Variable Generation, Reserves, Flexibility and Policy Interactions

Operational issues associated with the integration of variable generation (VG) have led system operators and researchers to re-evaluate how reliability services are procured and at what levels they are required. Ramping reserve constraints are now being proposed and applied by several system operators to address the increasing variability and uncertainty in system schedules. The increasing environmental, economic, geographic and temporal interconnectedness of power systems means that the impact of additional reserve products can no longer be assessed in isolation. Although additional reserve categories are a practical short-term solution, in the longer term, greater coherence is required between policy objectives and operational strategies to avoid sub optimal operation.