Dynamic Models of Concentrated Solar Receivers and Thermal Storage
To determine the market outcomes of adding various combinations of CSP receivers and TES to the California power grid, Terrafore developed and provided dynamic mathematical models of several thermal energy storage (TES) technologies to be used with concentrating solar receivers such as solar tower, parabolic trough and Fresnel Reflectors. TES systems selected for study included – Two-tank direct and indirect storage, phase change storage using Terrafore’s encapsulated TES, and a single tank dual media thermocline TES.
Under a contract from California Energy Commission, Terrafore together with KEMA-DNV, and Massachusetts Institute of Technology (MIT) are studying the market effectiveness of adding coupled CSP-TES capacity on the California grid. The study being conducted using KEMA’s proprietary grid analysis simulation software along with Terrafore’s dynamic models will evaluate the following benefits / impact of CSP-TES on the grid:
- Reduced required ancillary services and real time dispatch costs at a system level because of improved and managed variability and ramping behavior of CSP, and reduced emissions from substituting for generation for these services using conventional fuel;
- Improved system reliability as measured by system dynamic performance (area control error, frequency) and system’s ability to withstand events such as wind ramping, cloudiness and unit trips;
- Improved system reliability in terms of frequency response to disturbances that are improved as a result of CSP inertial and governor response. (As compared with the lack of same from PV and wind resources);
- Enhanced understanding of the economics – cost benefit comparison – of thermal storage and CSP reconfiguration to avoid gas co-firing and to allow the provision of ancillary services.
Recently, NREL using steady model of CSP-TES, showed that CSP-TES provides not only an option to increase grid flexibility, but the value of thermal storage is significantly higher than the simple approach of levelized cost of electricity. They also showed that utilities will be able to accept larger amount of PV on the grid when coupled with the benefits of dispatchable CSP-TES systems.
Terrafore with MIT and KEMA examined the impact of different ramp rate profiles, day-ahead schedules and frequency regulation. The study showed the CSP-TES can be highly profitable for utility ancillary markets such as regulation and up and down and spinning reserve. The ratio of CSP to TES and Power block for a given geographic location is all important to a profitable CSP system design.
The report will be published in the later part of 2014.
click for details : Dynamic Models of Concentrated Solar Power Plant to Study Response to Utility Demand Profiles (pdf document)
For details on models contact : terraforetechnologies.com