Battery Energy Storage Systems (BESS), Financial Model, Renewable Energy, Solar

Cash Flow Analysis, Dashboard, Debt Service Coverage, Excel, Financial Feasibility, IRR (Internal Rate of Return), NPV (Net Present Value), Project Finance, Revenue Projections, Scenario Analysis

Co-located solar and storage is now the default design for new European solar parks, because the battery earns the spreads that solar itself destroys. This model shows by how much, using real data instead of assumed spreads.

The model includes the full year of 2025 hourly day-ahead prices and the hourly shape of actual solar generation for eight European bidding zones (Germany-Luxembourg, Netherlands, Belgium, France, Austria, Poland, Czech Republic and Northern Italy). The solar plant and the battery share one grid connection. Every hour, the model values solar output at the real market price, applies the grid export limit and negative-price curtailment, and checks how much room the connection leaves for the battery. Every day, the battery charges in the cheapest eligible hours and discharges in the most expensive hours in which the grid has room next to the solar plant. It can absorb solar energy that would otherwise be curtailed or clipped, and you can restrict it to charging from solar only, as some subsidy and grid-connection rules require.

What you get

8,760-hour solar and grid simulation and 365-day battery dispatch on real prices
Solar capture price and capture rate, curtailed hours, energy lost to the export limit
Battery arbitrage with round-trip losses, variable O&M, degradation, augmentation and capture rate; optional ancillary services revenue
Switch for grid charging allowed / solar-only charging
Pay-as-produced PPA for the solar output plus merchant tail, route-to-market cost and guarantees of origin
Low / Base / High scenarios (market price trend, capture-rate drift, PV capex, battery capture rate, spread trend, battery capex)
Capex build-up for PV, battery, shared grid connection and development; O&M, insurance, lease, inflation; inverter replacement
Annuity debt with DSCR, corporate tax with loss carry-forward, depreciation
Project and equity IRR, NPV, payback, minimum and average DSCR, battery share of revenue
Dashboard with KPIs and charts, monthly profile of solar output, prices and battery revenue
Market comparison of all eight zones

Who it is for: developers adding storage to solar projects, investors and lenders comparing standalone and co-located designs, consultants and students.

Format: Excel (.xlsx), no macros, fully unlocked formulas, colour-coded inputs. Works in Microsoft Excel and LibreOffice.

Data sources: Energy-Charts.info (Fraunhofer ISE): day-ahead prices (Bundesnetzagentur | SMARD.de) and public net solar generation, both CC BY 4.0.

Limitations: one battery cycle per day on the day-ahead market; intraday and balancing markets are represented by a single ancillary input; the solar shape is the national fleet profile; 2025 is the base year for all future years. For planning purposes only, not investment advice.

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