Revenue by Configuration
The revenue opportunities of a battery storage asset depend critically on its regulatory configuration. Standalone storage, EEG green storage, hybrid models and wind/solar plants have different market access — with direct implications for achievable returns.
Wind or Solar Standalone
Standalone RE asset without co-located storage
A standalone wind or solar plant without an attached battery storage generates revenues primarily through direct marketing on the spot market or fixed feed-in tariffs under EEG. Dispatch follows the generation profile — no flexibility through storage. Innovation tenders enable co-located storage to be added as a follow-on project.
Direct Marketing EEG
| Revenue Stream | Description | 2020–2025 | 2025–2030 | 2031–2040 |
|---|---|---|---|---|
| Direct Marketing (Market Premium) | EEG market premium on top of spot market revenues — basis for assets ≥ 100 kWp | ~70 % | ~60 % | ~45 % |
| Feed-in Tariff | Fixed EEG tariff for existing assets below the direct marketing threshold | ~20 % | ~10 % | ~5 % |
| Innovation Tender | Support for innovative RE concepts — co-location with storage eligible | ~10 % | ~30 % | ~50 % |
Shares of total revenue — illustrative, not binding.
Direct Marketing without EEG
| Revenue Stream | Description | 2020–2025 | 2025–2030 | 2031–2040 |
|---|---|---|---|---|
| Day-Ahead | Daily spot auction for the next day — peak/off-peak spread | ~65 % | ~60 % | ~55 % |
| Intraday | Continuous trading until shortly before delivery — short-term price spikes | ~35 % | ~40 % | ~45 % |
Shares of total revenue — illustrative, not binding.
No storage revenue streams (FCR, aFRR). Revenue potential increases significantly when storage is co-located — then Green or Grey Co-Location applies.
Standalone BESS
Full market access, no charging restrictions
A pure grid-connected storage asset without co-located generation has unrestricted access to all energy markets. The asset can charge from the grid at any time — independent of generation patterns. This enables maximum cycle utilisation and optimal dispatch across FCR, aFRR, intraday and day-ahead.
| Revenue Stream | Description | 2020–2025 | 2025–2030 | 2031–2040 |
|---|---|---|---|---|
| FCR | Symmetric frequency containment reserve — weekly auctions | ~55 % | ~35 % | ~20 % |
| aFRR | Automatic frequency restoration — availability and activation revenues | ~25 % | ~30 % | ~30 % |
| Intraday | Short-term arbitrage on price spikes in continuous trading | ~15 % | ~25 % | ~35 % |
| Day-Ahead | Peak/off-peak spread as complement to FCR/aFRR stack | ~5 % | ~10 % | ~15 % |
Shares of total revenue — illustrative, not binding.
Highest revenue potential per MW — regulatory constraints from FCAs and ramp-rate requirements still apply.
Green Co-Location
EEG storage — charging exclusively from co-located generation
A green storage asset under EEG regulation charges exclusively from the co-located renewable generation plant (PV or wind). This restriction limits market access: when there is no generation, no charging capacity is available. Dispatch is therefore coupled to the generation profile — with corresponding effects on participation in markets requiring continuous availability.
| Revenue Stream | Description | 2020–2025 | 2025–2030 | 2031–2040 |
|---|---|---|---|---|
| EEG Optimisation | Generation surpluses are buffered and marketed with revenue optimisation | ~40 % | ~35 % | ~30 % |
| Intraday | Spot arbitrage within the generation window — limited charging capacity | ~20 % | ~30 % | ~38 % |
| FCR | Restricted — charging capacity only available during active generation | ~25 % | ~20 % | ~17 % |
| aFRR | Discharge always possible; charging only when generation is active | ~15 % | ~15 % | ~15 % |
Shares of total revenue — illustrative, not binding.
Lower revenues than standalone due to restricted charging flexibility — may be partially offset by reduced grid fees and EEG optimisation.
Grey Co-Location
Charging from grid and co-located generation
A hybrid grey storage asset can charge from both the grid (grey power) and the co-located generation plant. This combination enables significantly more flexible dispatch than pure green storage — while still utilising co-located generation. Grid fees apply for grid charging; the revenue structure approaches that of standalone BESS.
| Revenue Stream | Description | 2020–2025 | 2025–2030 | 2031–2040 |
|---|---|---|---|---|
| FCR | Full participation possible — grid charging secures state of charge at all times | ~45 % | ~30 % | ~18 % |
| aFRR | High availability through combined charging sources | ~22 % | ~28 % | ~27 % |
| Intraday | Arbitrage without dependency on generation window | ~22 % | ~30 % | ~40 % |
| Day-Ahead | Peak/off-peak spread as stack complement | ~11 % | ~12 % | ~15 % |
Shares of total revenue — illustrative, not binding.
Higher revenue potential than Green Co-Location. Grid fees for grid charging reduce net revenue — project-specific calculation required.
Constraints & Cost Factors
FCAs — Frequency Containment Agreements
FCAs regulate the simultaneous provision of FCR and aFRR (stacking). The rules limit how much aFRR capacity a storage asset may offer while simultaneously providing FCR. Depending on the configuration, FCAs can reduce the combined revenue stack by up to −41%. Catalyst models FCAs project- and control-zone-specifically directly within the dispatch optimiser.
Ramp Rates
FCR requires full power delivery within 30 seconds of a frequency deviation. Grid connection conditions may specify maximum power gradients (MW/min) that prevent full FCR participation or limit the bid capacity. Ramp-rate restrictions are site-specific and must be verified in the grid connection agreement.
Grid Fees — Netzentgelte
Grid fees consist of energy and capacity price components and vary significantly by grid level and network operator. Relevant for storage: the capacity-based grid fee structure and the AgNes surcharge. Grey storage assets (grid charging) are generally subject to full grid fees; certain storage exemptions apply under § 118 EnWG.
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