Structuring tool

BESS financing comparison

Merchant vs tolling vs insured revenue floor, per MW of battery. Rapid Venture Lab, July 2026. Figures in €k.

How to use this (read once, takes 2 minutes)

The story. A battery earns money every year, but nobody knows exactly how much, good years and bad years. Banks hate not knowing, so they lend little and charge a lot. The owner has three doors. Door A, merchant: keep every euro the battery earns, accept expensive small loans. Door B, tolling: a trader guarantees fixed payments and takes the battery's marketing over, banks are happy, but the trader keeps roughly a quarter to a third of the value forever. Door C, the floor: someone guarantees only a minimum, the owner keeps everything above it, pays a yearly premium and gives away a small slice of the good years, and the bank lends against the guaranteed minimum.
What the bars show. The three bars on the right are the same battery behind each door. The main view is return on equity: how hard each euro of the owner's own money works per year. Taller bar wins. Use the buttons under the chart to switch to net cash or to MW built per €1M of equity.
Where to start. Touch nothing first. The defaults are a real German project. Look at the bars: door C usually wins because the bank lends much more against a floor, so the owner puts in far less of their own money for the same battery.
The real game is two sliders. In real life everything is known except the price of the guarantee: the premium and the upside share. Drag the premium up slowly and watch bar C sink and the pills flip red. The premium where C stops winning is the most any counterparty can ever charge before the whole idea dies. That number is what we are negotiating around.
The two safety pills. The bank pill checks: even in the worst guaranteed year, do the loan payments still fit with room to spare? The sponsor pill checks: does our safety net cost less than the toller's cut? Both must stay green or the deal doesn't happen, and the verdict box always tells you which slider to move when one turns red.
One scary experiment. Drag expected revenue down toward 80. Watch everything break no matter what else you do. That's the market getting saturated over time, and it's why this product has a time window.

The project

The battery itself. Defaults: a real 2-hour German commercial project, 2026.

Expected revenue per MW per year€120kWhat the asset earns from trading before any financing. Everything else must fit inside this number.

Capex per MW€440kTurnkey build cost. More capex means more equity or more debt for the same revenue.

Opex per MW per year€6kRunning costs. Comes off the top behind every door.

The floor deal (door C)

The three prices of certainty. Higher floor = more debt possible but pricier guarantee. More upside share = lower premium but less of the good years kept.

Floor level, % of expected revenue50% = €60kThe guaranteed minimum. Floors are typically written around 50%: cheap to guarantee, still carries real debt.

Premium per MW per year€6kThe yearly price of the guarantee. THE unknown until a counterparty quotes. Drag up to find where the deal dies.

Upside share above floor20%The guarantor's slice of everything above the floor. Trades against the premium.

Arranger recurring fee€2kOur yearly fee for structuring and managing the pool. A one-off structuring fee (1.5% of debt over 7 years) is added automatically.

Bank terms

Debt with and without the floor. The gap between these rows is half the reason the floor exists.

Merchant: leverage35%Share of capex a bank lends against uncertain revenue. Reference: 37% offered on a live merchant project, plus a cash sweep (sweep not modeled, so reality is worse than shown).

Merchant: interest rate, 7y8.5%Reference: 8-9% for 7 years quoted on a merchant BESS in 2026.

With floor: leverage80%Share of capex lent when revenue is floored. Target structure; not yet confirmed by a bank against an actual floor.

With floor: interest rate, 10y5.25%Target from a live project plan; 10-year tenor confirmed available where revenue is secured.

The alternative (door B)

Tolling take, % of revenue28%What the toller effectively keeps for fixed payments. Market experience: 25-30%. The benchmark door C must beat.

Same battery, three doors

29.3%

38.9%

53.5%

Amerchant

Btolling

Cfloor via us

Bank: DSCR at floor 1.2 ✗ floor too low for this debtSponsor: certainty €20.8k vs toll €33.6kC vs A: 53.5% vs 29.3%C vs B: €47.1k vs €34.3k

Verdict

Bank not covered: the floor (€60k) minus opex covers loan payments only 1.2 times; banks want 1.25. Raise the floor slider (costs premium) or lower the with-floor leverage (costs equity efficiency).

	A	B	C
Owner equity €k/MW	286	88	88
Debt service €k/yr	30.1	46.1	46.1
Cost of certainty €k/yr	0	33.6	20.8
Net cash to equity €k/yr	83.9	34.3	47.1

Method, assumptions and sources

Bank test: (floor − opex) must cover annual debt service 1.25 times (standard DSCR cushion). Sponsor test: total certainty cost behind door C (premium + expected upside share + arranger fees) must be lower than the tolling take behind door B. Upside-share cost approximated as share × (expected revenue − floor): slightly overstated in good years, understated in bad ones; fine for comparing structures, not for signing term sheets. Tolling assumed to reach the same leverage as the floored case. Merchant case ignores cash-sweep clauses.

Default sources: revenue and capex from a live 3.4 MW German project teaser (July 2026); merchant leverage from a quoted bank offer (37% of capex plus 50% cash sweep); merchant rate from a quoted 8-9%, 7-year offer; floored-case terms from the same project's target structure (unconfirmed by a bank against an actual floor); tolling take from operator experience across 2026 negotiations. Premium and upside share are deliberately unknown: they are what a counterparty quote fills in.

Built by Rapid Venture Lab as a structuring aid. Not financial advice; all figures are scenario inputs, not offers.