The increasing use of renewable energy and decreasing inertia from large generators necessitate studying transient energy storage systems (TESSs) for better frequency stability. This paper examines UK National Grid data from 2014 to 2022 to propose initial design requirements for a TESS power‐train. It assesses second‐by‐second historical frequency data across various time frames to explore the impact on TESS sizing and strategies using the enhanced frequency response service 1 approach. The results establish an approach for determining the suitable battery energy capacity of TESSs offering frequency control services, contributing to the reduction of power demand and energy losses in the distribution grid. Moreover, the study presents a suitable deadband strategy for the enhanced frequency response service. The findings provide insights into the design and operational needs of TESSs in supporting grid frequency response, utilizing a statistical methodology driven by frequency data from the UK transmission network managed by National Grid Electricity Transmission. The primary aims of the paper are (a) to develop a suitable power and energy management philosophy for TESSs and thus inform future control objectives, and (b) assess the system energy specification requirements.