Battery energy storage systems (BESS) are being discussed as a way for renewable generators in the Western Balkans to deliver more predictable electricity export profiles to the European Union. The EU Carbon Border Adjustment Mechanism (CBAM) adds an additional layer of requirements when electricity is shifted between hours. Charging a battery from a renewable installation does not, on its own, establish that electricity discharged later can receive actual-emissions treatment as an import from that installation.
Dispatch flexibility and balancing services
Batteries can absorb midday solar generation, reduce imbalance penalties and support more stable export schedules. When installed alongside renewable generators, BESS can respond to changes in electricity nominations faster than generation assets operating without storage.
These services may improve the commercial performance of merchant projects and power purchase agreements (PPAs) without creating any additional CBAM-related advantage. Operational flexibility still needs to be separated from evidence that supports the actual emissions associated with qualifying imported electricity.
Electricity evidence files and allocation of energy origin
For CBAM purposes, 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. The documentation needs to cover how energy flows are treated across these steps.
Where a battery charges partly from an on-site solar installation and partly from the grid, operators need a transparent methodology for allocating the different energy sources. Whether that methodology is acceptable for CBAM claims is assessed against 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.
Solar-plus-battery example highlights accounting separation
A co-located 100 MW solar plant and 50 MW battery illustrates how accounting risks can arise. In one hour, the solar installation generates 80 MWh, sends 45 MWh directly to the market and charges the battery with 25 MWh, with remaining generation accounted for by losses and other uses.
Two hours later, the battery discharges 22 MWh. The charging energy and subsequent discharge are separate physical events, and the difference reflects losses or other storage-related accounting factors.
The operator must ensure that the original 25 MWh is not allocated at the same time to direct PPA delivery and to the battery’s later discharge. A robust ledger should identify each charging source, time interval and discharge quantity, assigning energy only once while recording associated losses.
Contract terms for metering and dispatch control
PPA contracts should specify the location of revenue meters and whether the battery and generator are treated as one or multiple relevant installations. Contracts also need to define which party controls charging and how stored electricity may be used by the trader.
Battery dispatch decisions can affect contractual delivery profiles. Operating a BESS to capture balancing-market revenue may conflict with a promised PPA schedule.
Where a battery can charge from the grid, the EU importer needs information on when discharged electricity falls outside the volume attributed to the installation covered by an emissions claim under CBAM.
Financing models separating storage revenues from CBAM premiums
Battery financial models should separate revenue streams tied to balancing services, intraday arbitrage, capacity and delivery-profile firming where available under local market rules. Any additional premium based on CBAM qualification should be tested under a downside scenario rather than included automatically in base valuation.
Lenders also need to account for battery augmentation requirements, degradation and round-trip energy losses when assessing long-term returns. These factors affect project economics independently of how CBAM claims are supported by energy-origin records.
Contract structures for limiting CBAM claims
One contractual approach 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 structure aims to reduce disputes over energy origin while preserving operational flexibility provided by storage.
More complex arrangements involving storage-backed qualifying exports may emerge as market participants, regulators and verifiers establish acceptable accounting and verification approaches. Under such structures, additional value under CBAM depends on whether energy-origin records can withstand rigorous hour-by-hour verification.