How to measure battery energy storage system

What is energy storage capacity?

Energy storage capacity is measured in megawatt-hours (MWh) or kilowatt-hours (kWh). Duration: The length of time that a battery can be discharged at its power rating until the battery must be recharged. The three quantities are related as follows: Duration = Energy Storage Capacity / Power Rating

What is a battery storage system (BESS)?

In addition to this initial performance characterization of an ESS, battery storage systems (BESS) require the tracking of the system’s health in terms of capacity loss and resistance growth of the battery cells.

How much SoH does a battery use?

Typically, batteries use up to 70% or 80% of their SoH for applications related to electrical mobility. This is considered the first life of the battery. Afterward, the battery embarks on a second phase of usefulness, allowing it to serve in applications of stationary energy storage systems.

How is energy storage capacity calculated?

The energy storage capacity, E, is calculated using the efficiency calculated above to represent energy losses in the BESS itself. This is an approximation since actual battery efficiency will depend on operating parameters such as charge/discharge rate (Amps) and temperature.

How do you calculate battery efficiency?

Efficiency is the sum of energy discharged from the battery divided by sum of energy charged into the battery (i.e., kWh in/kWh out). This must be summed over a time duration of many cycles so that initial and final states of charge become less important in the calculation of the value.

Can FEMP assess battery energy storage system performance?

This report describes development of an effort to assess Battery Energy Storage System (BESS) performance that the U.S. Department of Energy (DOE) Federal Energy Management Program (FEMP) and others can employ to evaluate performance of deployed BESS or solar photovoltaic (PV) +BESS systems.