  As variable renewable energy sources comprise a growing share of total
electricity generation, energy storage technologies are becoming increasingly
critical for balancing energy generation and demand.
  In this study, we modeled an existing thermal energy storage unit with
estimated capital costs that are sufficiently low to enable large-scale
deployment in the electric power system. Our analysis emphasizes the value of
using such units to cost-effectively improve renewable energy dispatchability.
This study modeled an existing real-world grid rather than simulating
hypothetical future electric power systems. The storage unit coupled with a
photovoltaic (PV) system was modeled with different storage capacities, whereas
each storage unit size had various discharge capacities.
  The modeling was performed under a baseline case with no emission constraints
and under hypothetical scenarios in which CO$_2$ emissions were reduced. The
results show that power availability increases with increasing storage size and
vastly increases in the hypothetical CO$_2$ reduction scenarios, as the storage
unit is utilized differently. When CO$_2$ emissions are reduced, the power
system must be less dependent on fossil fuel technologies that currently serve
the grid, and thus rely more on the power that is served from the PV + storage
unit.
  The proposed approach can provide increased knowledge to power system
planners regarding how adding PV + storage systems to existing grids can
contribute to the efficient stepwise decarbonization of electric power systems.
