Scottish independence risks leaving Scottish consumers with bigger energy bills as companies are forced to pass on the extra costs, the industry has warned.
A senior energy industry source blamed any rise in bills on the burden of government regulation, telling the Huffington Post UK: "A lot of what you see on the bill doesn't come from us. Do we want to pass on increased costs to customers? Of course we don't."
Another insider warned: "If Scotland goes it alone, Scottish customers will bear the cost of Scottish policy.
Scots could also be forced to pay more in energy due to changes in subsidies for renewable energy, which are currently paid by all British energy users for Scottish consumers in remote places like the Highlands.
David Cameron has claimed that business leaders are afraid of speaking out about the risks of independence as they fear being "shouted at on the telephone" by SNP government ministers.
One energy source admitted that companies were reluctant to speak out about independence because "we do business with everybody".
Angela Knight, head of the Energy UK industry trade body, told HuffPostUK in April that independence could be a "bit of a nightmare" for firms that risks adding to consumers' bills.
"If you separate the country into two parts, then what are you going to do about the legal and regulatory issues and who licenses who and for what?"
"If we end up with two regulators, two different sets of license conditions and customer requirements, two wholesale markets and all that sort of thing, it is inevitably adding costs to the system."
A Department for Energy and Climate Change spokesperson said Knight "raised important questions about the possible impacts of Scottish independence for the energy industry, our integrated single market and support for renewables in Scotland."
“The broad shoulders of the United Kingdom is unlocking the power of Scotland to take its place as one of the world’s great energy hubs – generating energy and generating jobs," the spokesperson added.
In response, a Scottish Government spokesperson said: “There are already examples across Europe of two or more independent countries coming together to participate in a single energy market, and their co-operation on the licensing and regulation of the participants in those markets.
“The most cost-effective location in the UK for renewable energy generation is Scotland – we are producing clean power in record amounts and consistently supplying over a third of all the UK’s clean energy in return for about 28% of total UK subsidy.
“The UK is facing the highest black-out risk in a generation, with reserve energy margins falling to as low as two per cent in the very near future – and the rest of the UK needs Scottish energy reserves to help keep the lights on. Short-term measures to plug the energy gap all mean additional expense for consumers – for example, payments to persuade energy-intensive users to consume less energy or payments to generators to bring back retired plant.”