How exactly are you paid?
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You fund and own the hardware. We deliver it as a one-stop service: sourcing, installation and commissioning. From then on we charge a performance fee: a share of the savings CESS produces, measured against your baseline and billed monthly. The share is set per site when we agree the baseline, so ask us and we will talk you through how it is worked out. There is no fee in a month with no saving to share, which is the whole point: our revenue and your return move together.
Who owns the battery, and who maintains it?
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You do. You fund it, it sits on your balance sheet, and it stays yours. We procure and install it, then operate and monitor it: dispatch optimisation, cell-health tracking, reporting. Procurement and installation are charged at cost plus a stated margin, and we show that margin as its own line in the model instead of burying it in a system price.
What happens if the savings underperform the model?
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We earn less, in direct proportion. Because our fee is a share of measured savings against an agreed baseline, an underperforming system cuts our revenue before it costs you anything. The feasibility model also states its assumptions explicitly (tariff structure, load profile, degradation curve), so when reality diverges you can see which assumption moved, and we report against the original model each month. We do not quietly replace it with a new one.
Will CESS work with the inverters we already have?
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Usually. CESS is a software layer that reads your existing inverter, meter and PV telemetry and sends dispatch commands back. Our pilot runs against Huawei FusionSolar and Deye equipment. If your hardware exposes a usable interface we can almost certainly work with it, and we confirm this during the feasibility stage, before you have signed anything.
Does installation disrupt production?
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Commissioning is scheduled around your production calendar. The battery sits alongside your existing supply, not in series with it, so the tie-in window is short and planned with your maintenance team rather than imposed on it.
Do we need solar installed already?
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No. Peak shaving and tariff arbitrage work on grid supply alone. But existing solar makes the case considerably stronger. Recovering curtailed generation is the largest single saving we have measured so far, and if you have an array that clips at midday or overproduces at the weekend, that is money already on your roof.
What if we stop paying the CESS fee?
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The hardware remains yours and keeps working. It reverts to conventional rule-based control. What you lose is the forecasting and optimisation layer, which is where most of the return in the model comes from. Since the fee is a share of savings, stopping it also means there were no savings to share, which is a conversation worth having before it gets that far.
What's the expected battery life, and what does replacement cost?
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The battery supplier projects a 15-year life. We model on 12 years, deliberately shorter, and your feasibility report states that life, the degradation curve and an end-of-life provision for replacing the cells. Payback is a separate figure: how long the savings take to repay what you invest, and the report states that too. A model that counts savings over many years without setting money aside to replace the cells is not a model worth acting on.
Does this qualify for BOI privileges?
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Energy-efficiency capital investment can attract BOI privileges, which changes the after-tax return meaningfully. Eligibility depends on your promotion status and the specific investment, so we flag it in the feasibility model and recommend confirming it with your own tax advisor rather than taking our word for it.