Warehouse rooftop solar: how much to install, how much will it save?
Enter roof area and daytime electricity load — the tool calculates installed capacity, output from EVN sunshine data for each region, self-consumption, surplus power and electricity cost savings under the EVN tariff.
What the model calculates, and what it doesn't
Capacity = available roof area × installation density. Output based on the theoretical PVout figures published by EVN in 2026 for each region (kWh/kWp/year). Every 15 minutes, the power generated is compared with the daytime load: the smaller of the two is self-consumption, the excess is surplus. Savings = self-consumed electricity × EVN rate for the correct time band (industrial or commercial, by voltage level).
Not calculated: revenue from surplus power sales (Decree 135/2024/NĐ-CP allows selling up to 20%), dust and heat losses, annual panel degradation, seasonal variation, roof structure inspection, maintenance. The investment cost is entered by you from a quote — the tool does not assume equipment prices.
Frequently asked questions
Is rooftop solar worth installing on warehouses in northern Vietnam?
The theoretical output announced by EVN for Hanoi, Hai Phong, Hung Yen is about 900 kWh/kWp/year, about 35% lower than Ho Chi Minh City. It may still be worth it if the daytime load absorbs all the electricity generated — the tool shows self-consumption rates and savings at EVN prices.
Why isn't covering the whole roof necessarily worthwhile?
Surplus power that is not self-consumed can only be sold up to 20% under Decree 135/2024/NĐ-CP, at a low price. When the daytime load is small relative to the roof, most of the added capacity becomes surplus.
Can solar power reduce peak electricity bills?
Very little. EVN's peak hours are currently 5:30 p.m.–10:30 p.m., when there is no sun. Solar mainly displaces normal-hour electricity; reducing peak-hour cost requires storage or load shifting.
Have real project parameters? Send them to CGD and get feedback on the design scope
This simulation stops at the principle. For a specific project, CGD builds the model on real operating data and floor plan drawings.
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