Solar Glossary: Key Terms You Actually Need in Bangladesh
Most people don’t open a solar glossary out of curiosity. They open it because someone just handed them a quotation with the word “sanctioned load” on it, or because a net metering form from their distribution utility is sitting half-filled on their desk, or because a contractor just said “hybrid” and “grid-tied” in the same sentence and they’re not sure which one they actually need.
That’s the situation this glossary is written for. Not a textbook run-through of photovoltaic physics, but a working reference you can keep open in a second tab while you’re reading a proposal or filling out paperwork.
A quick note before we get into it: a lot of solar glossaries online are written for the US or UK market, and they’re full of terms — federal tax credits, SREC markets, specific electrical codes — that simply don’t apply here. We’ve left those out, or flagged them clearly where the concept exists in Bangladesh but works differently. What’s included instead is the vocabulary you’ll actually run into: from basic energy units to the specific language used in Bangladesh’s Net Metering Guidelines 2025.
Quick-Reference: The Terms People Search For Most
| Term | Plain-English Meaning |
| kW (kilowatt) | The size or output capacity of a solar system |
| kWh (kilowatt-hour) | The actual amount of electricity used or produced |
| Net metering | A system that credits you for solar power sent back to the grid |
| Sanctioned load | The maximum power your utility allows you to draw or install against |
| Grid-tied | A system connected to the national grid, with no standalone battery |
| Off-grid | A fully independent system, not connected to the grid at all |
| Hybrid | Grid-connected, but with battery backup for outages or load shedding |
| Inverter | The device that turns your panels’ DC output into usable AC power |
| LCOE | The average cost of every unit of electricity your system produces over its lifetime |
| SREDA | Bangladesh’s renewable energy regulator |
If you only remember ten words before calling an installer, these are the ones worth knowing. Everything below builds on them.
The Basic Units: kW, kWh, and Why Installers Use Both
Kilowatt (kW) describes power — how much electricity a system can produce or a device can draw at any given moment. When someone tells you they’re installing a “5kW system,” they’re describing its size, not how much electricity it will actually generate in a day.
Kilowatt-hour (kWh) describes energy — power used or produced over time. This is the unit on your electricity bill, and it’s the number that actually determines your savings. A 5kW system doesn’t produce 5kWh every hour; output depends on sunlight, shading, panel angle, and time of day.
Why this distinction matters in a quote: if a contractor only ever talks in kW and never mentions expected kWh output, ask directly. System size tells you what was installed. Energy output tells you what you’re actually going to save.
Peak sun hours is the term used to describe how much usable sunlight a location gets — specifically, the number of hours per day where sunlight intensity would be strong enough to be considered “full sun” (1,000 watts per square meter) if it stayed constant. Bangladesh generally sees somewhere in the range of 4 to 5 peak sun hours a day on average, though this varies by season, cloud cover, and region — treat any specific number as a planning estimate, not a guarantee, since actual output depends on your exact rooftop and local weather. For a deeper look at how this is calculated, see our guide to peak sun hours.
Irradiance and insolation are related but different: irradiance is the instantaneous strength of sunlight hitting a surface (measured in watts per square meter), while insolation is the total solar energy received over a period of time, usually a day (measured in kWh per square meter per day). Installers use insolation data to estimate how much energy your system will actually generate across a full year.
LCOE (Levelized Cost of Energy) is the average cost of every unit of electricity a system produces over its entire working life, once you account for the upfront cost, maintenance, and expected output. It’s a useful way to compare solar against your grid tariff on equal footing. Some industry estimates put rooftop solar’s LCOE in Bangladesh at roughly ৳5 per kWh, against a national average grid tariff that has been reported around ৳10.6 per kWh — but treat both figures as estimates that shift with panel prices, system quality, and location, not fixed numbers. Read more in our breakdown of LCOE for solar in Bangladesh.
The Hardware: What’s Actually on Your Roof
Photovoltaic (PV) cell is the basic building block — a small semiconductor wafer, usually silicon, that converts sunlight directly into electricity. Several dozen PV cells wired together make up a single panel or module. Several panels wired together form an array.
Inverter is the device that converts the DC (direct current) electricity your panels produce into AC (alternating current), which is what your home or factory’s wiring and appliances actually use. Almost nothing in your building runs on raw DC power, so every solar system needs one.
Micro-inverter is a variation where each individual panel gets its own small inverter, instead of one central inverter handling the whole array. This costs more upfront, but it means one shaded or faulty panel doesn’t drag down the output of the entire array — worth knowing if your roof has partial shading from a water tank, stairwell, or neighboring building, which is common on Dhaka apartment rooftops.
