In April 2011, the IEA publication Harnessing Variable Renewables: a Guide to the Balancing Challenge analysed how to manage power systems with large shares of variable renewables, in particular wind and solar PV. Concluding the second phase of the Grid Integration of Variable Renewables project (GIVAR), it presented a step-by-step approach developed by the IEA to assess the flexibility of power systems to absorb variable renewables – the Flexibility Assessment Tool (FAST). FAST identifies the already present resources that could help meet the twin challenges of variability and uncertainty. The analysis comprises all distinct flexibility resources: flexible generation, interconnection and storage as well as demand side management. The FAST method provided a first approximation to what is possible in a power system with a given flexible resource, from a technical perspective.
GIVAR Phase III: The third phase of GIVAR deepens and expands IEA work on variable renewable energy (VRE) integration. It deepens the technical analysis, putting additional emphasis on solar PV and providing a revised version of FAST: FAST2. It expands the work to also include an economic assessment of different flexibility options and assessing their relative cost/benefit.
The project draws on the extensive academic expertise available, in particular through collaborating with IEA implementing agreements. It also benefits from other ongoing IEA analysis on closely linked topics, in particular the IEA Energy Security Action Plan.
The main publication from GIVAR Phase III is The Power of Transformation - Wind, Sun and the Economics of Flexible Power Systems, the landmark study that confirms that integrating high shares – i.e., 30% of annual electricity production or more – of wind and solar PV in power systems can come at little additional cost in the long term. However, costs depend on how flexible the system currently is and what strategy is adopted to develop system flexibility over the long term. Managing this transition will be more difficult for some countries or power systems than others, the study says.
GIVAR project description: GIVAR Phase III