By Dr. Rashi Gupta, MD-Vision Mechatronics Pvt Ltd
Energy storage can play a major role in greening the grid by providing an eco-friendly solution for improving operational flexibility of the grid and facilitating integration of renewables. Worldwide efforts are being made for increasing the share of renewable generation in the Grid. India has set targets of around 450GW of renewable generation by 2030. The intermittency and uncertainty of renewable generation affects performance and stability of the grid. A continuous balance between supply and demand needs to be achieved in the grid for maintaining its stability. The continuous advancement in energy storage technology and their falling prices has opened numerous feasible opportunities for reducing the carbon footprint of the grid.
Energy Storage is very versatile that a single ESS can perform all the enlisted functions to make the grid greener.
- Increasing share of renewable generation
Excess renewable generation during lower demand often cannot be fed back to conventional grid due to its limited flexibility and is often curtailed. Energy storage reduces curtailment of renewable generation by storing the excess generation and supplying it during peak demand. This helps in reducing intermittency of renewable generation and increasing their reliability.
Renewable generation being distributed in nature requires energy storage nearby for integrating with conventional grid. Energy storage technologies like Lithium batteries can be installed at almost any location of the world. Such energy storage can be located near renewable generation sources for better integration with the grid without major changes in the existing grid infrastructure.
- Increasing reliability
Due to reducing cost of energy storage, it is increasingly replacing conventional diesel generators for backup. This not only reduces consumption of fossil fuels but also increases the capacity of the system for incorporating renewables. During outage it is not possible to feed excess renewable generation to the grid. This generation can be stored for use locally, thereby increasing reliability of local supply.
- Peak demand reduction
Energy storage is also replacing peaking power plants which are used for supplying peak demands on the grid. Gas and diesel generators have been conventionally used for peak demand reduction. Energy storage can store energy during low demand from renewable generation and supply during peak demand. By placing energy storage at strategic locations, Transmission and Distribution upgrade deferral can also be achieved as a result of reducing peak demand on the grid.
- Ancillary services
Energy storage like Lithium batteries can provide instantaneous high charging and discharging rates. This property of energy storage enables it to manage the disturbances and rapid changes in demand and generation in the grid enabling the Grid operators to use energy storage for various ancillary services like frequency and voltage regulation and maintaining stability of the grid. These services were traditionally obtained using spinning reserves and supplemental reserves. High efficiency energy storage like lithium batteries, are being considered as a greener alternative for providing ancillary services.
- Black Start
Black start generators are used for starting large power plants after system failure. Energy storage is being considered for providing black start, which was traditionally obtained from fossil fuel generators.
Energy storage along with renewables is emerging as a replacement for various services in the grid which were provided by conventional generators, thereby becoming a key driver for greening the grid.