As more intermittent renewable capacity is added to grid networks around the world, the need for greater system flexibility in order to cope with the variable supply is growing. In parts of the Europe, grid operators complain that balancing the system is becoming more and more difficult as new renewable sources are added, requiring ever more complex management techniques, as well as repeated use of polluting and inefficient standby capacity. Surges of solar and wind power are often not fully utilised, causing some to question the wisdom of adding further variable renewable capacity.
