Exploration of the Suitability of Gravity Energy Storage in Malaysian Grid Systems

Abstract

A photovoltaic system is a part of the renewable energy family. The Photovoltaic system's operating principle is based on converting sun radiation directly into electricity and therefore it needs energy storage to accumulate the excess energy generated by the system to use in times of need. The most common energy storage type used in Malaysia is batteries (BESS), a short-term storage solution with many drawbacks such as a high yearly storage cost and negative environmental impact resulting from emitting carbon dioxide during operation and recycling stages. These disadvantages have inspired studying the benefits of a new energy storage technique proposed in the market, gravity energy storage system (GESS). The gravity energy storage has been discussed in the past couple of years as the perfect alternative to batteries with advantages of high-power capacity and low environmental impact. This study considers a small grid size energy generation system of less than 10 MW using a PV system and two types of energy storage, the BESS and GESS. The study also includes a comparison between BESS and GESS systems in terms of their power generation, storage capacity, carbon footprint, and usable capacity when connected to a built PV system. The outcome of the study shows that GESS has the potential to outweigh BESS making it a more suitable energy storage option for the PV system. The BES system results in a carbon dioxide footprint of 3199- 13710 g CO2-eq per battery with an operating cost much higher than that of the GESS system and a usable capacity lesser than the GESS system due to the depth of discharge (DoD) and round-trip efficiency. Nonetheless, the BESS has the advantage in terms of installation cost, as the GESS installation can cost up to 2.97 million MYR, while BESS costs 1.25 million MYR for a similar system.