Power System Planning Reforms
The National Renewable Energy Lab (NREL), the lead for this component, undertook collaborative studies with India’s key technical institutions, built capacity of India’s power sector stakeholders, and supported pilot programs led by GTG-RISE through analysis and modeling
Grid integration studies
Greening the Grid: Pathways To Integrate 175 Gigawatts of Renewable Energy into India’s Electric Grid Vol. I—National Study and Vol. II—Regional Study, released by Piyush Goyal, Former Minister of State (IC) for Power, Coal, New and Renewable Energy, and Mines, Government of India, in June 2017 formed the cornerstone for the Greening the Grid program including the pilots that followed. The ‘National Study’ informed actions needed to help integrate 175 GW of RE by 2022. As a part of the study, NREL in collaboration with Lawrence Berkley National Lab (LBNL) and Power System Operation Corporation Ltd (POSOCO) created a detailed production cost model of the Indian power grid. Through this model, RE generation variability, least-cost scheduling and dispatch, effects of increasing the flexibility of thermal generation, periods of stress, and RE curtailment were evaluated.
An important highlight of the grid integration studies was the collaboration with India’s power sector stakeholders. In addition to technical review committee meetings, NREL led collaboration efforts with LBNL, POSOCO Central Electricity Authority (CEA), POWERGRID, and state load dispatch centers in Maharashtra, Gujarat, Tamil Nadu, Karnataka, Rajasthan, and Andhra Pradesh. This included several consultations on the PLEXOS model of India, relevant state-level models and training webinars on the model details and capabilities.
Reports published as part of GTG Integration Studies
- Study overview fact sheet
- Advances in production cost modeling fact sheet
- Vol. I—National Study full report
- Vol. I—National Study Executive summary
- Vol. II—Regional Study full report
- State Chapters: Andhra Pradesh, Gujarat, Karnataka, Maharashtra, Rajasthan,Tamil Nadu
- Summary Fact Sheets, Southern region, Western region
Publicly available resource data for South Asia region and links to all grid integration report and related publications are available at: https://www.nrel.gov/analysis/india-renewable-integration-study.html
The grid integration study broke new ground—detailing specific regulatory framework gaps, grid stability issues, options for optimizing grid system dispatch, and sources of potential flexibility required to further integrate solar and wind renewable energy sources—variable renewable energy (VRE)—into the power system. Two critical challenges
emerged from the study:
- Challenge 1: Enable conventional thermal plants to flexibly generate electricity. India’s conventional coal-powered plants need the ability to operate at less than maximum capacity to flexibly generate electricity in response to VRE and demand variability. Without increased power generation flexibility, coal-powered plants operate at maximum capacity or not at all—limiting the integration of RE sources that generate power at near zero marginal cost during the day or when the wind blows.
- Challenge 2: Increase power grid balancing areas. India’s power grid primarily operates at the state-level. With thirty states and union territories, grid control areas are fragmented—increasing complexity to schedule and balance power within relatively small boundaries. Without closer regional or national grid integration, system operators cannot as efficiently balance power supply and demand by sharing power reserves to manage grid reliability or accessing VRE and flexible generation sources. These challenges were addressed through grid integration pilots implemented under GTG-RISE initiative.
- Modeling Studies and support to Grid Integration Pilots
- Policy Briefs and Technical Report
- White paper and modeling studies
In addition, this GTG component analyzed solar parks, battery energy storage systems, and electric vehicles to support the narrative on large-scale integration of renewable energy, as well as developed an open-source tool for net demand forecasting. Further it supported grid integration pilot implemented under GTG-RISE.
Battery energy storage system (BESS) Pilot with BSES Rajdhani Power Limited (BRPL)
The goal of the modeling analysis was to understand the technical and economic value of BESS on BRPLs feeders and test the applications that might provide the greatest impact to the system. BRPL used this analysis to make a justification to their regulator on the need to pilot certain applications. An output of this modeling was an open source framework for distribution companies to assess the impact of distributed energy resources on their system. A primary outcome was approval by DERC for BRPL to pursue a pilot on BESS in place of other system upgrades. To find more information on the report, please visit https://www.nrel.gov/docs/fy20osti/75973.pdf
Net Demand Pilot with BSES Yamuna Power Limited (BYPL)
In collaboration with GTG-RISE and BYPL, NREL implemented the modeling study to address a lack of understanding about RE contributions and challenges to the power grid. The pilot was split into two technical analysis tracks as follows:
- The power procurement track investigated the contribution that utility-scale RE procurement provides to distribution utilities. NREL assessed the contribution of RE from both energy value and capacity value perspectives, and also shared the tools to allow BYPL to perform similar analyses for future RE procurements.
