Bangladesh built one of the largest off-grid solar programmes in the world through IDCOL. Today the engineering work has moved to rooftop C&I systems under net metering and to utility plants backed by development banks. Each route has its own rules for what a design must show.
Quick answer. Bangladesh solar engineering follows three routes. IDCOL-financed projects must use equipment approved by IDCOL’s Technical Standards Committee. Rooftop systems under the Net Metering Guideline 2018 are capped at 70% of sanctioned load and 10 MW. Utility plants with DFI debt, such as the IsDB-backed Sonagazi 220 MW project, need a full lender-grade engineering file.
TL;DR
- IDCOL (Infrastructure Development Company Limited) is a state-owned financier for renewable projects.
- Its Technical Standards Committee approves suppliers and equipment before installation.
- Net-metered rooftop systems are limited to 70% of sanctioned load, up to 10 MW.
- Large plants with DFI debt follow lender review, not just local approval.
- Land is scarce, so layout density and flood risk drive ground-mount design.
This guide is for EPCs, developers and consultants working on Bangladeshi projects. It explains what each financing route asks of the engineering, with links to the primary documents.
What IDCOL Is and Why Engineers Care
IDCOL started its Solar Home System (SHS) programme in 2003 with World Bank support. By January 2019, about 4.13 million systems had been installed, serving around 18 million people, according to IDCOL.
The programme ran through partner organisations, which sold, financed and installed the systems. IDCOL’s role was finance and quality control. That quality control is what matters for engineers.
Bangladesh Solar Engineering Under IDCOL’s Technical Standards Committee
IDCOL’s Technical Standards Committee (TSC) sets equipment standards and approves suppliers. Before installation, the TSC approves the suppliers and equipment. After installation, IDCOL audits that only approved equipment was used.
The TSC’s specifications reference international standards. For example, crystalline silicon PV modules must meet IEC 61215, per the IDCOL TSC specifications (March 2017).
What this means for your design:
- Pick equipment from the approved list first. A design built around unapproved equipment will need rework.
- Match the datasheets. The drawings and BOQ should name the exact approved models.
- Plan for audit. Keep as-built records that let an auditor trace each component.
The 2017 specification is old. Ask IDCOL for the current version before you finalise a bill of quantities.
Net Metering Under the 2018 Guideline
The Power Division issued the Net Metering Guideline in July 2018 and revised it in 2019. Its main limit: a system can be up to 70% of the consumer’s sanctioned load, with a 10 MW ceiling, per the English translation of the guideline (2018).
The guideline defines “rooftop” broadly. It includes roofs, facades, parking areas, factory sheds and empty space within the consumer’s boundary.
| Item | 2018 guideline rule | Design effect |
|---|---|---|
| Size limit | 70% of sanctioned load, max 10 MW | Check sanctioned load before layout |
| Metering | Bidirectional meter | Show meter location on the SLD |
| OPEX model | Generation and self-consumption meters mandatory | Extra metering on the SLD |
| Eligible space | Roofs, sheds, carports, boundary land | Wider layout options for factories |
The Sustainable and Renewable Energy Development Authority (SREDA) supports the programme. It runs a National Solar Help Desk and a net metering calculator for early estimates. Confirm current rules and connection steps with the distribution utility before you design.
For a factory roof, the structure is often the limit, not the guideline. Many sheds were not designed for added load. A site-specific structural calculation report answers that early, and our tin-shed rooftop design guide covers sheet roofs in detail.
Utility-Scale Plants With DFI Debt
Larger plants now use development bank finance. In 2025, the IsDB approved US$143.28 million for the Sonagazi 220 MW Solar Power and Livelihoods Improvement Project in Feni district, per the IsDB.
Lender-backed plants need a different file from a net-metered roof:
| Deliverable | Net-metered rooftop | DFI-financed utility plant |
|---|---|---|
| Yield report | Simple estimate often enough | Bankable PVsyst report with P50/P90 |
| Structure | Roof check | Geotechnical study and pile design |
| Grid | Utility connection steps | Grid study and protection coordination |
| Review | Utility | Lenders’ independent engineer |
| Handover | Basic test records | IEC 62446-1 commissioning file |
The lender file follows the same logic as our MENA DFI guide for IsDB and EBRD projects.
Design Risks Specific to Bangladesh
| Risk | Why it matters | What to do |
|---|---|---|
| Land scarcity | Every acre is contested | Optimise ground coverage ratio and row spacing |
| Flooding | Low-lying deltas flood in monsoon | Raise equipment above flood levels from local data |
| Cyclones | Coastal sites face high winds | Use site-specific wind loads |
| Humidity and heat | Affects losses and equipment | Thermal and humidity ratings in the design basis |
| Soft soils | Delta soils need deeper foundations | Geotechnical testing before pile design |
Do not borrow an Indian or Gulf design without rechecking these inputs. Flood level and soil data change the structure more than any other factor. For pile depth in soft delta soils, see STAAD Pro pile foundation modelling.
Pre-Design Checklist for Bangladesh
- Identify the route: IDCOL finance, net metering or DFI-backed utility plant.
- Get the current equipment rules for that route.
- Confirm sanctioned load for net-metered sites.
- Check roof structure or site geotechnics.
- Collect flood, wind and soil data for ground mounts.
- Prepare a yield report matched to the reviewer.
- Plan commissioning tests to IEC 62446-1. Our IEC 62446 acceptance testing guide lists the test sequence.
Where Heaven Designs Fits
Heaven Designs provides remote solar design: rooftop and ground-mount layouts, SLDs, PVsyst reports and structural calculations. We are not affiliated with IDCOL or SREDA, and we do not file applications. A local partner handles approvals and installation.
FAQ
Is the IDCOL Solar Home System programme still running?
IDCOL’s website reports installations up to January 2019. Contact IDCOL for the current status of its programmes.
Can a factory install more than 70% of sanctioned load under net metering?
Not under the 2018 guideline as published. Check with your utility for any later change.
Do I need IEC-certified modules in Bangladesh?
IDCOL’s TSC specifications reference IEC standards such as IEC 61215. Other routes may set their own rules, so confirm with the financier or utility.
Next Step
Send us your site, sanctioned load and financing route. We will scope the design package. Get a project quote, and we reply within 1 business day.