Power Reserves: Key role of energy storage in load balancing

Key role of energy storage in load balancing

Energy storage was one of the key themes at the India Smart Utility Week 2019, where an expert panel discussed its importance for Indian smart utilities. The discussion was focused on battery technologies for grid applications and e-mobility, storage projects, pilot projects in India, and manufacturing of energy storage systems in India. There are two key aspects of energy storage – business models for project implementation and the existing regulatory framework.

The key drivers for the development and adoption of energy storage solutions are policy and regulatory changes, especially those focused on renewable energy. In addition, the prices of lithium-ion (Li-ion) batteries have declined. Energy storage solutions are also expected to flatten the load curve, thus easing the burden on assets and delaying ageing of assets.

The size and location of energy storage solutions are key considerations in its planning. Another critical requirement for the smooth integration of energy storage is a robust communication network that is responsible for maintaining connectivity with the enterprise bus. The collection of performance and reliability data, modelling and analysis, and adoption of project best practices will further support the transition from the research and development stage to the operational stage of energy storage solutions.

A study by the World Resources Institute predicts global water stress in the near future. Conventional coal plants further pollute the ground- water. Hence, innovative technologies need to be introduced to support the production of clean energy. For instance, a new technology showcased by US-based Thomas Jefferson Lab uses solar energy to produce hydrogen and oxygen through the process of electrolysis, which can then be stored and used to inject energy into the system. Energy storage enables the flexible use of renewable energy. It helps in peak load management, and acts as a balancing reserve and ancillary support.

Storage could also prove to be a bottleneck in renewable energy deployment. Battery-based technology options are available, but there are issues pertaining to the cost, energy, charging time, battery life and safety needs. The performance parameters and the choice of battery technology depend on its applications such as portable electronic devices, e-mobility and grid storage. There are four stages in the development of battery storage solutions. The first and second stages are focused on materials development and cell manufacturing, followed by cell integration, and packaging and provision of infrastructure for electric vehicles. The stage of material development is difficult and involves multiple stages.

Further, the cost of battery-based grid-scale storage needs to be made competitive. Conventional flow batteries suffer from chemical cross-over, limiting their efficiency. The key is to focus on technologies that use materials abundant in nature to bring the costs down. Besides the high cost, there is a lack of a clear regulatory and market framework. There is also no clarity on the tariff mechanism for energy storage. The key recommendations for promoting the deployment of energy storage and ensuring its smoother integration include setting national- and state-level storage targets in line with the renewable purchase obligations, assessing the impact of renewable energy addition through a probabilistic study, and encouraging domestic manufacturing using multiple technologies.

Battery energy storage systems can be used across power generation and transmission cycles. There is a need to match resource availability with the load, where energy storage plays an important role. Energy storage can be used along with traditional fossil fuels, renewables and microgrids. Storage-based assets can help stabilise the grid, and enable peak shaving, wherein surplus energy can be stored and used when needed. In addition, it reduces intermittency in both wind and solar generation, which can help in better forecasting. ABB has implemented a “power store” at its plant in Vadodara, which is a Li-ion battery with a remote monitoring system and a decentralised automation system. The company expects to reduce the operational cost and return on investment over the next five to six years.

Under the National Energy Storage Mission, the government is focusing on demand creation, indigenous manufacturing, innovation and energy storage. The energy storage policy is also at the final stage. The sector is witnessing an evolution of the policy framework with the involvement of different stakeholders. The utilities have reached commercial maturity and are no longer driven merely by government policies.