CEA releases new AWS rules to improve weather data in renewable projects

The Central Electricity Authority (CEA) has issued revised guidelines for Automatic Weather Stations (AWS) in solar and wind power plants. The rules will improve the accuracy of real-time weather data, strengthen grid reliability, and support regulatory compliance for renewable energy developers.

AWS units are to be installed within the boundaries of the project site. For solar plants, the AWS location should reflect the terrain and panel tilt. For wind projects, it should capture the actual wind regime of the site. The installation area is to be 10 metres by 10 metres, levelled, treated with herbicide, and kept free of physical obstructions. Fencing is required using galvanised iron chainlink mesh, red-oxide-coated support angles, and a lockable gate.

Each AWS is to include a 10-metre tiltable aluminium mast, painted with red-and-white stripes and supported by stainless steel guy wires. The guidelines specify the use of calibrated sensors, including pyranometers for irradiance, ultrasonic wind sensors, rain gauges, and temperature and humidity probes. These instruments are expected to meet high accuracy standards.

Data from the AWS is to be collected through a secure Data Acquisition System (DAS). The system is required to store at least 30 days of encrypted data, synchronise with NAVIC time, and transmit information using 5G or 4G modems to the servers of the National Centre for Medium Range Weather Forecasting (NCMRWF) and the India Meteorological Department (IMD).

The new rules introduce minimum cybersecurity measures, including firewalls, IP whitelisting, and a 180-day log retention protocol. AWS units should operate remotely for up to 20 days, powered by solar-charged batteries. All components are to be housed in weather-resistant FRP enclosures with IP66 protection.

These rules are expected to benefit states with high renewable capacity, particularly Rajasthan, Gujarat, and Tamil Nadu. Improved weather data can help reduce curtailments, support better forecasting, and aid compliance with grid codes.