Charge controller regulates the voltage and current flowing from your panels into a battery, preventing overcharging. This component only matters if your system includes battery storage — a purely grid-tied system without batteries doesn’t need one.
Battery storage stores surplus solar energy for later use — during the evening, during load shedding, or during a grid outage. Most residential and commercial batteries in Bangladesh today are lithium-ion, which cost more upfront than older lead-acid batteries but last longer and need less maintenance. Battery capacity is the single biggest cost variable in a hybrid system, so this is where quotes tend to diverge the most between installers. See our guide on battery bank sizing if you’re comparing proposals.
Racking or mounting is the physical structure that holds panels in place, whether on a sloped roof, a flat roof, or the ground. Tilt angle is how steeply the panels are angled relative to horizontal, and azimuth is the compass direction they face. Because Bangladesh sits close to the Tropic of Cancer, the ideal tilt here is generally shallower than what you’d see recommended in a US or European glossary — panels facing south, tilted at a relatively low angle, tend to perform best across the year. Your installer should be able to explain the specific angle chosen for your roof rather than applying a generic default. More detail in our guide to optimal solar tilt angle.
Grid-Tied, Off-Grid, or Hybrid — Which Is Which
This is probably the single most confused set of terms in the entire industry, and getting it wrong on a quote can mean paying for equipment you didn’t need — or missing backup power you actually wanted.
| System type | Connected to grid? | Has battery? | Works during load shedding? | Typical use case |
| Grid-tied (on-grid) | Yes | No | No — shuts down with the grid for safety | Homes/businesses wanting to cut electricity bills, with no need for backup |
| Off-grid | No | Yes, substantial | Not applicable — never connected in the first place | Remote locations with no grid access |
| Hybrid | Yes | Yes | Yes, if sized for it | Homes/businesses that want both bill savings and outage backup |
Grid-tied systems are the most common and generally the cheapest, since they skip battery costs entirely. But there’s a detail people are frequently surprised by: for safety reasons, a standard grid-tied system automatically shuts down during a grid outage or scheduled load shedding, even though the sun is still shining. It’s designed that way so it doesn’t send electricity back into lines that utility workers might be repairing. If your main reason for going solar is reducing load-shedding pain, a plain grid-tied system alone won’t solve that.
Off-grid systems are fully self-sufficient, with no grid connection at all, which means they need enough battery capacity to cover night-time and low-sunlight periods entirely on their own. These are far less common in urban Bangladesh now that grid coverage is extensive, but they remain relevant for remote sites, agricultural operations, or telecom towers. Read more about off-grid solar systems.
Hybrid systems combine both — connected to the grid for day-to-day use, but with battery backup that kicks in during outages. This is generally the system Bangladeshi buyers are actually asking for when they say they want backup during load shedding, even if they use the word “grid-tied” loosely in conversation. It’s worth confirming directly with your installer which category your quote actually falls into, since the terminology gets mixed up often in casual sales conversations. See our comparison of grid-tied, off-grid, and hybrid systems for a fuller picture, or our dedicated guide to hybrid solar systems.
The Terms Your Utility Form Actually Uses
This is the section most solar glossaries — almost all of them written for the US market — simply don’t have, because these terms are specific to how Bangladesh regulates rooftop solar.
Net metering is the billing arrangement that lets you send surplus solar electricity back to the grid and receive credit for it, rather than that energy going to waste. Under Bangladesh’s Net Metering Guidelines 2025, which replaced the earlier 2018 framework, several things changed meaningfully:
- Your net-metered system can now be sized up to 100% of your sanctioned load, up from a previous cap of 70%.
- Applications are now handled through an online system, rather than the older manual/paper process.
- Consumers with prepaid or single-phase meters — previously excluded — are now eligible to participate.
- Any surplus credit you build up is settled on a quarterly basis (ending in March, June, September, and December), and any credit remaining at the end of that period is paid out by your distribution utility at a government-set rate, rather than simply expiring.
Because these rules have already been revised more than once in the 2025–2026 period, treat the specifics above as accurate as of this writing, and confirm the current version with your utility or a net metering application guide before you apply.
Sanctioned load is the maximum electrical load your utility has officially authorized for your connection — essentially the ceiling your net-metered solar system’s capacity is measured against. If you’re planning to increase your sanctioned load (say, for a business expansion), it’s worth knowing that a Power Division circular issued in December 2025 introduced a rule requiring rooftop solar installation for larger buildings applying for new connections, and separately, three-phase industrial or commercial consumers above a certain load threshold may now be required to install a minimum solar capacity as a condition of that load increase. This is a regulatory area that’s actively evolving, so anyone in this situation should verify the current requirement directly with their distribution utility rather than relying on secondhand summaries — including this one.
