By Kari Williamson

The book, Deploying Renewables 2011: Best and Future Policy Practice, analyses the recent successes in renewable energy, which now accounts for almost a fifth of all electricity produced worldwide, and addresses how countries can best capitalise on that growth to realise a sustainable energy future.

IEA Executive Director Maria van der Hoeven says renewable energy deployment must be stepped up: "As the IEA’s analysis has shown, without an urgent and radical change of policy direction, the world will lock itself into an insecure, inefficient and high-carbon energy system.

"Renewables already play a central role in fostering sustainability and energy security, and their significance will only grow in the coming decades. Against this backdrop, Deploying Renewables 2011 provides a major review of renewable energy markets and policies at this critical juncture."

IEA says the growth in renewable energy has so far focused on just a few of the available technologies, and rapid deployment is confined to a relatively small number of countries. In more advanced markets, managing support costs and system integration of large shares of renewable energy in a time of economic weakness and budget austerity has sparked vigorous political debate.