potential.

“We also need to be building more power stations and looking at different options to deliver our energy instead of focusing solely on renewables. Our policy is to balance a mix of including renewables, nuclear, oil and gas.”

The Scottish Government has set the target for the amount of electricity generated annually through renewable sources at 100 per cent by 2020.

Yesterday, a new study claimed Scotland needed to shift one-fifth of its spending on new buildings and transport towards backing for its targets of big cuts in carbon emissions.

Compiled by the Green Alliance think tank, the report claims there are "critical weaknesses" in the way Scotland now spends.

It said international comparisons suggest 72 per cent of infrastructure spending in other countries is on projects designed to reduce carbon emissions, whereas that is thought to be 52 per cent in Scotland.