The problem it actually solves
Typical scene: a park wants twenty fast chargers; the utility measures and replies that the existing transformer cannot carry them — reinforcement required. Reinforcement means not just a transformer but external line works, land and approvals; months of schedule and a bill starting in the hundreds of thousands of RMB. PV-storage-charging offers another road: no reinforcement — cut the peak with storage. The battery charges on cheap valley power at night and discharges into the chargers during the day, so the peak the transformer actually sees stays inside its rating.
Two conditions make the logic work: a meaningful peak-valley tariff spread, and a charging load with clear peaks and troughs. Where neither holds, storage only adds cost — and we will say so instead of selling hardware.
What the system consists of
| Component | Where | What it does | How to size |
|---|---|---|---|
| PV array | Rooftops, shelter roofs, spare ground | Self-consumption; offsets grid purchases by day | By installable area |
| Battery (LFP) | Cabinet or container | Charge at valley, discharge at peak; shave the load | By capacity gap and tariff spread |
| PCS converter | Next to battery | AC/DC conversion; sets power and response | Matched to battery |
| Chargers | Bays and shelters | The revenue-facing equipment | By dwell time and fleet mix |
| EMS | Cloud / edge | Decides when to charge and discharge | Strategy quality drives the return |
The EMS is the most underrated part. Identical hardware with a crude versus a carefully tuned strategy can differ by a wide margin in annual yield. Judge a proposal by whether it states its charge/discharge strategy in writing — not by the length of its equipment list.
Sites that fit
- Parks at capacity — the classic case; storage replaces reinforcement at a fraction of the price.
- Factories with roof or open land — PV self-consumption offsets expensive daytime purchases directly.
- Logistics yards and depots — fleets return at night; concentrated load curves give the storage strategy room to work.
- Malls and offices — charging overlaps air-conditioning peaks; with two-part tariffs, peak shaving saves demand charges too.
- Shelter retrofits — PV roof over charging shelters: shade and generation in one structure.
Revenue: three layers, not one
Peak-valley spread — buy at valley, discharge at peak; the steadiest storage income, provided the local spread is wide. Demand management — two-part tariff users pay a basic charge on maximum demand or transformer capacity; shaving peaks cuts it directly, often worth more than the spread in park projects. PV self-consumption — daytime generation feeds chargers and loads instead of grid purchases. And an honest footnote: batteries age. Cycle life, usable depth and eventual replacement are real costs — count them, or the payback will flatter the project. Get a feel for the numbers with the payback calculator before talking engineering.
Investment references and payback logic
Public industry ranges, not our quotation: storage pricing per watt-hour has fallen markedly in recent years but moves with the market — use current vendor quotes for anything real. PV module and mounting prices vary by roof type and reinforcement needs. AC and DC chargers differ by an order of magnitude in price; choose by dwell time, not by prestige. Civil works, cable trays, switchgear and protection are the line most budgets forget, and they take a real share of the total. Payback is driven by the tariff spread and daily cycles; wide spread and frequent cycling shorten it. All figures here are theoretical values under ideal assumptions — the survey and the signed proposal prevail.
Filing and grid connection
A PV-storage-charging project touches PV filing, storage interconnection and possibly reinforcement — three procedures that often outlast construction, so plan them first. Preparation: ownership proof, electricity account number, the last 12 months of load curves, and a site plan. Then: scheme design and interconnection application → utility review → equipment and construction → commissioning and metering. We assemble the dossier and deal with the utility, so the schedule does not slip on paperwork.