Session: 6.1.1 - Student Competition

Paper Number: 108530

108530 - Comparative Analysis of Mechanical Energy Storage Systems 

With 70% of the global greenhouse gas emissions from the energy sector, decarbonisation of the electricity grid has become more critical than ever, and renewables have a significant role to play in this. In 2020, only 29% of the global electricity production was from renewables including biofuels. In the coming years, wind and solar photovoltaics are predicted to account for two-thirds of the growth in electricity from renewables. However, intermittency of renewable energy systems remains as one of the major impediments in their adoption. The fluctuations in energy production from renewables varies with the season and the type of renewable source used. Most of the utility-scale renewable energy plants do not have any form of energy storage coupled with them which prevents them from storing the excess energy generated. Large-scale energy storage is essential for the development of flexible, reliable electricity grids and integration of renewables with the grid.   

Based on their construction and working principle, energy storage systems are mainly divided into four categories: mechanical, electrochemical, electromagnetic and thermal. Ideally, energy storage systems should exhibit high storage capacity, high energy density, flexible power density, shorter charging time, longer discharge time, high efficiency, and durability. The most common forms of energy storage are lead-acid and lithium-ion batteries, they are expensive, use toxic chemicals, have low energy density and have to be replaced every 3-7 years.

On the other hand, mechanical energy storage systems are better suited for utility-scale energy storage. These systems work on existing technology, can be scaled up to have a high energy capacity, and do not have to be replaced after every few years. They include pumped hydro systems, energy storage using concrete blocks, flywheels, pendulum energy harvesters, metal-organic frameworks, and carbon nanotubes. Currently, 75% of the world’s stored energy is in the form of pumped hydro. Pumped hydro and concrete block methods store energy in the form of gravitational potential energy. Flywheels store the excess electrical energy in the form of kinetic energy via a rotating mass. Metal-organic frameworks store potential energy in their structure under compressive forces. Pendulum energy harvesters store the kinetic energy of the pendulum as potential energy, which can be converted to electrical energy using a geared motor. The application for these systems varies depending on factors such as energy density, power density, discharge time, and energy generation method. This work aims to present a comparative study of these mechanical energy storage systems based on their working, factors that affect their performance, their application, their advantages and disadvantages, and the developments in their technology.      

Presenting Author: Javier Sandoval Bustamante University of Cambridge

Presenting Author Biography: Javier Sandoval has a bachelor’s degree in Sustainable Development Engineering from Tecnologico de Monterrey, where he graduated in Mexico in 2018. Javier has experience in energy research, having completed a research internship in Ecole Polytechnique de Montreal in 2017, where he worked on a model for Life Cycle Assessment of 2nd generation biofuels in Canada. Additionally, he participated as speaker in the 2019 Young Energy Efficiency Researchers pathway of the World Sustainable Energy Days conference in Vienna, Austria. His experience in industry includes work as an analyst and project manager in Mexican energy efficiency startup S2G Energy and as an energy efficiency specialist for the retail sector in Walmart Mexico, where he has also collaborated to execute education related projects for future energy engineers in collaboration with Tecnologico de Monterrey. During his time in industry, Javier has been involved in projects related to energy efficiency, power factor correction, and Battery Energy Storage Systems and is currently completing the MPhil in Energy Technologies programme at the University of Cambridge.