BESS-Market
Tool 03

ROI Calculator

The ROI Calculator models the economics of your storage project: CAPEX and OPEX against a revenue stack of balancing services (FCR, aFRR, mFRR), arbitrage (day-ahead, intraday) and peak shaving. From this it derives IRR, NPV, payback, DSCR and the levelized cost of storage — in base, optimistic and pessimistic scenarios.

Price assumptions are indicative market averages for Germany (as of 2025/2026). You can adjust every input to your project assumptions; the calculation runs locally in your browser.

How it works

  1. 01

    Enter project parameters: CAPEX, OPEX, WACC, lifetime, degradation, efficiency.

  2. 02

    Select revenue streams: balancing services, arbitrage, peak shaving — with risk flags.

  3. 03

    Optionally add debt: leverage, interest rate and tenor for the DSCR view.

  4. 04

    Read the result: scenarios, key metrics, revenue breakdown and sensitivity to WACC and revenue level.

01Project parameters
02Select revenue streams
03Debt (optional, for DSCR)
04Scenarios
Pessimistic (−30 %)
Revenue per year
€ 501 k
NPV
€ -4.44 M
IRR
-3.7 %
Base
Revenue per year
€ 716 k
NPV
€ -2.60 M
IRR
2.0 %
Optimistic (+30 %)
Revenue per year
€ 931 k
NPV
€ -758 k
IRR
6.4 %

Key metrics (base scenario)

OPEX per year
€175,000
Payback
15.8 years
LCOS
26.3 €/kWh
Revenue streams
3 of 6

Revenue breakdown

FCR (primary reserve)
€280,000
39 %
aFRR (secondary reserve)
€180,000
25 %
Day-ahead arbitrage
€256,000
36 %

Sensitivity — NPV

WACC ±2 pp
−2 pp
€ -1.94 M
Base
€ -2.60 M
+2 pp
€ -3.13 M
Revenues ±15 %
−15 %
€ -3.52 M
Base
€ -2.60 M
+15 %
€ -1.68 M

Indicative calculation based on average market prices. Balancing prices are historically volatile; actual revenues depend on marketing strategy, grid region and dispatch.

Methodology and scope

Scenarios stress revenues by ±30 %. Revenues scale with remaining capacity (degradation). DSCR is computed from annual pre-debt cash flow against annuity debt service. All values are indicative and do not replace a bankable revenue report.

Next step

Start your project or talk to us — we will connect you with the right contact.