Security
the electricity system’s ability to withstand changes in its operating status following sudden disturbances, without violating the system’s operating limits.
Adequacy
the system’s ability to satisfy electricity demand while complying with safety and quality of service requirements.
Quality of service
the ability to ensure the continuity and quality of service.
Resilience
the system’s ability to withstand stresses above its set limits and to return to normal operating status, possibly with temporary actions.
Efficiency
the ability to operate the electricity system in compliance with the requirements of security, adequacy and quality, at the minimum total cost to the citizen/user.