  Storage is vital to power systems as it provides the urgently needed
flexibility to the system. Meanwhile, it can contribute more than flexibility.
In this paper, we study the possibility of utilizing storage system for carbon
emission reduction. The opportunity arises due to the pending implementation of
carbon tax throughout the world. Without the right incentive, most system
operators have to dispatch the generators according to the merit order of the
fuel costs, without any control for carbon emissions. However, we submit that
storage may provide necessary flexibility in carbon emission reduction even
without carbon tax. We identify the non-convex structure to conduct storage
control for this task and propose an easy to implement dynamic programming
algorithm to investigate the value of storage in carbon emission reduction.