Bidirectional meter is the type of meter net metering requires — one that can measure electricity flowing in both directions, since you’re both drawing power from the grid and sending power back to it.
Distribution utility refers to whichever company manages your local electricity connection — BREB, DESCO, DPDC, NESCO, WZPDCL, or BPDB depending on where you’re located. Net metering applications, approvals, and settlements are all handled through your specific distribution utility, not a single national body.
SREDA (Sustainable and Renewable Energy Development Authority) is Bangladesh’s dedicated renewable energy regulator. Among other things, SREDA maintains an approved-equipment list for solar panels and inverters. Asking whether the components in your quote are on SREDA’s approved list is a reasonable, specific question to put to any installer — and one that filters out a lot of low-quality proposals quickly.
Feed-in tariff is a separate mechanism from net metering credit — a fixed rate paid for surplus solar electricity exported to the grid, sometimes tied to a specific incentive window rather than the standard net metering arrangement. Bangladesh has recently introduced incentive programs along these lines; because eligibility windows and rates in this space tend to be time-limited and subject to change, confirm current terms before factoring them into a savings calculation. See our explainer on feed-in tariffs for solar.
A Note on Load Shedding, Because It’s Different Here
Most international solar content frames battery backup around storms and grid emergencies — occasional, unpredictable events. In Bangladesh, the more common driver is load shedding: scheduled or semi-scheduled outages that happen with enough regularity that they shape daily life, particularly for factories running production lines or households managing refrigeration and water pumps. That’s a genuinely different design problem. A battery sized to handle an occasional multi-hour outage a few times a year is not the same as one sized to handle daily interruptions — and it’s worth being explicit with your installer about which situation you’re actually solving for, since it changes both the battery specification and the price.
What This Means If You’re Comparing Quotes
A few practical checkpoints, drawn directly from the terms above:
- Ask for expected kWh output, not just kW system size.
- Confirm whether the proposal is grid-tied, off-grid, or hybrid — using the definitions above, not the installer’s casual wording.
- If backup during load shedding matters to you, confirm the battery is sized for daily cycling, not just occasional emergencies.
- Ask whether panels and inverters are on SREDA’s approved equipment list.
- If net metering is part of the plan, confirm your sanctioned load and whether your meter type (prepaid, single-phase, three-phase) is currently eligible under the latest guidelines.
- Ask for the source and date behind any savings or payback-period figures — legitimate installers should be able to show their assumptions, not just a final number.
We’ve worked on both institutional and industrial rooftop solar projects across Bangladesh — mostly grid-tied and hybrid systems for government, healthcare, and educational facilities — and the quotes that cause the fewest problems later are the ones where this vocabulary was clear from the start. If you’re at the stage of comparing proposals for your home or facility, our team can walk through a quote with you and explain exactly what’s being offered. For more on evaluating what you’re being sent, see our guide to evaluating solar quotes.
FAQs
What does “sanctioned load” mean for my solar system size?
Your sanctioned load is the maximum electrical capacity your utility has approved for your connection. Under the current Net Metering Guidelines 2025, your net-metered solar system can be sized up to 100% of that sanctioned load — so a higher sanctioned load generally allows a larger system, though your actual roof space and budget are the other limiting factors.
What happens to unused solar credits under net metering in Bangladesh?
Surplus generation is credited against your bill and rolled over. At the end of each quarterly settlement period (March, June, September, December), any remaining credit is paid out by your distribution utility at a government-set rate, rather than being lost.
Do I need a charge controller if I’m installing a grid-tied system with no battery?
No. A charge controller’s job is to regulate charging into a battery. If your system is purely grid-tied with no battery storage, you don’t need one — your inverter alone handles the conversion from DC to AC.
Is rooftop solar mandatory for my home or building?
It depends on your building’s roof size and connection type. A December 2025 circular introduced a rooftop solar requirement tied to net metering for buildings with a certain amount of usable roof space applying for new connections, and separate rules apply to some industrial/commercial consumers increasing their sanctioned load. Because this policy area has already been revised and continues to evolve, confirm your specific obligation directly with your distribution utility.
What’s the real difference between grid-tied and hybrid solar systems?
A grid-tied system has no battery and shuts off during a grid outage or load shedding for safety reasons. A hybrid system adds battery storage, so it can continue supplying power during those outages if it’s sized correctly for that purpose. If avoiding load-shedding disruption is your main goal, a hybrid system — not a standard grid-tied one — is what actually solves that problem.
How much does a basic solar system cost in Bangladesh?
Costs vary widely by system size, battery inclusion, and equipment quality, and pricing shifts over time, so treat any figure as an estimate rather than a fixed price. It’s worth requesting a written, itemized quote — covering panels, inverter, mounting, wiring, and labor separately — so you can compare proposals on equal terms.
