The oil services tycoon, Scotland’s second-richest man, has invested in wind farms and carbon-capture technology. But he believes renewables alone will be unable to keep up with Scottish demand.

The SNP Government has said it will not allow any of the four new nuclear power stations proposed by the UK government to be sited north of the border, calling the energy source “dangerous, expensive, unreliable and unnecessary.”

Energy policy belongs to Westminster, but Alex Salmond has vowed to use planning rules to stop new stations being built here. Ministers say most of Scotland’s future energy needs can be met with wind and wave power, but Sir Ian, chairman of global oil services firm Wood Group, said such an energy policy was unsustainable.

He believes the country will only keep up with energy demands with a mix of renewable, hydrocarbon and nuclear sources.

“Scotland has the potential to be a world energy centre, but we have to have renewable energy alongside nuclear, which Scotland is in self-denial about,” he said.“A country like Scotland – and the UK – with the energy challenge we have ahead of us, needs to have some nuclear content.”

Sir Ian, a former RBS director, added Scotland faces a possible energy crisis in the next decade and pointed to increases in the cost of fuel.

“Relying solely on ­renewable energy is impossible,” he said.

“We couldn’t produce enough quickly enough, and hydrocarbons are inevitably going to reduce. Although renewables will generate a significant amount of energy, they will hardly keep pace with the increased demand.

“There is going to be a huge increase in the demand for energy in the coming years as countries like China and India begin to use more energy.

“Sadly, the cost of energy is going to have to increase to make it viable. Nuclear is expensive, that is true, but we don’t want to get to the point where a little old lady is going to be very cold or sitting in her flat in the dark because she actually can’t ever afford to put the heating or lighting on because energy is in such short supply.”

Scotland has some of the strictest carbon targets in the world, set by the SNP, with pledges to cut emissions by 42% by 2020 and 80% by 2050.

The SNP defended its energy policy, insisting renewables would propel the economy after the recession.

Scottish Energy Minister Jim Mather said: “Investment in renewable energy is driving Scotland’s economic recovery, with projects up and down the country supporting highly skilled, low-carbon jobs.”