By Vvon Engineering Team | Published | Updated
How quarterly net-metering credit, direct consumption and AC capacity limits shape a Bangladesh rooftop solar financial model.
Solar EPC & street lighting RFQ checklist (TXT)
For a factory, hospital or university with a suitable roof, rooftop solar can reduce purchased daytime electricity. The financial result depends on the site's demand, generation, connection and tariff assumptions, together with the installed cost and ongoing expenses. A useful net-metering assessment makes those assumptions visible instead of promising to lock in the total electricity bill for 25 years.
This guide addresses project economics: daytime demand, generation assumptions and export-credit sensitivity. Use the separate application guide for the official portal and submission process. Related reading: Net Metering Application in Bangladesh: Documents and Utility Steps.
The 2025 guideline defines system capacity using aggregate inverter AC output. Clause 3.3 limits AC output to sanctioned load and, for medium- to extra-high-voltage consumers, to 80% of the transformer or parallel-transformer rated capacity. These are not direct limits on module DC kWp. Confirm the proposed design and any applicable additional conditions with the utility.
Under clauses 3.4–3.5 of the 2025 guideline, billing credits are reconciled quarterly after March, June, September and December. The guideline deducts 10% of net exported electricity as a distribution maintenance charge before crediting the remaining 90%. Residual settlement uses the applicable BERC bulk rate; fixed charges can remain. Check the signed agreement and current utility billing implementation when modelling value.
The value of a proposal depends on the share of generation consumed on site and the treatment of exported energy. Plants with the same installed capacity can have different generation and returns because of site conditions, downtime and demand. Ask the contractor to show the expected self-consumption and exports month by month, with the applicable tariff and settlement assumptions stated separately.
Read the demand-charge basis and integration interval on the applicable tariff. Charges can involve contracted capacity, measured demand or minimum floors. Model PV against those rules; energy generation does not by itself establish a demand-charge reduction.
Use a location-specific resource dataset and a surveyed layout. Roof area per kWp varies with module dimensions, walkways, fire access, tilt and shading. Do not use one national generation figure or module brand tier as a substitute for a yield assessment.
| Input | Evidence needed | Why it matters |
|---|---|---|
| Consumption | Twelve months of bills and representative interval demand | Separates direct use, exports and changing demand. |
| Generation | Location, layout, weather dataset and loss assumptions | Estimates output month by month. |
| Connection | Sanctioned load, transformer and utility requirements | Establishes eligible capacity and approval conditions. |
| Installed cost | Dated itemised quotation and exclusions | Includes roof work, connection and commissioning. |
| Operating cost | Maintenance, insurance and replacement assumptions | Avoids treating later electricity as cost-free. |
The feasibility assessment should identify the limiting roof, electrical and utility conditions before final capacity is quoted. Agree which survey, drawings and calculations form part of the proposal.
Check both sanctioned capacity and physical constraints early. A load revision may be possible but requires utility approval and may change charges; do not assume it will unlock a particular array size.
The roof gives you a ceiling. The load curve gives you the answer. Take twelve months of bills, get daytime consumption between roughly 9am and 4pm from your energy meter or a temporary logger, and compare it against the generation profile of the proposed array. Facility types behave very differently once you do.
For mosques, offices and other variable-use buildings, use measured daytime demand rather than assuming nearly all generation is exported. The economics depend on actual overlap and approved credit treatment.
A published installation capacity is useful evidence of project scale. It does not establish measured generation, customer savings or payback without supporting operating and financial records.
| Published project reference | Capacity | Evidence required before financial comparison |
|---|---|---|
| Akij Agro Feed | 1,503 kWp | Dated generation, self-consumption, tariff, cost and operating records. |
| Ahad Jute Mills | 575 kWp | The same records; do not infer returns from capacity alone. |
These project examples should not be treated as a forecast for another roof. Payback calculations need stated generation, self-consumption, tariff and settlement assumptions, together with maintenance, degradation, financing and possible equipment replacement costs. Recovering the initial capital does not make subsequent electricity cost-free. Request a site-specific calculation and a lower-generation scenario before making an investment decision.
A plant is a 25-year asset installed against a snapshot of how your business ran last year.
| Change at the site | Effect on net-metering value | Design response |
|---|---|---|
| Second or third shift added | New load is at night, so solar offsets a smaller share of a bigger bill | Be clear that solar addresses the daytime portion only |
| Line electrified or expanded | Daytime load rises, more output self-consumed at retail tariff | Recheck sanctioned load and transformer headroom |
| Line shut down or output cut | Exports rise, average value per kWh drops toward the settlement rate | Do not size to the ceiling where order books are volatile |
| Generator replaced by grid supply | Grid consumption rises, self-consumption improves | Confirm inverter behaviour while running on generator |
| Site relocates or the lease ends | The asset sits on a roof you no longer occupy | Match tenure to payback; price relocation into the contract |
| New block built next door | Permanent shading across part of the array | Design a shading margin; keep the layout able to be restrung |
Review new buildings, tanks and trees for shading changes. Suitable monitoring and periodic comparison with the expected profile can help identify losses, with the monitoring detail chosen for the array design.
Discuss the solar EPC scope with Vvon and request the proposed equipment, responsible specialists and documented project references. Confirm manufacturer authorisation and service arrangements for each offered model rather than inferring them from a brand list.
Consult the relevant edition and the documents for the exact equipment and site: SREDA: Net Metering Guidelines and current application documents; IEA PVPS: operation and maintenance in different climates; JinkoSolar: model datasheets, certificates, installation manuals and warranties; BloombergNEF: PV module tiering methodology. Net Metering Guidelines 2025, English.
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