India’s power system must safely and successfully accelerate the adoption of Distributed Energy Resources (DER) such as solar, storage, and electric vehicles for it to meet its climate and energy goals, the U.S.-based National Renewable Energy Laboratory (NREL) has said.

Increased DER integration will curb the country’s emissions and lower customers’ costs, improve system reliability, and present economic opportunities for India’s private sector.

At the same time, more DERs mean the state utilities that manage India’s grid must grapple with the potential impacts, such as voltage violations and demand shifts, that DERs may have on the country’s medium- and low-voltage distribution networks. Failure to manage these changes and risks could delay the rollout of DERs and other renewable energy technologies and slow down India’s overall energy transition.

As India aims to increase wind and solar generation capacity by 2030 considerably, it is crucial to monitor how the distribution system (small-scale wind and solar generation connected to the distribution system) responds to and supports the Indian power grid.

This alone will allow India to reach levels of more than 20% of online instantaneous electricity generation being supplied by DERs. The DER systems are likely to impact bulk power system performance, reliability, and stability and highlight the need for well-designed, locally appropriate interconnection standards.

Last year, India’s Central Electricity Regulatory Commission issued regulations to limit frequency fluctuations within the operating band in the interest of grid security.

In the past, NREL has supported the Bureau of Indian Standards (BIS) in adopting the Institute of Electrical and Electronics Engineers (IEEE) 1547-2018 standard in 2023. While this marks a significant step towards implementation, this standard’s requirements are yet to be incorporated into India’s grid code. NREL has made a few recommendations on seamless DER integration.

Improving data management

NREL has worked with distribution utilities in Delhi—BSES Yamuna Power Limited (BYPL) and BSES Rajdhani Power Limited (BRPL), where the tools and processes to collect data for DER modeling were lacking. This prevents the government bodies from understanding the landscape of their energy profile and the impacts DER integration might have on the distribution grid.

To navigate this, NREL created the Simple Synthetic Distribution Feeder Generation Tool. The tool, which builds synthetic distribution feeder data models using existing, open-source information for the local area, can help BYPL and BRPL overcome data availability issues and kick-start their DER analysis projects.

This also saves them from waiting for months or even years to collect this data.

Advanced DER risk analysis

DER growth and interconnection must also ensure that it does not cause power quality issues, resulting in outages.

NREL and Tamil Nadu Generation and Distribution Corporation Limited (TANGEDCO) devised an approach to distribution network analysis that defined risk by assessing the magnitude of power quality violations, the number of customers impacted, and the duration of violations. Through this approach, NREL found that distributed solar can improve TANGEDCO’s network conditions.

Solar inverters without advanced inverter functions (or the ability to change their power output as a function of control parameters, such as voltage) were sufficient to reduce undervoltage problems. However, an advanced inverter function would certainly provide more benefit as solar deployment levels increase to address overvoltage and undervoltage problems.

Drafting India-specific standards

As the IEEE standard is fundamentally a U.S.-centric standard designed around a 60-hertz system, there is a need to use real-world Indian power system data, which is critical to designing grid support functions specific to the country.

In its efforts to facilitate India’s adoption of the IEEE standard 1547-2018, NREL attempted to understand how the standard applies to international power systems that may have different operating characteristics.

It found that India’s 50-Hz system requires a locally appropriate adaptation of the standard, involving looking into active voltage regulation, unique grid topologies, levels of DER adoption (present and future), system protection schemes, and bulk power system frequency response.

NREL is also figuring out a way to adapt its PREconfiguring and Controlling Inverter Set-Points (PRECISE) tool as another method for modeling each utility’s needs for interconnection.

However, India’s state bodies are taking the lead in adopting tools that optimize DER growth to support a more sustainable power system for the future.