How do you compare and benchmark the reliability performance of different power systems and regions?

1 Reliability definitions and dimensions

Reliability can be broadly defined as the ability of a power system to deliver electricity to its customers without interruption or degradation. However, this general definition can be further divided into different dimensions, such as adequacy, security, quality, and resilience. Adequacy refers to the sufficiency of generation and transmission capacity to meet the demand. Security refers to the stability and robustness of the system to withstand disturbances and contingencies. Quality refers to the consistency and conformity of the voltage and frequency levels to the standards. Resilience refers to the adaptability and recoverability of the system to cope with extreme events and uncertainties.

2 Reliability metrics and indicators

To measure and quantify the reliability performance of different power systems and regions, various metrics and indicators can be used. These depend on the reliability dimension, data availability, and stakeholder perspective; some common examples are Loss of Load Probability (LOLP), Loss of Load Expectation (LOLE), Expected Energy Not Supplied (EENS), System Average Interruption Frequency Index (SAIFI), System Average Interruption Duration Index (SAIDI), Customer Average Interruption Duration Index (CAIDI), and voltage and frequency deviations. These metrics and indicators can help to identify capacity shortages in a given period, the average number of interruptions per customer, the average duration of interruptions per customer, the average duration of interruptions per interrupted customer, as well as deviations from nominal or target values.

3 Reliability benchmarks and standards

To compare and benchmark the reliability performance of different power systems and regions, some reference values or criteria are needed, which can be derived from historical data, statistical analysis, regulatory requirements, or customer expectations. For example, NERC (North American Electric Reliability Corporation) standards are mandatory and enforceable reliability standards for the bulk power system in North America that cover adequacy, security, quality, and resilience aspects. The Institute of Electrical and Electronics Engineers (IEEE) has voluntary and consensus-based reliability standards for power systems that cover various aspects such as planning, design, operation, maintenance, and protection. Additionally, ENTSO-E (European Network of Transmission System Operators for Electricity) standards are binding and harmonized reliability standards for the transmission system in Europe that cover adequacy, security, quality, and resilience aspects. Lastly, customer surveys are surveys conducted by utilities or regulators to elicit customer preferences, satisfaction, and willingness to pay for different levels of reliability.

4 Reliability assessment methods and tools

Various methods and tools can be used to perform a reliability assessment of different power systems and regions, depending on the complexity, uncertainty, and scope of the analysis. Analytical methods use mathematical models and formulas to calculate the reliability metrics and indicators, while simulation methods use computer programs to simulate system behavior and record the reliability metrics. Benchmarking tools utilize databases, dashboards, and reports to compare and visualize the reliability performance of different power systems and regions. Examples of these tools include NERC TADS (Transmission Availability Data System), IEEE RADB (Reliability Assessment Database), and ENTSO-E SO&AF (System Outlook and Adequacy Forecast).

5 Reliability improvement strategies and best practices

Various strategies and best practices can be implemented to improve the reliability performance of different power systems and regions, depending on the reliability dimension, problem, and solution. Common strategies include capacity expansion, system reinforcement, system coordination, system protection, system restoration, and customer engagement. Capacity expansion involves adding more generation and transmission capacity to reduce the risk of capacity shortages and increase the reserve margin. System reinforcement entails upgrading or replacing existing system components to enhance the system strength and reduce vulnerability to failures and faults. System coordination optimizes resource allocation and utilization by coordinating the operation and planning of the system across different regions, markets, or entities. System protection involves installing or improving protection devices and schemes to detect and isolate disturbances and contingencies. System restoration plans and procedures should be developed or updated to restore service as quickly and safely as possible after an interruption or outage. Lastly, customer engagement can involve providing information, incentives, or options for customers to participate in demand response, distributed generation, energy efficiency, or self-healing programs.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?