  As the world seeks to transition to a sustainable energy future, energy
storage technologies are increasingly recognized as critical enablers. However,
the macro-energy system assessment of energy storage has often focused on
isolated storage technologies and neglected competition between them, thus
leaving out which energy storage to prioritise. The article applies a
systematic deployment analysis method that enables system-value evaluation in
perfect competitive markets and demonstrates its application to 20 different
energy storage technologies across 40 distinct scenarios for a representative
future power system in Africa. Here, each storage solution is explored alone
and in competition with others, examining specific total system costs,
deployment configuration, and cost synergies between the storage technologies.
The results demonstrate the significant benefits of optimizing energy storage
with competition compared to without (+10% cost savings), and highlight the
relevance of several energy storage technologies in different scenarios. This
work provides insights into the role of energy storage in decarbonizing power
systems and informs future research and policy decisions. There is no
one-size-fits-all energy storage, but rather an ideal combination of multiple
energy storage options designed and operated in symbiosis.
