Harnessing Variable Renewables

According to the International Energy Agency (IEA), the challenge for policy-makers in coming decades will be how best to manage the widespread uptake of a multitude of renewable energy sources as the world discards its dependence on fossil-fuels. 
A new book from the IEA, Harnessing Variable Renewables: a Guide to the Balancing Challenge, looks at the flexibility of energy systems in a world where power grids are fed by de-centralised renewable sources, such as PV solar energy, wind farms and tidal power.
The book provides advice for governments and decision makers on managing the variable nature of electricity supply from renewable energy by designing flexible power systems which ensure energy demands are met without jeopardising stability. 
The Variable Renewables report provides cases studies on different regions featuring assessment criteria along with methods of overcoming barriers to flexibility of energy resources. These methods include rerouting and interconnection of electricity supply in times of high demand, improved storage capacities and dispatchable power plants. 
Norway, with its extensive hydropower infrastructure was found to be the nation with the most flexible energy resources. Japan was the least flexible, relying heavily on nuclear and coal for power, energy sources which take a long time to respond when demand spikes.
"While some areas are clearly more flexible than others, all power areas assessed show that greater technical potential for balancing variable renewable energy output exists than is commonly supposed," said Richard Jones, the IEA Deputy Executive Director.
Finding this balance is essential, according the report, if the world is to achieve a “more secure, diverse and sustainable energy mix.” 
Wind and solar energy have been growing by double digits in the last five years, and the IEA World Energy Outlook states that, by 2035, 17 percent of the world’s electricity must come from renewable energy sources – up from 1 percent on 2008 – to avoid a global temperature rise of no more than 2 degrees C.