Rapid changes underway in the energy sector have resulted in increased complexity of planning and operations in the sector, requiring sophisticated modelling tools and approaches. This has resulted institutional responses involving the central government and electricity regulators, who have taken several initiatives to adapt to the changes and to mandate demand forecasting and resource adequacy studies to help better plan for the next few decades.

It is desirable that modelling studies used for planning, regulation and policy formulation in the energy sector are done in an open and transparent manner. Doing so increases reproducibility and hence credibility of the studies, resulting in greater buy-in and acceptance from all stakeholders and lesser policy and regulatory friction. Openness refers to both data - the inputs and assumptions that form the model - as well as the source code of the software used for formulating and running the models.

In this context, Prayas (Energy Group) and University of California at Santa Barbara organised a 1.5-day hybrid event on December 22-23 2025 in New Delhi to present the following open-source and open-data studies for the Indian power and energy systems with detail up to the state level:

• PIER v2: an energy demand estimation and supply optimisation model up to 2040-41
• GridPath-India: capacity expansion and production cost model up to 2050
• GridPath-India RA study: resource adequacy study till 2040

The event ended with a roundtable discussion on data, methods and tools for state-level RA studies in India.

There were over 60 attendees over the two days including 18 that joined online. Following is a summary of the discussions:

• All 3 studies presented fill existing gaps in the Indian modelling ecosystem, especially with respect to bottom-up demand estimation and supply planning with state-level detail, and advanced methods with associated data for a long-term resource adequacy.
• It was also appreciated that these studies are based on open source tools and that the models will be placed in the public domain once they are finalised.
• Several suggestions were provided to further improve the studies by considering important changes that are underway in terms of increasing mechanisation and electrification, new loads such as data centers, geopolitical factors, inter-sectoral dynamics and decarbonisation technologies.
• Several participants noted that there is a need to build analytical capability within the various institutions in the electricity sector at the state level on an urgent and persistent basis. Industry-academia-research collaborations can play an important role in achieving this.
• It was pointed out that there is also a need for consistent data to be collected and made available by the various institutions in predefined spreadsheet formats, and that Regulatory Commissions need to make this happen as this does not entail significant effort from the data providers.

There is also significant uncertainty with respect to the electricity demand that various entities need to plan for in the context of sales migration away from DISCOMs, and separate agriculture distribution companies parallel distribution licensees being proposed