BESS net revenue in Ukraine: charging costs, losses and working capital

Start with energy at a consistent boundary

State whether energy is measured at cells, inverter terminals or the commercial connection point. For an AC-to-AC round-trip efficiency of 90%, delivering 4 MWh requires 4 / 0.90 = 4.444444 MWh of input, under the assumed operating conditions. If auxiliary loads are already included in that efficiency, do not subtract them again. If they are outside it, budget them separately.

Usable energy, directional grid limits and reserved service capability constrain the schedule. A revenue model cannot sell an unrestricted arbitrage cycle while promising the same power and energy to another incompatible obligation. Keep degradation and augmentation funding visible even where no replacement invoice is due today.

Build the cost map before importing prices

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Article 30-1 must be read with section II, points 1 and 4 of Law 4834-IX. As at 31 October 2026, the temporary wording of part 8 calculates transmission, distribution and dispatch-service charges on the absolute difference between monthly storage import and export, at the relevant tariffs and under the applicable codes/rules. It counts external-network flows at the connection point(s). The replacement provisions identified there commence on 1 May 2027. The temporary wording also contains a separate commissioning qualification for pumped storage; do not transfer that qualification to an ordinary battery by analogy. Establish the actual configuration, service and invoicing period before applying a rate. A monthly volume basis is not automatically a separate fee on each arbitrage cycle. The example below uses an invented cash amount rather than a statutory tariff calculation.

Section VI of the Market Rules addresses financial guarantees for relevant balance-responsible parties and permits defined forms, including cash and bank guarantees. This is distinct from chapter 2.2 of the day-ahead/intraday rules, which provides for escrow arrangements and sufficient funding for submitted purchases and Market Operator services, including the relevant VAT amounts. Map both regimes only where they apply to the chosen route; do not assume every battery posts identical security twice.

A synthetic one-cycle operating calculation

Assume a 2 MW battery can deliver 4 MWh usable AC energy at the commercial boundary, with 90% AC-to-AC efficiency. The stated grid limits permit the schedule; there are no competing reserve obligations or initial stored energy. Each interval lasts one hour. Prices and every cost below are invented educational inputs. Amounts exclude VAT solely to isolate the arithmetic; a real funding model must use actual tax-inclusive payment timing.

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The unrounded input total is 40/9 MWh. Charging cost is UAH 7,838.89; sales are UAH 19,000.00; energy contribution is UAH 11,161.11. The charging powers remain below 2 MW and the two discharge intervals use the 4 MWh deliverable capacity. This is a feasible arithmetic schedule under its assumptions, not proof that those prices could have been secured in advance.

Assume further cash operating costs of UAH 1,800 for network/dispatch, 400 for imbalance, 600 for the trading route and 250 for maintenance. Their total is UAH 3,050. The operating cash contribution before tax, debt service and CAPEX is therefore UAH 8,111.11. Earmarking another UAH 600 for future lifecycle work leaves UAH 7,511.11 available under this management policy. The reserve is separately identified; it is not automatically an accounting expense or a supplier payment.

Calculate peak funding from the payment calendar

Now assume UAH 25,000 of separate cash security is locked on day 0, charging and operating costs are paid on day 1, sales are collected on day 3 and security is released on day 4. These timings and the security amount are invented, not statutory requirements.

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Peak initial funding is UAH 35,888.89 before a contingency buffer, even though the cycle contributes UAH 8,111.11. Returning security is recovery of restricted cash, not another revenue stream. In a continuing operation security might remain locked; delayed settlement, additional calls and subsequent charging cycles can increase the peak requirement. A bank guarantee can change the cash pattern but introduces fees, credit availability and possibly its own collateral.

Underwrite repeatability rather than a perfect historical spread

The Market Operator's published hourly results, consulted on 31 October 2026, provide a dated public price reference. They are not the invented prices above and do not establish an individual battery's executions. A backtest needs a preserved dataset, time-zone treatment, bidding assumptions, forecast information available at the decision time, losses, outages and actual commercial constraints. Selecting the cheapest and most expensive hours after the event is an upper-bound exercise, not a trading forecast.

Request downside cases with weaker selling prices, more expensive charging, lower efficiency, delayed receipts and higher security requirements together. Reconcile the resulting cash deficit to committed funding and the actual lender covenants. For an acquisition, keep seller consideration, completion CAPEX and this operating liquidity as separate uses of funds.

Read the BESS diligence guide, revenue compatibility framework and bankability assessment. Discuss your mandate with the net-cash and liquidity assumptions your investment committee needs to test.