The investment climate for renewable energy projects is likely to remain tough over the next few years, according to the influential International Energy Agency (IEA).

Fatih Birol, chief economist at the IEA, told reporters at the World Future Energy Summit in Abu Dhabi yesterday that public deficits, along with falling green energy subsidies and decreasing demand for power in developed countries may hinder the expansion of renewable energy projects.

"Governments' attention is focusing on public deficits and legitimately so," he said. "When there's a fire in the kitchen you can't go to the library and think of what book to take on your summer holiday.

"Subsidies are falling... and as a result of lower electricity demand, less power plants will be built. Renewable energy will still grow, but we may see a slowdown in that growth."

While he admitted the Fukushima disaster and some countries' decision to pull out of nuclear power as a result could provide a boost to renewable energy investment in a number of key markets, Birol said the shift away from nuclear was equally likely to benefit coal and natural gas in the short term, presenting severe implications for climate change policies.

"Lower gas prices [will also] make life much more challenging for renewables," he added.

Birol's words came as UN chief Ban Ki-Moon today called on the private sector to support his newly launched campaign, Sustainable Energy for All, which marked the beginning of the UN Year of Sustainable Energy for All.

Ban told the World Future Energy Summit that the experience of growing up in post-war Korea, where he studied by gaslight and bought candles before exams, had inspired the push to deploy renewable energy technologies in communities without access to reliable power supplies.

He set out three goals: ensuring universal access to modern energy services for all, doubling the rate of improvement for energy efficiency, and doubling the share of renewable energy across the globe, which he said could only be achieved if the private sector worked in tandem with governments.

"Business plays an important role already, but it can play a bigger role," Ban told a press conference on the sidelines of the event, adding that IEA statistics showed just three to four per cent of the global investment in energy to 2030 would be needed to achieve the UN's renewable energy goals.

He outlined the need for renewable alternatives to fossil fuels by claiming one person in five lacks access to modern electricity, while three billion rely on coal, wood or charcoal for cooking or heating.

At an event earlier in the day Ban said it was "encouraging" that the private sector already invests huge amounts of money in renewable energy, but added: "We need governments and the private sector to invest more [and] invest in a smart way.

"We need to strengthen the partnership between governments and the private sector – then we can accelerate and scale up these targets."

His comments were echoed by Chad Holliday, chairman of the Bank of America, who told reporters that the only way the UN's three energy goals would be achieved by 2030 is if business finds a way to make a profit investing in alternative energy projects.

"Countries need to develop a plan to describe what they need in terms of energy ... then business can come in and see how they can meet that need," Holliday said. "This plan is missing in some countries, but you only have to look at China to see how it can be successful."

In related news, The South Korean government confirmed yesterday that it has been named the chair of a UN working group committed to developing policies for stimulating green growth among the G20 economies.

Officials confirmed that current chair of the G20, Mexico, had asked the South Korean government to lead the working group, which has been tasked with identifying international and domestic measures that can help drive green growth.