In 2020 more than 100.000 battery systems are installed in German households alone. This indicates a steep increase in battery usage in combination with PV systems.

What is a BESS actually?

A BESS is a compound system comprising hardware components along with low-level and high-level software. The main BESS parts include:

• A battery system. It contains individual battery cells that convert chemical energy into electrical energy. The cells are arranged in modules that, in their turn, form battery packs.
• A battery management system (BMS). A BMS ensures the safety of the battery system. It monitors the condition of battery cells, measures their parameters and states, such as state-of-charge (SOC) and state-of-health (SOH), and protects batteries from fires and other hazards.
• An inverter or a power conversion system (PCS). This converts direct current (DC) produced by batteries into alternating current (AC) supplied to facilities. Battery energy storage systems have bi-directional inverters that allow for both charging and discharging.
• An energy management system (EMS). This is responsible for monitoring and control of the energy flow within a battery storage system.  An EMS coordinates the work of a BMS, a PCS, and other components of a BESS. By collecting and analyzing energy data, an EMS can efficiently manage the power resources of the system.

In sum, a BESS collects energy from an electricity grid or renewable power sources, such as solar and wind, and stores it using battery storage technology. Then, batteries discharge and release the energy when necessary—during peak demands, power outages, and in a variety of other applications.

One of those applications is feeding the power back to the grid. This seems like an uncomplicated process but this is exactly where there is a lot of revenue to be made. This has all to do with the fluctuating prices of electricity per hour, or even per minute. Energy is traded on several European trading platforms and if you have enough KWs or MWs.

Because renewable energy only produces energy when the sun shines or when the wind blows. And the market is a traditional market where supply and demand dictate the price. On most exchanges prices of tomorrow are defined today. So on a windy and sunny day around 2.30 PM there is a lot of supply and very little demand. The prices drop radically. The same goes for other moments of the day when there is high supply and low demand. If you can store your energy and supply it to the grid at the highest price a revenue increase of 20-30 percent is not out of the ordinary.

The next step for even more efficiency is to manage your power consumption so you use power when the price is low. This way you don’t occupy battery storage. As you can imagine this is a process of continuous calculations for this power management. There are several companies out there that can assist you with this challenge.