Siemens has entered the important and quickly-growing large-scale battery storage market with a new modular design that lets utilities scale up as needed.
The Siestorage lithium-ion battery system starts at 16kWh of storage and can be scaled up to 2 MWh of storage. The 500 kWh unit is small enough to fit into a normal shipping container and can store the daily average energy consumption of 50 households. The system includes a power inverter and controller that connects the system to the grid. It has a maximum power output of 8 MW.
When renewable power sources get connected to the grid, the fluctuations in power generation can be a problem for grid stability. A solar array's output fluctuates not just between day and night, but between sunny and cloudy. Wind speed changes throughout the day. So, having a reliable back-up to balance power loads during lag times is crucial for growing renewable energy in the grid.
Hawaii has been one of the first adopters of large-scale battery storage, using battery systems from Xtreme Power to back up two of Oahu's wind farms. Islands are especially good candidates for this type of power storage because they operate smaller independent grids that are more vulnerable to the problems that renewable energy fluctuations could cause.
Siemens has already installed a 500 kWh system with Italy's largest energy company Enel. The utility is using the power storage to help integrate solar PV plants and an electric car charging station into the grid.