Low- Cost Thermal Energy Storage for Dispatchable CSP
Demonstrating an innovative and low-cost approach to utility-scale thermal energy storage
The Issue
There is a growing problem facing the California electric grid as more and more electricity is being generated by renewable resources such as wind and solar. While there are many benefits to these resources, by their nature, they are 1) unable to match power production to usage, and 2) highly variable and/or intermittent in their production when compared to traditional electricity sources. A possible solution to these issues is increased use of thermal energy storage (TES) with concentrating solar power (CSP). Unfortunately, current TES technologies are prohibitively expensive and difficult to dispatch.
Project Innovation
The purpose of this project is the development and demonstration of a cost-optimal, robust, and low-cost thermal energy storage (TES) fluid, elemental sulfur. Use of sulfur as a TES fluid will enable overall low system costs, long lifetime, and scalability for a wide range of concentrating solar power (CSP) applications and temperatures.
Project Benefits
This project will develop a low-cost thermal storage fluid, elemental sulfur, which enables overall low system costs, long lifetime, and scalability for a wide range of concentrating solar power applications.
Lower Costs: This project aims to reduce the cost of TES to $15/kWh. Compared to current state-of-the-art, this leads to a decrease in LCOE from 3 cents/kWh to 0.4 cents/kWh, providing $0.66 billion to $1.32 billion in annual savings depending on CSP penetration.
Greater Reliability: Use of TES allows excess harvested solar energy to be stored during the day to be used during peak or non-solar hours, which increases dispatchability of renewable resources and provides load shifting.
Economic Development: Assuming 5% to 10% penetration of CSP and deployment beginning in 2017, the 10-year net present value of this technology is estimated to be between $680 and $906 million.
Environmental Benefits: Assuming 5% to 10% penetration of CSP and 1010 MWh of TES by 2020, significant GHG and criteria air pollutant reductions would be achieved: 2791 ton/MW of CO2, 37 ton/MW of SO2, 5 ton/MW of NOx, and 2.4 ton/MW of CO.