Advancing plans for a fleet of large offshore wind projects have seen the UK rise to fifth on a list of the world’s most attractive countries for renewable energy investors, providing a timely boost to the government’s green agenda.

Plans for the world’s largest wind farm, a £4.5bn, 1,500MW development 13 miles off the coast of Caithness in Scotland, as well as the award of a £150m European Investment Bank loan to wind farm developer Vattenfall to support the extension of the existing Thanet offshore wind farm were cited as the main drivers behind Ernst & Young’s decision to move the UK up one place in its quarterly Country Attractiveness Index report.

The UK rose to fifth on the list, moving it above Italy which drops to sixth on the list.

The move comes just a day after a survey by the Guardian newspaper revealed some of the world’s largest wind energy companies are reviewing their investment plans in the UK in response to growing political opposition to wind energy from some influential MPs.

Ernst & Young said that it had upgraded the UK’s position following the increased investment in offshore wind energy, as well as a 762MW rise in solar capacity during 2011, and the launch of a government consultation on PV subsidy levels that promises to provide some much needed clarity for the sector and “control expenditures going forward within its existing spending framework”.

The company also highlighted how proposed improvements to the Renewables Obligation support mechanism for marine energy and biomass projects had informed the shift in the change in the league table.

China, the USA, Germany and India led the way among the 40 countries assessed for the Country Attractiveness Indices report (CAI) with the report also predicting that emerging renewable energy markets will continue to prosper at the expense of Western nations during 2012.

A combination of capital scarcity and the sovereign debt crisis is expected to continue to stifle investment and policy ambition in the Eurozone, Ernst & Yound said.

Spain, rated the most attractive country five years ago, is now outside the top 10 entirely after it suspended payments to new renewables plants, while many other countries across Europe have cut subsidies.

In contrast, China has upped its solar target for three years’ time to 15GW while the Indian government has similarly signalled that it wants to accelerate the development of its renewables sector.

The report also highlighted on-going policy uncertainty in the US and Germany, despite their position as leading renewable energy markets.

The US is seeing record investment in onshore wind last year as developers scramble to take advantage of the expiring 1603 grant, which could be axed at the end of the year. The report predicted the boom could prove short-lived if the incentive expires at the end of the year, noting that while President Obama has indicated he wants to extend it there remains a great deal of uncertainty about whether he will be able to do so.

The report also detailed how Germany’s decision to shut down its nuclear plants in 2022 gave its renewable industry a timely boost, but warned that finding capital is likely to be more difficult as lending costs rise.

“Access to capital over the next 12 months, whether debt or equity, is likely to define more than any other factor the difference between survival or failure,” said Ben Warren, Ernst & Young’s energy and environmental finance leader.

“Capital constraints will therefore be a major driver for transaction activity, from distressed consolidation to creative joint ventures and partnerships.”

The latest league table was welcomed by the UK’s Department of Energy and Climate Change, which hailed it as evidence the country remains well placed to attract international investors.

“We remain top of the pile for offshore wind, and fifth overall for all renewables - up one place on last year,” he said. “We’re in this market to win it for the UK, and this is welcome proof that investors see the UK as a leading clean energy destination.”