In the context of a Battery Energy Storage System (BESS), MW (megawatts) and MWh (megawatt-hours) are two crucial specifications that describe different aspects of the system's performance. Understanding the difference between these two units is key to comprehending the capabilities and limitations of a BESS. 1.
Energy Storage: MWh is used to describe the capacity of battery storage systems. For example, a 5 MWh battery system can store 5 megawatt-hours of energy when fully charged. Energy Consumption: MWh is also used to measure the energy consumption of large facilities, such as factories or data centers, on a daily or monthly basis.
Energy Capacity (MWh) indicates the total amount of energy a BESS can store and subsequently deliver over time. It defines the duration for which the system can supply power before recharging is necessary. For instance, a BESS with an energy capacity of 20 MWh can provide 10 MW of power continuously for 2 hours (since 10 MW × 2 hours = 20 MWh).
Power Capacity (MW) refers to the maximum rate at which a BESS can charge or discharge electricity. It determines how quickly the system can respond to fluctuations in energy demand or supply. For example, a BESS rated at 10 MW can deliver or absorb up to 10 megawatts of power instantaneously.
This can be compared to the output of a power plant. 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.
What is MW? MW is a unit of power that indicates the rate at which energy is generated or consumed by a system at any given moment. 1 MW equals 1,000,000 watts (W). Power, in this context, refers to the rate of energy conversion, such as how much energy a power plant can produce per hour or how much power an electric motor consumes while operating.