The analysts warned that a referendum on independence from the rest of the UK – due towards the end of the current parliament in 2016 - would "create huge uncertainty" at a time when major investment decisions in areas like offshore wind were due to be made.
The report also argues that an independent Scotland would have too small a consumer base to generate the annual subsidy of £4bn, which they believe would be needed to support a hugely increased reliance on renewable energy.
It states: "Continued subsidy from consumers in England and Wales would be required, but Scotland seceding from the UK would clearly place this subsidy stream at grave risk.
"Renewable investors risk seeing their assets stranded in a newly independent Scotland."
The report concludes: "Utilities and other investors should exercise extreme caution in committing further capital to Scotland."
Scotland's First Minister Salmond dismissed the report, saying the Citigroup analysts had misunderstood the nature of Scotland's renewable energy programme, and the fact that large amounts of the electricity generated will be exported to England.
Salmond told BBC Radio Scotland's Good Morning Scotland programme: "In order to get anywhere near the renewable energy obligations that London is going to have, England is going to have to have Scottish renewables from the sea.
"Perhaps the reason why all these international companies are committing funds to Scotland is because in 10 years' time, without Scottish offshore wind power, then there would be a severe danger of the lights going off in England. I don't think anybody is going to want or allow that to happen."