Overview
IEC TS 61724-3:2016 - Photovoltaic system performance, Part 3: Energy evaluation method defines a standardized procedure to measure and analyze the electrical energy production of a specific photovoltaic (PV) system and compare it with the expected electrical energy based on actual weather conditions agreed by stakeholders. The Technical Specification covers how to characterize energy during times the system is available and how to quantify periods of unavailability as an availability metric. (The February 2018 corrigendum is included in this edition.)
Key Topics and Requirements
- Scope and test planning
- Define test boundary, schedule and duration (commonly a full year) to capture seasonal/weather variability.
- Predicted, expected and measured energy
- Document initial predicted energy and methods; use measured meteorological inputs to calculate the expected energy for the test period.
- Model inputs and calculations
- Specify meteorological inputs (irradiance, ambient temperature, wind as applicable) and PV system inputs (module, inverter, mounting).
- Define the modelling approach and uncertainty bounds before testing.
- Data acquisition and quality control
- Requirements for equipment, measurement intervals, time-stamp alignment and sensor calibration.
- Procedures to identify erroneous or missing data, shading of sensors, data substitution, and handling of curtailment or grid events.
- Performance metrics
- Calculation of energy performance index, availability, capacity factor, performance ratio, and uncertainty analysis.
- Documentation and reporting
- Test procedure documentation and a formal test report describing methods, inputs, results, and uncertainty.
Applications and Who Uses It
IEC TS 61724-3 is used by:
- PV system owners and operators for verifying long‑term energy production.
- O&M teams and performance engineers to diagnose underperformance and optimize operations.
- Investors, asset managers and lenders for due diligence and performance guarantees.
- Certification bodies and regulators for compliance benchmarking.
- Researchers and consultants performing site-specific energy evaluations and comparisons against modeled expectations.
Practical uses include validating performance guarantees, informing maintenance prioritization, supporting project financing, and benchmarking fleet performance across weather-normalized conditions.
Related Standards
- IEC 61724-1 (PV performance data definitions)
- IEC TS 61724-2 (power measurements)
- IEC 62446 (system commissioning and verification)
- IEC 62670-2 (CPV energy measurement)
- ASTM E2848-11 (short-term power capacity measurement)
Keywords: IEC TS 61724-3, photovoltaic system performance, energy evaluation method, PV energy evaluation, expected vs measured energy, performance ratio, availability, energy performance index.