Thermal energy storage involves heating or cooling a substance to preserve energy for later use. In its simplest form, this process includes heating water during periods of abundant energy, storing it, and later using the stored energy. This utilizes storage options like water, ice-slush-filled tanks, earth, or large bodies of water below ground.
Defined as a technology enabling the transfer and storage of heat energy, thermal energy storage integrates with modern energy solutions like solar and hydro technologies. During off-peak electrical demand, chilled or hot water is generated and stored, later withdrawn and distributed during peak periods. The storage tank, equipped with diffusers at the top and bottom, facilitates the stratification of water, creating a transition layer between warm and cold water regions. The cost-effectiveness of electricity used for thermal energy generation is higher at night than during the day.
What are the Types of Thermal Energy?
Thermal energy storage employs various technologies, offering storage times ranging from hours to months. Different material properties are utilized in Thermal Energy Storage (TES) applications, categorized into three methods based on thermal mechanisms: sensible heat, latent heat, and thermochemical heat.
1. Sensible thermal energy storage is a viable option for lowering energy consumption and CO2 emissions, particularly in residential buildings. This method involves using water or rock to store and release heat by varying the temperature of the material.
2. Latent heat storage systems store energy by changing the state of the medium without altering its temperature. Phase change materials, applied in solar technologies and building materials, can store heat as latent heat, allowing for the absorption and storage of excess building heat.
3. Thermochemical heat storage systems rely on chemical reactions or sorption processes on the material’s surface, enabling the material to absorb or emit heat.
Also See: What is Ocean Thermal Energy Conversion (OTEC)?
What are the Benefits of Thermal Energy Storage?
Thermal energy storage offers several advantages:
- It lowers peak demand and stabilizes overall demand by storing energy during low-demand periods and releasing it during high-demand periods.
- It reduces CO2 emissions and costs by optimizing energy use during more economical times when a higher proportion of renewable energy is available.
- It enhances the overall energy efficiency of energy systems.
- It plays a crucial role in peak shaving systems, where off-peak power drives heat pumps to generate heat or cold, using cost-effective electric power and waste heat from industrial sources to balance loads in the energy system.
Also See: What is Pondage in Hydropower Plant?
What is the Need for Thermal Energy Storage?
Many countries prioritize decarbonization strategies, emphasizing renewable energy and increased electrification, as these approaches can achieve up to 90% of emission reductions. The decreasing costs of renewable energy underscore the importance of this transition. However, the inherent variability of renewable energy sources necessitates increased energy storage to ensure a consistent supply of clean energy during periods of fluctuation, such as when the wind is calm or the sun is not producing solar energy.
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