Overview

Solar energy is rapidly gaining importance as a clean and renewable energy source worldwide. To fully harness its potential, it's crucial to understand local solar resources and monitor the real-time performance of solar energy systems. This is where solar radiation monitoring systems come into play, playing a key role in both solar resource assessment and performance evaluation of photovoltaic (PV) plants. These systems help ensure that solar plants operate at their highest efficiency, providing valuable data to improve performance and maintenance decisions.

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In line with this need, the Central Authority for Energy (CAE), through the Ministry of Power and the Central Electricity Authority (CEA), has introduced the 2025 Guidelines for Automatic Weather Stations (AWS). These guidelines aim to standardize and enhance the weather data infrastructure for solar PV plants, ensuring precise, real-time measurement of critical meteorological parameters. This, in turn, will improve plant performance evaluation, enable better forecasting, and contribute to greater grid reliability.


Purpose and Significance of Solar PV Monitoring

Purpose

To capture high-resolution meteorological data required for assessing real-time and long-term performance of solar PV plants.

To enable compliance with national forecasting and grid integration norms.

To provide consistent input to stakeholders including plant operators, regulators, DISCOMs, and forecasting agencies.

Significance

Ensures accurate and uniform weather data across solar projects, as per CEA guidelines for performance and grid compliance.

Enables performance benchmarking using actual site conditions.

Supports forecasting models for load dispatch centres and national weather agencies.

Enhances investment confidence through traceable and reliable operational data.

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MoP-issued-the-CEA Guidelines for Automatic Weather Stations (AWS) for Solar and Wind Power Plants
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Compliance for CEA guidelines 2025 for automatic Weather Station


Key Components of Solar PV Monitoring

A. Measured Parameters for Solar Plants:

Global Horizontal Irradiance (GHI) - To assess total solar input on horizontal surface.

Ambient Temperature - Temperature’s impact on PV module efficiency.

Relative Humidity - Impact on module degradation and cooling.

Rainfall - Soiling loss identification & cleaning schedule.

Wind Speed and Direction - Safety and structural monitoring.

Global Inclined Irradiance (GII) - Irradiance on module tilt plane (POA).

Barometric Pressure - Optional – for forecasting & diagnostics.


B. Sensor Specifications (Mandatory):

Pyranometer (GHI/GII) - ISO 9060 thermopile, <±0.5% non-linearity, IP65, response time ≤5 sec.

Temperature & Humidity - Accuracy: ±0.35°C and ±3% RH, thermoplastic shield with ≥9 louvres.

Wind (Ultrasonic) - Speed: 0–75 m/s, Accuracy: ±2%; Direction: ±3°, IP65 rated.

Rain Gauge (Tipping Bucket) - Resolution: 0.5 mm, Accuracy: ±2% (up to 25 mm/hr), marine-grade or FRP body.

Pressure Sensor - 600–1100 hPa, Accuracy: ±20 Pa, digital output.


C. Physical Infrastructure:

10m Tiltable Mast: Painted red & white, with stainless steel guy wires.

Rain Gauge Foundation: 1 ft × 1 ft base, 2 ft height.

Fenced Area: 10m × 10m fenced plot with MS angle and chain link.

Earthing & Lightning Protection: Separate pits for signal and surge, with copper rods and plates.


D. Data Acquisition System (DAS):

Multi-channel (analog/digital) compatibility with built-in Real-Time Clock (RTC).

Data Encryption: AES-256 with user-access logs retained for 180 days.

Time synchronization via NAVIC.

Remote configuration with secure authentication.

Storage: 30-day backup with QC procedures per WMO standards.

Communication via MODBUS/IEC 104, cellular modem (3G/4G/5G), dual SIM support.

SCADA and NCMRWF/IMD integration via SFTP.


E. Power System & Enclosure:

Off-grid powered via SMF battery, MPPT solar charge controller, and PV panel.

Enclosures: Dual IP66-rated FRP enclosures for DAS and battery with ventilation and locking mechanism.

