FIRST Minister Alex Salmond sees energy as an ace in an independent Scotland's pack.

Enviable renewable energy resources, among the best in Europe, could be at the heart of a world-beating new industry, he argues. The No campaign does not dispute their worth but argues Scottish renewables will only achieve their full potential as part of a UK-wide energy market.

Q Would the lights go out in an independent Scotland?

A No. Scotland produces more electricity than it needs almost all of the time. Over the past three years, power has been imported from England on 162 days. On 10 occasions power had to be imported continuously throughout the day to keep the lights on. The rest of the time, Scotland has exported power south.

Q So nothing would change?

A Here's where the two sides disagree. The Scottish Government says an independent Scotland and the rest of the UK would be best served by maintaining Britain's existing single market in electricity (and gas). It cites international examples of cross-border markets - Ireland, Iberia and Scandinavia - to show it could happen. The UK Government insists the British energy market "could not continue in its current form".

Q Who is right?

A As with other questions, the answer would ultimately depend on negotiations between the two countries following a Yes vote. The Scottish Government claims that the rest of the UK would need to buy Scotland's green energy to help meet environmental obligations. The UK Government says it has plenty of other options - French nuclear power, for example - and would only import Scottish renewables "on a commercial basis," ie. if it was cost-effective.

Q Could an independent Scotland continue to support renewable energy enough for the industry to expand as planned?

A Renewables are on track to meet the Scottish Government's target to producing the equivalent of the country's total energy needs by 2020. Last year, green power equated to a record 46% of the country's energy demand. However, the industry is growing thanks to subsidies paid by consumers across the UK - a third of all the subsidies go to projects in Scotland. The Scottish Government says this should continue after independence. The UK Government says it would not. A recent European Court ruling made clear the UK would not be obliged to subsidise Scottish renewables if the two countries were to split.

Q What would happen to electricity bills in an independent Scotland?

A The UK Government says average bills would rise by up to £189 if an independent Scotland continued to develop its renewable energy industry as planned without support from UK consumers. The Scottish Government has promised to save consumers £70, on average, by removing energy efficiency and fuel poverty levies from bills, though the pledge has raised questions about possible tax rises to cover the shortfall.

Q Apart from wind farms, what would power an independent Scotland?

A In the long run, this is a much bigger question than the impact of independence on bills. Scotland's two nuclear plants are expected to close in 2023 and Longannet coal-fired power station not long after. Between them they provide most of the "baseload," or constantly available, power which is critical when the wind isn't blowing. Time is running out, warn experts, to build replacements. With the SNP opposed to new nuclear or coal power, it could leave Scotland burning natural gas extracted off the English coast.