Role Of Energy Storage In Greening The Grid

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Solar Panel, wind turbines and Li-ion Battery Container With Blue Sky Background. Energy Storage System.

By Preetesh Singh  – Manager & Prakhar Singh- Deputy Senior Consultant, Nomura Research Institute

India has set itself a target of 175 GW renewable energy capacity by 2022. This is in-line with commitments under The Paris Agreement, aimed at reducing global greenhouse gas emissions to limit the ill effects of climate change. 

However, the integration of renewable energy brings various challenges for grid operations. Electricity has been generated and consumed in real time. Conventional fuel sources permit us to increase or decrease the supply to match demand patterns. If the demand pattern shows more consumption in the evening, then the thermal and hydro power plants can operate at a higher load factor.

Fine-tuning supply to meet demand is much difficult with renewable energy. Intermittency and variability associated with solar and wind, the predominant sources of renewable energy, is a key concern. The output is dependent on the time and intensity of sun shining and wind blowing.

Source: Grid Integration of Renewable Energy, Ministry of Power

Further, the time of the day when renewable generation peaks does not correspond to the time of the day when consumption peaks, resulting in supply demand mismatch.

Source: Flexible operation of thermal power plant for integration of renewable generation, Central Electricity Authority

Thus, greening the grid presents technical challenges. The Central Electricity Authority has outlined two key challenges, as illustrated in the graph below. One, the challenge with ramping thermal power up and down. Two, the low load factor for thermal power plants at times of high renewable generation.

Source: Flexible operation of thermal power plant for integration of renewable generation, Central Electricity Authority

The solutions to the challenges posed are manifold – strengthening forecasting from renewables, smoothing renewable energy outputs, exploring flexible generation mechanisms, and managing demand profile. Each of these solutions are made more effective with use of energy storage solutions.

Energy storage solutions when co-deployed with solar and wind farms can provide low-latency high-flexibility power outputs for smoothing renewable energy outputs. This results in a predictable supply, reducing the ill effects of RE integration which could have caused frequency fluctuations and supply shortfall. Solar Energy Corporation of India (SECI) has started moving towards this solution already as it has floated tenders to this effect.

Energy storage solutions can also be deployed on their own for flexible generation. Energy storage solutions are superior to the power-generating plants at load-following, ramping rate, and the ramping range. SECI has also floated an RE based flexible peak power tender.

Energy storage when deployed at consumption end provides for managing demand flexibly. Coupled with policy measures such as time of day tariffs, the consumer uptake of energy storage solutions can be incentivized.

It is clear that energy storage solutions can smoothen the technical challenges of greening the grid. With increasing maturity of such solutions, their adoption is imperative. It is in the interest of the renewable energy generators to hasten the adoption, as the generators have been at the receiving end of the challenges such as high RE curtailment, non-compliance of PPAs, etc.

By Preetesh Singh  – Manager & Prakhar Singh- Deputy Senior Consultant, Nomura Research Institute

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