India has been witnessing an increasing trend in the share of renewable power installed capacity over the last few years. Globally, India is the fastest-growing electricity sector, although in terms of total energy production its share of renewable energy is only around 7 percent. With the growing penetration of renewable energy sources (RES), such as wind, solar, biomass, etc., into the distribution system, it has become indispensable to incorporate large-scale integration of energy storage, which gives us the flexibility to quickly ramp up supply in case the need arises.
Energy Storage Application in Indian Power Scenario
Indian utilities have had a long history of having one of the highest global aggregated technical and commercial (ATC) losses of around 30 percent; to further aggravate the situation the average supply demand deficit is around 3.6 percent with peak deficit at 5 percent. This leads to an additional burden on already strained system, which further leads to inefficient operation. Most of this supply-demand mismatch is during peak hours of the day, causing localized hot-spots (most strained part) in transmission and distribution (T&D) infrastructure. This also leads to a large inter-area power transfer, causing a larger power loss in the connecting infrastructure. A judicious placement of energy storage along these hot-spots (critical electrical pathways/locations) would certainly reduce the overall T&D losses and would result in greater overall system efficiency.
Reports suggest there is an underutilization of solar plants in India. This is either due to poor maintenance/service, or the inability of the grid infrastructure to absorb the power when it is generated at the source, thus leading to wasteful loss of energy. Energy storage provides the exact solution to this problem by offering flexibility of storing excess energy and dispatching/rescheduling it at a more convenient time. This also leads to an increase in overall efficiency of solar installations as most of the connected equipment could now be used at their rated or best operating points. Energy storage when deployed for advance power management, such as demand response, a technique used to control the load demand as per the received external signal, offers excellent operational tractability for realizing energy/cost saving. For example, a facility (commercial or industrial) may install energy storage system within its premises and use it to change the power drawn during peak hours (peak shift) from grid to reduce overall energy charges. Now this scheme, when implemented at a larger scale, would lead to an overall reduction in the system peak.
With increasing share of grid-tied solar installations, currently at 1.5 percent of the total installed capacity and poised to grow rapidly in future, a considerable part of power supply during day time would be met by solar installations. This though seems to be an ideal fit for the network and could pose some operational problem in future as more and more solar installations are integrated into the system.
In overall perspective, integrating energy storage into the power system offers multi-faceted direct or indirect benefits to realize effective operation. Key benefits could be summarized as follows:
- Load firming
- Increased operational flexibility
- Reduced T&D losses
- Improved power quality
- Deferred/reduced infrastructure investment
- Lesser greenhouse gases emission due to increased efficiency
- Improved power availability