According to the Global Trends in Renewable Energy report, published by the UN’s Environment Programme (UNEP), the US closed in on China in the race to be the lead investor in renewable energy, with a 57% leap in its outlays to $51 billion. India however, displayed the fastest expansion rate for investment of any large renewables market in the world in 2011, with a 62% increase to $12 billion.

The leap in investment has been in part fuelled by a boom in solar over the past five years. Solar PV grew the fastest of all renewable technologies, with operating capacity increasing by an average of 58% annually, followed by concentrated solar thermal power (CSP), which increased almost 37% annually. Wind power grew by 26% each year.

Demand is also growing rapidly for solar thermal heat systems, geothermal ground-source heat pumps, and some solid biomass fuels, such as wood pellets, the report said, while the development of liquid biofuels has been mixed in recent years, with biodiesel production expanding in 2011 and ethanol production stable or down slightly compared with 2010.

“One of the dominant features of the renewable energy landscape in 2011 was falling technology costs,” UNEP said. “Photovoltaic module prices fell by close to 50%, and onshore wind turbine prices by around 10%. These changes brought these two leading renewable power technologies closer to competitiveness with fossil-fuel alternatives such as coal and gas.”

However, the report warned that the renewables sector faced “weakening policy support” in many developed countries, due to austerity pressures, particularly in Europe, and legislative deadlock in the US Congress.

UNEP said renewable energy sources have grown to supply an estimated 16.7% of global final energy consumption in 2010. Of this total, modern renewable energy accounted for an estimated 8.2%, a share that has increased in recent years, while the share from traditional biomass declined slightly to an estimated 8.5%. During 2011, modern renewables continued to grow strongly in all end-use sectors: power, heating and cooling, and transport.