The gross revenue generated by a standalone battery (standalone BESS) on the imbalance market is comparable to that of a local battery installation (embedded BESS). However, standalone BESS enjoy significant exemptions from grid costs. As a result, the net revenues for a standalone BESS can be higher. A standalone battery is therefore certainly an interesting investment if your company has a new or unused grid connection available.

Similar turnover on the imbalance market

The basic principle of a standalone battery is exactly the same as that of local battery storage: purchase energy at an attractive (low) price and sell it at a high price.

The big difference in control lies, of course, in the origin and destination of this energy. A standalone battery is used 100% to purchase energy from the grid at a favourable price and feed it back at the right moments. Standalone batteries therefore work 24/7 to stabilise the electricity grid.

Embedded BESS are also used for local optimisation: surpluses from local production are stored in the battery and at other times the battery supplies energy to the business site at a favourable price. This avoids grid costs: a second important revenue stream.

The revenue that standalone BESS generate in the imbalance market is, in most cases, similar to the revenue generated by an embedded battery. Because their control is entirely focused on grid stabilisation, standalone batteries are 100% dependent on market conditions. Embedded BESS are more diversified in this respect, due to the combination of local optimisation and imbalance control.

Lower grid costs due to specific exemptions

In Flanders, within the Fluvius network, the following advantages apply to standalone BESS:

  • Volume-based grid tariffs (EUR/MWh), such as public service obligations, are not charged

  • 80% exemption on the part of the grid tariffs that goes to the transmission grid

    • On average, this results in a 40-45% discount on capacity-based tariffs for peak consumption (EUR/kW/month) and access (EUR/kVA/month)

    • Given that these capacity tariffs carry significant weight, this represents a considerable discount

For a standalone BESS project on the Fluvius distribution network, grid costs currently amount to approximately €60,000 per MW per year, thanks to these exemptions. Without the benefits, this would amount to around €80,000–90,000 per MW per year.

The current exemptions are valid from 2025 to 2028, but they are expected to be extended in the coming years. This is because BESS connected to the Elia grid are subject to a 10-year exemption. An extension is therefore likely.

At present, the exemptions only apply to standalone BESS behind the main meter. For installations behind a sub-meter, there is no official recognition as “standalone”.