- The DER track focused on the challenges and opportunities caused by many small-scale distributed renewable resource integrations in distribution systems and assessed the net-load evolution that distribution utilities observe as these emerging technologies make their way to the grid. Under the DER track, NREL developed an open-source tool, EVOLVE (Evolution of Net-Load Variation from Emerging Technologies), that provides a window for utilities to better understand their future state, quantifying feeder-level impacts of integrating emerging technologies, such as solar PVs, EVs, and BESSs. To find more information on the report, please visit https://www.nrel.gov/docs/fy21osti/79069.pdf and for open-source modeling tool EVOLVE please visit: https://github.com/nrel/evolve
Automated Demand Side Management (ADSM) pilot with BSES – BRPL
This was another collaboration between the GTG partners – NREL and GTG-RISE – with BSES-BRPL on customers willingness and ability to allow for demand side management. The data collected by BRPL and GTG-RISE allowed NREL to develop a model that helps BRPL understand the potential of a DSM program to bring down system costs and shift loads to off-peak periods of the day. The model considers the potential of time-varying rate structures by using sensitivity analysis on real survey data from BRPL’s customers. An optimization framework was developed for various outcomes that BRPL can explore, such as reducing peak demand. An open-source modeling tool called EFFORT (Effectiveness of rate structures for enabling demand response) was developed to help model and design optimized time-of-use (TOU) tariffs. To find more information on the report, please visit https://www.gtg-india.com/wp-content/uploads/2021/07/79375.pdf
As a part of GTG, NREL also collaborated with POSOCO to research timely technical topics and develop research and white papers to support large-scale integration. These included:
Ramping in India’s power system co-authored with POSOCO
Ramping is one of the key attributes of flexible operation of existing generating resources. With implementation of nationallevel security constrained economic dispatch (SCED), the national operator POSOCO observed occasional constraints in ramping capability obtained from generators under SCED, which would be aggravated with more variable RE integration. This paper focused on complexities of ramping with high shares of renewables in the Indian context. To find more information on the report, please visit https://www.nrel.gov/docs/fy20osti/77639.pdf
Technical report on gate closure co-authored with POSOCO
NREL collaborated with POSOCO to explore the concept of gate closure, the time at which market participants submit final bids and offers for electricity. Gate closure is typically considered a minor feature of market design, but its implementation is pivotal to how power markets operate under high RE penetration. This report analyzed global experiences with gate closure, and then reviewed the unique benefits, challenges, and other considerations that impact the implementation of gate closure in the Indian electricity market. To find more information on the report, please visit https://www.nrel.gov/docs/fy19osti/72665.pdf
White paper on resource analysis of NP-Kunta solar park site
The paper researched the resource variability analysis of the 250-MW NP Kunta solar plant site and compared the resource variability of a 250-MW solar plant at the NP Kunta site with a similarly sized plant at Bhadla solar plant site. The analysis shows the intertemporal variability of the NP Kunta solar plant site and also demonstrates the use of publicly available resource quality data, which can be utilized by various stakeholders to better understand the variability of any existing or potential RE site in India and possibly increase confidence in decisions or help understand the impacts that can be expected. The two sites analyzed show different levels of variability in terms of annual/monthly energy and generation during each time period. The sensitivity towards this variability could be different among different stakeholders which is an area for future work. To find more information on the paper, please visit https://www.nrel.gov/docs/fy20osti/77784.pdf.
Regulatory analysis for enabling Automatic Generation Control (AGC) support from hydro and RE units.
NREL produced a report examining the technical and regulatory needs to successfully integrate AGC into grid operations, with a special focus on wind and solar generators. The report detailed the challenges and pathways to increasing reliability of the whole grid by enabling wind and solar to play a large role in reliability through markets, regulations, and other mechanisms. To find more information on the paper, please visit https://www.nrel.gov/docs/fy19osti/73866.pdf
In close collaboration with Ministry of Power, GTG-RISE initiative supported the development of two white papers for RE integration planning. These included:
Electric Vehicle Charging Infrastructure and Impacts on Distribution Network.
The white paper studied the growing impact of integrating EV onto the distribution grid. Similar in impact to integrating RE from a distribution management perspective, GTG-RISE modeled scenarios of further EV market share and determined how that would impact the grid. The paper also detailed the required changes to electricity pricing and tariff regulations for EV charging infrastructure and how DISCOMS could plan for and effectively distribute electricity to EV charging stations. Results from the paper informed GOI regulators on possible pathways, informed by international leading practices, for further consideration and adoption. To find more information on the paper, please visit https://www.gtg-india.com/wp-content/uploads/2020/07/EV-White-paper-Revised-13-07-2020.pdf
Intra-state Trade of Renewable Energy.
This white paper studied how inter-state RE exchange, which will play a critical role in creating more RE demand in India, resulting in higher RE capacity additions. RE power exchange between Indian states is currently at low levels. Increasing it requires policy and regulatory frameworks that support such exchanges. This white paper is developed with the aim of supporting a deep understanding of the issues that India must address to successfully promote inter-state exchange of RE power. To find more information on the paper, please visit www.gtg-india.com/wp-content/uploads/2021/02/RE-White-PaperNew-08-02-2021-revised.pdf.