Gravity-Based Storage Devised for Residential Rooftop Solar Applications

Two researchers from the School of Engineering and Sustainable Development, De Montfort University, Leicester, United Kingdom, and a researcher from the Ahmadu Bello University, Zaria, Nigeria, have designed a residential solar-plus-storage system based on gravity.
Their research proposes a design model for conserving and utilizing energy affordably, considering the increasing support of renewable energy sources for cheaper electricity generation and solar energy potential, especially in the continents of Africa and Asia.
Gravity-based energy storage has been proposed as a potential solution with unique advantages of short response time and flexibility. In such systems, electricity is used to lift mass to a higher elevation, thereby storing potential energy and lowering this mass discharges the energy that can again be converted to electricity.
The team’s research integrates and formulates different ideologies, factors, and variables that have been adopted in previous research studies to create an efficient system and includes pumped hydro gravity storage system, compressed air gravity storage system, suspended weight in an abandoned mine shaft, dynamic modeling of gravity energy storage coupled with a PV energy plant and deep ocean gravity energy storage.
Their research aims to design an integrated solar energy storage system utilizing the potential of gravity using a suspended mass. It will be achieved by using a solar PV cell, bulk booster charge controller, inverter unit, solenoid device, deep cycle battery, pulley block, geared motor, a micro-controller, and wire ropes.
The design will store energy using the principle of potential energy conservation to store large amounts of energy during the daylight hours and release the stored energy during the night hours proportionately.
The complete system is made up of solar panels rigidly fixed on the roof of a building. Electric cables of considerable length and diameter are used to connect the panels via a diode to a charge controller augmented with an Arduino, regulating charges supplied to the deep cycle batteries, the electric geared motor, and standby load.
The deep cycle battery is charged, and it is connected to an inverter, which is connected to AC loads in a given space.
Efficiencies reaching up to 62% were achieved using the chosen design experimental parameters adopted in this work. However, this efficiency can be tremendously improved upon if the design parameters are modified, putting certain key factors highlighted in the limitation aspect of this research into consideration.
In 2018, Indian power conglomerate Tata Power announced that it would deploy a 35 MWh energy vault system in the next year. The energy vault system is based on the principles of traditional gravity-based pumped hydro projects that rely on the power of gravity and the movement of water to store and discharge electricity. The technology combines both potential and kinetic energy with patented cloud-based software.
In 2019, the Ministry of New and Renewable Energy (MNRE) issued invitations requesting proposals to develop gravity storage projects and utilize solar photovoltaic (PV) to produce hydrogen from seawater. The ministry believes that with the increasing share of renewables in the country, there will soon be a requirement for energy storage to absorb fluctuations and for grid balancing.