Battery energy storage systems (BESS) could help Western Balkan renewable generators deliver more predictable electricity export profiles to the European Union. However, shifting electricity between hours introduces additional requirements for tracking energy origin under the EU Carbon Border Adjustment Mechanism (CBAM). Charging a battery from a renewable installation does not, by itself, establish that electricity discharged later can qualify for actual-emissions treatment as an import from that installation.
Storage Improves Dispatch Flexibility and Balancing
Battery systems can absorb midday solar generation, reduce imbalance penalties and support more stable export schedules. Batteries installed alongside renewable generators can also respond to changes in electricity nominations more quickly than generation assets operating alone.
These services may improve the commercial performance of merchant projects and power purchase agreements (PPAs), independently of any additional CBAM benefit. Operational flexibility, however, must be distinguished from evidence demonstrating the actual emissions associated with qualifying imported electricity.
Energy Origin Requires Detailed Accounting
An electricity evidence file must distinguish between direct exports from a generating installation, battery charging, electricity imported from the grid, battery discharge, internal losses and electricity delivered across the EU border.
Where a battery charges partly from an on-site solar installation and partly from the grid, its operator needs a transparent methodology for allocating the different energy sources. Whether that methodology is acceptable for CBAM claims must be assessed against the applicable rules and the verifier’s interpretation. There is no general guarantee that discharged electricity automatically inherits the actual-emissions status of the original solar generation.
A Solar and Battery Example Illustrates the Accounting Risk
Consider a co-located 100 MW solar plant and 50 MW battery. During one hour, the solar installation generates 80 MWh, sends 45 MWh directly to the market and charges the battery with 25 MWh. The remaining generation is accounted for by losses and other uses.
Two hours later, the battery discharges 22 MWh. The original charging energy and the subsequent discharge represent separate physical events, with the difference reflecting losses or other storage-related accounting factors.
The operator must ensure that the original 25 MWh is not simultaneously allocated to direct PPA delivery and the battery’s later discharge. A robust ledger should identify each charging source, time interval and discharge quantity, assigning energy only once and recording associated losses.
PPAs Must Define Metering and Dispatch Responsibilities
Contracts should specify the location of revenue meters, whether the battery and generator are treated as one or multiple relevant installations, which party controls charging, and how stored electricity may be used by the trader.
Battery dispatch decisions can also affect contractual delivery profiles. For example, operating a BESS to capture balancing-market revenue may conflict with a promised PPA schedule. Where the battery can charge from the grid, the EU importer needs to know when discharged electricity falls outside the volume attributed to the installation covered by the emissions claim.
Project Finance Must Separate Storage Revenues from CBAM Premiums
Battery financial models should distinguish between revenue streams associated with balancing services, intraday arbitrage, capacity and delivery-profile firming, where these opportunities are available under local market rules.
Any additional premium based on CBAM qualification should be tested under a downside scenario rather than automatically included in the project’s base valuation. Lenders must also account for battery augmentation requirements, degradation and round-trip energy losses when assessing long-term returns.
Direct Generation Claims Offer a Simpler Contractual Route
One possible contractual structure is to restrict the physical CBAM claim to directly metered eligible generation while using the battery for ordinary balancing and other electricity-market services. This approach reduces the potential for disputes over energy origin while retaining much of the operational flexibility provided by storage.
More complex arrangements involving storage-backed qualifying exports may develop as market participants, regulators and verifiers establish acceptable accounting and verification approaches.
Battery storage could become important infrastructure for regional electricity trading, with its immediate commercial value centred on operational flexibility. Additional value under CBAM will depend on whether the associated energy-origin records can withstand rigorous hour-by-hour verification.
