INVESTIGATION OF ENERGY STORAGE SYSTEMS: ROADMAP AND OBSTACLES

Abstract

The energy storage systems (ESS) are likely to be indispensable in renewable energy integration to the power grid. Hence, it is vital to understand ESS roles and applications, technical characteristics, and supporting mechanisms for sustainable deployment before adopting the technology. This report evaluates key characteristics of ESS technologies using SWOT analysis and addresses policies and regulations necessary for the deployment.

The evaluation indicates that battery storage systems, especially Lithium-ion, are becoming dominant in a broad range of renewables integration applications that require high power and energy density, fast response, medium-to-high power rating, as an example of the world's biggest Li-on battery 100MW/129MWH at Hornsdale Wind Farm in Australia. Nevertheless, emerging battery technologies, namely Solid-state Lithium-ion and Redox flow battery are expected to be more compact, more durable, and safer, whereas mechanical storage systems with key characteristics on high power rating, low energy capital cost, and long discharge duration, can still be a great support in renewables integration despite its low power density.

For example, China is deploying more 60 GW PHS to support large-scale remote wind and solar PV farms. Other technologies, namely FES, SCES, and SMES, are more appropriate for applications that require a high power rate within a short time, such as regulations grid frequency, affected by renewables intermittency. Notably, because of an independent power rating and the ability to store energy in the different forms of fuel (hydrogen and methanol), chemical storage systems have been recently recognized as a promising alternative for longterm renewable energy integration, especially in high penetration rate scenario. However, low overall efficiency is still a major drawback. On the other hand, supporting mechanisms are also integral for the sustainable deployment of ESS. Policies and regulations implemented by leading countries in ESS global market are reviewed. The remarkable practices can be outlined as follows: Establishment of official association or task force team whose are obliged to study, develop, and implement ESS deployment as an example from New York state and Japan; Policy mandate has also been broadly used to accelerate the ESS deployment rate by setting a firm target of ESS installed capacity as the practices from California, New York, and Texas; Legitimization of ESS rights as an entity helps define clear roles of ESS and enable ESS to create economic value in the market. For instance, Texas passed the bill that gives ESS the same rights as generators, allowing ESS to buy or sell electricity as a legitimate entity; Technology-push incentive policies are essential to encourage and foster the development or commercialization of ESS technology by subsidizing research institutes, demonstrating projects, or innovative companies. The Australian government's Venture Capital already invested AUD $19 million in three ESS-related companies; Market-pull incentive policies are considered the widely-used policy. This approach aims to elevate ESS installation demand by providing financial benefits, such as rebates, low-rate loans, or tax benefits. However, policymakers should also beware of over subsidizing and market bias, which could negatively impact the market.