Anonymised Client Case
BESS Cluster for Distributed Industrial and Multi-Site Operations
How a mid-size company with distributed sites reached the 1 MW FCR minimum bid size by clustering smaller storage units, while reducing peak loads at each plant connection.
Client and Situation
Private mid-size company with 8 distributed sites in Germany (industry / retail network / logistics – anonymised). Per site: 250-630 kW grid connections, 80-300 kWp PV. Problem: individual sites are too small for stand-alone balancing reserve marketing (FCR minimum lot 1 MW). Peak loads vary per site, grid charges between EUR 8-25k/year per site. Previously self-consumption only, no market access.
BESS Cluster Sizing
Storage per site
from 100 kW
Capacity per site
300-600 kWh
Cluster total
≥ 1.2 MW / 2.4 MWh
Technology
LFP, IP55
Per site storage from 100 kW upwards, sized for local peak-load needs. Aggregation via central EMS and pool aggregator into a virtual 1.2+ MW cluster. Advantage over single large storage: lower CAPEX per unit, § 7g EStG eligible sizes per entity, decentralised resilience, no single grid bottleneck.
Multi-Use Marketing within the Cluster
FCR pool marketing
~EUR 50/MWh
Aggregation of all sites to 1 MW minimum lot. Pool aggregator handles bid strategy.
Per-site peak shaving
EUR 8-25k/year/site
Local peak reduction at the plant connection (StromNEV § 19).
Self-consumption optimisation
~EUR 30/MWh
Buffering PV surplus per site.
Selective intraday arbitrage
seasonal
EPEX SPOT at high spreads, orchestrated by central EMS.
Tax Optimisation – Cluster Advantage
- § 7g EStG IAB usable per site/entity (profit cap EUR 200,000 each) – clustering maximises IAB volume vs. a single large unit.
- Special depreciation 40 % per site in year of acquisition + 4 following.
- Electricity tax exemption per site via Hauptzollamt registration.
- Across 8 sites at EUR 80-150k investment each: total tax shield in the EUR 250-400k range over 5 years.
Outcome
- Cluster of 8 storage units with virtual 1.2 MW capacity successfully placed in the FCR market.
- Peak shaving per site EUR 8-25k/year, cluster sum ~EUR 120k/year.
- Blended yield FCR + peak shaving + self-consumption consolidated ~EUR 80/MWh.
- Payback projected ≤ 7 years through aggregated tax benefits.
- Scaling potential: further sites can join the existing pool seamlessly.
Risks and Sensitivities
- Pool aggregator dependency: contract terms on yield distribution, exit options.
- Communications infrastructure: stable connection of all sites to central EMS (4G/fibre redundancy recommended).
- Market design risk: TSO adjustments to the FCR market possible.
- Site disparity: load profiles, PV ratios and grid charge structures vary per site – individual sizing rather than uniform hardware recommended.