I have not used the storage feature by myself, but there is functionality to add storage in LEAP, but it works only with optimization model using NEMO.
Please refer to LEAP help files regarding optimization available here.
Thanks for your response. I am using NEMO and will peruse the help files in case I missed something. With the element of cost in mind, not sure how to link the CSP plant to the storage component so they can be dispatched together.