The Central Electricity Authority released comprehensive new guidelines for the installation and operation of automatic weather stations at solar and wind power plants, seeking to enhance forecasting accuracy, grid reliability and the overall efficiency of renewable energy generation.
The guidelines, published on July 7, set mandatory technical specifications and siting standards for AWS at renewable energy sites with a capacity of 50 MW and above.
They mark a significant step in harmonizing data acquisition, system design and cybersecurity across India’s rapidly growing clean energy sector.
Real-Time Weather Monitoring to Boost RE Integration
The AWS systems are designed to measure critical meteorological parameters — including wind speed, direction, solar irradiance, rainfall, temperature, pressure and humidity — and transmit real-time data to centralized forecasting centers such as the National Centre for Medium Range Weather Forecasting.
“The objective is to enable accurate, real-time measurement of weather to optimize renewable energy generation,” the report stated. This is expected to improve generation predictability, enhance grid stability, and meet regulatory mandates from CERC and SERCs.
Granular Sensor and Data Standards
Among the most significant features of the new guidelines is the standardization of sensors. Pyranometers measuring global horizontal and inclined irradiance must have a spectral range of 285 nanometers to 3,000 nm and a response time of under five seconds.
Ultrasonic wind sensors should detect speeds up to 75 meters per second with 2 percent accuracy.
Barometric pressure sensors must offer precision within ±20 pascals, and tipping bucket rain gauges must achieve up to ±2 percent accuracy for rainfall rates up to 25 mm per hour.
All sensors must be capable of digital output and withstand harsh operating conditions, with housing rated at IP65 or higher.
Data Acquisition and Security Requirements
The Data Acquisition System integrated with each AWS must have real-time clock functionality, support encrypted data storage using AES 256-bit standards and retain operational logs for at least 180 days.
Time synchronization with the NAVIC satellite system is mandated to eliminate dependency on the internet.
Data must be transmitted securely over cellular networks — using secure file transfer protocols — at intervals configurable from 1 to 15 minutes. The DAS must also integrate with on-site supervisory control and data acquisition systems using MODBUS or IEC-104 protocols, with strong firewall protection and intrusion detection.
Remote access is permitted only under controlled, auditable conditions for troubleshooting, adhering to strict cybersecurity protocols in line with the 2021 CEA Cybersecurity Guidelines.
Power Autonomy and Durability
The AWS must operate autonomously using maintenance-free batteries charged by solar panels with MPPT controllers. The system must sustain operations for at least 20 days under full load during continuous overcast conditions.
Weatherproof enclosures made from UV-resistant FRP with IP66 ratings are required to protect both electronics and power systems. Additional design features include dual SIM modems for 3G/4G/5G data transmission and rugged chainlink fencing to secure the AWS site.
National Integration with Forecasting Models
Data from the AWS installations will be used to feed NCMRWF’s Numerical Weather Prediction models, enhancing day-ahead and real-time forecasting for India’s energy grid.
The guidelines also require compliance with international quality control standards, ensuring consistency in sensor calibration and data validation.
IMD will specify periodic testing, calibration, and maintenance procedures. Additionally, the guidelines include future-proofing clauses, allowing for upgrades to newer communication technologies without data loss or compatibility issues.
As India aims to achieve 500 gigawatts of non-fossil fuel capacity by 2030, these AWS standards are expected to play a pivotal role in ensuring the integration of variable renewable energy into the national grid with higher reliability and accuracy.
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