AN INTRODUCTION TO BESS
What are THE benefits of a battery energy storage system (BESS)?
End users can have several benefits from an on-site battery storage system. BESS plays a key role in ensuring homes and businesses are powered by green energy, even when the sun isn’t shining or the wind isn’t blowing.
Moreover, electricity can be purchased at a time of day when it’s cheaper, then stored for later use.
BESS can be used as a buffer for large loads like EV fast chargers, without the need to upgrade the grid connection capacity or increase the contracted power (€/kW).
Finally, BESS allows organizations to access grid ancillary services contracts with the national grid operator by selling services like Unbalance, FCR (Frequency Control Regulation) and aFRR and generate significant (additional) revenue streams for their organization.
What battery size and configuration is the most optimal ?
When we talk about the size of BESS, we tend to think about three things, rated power, energy capacity and duration.
However, this can be quite confusing, as the term capacity is often used interchangeably with rated power. To make the picture more clearer, imagine a bucket with two pipes, one at the top and the other on the bottom.
- The amount of water the requisite pipe can let in or out instantly, represents the rated power (in kilowatt or kW)
- The amount of water that the bucket can hold represents the capacity (in kilowatt-hour or kWh)
- The amount of time it takes for that bucket to empty or fill up represents the duration (hours / or how many hours the system can run on a charge).
For residential BESS, there are some rules of thumbs to use for battery sizing. It is primarily about single or three phase loads, although the smart energy meter in the Netherlands flattens the loads over the phases (pls. see this interesting article on that subject) and about the load usage profile during day and night.
However, for commercial and industrial applications, we definitely recommend to apply for professional help. There are more variables, everything needs to be technically matched and a larger investment is at stake.
