The NEM, like power systems worldwide, is being transformed from a system dominated by large thermal power stations, to a system including a multitude of power generation resources and technologies of various sizes. At the same time, customers are engaging with their electricity supply in new ways.

The energy transformation involves a shift from:

• Homogenous to diverse supply resources.
• Synchronous to non-synchronous generation.
• A centralised to a decentralised system
• Passive to active consumers.

Each of these trends acts to increase the variability of the power system. AEMO’s challenge is to continually meet the needs of the power system, in the face of major structural changes and the resulting uncertainty across investment and operational timeframes.

While the power system is being transformed, the laws of physics that determine electrical flows do not change. This Power System Requirements paper outlines the interdependent technical and operational needs which must be met at all times to maintain a secure and reliable system.