Rumi: An open-source energy systems modelling platform developed by Prayas (Energy Group). Rumi is available for download and use at

PIER: a fully functional model of the Indian energy system built on Rumi, is available for download and use at

In order to inform energy policy and research in a rapidly evolving sector, Prayas (Energy Group) built an open-source, generic, customisable, free-to-use and feature-rich demand-oriented energy systems modelling platform called Rumi. Using the Rumi framework, PEG built the PIER (Perspectives on Indian Energy based on Rumi) energy model of India. In PIER, India is modelled as 5 regions and 25 ‘states', with a model horizon year FY2030-31. Each year in the model consists of 5 seasons, each season consists of one typical day of six ‘day slices’ (for electricity). Five demand sectors namely, Residential, Industry, Transport, Agriculture, and ‘Others’ are modelled. The energy carriers modelled are steam coal, coking coal, crude oil, natural gas, biomass, biogas, petroleum products (MS, HSD, ATF, LPG, Others) and electricity. Nine electricity generation technologies (Coal, OCGT, CCGT, nuclear, large hydro, small hydro, biomass, solar, wind) are modelled in addition to refineries. Three energy storage technologies are modelled, all of which store electricity-- pumped hydro storage (PHS), and two kinds of battery electricity storage system (BESS), 4-hour BESS and 6-hour BESS.

The complete PIER report with inputs, results and insights is available here and in the PIER git repository. 


August 2023: PIER 1.5- More with less: Insights from residential energy demand assessment using PIER
An updated version of PIER residential model (PIER 1.5) which improves upon the earlier residential energy estimates using more current data and assumptions. Specifically, appliance penetrations have been updated using the more recent NFHS surveys, more recent population and household estimates are used, appliance stock-flow estimates and efficiency standard announcements from BEE are used to obtain better stock-efficiencies, time horizon has been extended to FY2041 and more scenarios are explored. Full report is available here.

July-August 2022: Blog series on PIER 1.1
A blog series was published to explain the results and insights of PIER 1.1 in an easily accessible manner. The six posts of the series are as follows:

  1. Bird’s eye-view of India’s energy sector 
  2. Electricity demand and supply in PIER 
  3. How much coal do we need?
  4. Residential cooling demand and consumer behavioural change
  5. State of clean cooking in India as per PIER
  6. Official targets, goals & projections: what does PIER say?

April 2022: Rumi v1.1.0, PIER v1.1.0
A post-processing module was added to Rumi. In this release, the post-process module processes emission specific inputs and produces emission related outputs.
Subsequently, PIER is updated with various emission inputs and outputs obtained through Rumi v1.1.0. In addition to these, a few code and processing enhancements have been done and some minor bugs have been fixed. All relevant documentation is available in the respective repositories. The updated PIER repository includes the emission-specific inputs and outputs for GHG emissions.

November 2021: Initial release- Rumi v1.0.0, PIER v1.0.0
Residential energy demand in this version is modelled in a detailed bottom-up manner while other demand sectors are top-down based on GDP elasticity considerations. For residential sector, 250 consumer types are modelled (25- states, 2 – urban/rural, 5- expenditure quintiles).