The Magaldi Green Thermal Energy Storage (MGTES) is a flexible, short and long duration, high temperature Thermal Energy Storage (TES) technology that utilizes a fluidized bed of solid particles. This system is capable of using both electricity and heat for the charging phase and then it releases energy in the form of heat when needed.
The MGTES technology is modular and provides high flexibility in terms of cycles, temperatures and scalability. Furthermore, thanks to its robust design, low thermal loses and ease of maintenance, MGTES represents a Long Duration Thermal Storage solution with a useful life of 30+ years: it will play an important role in the global decarbonization of industrial processes and power systems.
The MGTES is designed both for short (<4 hour) and long duration (4+ hour) large-scale energy storage application up to days and weeks.
The system consists of insulated modules that contain a granular storage medium (simple silica sand), that can be heated to temperatures above 1000°C.
A key element to increasing thermal energy transfer during the charging and discharging of the MGTES is the fluidization system. When the system is in charging and discharging mode, air is blown through the sand bed.
When energy is needed, the process is reversed, and thermal energy is released through high pressure steam, CO2 or even hot air systems. This fluidization of sand particles dramatically increases in the heat exchange coefficient and the response time of the entire system.
The MGTES system operates in three phases:
- Charge: The system is charged by immersing active elements in a fluidizable bed of solid particles (sand). Both electrical energy, through an array of electrical resistors (Joule effect), and thermal energy, through integrated heat exchanger, can be used.
- Storage: The fluidization is switched off and the sand packs at the bottom of the module. The absence of convection and the insulation of the tank limit the heat exchange with the outside of the casing, thus minimizing energy losses
- Discharge: The system is discharged by reversing the integrated heat exchanger within the fluidized bed of solid particles. This stored energy is released as superheated steam or whatever high temperature fluids (such as hot air) are needed by the industrial processes. The system can even be adapted to work in combination with a power-block to generate electricity
By varying the mass of solid particles contained in each module, it is possible to configure a storage capacity between 5 and 100 MWh. Charge, discharge and energy storage capacity can be independently scaled. Several modules can work in series and/or parallel, meeting the required demand up to GWh. Thus, this modular technology can be configured for every application to maximize the return on investment.
In terms of discharge duration, MGTES technology is able to cover a wide operating range. Depending upon the final configuration, including insulation type and thickness, the system can be designed to store energy efficiently from a few hours to multiple days with minimum thermal losses.
- Sustainability: Magaldi based its technology on the use of readily available and reusable materials. MGTES is mainly made up of silica sand and steel, representing an environmentally friendly solution, which does not contain or produce pollutants
- Flexibility: MGTES increases the flexibility of any energy production system in which it is integrated, decoupling energy production from consumption. The system can be integrated into existing thermoelectric power plants, industrial plants, variable renewable plants (such as wind or solar) as well as the electrical grid
- Efficiency: When the fluidized sand bed reaches its maximum design temperature, the system stops the heat input transfer and fluidization. Once stopped, the thermal losses are dramatically reduced to negligible amounts (typically <2% per 24h). Accordingly, the thermal energy can be stored for hours, up to several days, and then released when required. In a thermal-to-thermal application, the Round Trip Efficiency (RTE) is expected to be greater than 90%. The efficiencies are lower (35-45%) if thermal energy needs to be converted in electricity.