Can thermal energy storage be integrated with existing renewable energy systems

Thermal energy storage (TES) can indeed be integrated effectively with existing renewable energy systems, providing numerous benefits such as balancing energy supply and demand, enhancing grid stability, reducing costs, and enabling deeper decarbonization.

How TES Integrates with Renewable Energy Systems

• Decoupling Energy Production and Use: TES systems store excess thermal energy generated by renewable sources like solar or wind during periods of high production and low immediate demand. This stored energy can then be released as heating or cooling when demand exceeds renewable supply, effectively bridging timing gaps between energy generation and consumption.
• Thermal Batteries for Buildings: TES can be embedded in building systems, transforming buildings into “thermal batteries.” Materials such as ice, wax, salt hydrates, or sand absorb and store heat or cold produced by renewables, then release it later to meet heating, cooling, or hot water needs. This reduces reliance on electricity for HVAC and smooths peak load demands, making buildings more energy-efficient and cost-effective.
• Complement to Battery Storage: While lithium-ion batteries excel in short-term electricity storage with rapid response, TES systems provide long-duration storage capacity focused on thermal energy. Combined, they optimize overall system reliability and performance for grids with high renewable penetration.
• Support for Grid Stability and Demand Management: TES helps level out peak energy demands, reduce potential grid outages, and allow for higher penetration of variable renewable energy resources by shifting when heating or cooling loads occur. This is especially valuable for integrating intermittent renewables like solar and wind.

Applications Across Scales

• Residential: TES enables homes to store solar thermal energy or excess grid electricity as heat or cold, lowering peak electricity use and facilitating electrification of heating loads, which supports grid decarbonization efforts.
• Commercial and Industrial: TES stores process heat, optimizes building energy use, and smooths out renewable generation variability in larger facilities and district energy systems.
• Utility Scale: TES is paired with renewable power plants (e.g., concentrating solar power with molten salt storage) to provide dispatchable electricity, grid services, and continuous power availability despite renewable intermittency.

Challenges and Ongoing Research

• Cost and Scalability: Large-scale TES deployment requires investment in materials, infrastructure, and technology development. Current research focuses on creating low-cost, high-storage-density materials such as salt hydrates and thermochemical materials with phase-change properties near typical indoor temperatures to improve affordability and efficiency.
• Standardization and Integration Tools: Efforts involve developing standards to characterize TES system performance and simulation tools that model integration with electrical grids and renewable sources to optimize deployment strategies.

Outlook

The TES market is expected to grow significantly by 2030, driven by falling renewable costs and technology advancements. TES technologies are poised to play a crucial role in deep decarbonization by increasing the flexibility and resilience of renewable energy systems across buildings, industry, and power generation sectors.

In summary, thermal energy storage is highly compatible and integrable with existing renewable energy systems, enabling more efficient, reliable, and flexible use of renewable electricity and thermal energy. It supports building decarbonization, grid stability, and higher renewable penetration through various materials and system innovations currently under active development and deployment worldwide.