The Ministry of New and Renewable Energy (MNRE) has mandated that all original equipment manufacturers (OEMs) enlisted for the supply of inverters under the PM Surya Ghar: Muft Bijli Yojana integrate inverter communication devices with the PM Surya Ghar portal.

The move comes in the background of inverter communication devices transmitting data to servers outside India, potentially risking grid disruptions.

The inverters must also be connected to software managed by the MNRE or any other agency designated by it.

The integration of inverter communication devices with the portal will be rolled out for the testing phase from September 1, 2025.

According to the new guidelines, all inverter communication devices/dongles/data loggers must have machine-to-machine SIM communication protocol to enable secure and reliable data transmission.

In another notification, MNRE issued draft guidelines for remote monitoring systems (RMS) and inverter communication devices, such as dongles and data loggers, under the PM Surya Ghar program.

Data Monitoring

The guidelines seek to establish a multi-layered security and communication protocol to ensure that data from rooftop solar installations is reliably captured, transmitted, and monitored. This initiative is considered critical for PM Surya Ghar’s success.

They aim to ensure that all RMS devices, which serve as the digital bridge between solar inverters and central servers, adhere to a secure and structured communication architecture.

Stakeholders can submit their comments and suggestions by July 31, 2025.

Security is a core focus of the document. The communication between RMS devices and the centralized Internet of Things (IoT) platform will be encrypted using AES-256 protocols over Transport Layer Security (TLS) or Secure Sockets Layer (SSL) protocols. Each RMS must be uniquely identified using its International Mobile Equipment Identity (IMEI) number and will be assigned a digital certificate for secure authentication.

The use of a time-sensitive one-time password in every message exchange will provide transaction-level security, protecting the system against unauthorized access and bots.

RMS registration is mandatory for vendors and suppliers. Each device must be registered with the centralized IoT platform using its IMEI number. Upon registration, a secure Application Programming Interface will return essential credentials, including client certificates, authentication tokens, server URLs, and topic structures. These credentials allow the RMS to communicate with the device management server, where it will receive further configuration instructions. Renewals and updates to certificates will be managed through File Transfer Protocol access.

Communication between RMS devices and the server will follow the Message Queuing Telemetry Transport (MQTT) protocol. The guidelines outline a detailed topic structure, including default information topics, heartbeat signals, periodic data, event-based messages, and on-demand commands. This structure aims to ensure efficient communication for both real-time monitoring and the retrieval of historical data. For instance, if the server detects missing data from a previous interval, it can request indexed records from the RMS.

Multiple communication modes are defined. These include periodic pushes of inverter and sensor data, push-on-event when alarms or faults occur, and on-demand read and write functions that enable remote diagnostics and control. Configurations, such as inverter set points, battery charging parameters, and communication intervals, can be updated remotely using a predefined command structure.

The document also provides a unified message format using the JavaScript Object Notation (JSON) language. Parameters are standardized across various devices, including single- and three-phase inverters, hybrid inverters, energy meters, string combiner boxes, and weather monitoring units. Each parameter is tagged using a consistent identifier format, allowing seamless data interpretation at the server end.

In April, MNRE mandated generating and inputting the 16-digit domestic content requirement certificate number on the PM Surya Ghar portal to prevent duplicate module serial number issues.

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