Solar Plant

Applications / Compliance & Standards

Applications

Applications Utility
Performance Evaluation Accurate PR, CUF, and energy yield analysis using real-time POA/GHI
Forecasting & Grid Dispatch Enables short and medium-term solar forecasting
SCADA Integration Automated O&M alerts, remote diagnostics
Regulatory Compliance Meets CERC/SERC mandates and CAE 2025 requirements
Loss Analysis Detects temperature derating, soiling losses, and wind effects
Data Reporting to IMD/NCMRWF National meteorological and energy modeling

Compliance & Standards

Aspect Standard / Requirement
Pyranometers ISO 9060:2018, IEC 61724-1:2021
Sensor Calibration NABL traceable / as per IMD procedures
Data Logging & Time Sync Satellite (NAVIC), RTC with 1-year battery backup
DAS Data Security AES 256-bit encryption, cyber-secure access control, IDS/Firewall
Quality Control of Data WMO Guide No. 8, Chapter 1, Level I–III QC checks
Communication Protocols MODBUS/IEC-104, SFTP, dual SIM modem
Cyber Security CEA 2021 Cybersecurity Guidelines, CERT-In retention of logs for 180 days
Reporting to National Agencies Data push to IMD/NCMRWF every 15 minutes or 1 minute during events

Pyranometer

Pyranometer

Measures solar radiation on a flat surface, used in meteorology and solar energy studies to assess solar panel efficiency and weather conditions.

Albedometer

Albedometer

Measures the reflectance (albedo) of surfaces, helping in climate research and environmental monitoring by determining how much sunlight is reflected by surfaces.

MS-80SH Plus+

MS-80SH Plus+

Solar radiation sensor for measuring direct and diffuse solar radiation, used in energy research and meteorology to evaluate solar panel efficiency.

Cloud Cover Sensor

Cloud Cover Sensor

Measures cloud density and coverage, essential for weather forecasting, solar energy generation, and understanding the effect of clouds on solar radiation.

Solar Pathfinder

Solar Pathfinder

Maps shading patterns to assess solar potential, helping optimize solar panel placement by identifying areas with the best sunlight exposure.

Soiling Sensor

Soiling Sensor

Measures dust accumulation on solar panels. Helps determine optimal cleaning schedules by quantifying the impact of soiling on panel performance.

Pyrheliometers

Pyrheliometers

Measures direct solar radiation, crucial in solar energy research and atmospheric studies for assessing solar intensity from the sun's rays.

Anemometer

Anemometer

Measures wind speed and direction, essential for weather forecasting, renewable energy, and assessing turbine performance.

Barometric Pressure Sensor

Barometric Pressure Sensor

Measures atmospheric pressure, vital for weather forecasting, altitude determination, and analyzing pressure changes associated with weather systems.

Ambient Temperature Sensor

Ambient Temperature Sensor

Measures the surrounding temperature, used in weather forecasting, climate control, and solar panel performance monitoring.

Module Temperature Sensor

Module Temperature Sensor

Measures the temperature of solar panels, helping monitor solar module temperature to ensure optimal performance and efficiency in solar energy generation.

PV Reference Cell

PV Reference Cell

A calibrated solar cell used as a standard to compare the efficiency of photovoltaic panels, ensuring accurate performance assessments.

Rain Gauge

Rain Gauge

Measures rainfall amounts, used in meteorology and environmental studies for monitoring precipitation levels and aiding in flood forecasting.

Data Logger

Data Logger

Records data over time, including temperature and humidity, for long-term environmental monitoring and scientific research.

Tripod

Tripod

A three-legged stand used for stabilizing instruments or cameras, providing stability for scientific research, photography, and solar panel installations.

Enclosure Box

Enclosure Box

A protective case for electronic equipment, shielding instruments from environmental elements to ensure their durability and reliable outdoor performance.


Frequently Asked Questions

Solar energy monitoring is the process of measuring and analyzing the performance of a solar photovoltaic (PV) system. This includes tracking metrics such as power output, energy production, and system efficiency, among others.

Solar energy monitoring helps PV plant owners and researchers to identify and diagnose issues with their system, optimize its performance, and ultimately maximize its energy production. It also helps to ensure that the system is operating safely and within its intended parameters.

There are a variety of solar energy monitoring systems available, including web-based monitoring platforms, and data loggers. The type of system used will depend on the specific needs and requirements of the PV plant owner or researcher.

Solar energy monitoring systems collect a wide range of data, including weather parameters like solar radiation, Atmospheric pressure, Precipitation, and others.

The data from a solar energy monitoring system is used to optimize the performance of the PV system and identify any issues that may be affecting its operation. It can also be used to generate reports and analytics that provide insights into the system's performance over time

Solar energy monitoring is not necessarily required for all PV systems, but it is highly recommended. PV plant owners and researchers who invest in solar energy monitoring are able to identify and resolve issues more quickly, optimize their system's performance, and ultimately maximize their return on investment.

To get started with solar energy monitoring, you can contact a solar energy monitoring provider like us to discuss your specific needs and requirements. We can help you select the right monitoring system for your PV plant, install and configure it, and provide ongoing support and maintenance as needed.