The efficiency of molten salt energy storage systems has a significant impact on their overall cost, primarily because it influences both capital and operational expenses as well as the levelized cost of storage.
Impact of Efficiency on Cost in Molten Salt Energy Storage Systems
- Energy Storage Cost Advantage: Molten salt thermal energy storage (TES) is notably cheaper than other forms such as lithium-ion batteries when measured by the cost per kilowatt-hour stored. Molten salt tanks can be around 33 times less expensive per kWh stored compared to electric batteries, with heat storage costs ranging roughly from 15 to 25 EUR/kWh thermal, compared to much higher costs for electric storage at about 833 EUR/kWh electric equivalence.
- Operational Efficiency and Temperature Gradient: The efficiency of molten salt TES depends on the temperature difference achievable in the system. Larger temperature swings (around 280 K) allow the storage to capture and release more heat, improving the effective energy stored per unit volume. However, achieving higher temperature gradients can increase capital cost due to the need for more robust heat exchangers and materials. Thus, better efficiency may raise upfront costs but reduce costs per stored or delivered unit of energy over time.
- Capital and O&M Costs: The capital expenditure (CAPEX) and operational and maintenance (O&M) costs for molten salt storage are linked to the system’s power rating and storage capacity. Higher efficiency means that less energy input is lost during storage and retrieval cycles, which translates into better utilization of the system, potentially lowering the levelized cost of storage. This is because the same capital investment yields more usable energy output.
- Levelized Cost of Storage (LCOS): The LCOS of molten salt energy storage typically ranges from about 127 to 255 €/MWh depending on the system configuration and efficiency. Improving efficiency reduces the LCOS by enabling more energy to be stored and delivered per unit input and per unit of installed capacity, helping to optimize the cost-effectiveness of the entire storage system.
- System Integration Benefits: High efficiency in molten salt storage facilitates better integration with renewable energy systems, allowing stored thermal energy to be used effectively when solar or wind resources are insufficient. This continuous provision of energy without reliance on fossil fuels enhances the overall economic and environmental value of the system, indirectly impacting cost through improved reliability and reduced fuel costs.
Summary Table
| Aspect | Effect of Higher Efficiency | Impact on Cost |
|---|---|---|
| Temperature Gradient | Larger temperature swings increase storage capacity | May increase upfront costs but improves energy density and utilization |
| Capital Expenditure (CAPEX) | More robust materials needed at higher temps | Higher CAPEX but potential for lower cost per kWh stored |
| Operational Costs (O&M) | Less energy lost, higher utilization | Lower operational cost relative to energy output |
| Levelized Cost of Storage | More energy delivered per system cost | Decreases LCOS, making storage more economically viable |
| System Integration | Enables continuous energy supply | Enhances system value and reduces fossil fuel reliance, lowering overall lifecycle costs |
In conclusion, the efficiency of molten salt energy storage systems directly influences their overall cost by determining how effectively the stored thermal energy can be converted to usable output and by affecting the scale and robustness of the system components. Enhanced efficiency improves energy utilization and reduces the cost per unit of stored energy, making molten salt TES a highly cost-effective energy storage option, particularly suited for large-scale and high-temperature applications like concentrated solar power.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/how-does-the-efficiency-of-molten-salt-energy-storage-systems-impact-their-overall-cost/
