Grid-tied and hybrid solar solve different problems. This compares cost, outage behaviour, generator interaction and battery siting for Bangladeshi industrial sites, and sets out which architecture suits which load profile.
When evaluating a solar investment for your business in Bangladesh, one of the first decisions is whether to install a grid-tied system (solar plus grid, no battery) or a hybrid system (solar plus battery plus grid). Both reduce your electricity bill, but they have different costs, capabilities and payback periods, and they are not really competing products. One lowers your energy cost. The other lowers your energy cost and buys you ride-through during an outage. The right choice depends on your grid reliability, load profile and budget, and on how much of your load genuinely cannot be interrupted.
A grid-tied solar system connects directly to the utility grid. Solar panels generate DC electricity, the string inverter converts it to AC, and the power flows to your loads. If solar generates more than you consume, the surplus is exported to the grid, earning a credit under net-metering. If solar generates less than you need, the deficit is automatically drawn from the grid. No battery is involved. When the grid goes down, the system shuts off automatically, for safety reasons.
That last sentence surprises people, so it is worth stating plainly. On a grid-tied plant, a load-shedding event at noon on a bright day stops your solar generation as well. The inverter's anti-islanding function detects the loss of grid and disconnects, because feeding an unenergised network would endanger anyone working on it. It is not a fault and it is not something a better inverter avoids. It is the behaviour the utility requires and approves. If you need generation to continue during an outage, that is a different architecture, and it costs more.
A hybrid system adds battery storage and an inverter capable of forming its own grid. When utility supply fails, the hybrid inverter disconnects from the network, energises a separate backed-up distribution board, and continues to run the loads on that board from battery and solar together. The important word is separate. A hybrid plant on an industrial site does not usually back up the whole factory. It backs up a defined subset: the cold room compressors, the operating theatre and the imaging room, the server room and the security system, the process controls that must not lose state.
The design work is therefore load selection before it is battery sizing. Walk the site and write down, circuit by circuit, what genuinely cannot be interrupted and for how long. That list, plus the duration you want, gives you the battery capacity. Starting from a battery figure and working backwards produces either an expensive system that backs up lighting, or a cheap one that trips the moment a compressor starts. Motor starting current is the usual trap: a battery bank sized on average kWh can be perfectly correct on energy and still fail on the inrush of a single large compressor.
A hybrid inverter is also not a UPS. There is a short transfer as the inverter detects grid loss and switches over, brief but real. Equipment that cannot tolerate any break, imaging systems, some laboratory instruments, servers, still needs its own UPS in front of it. The hybrid plant then keeps the UPS batteries charged through a long outage instead of replacing them.
| Feature | Grid-Tied | Hybrid (Solar + Battery) |
|---|---|---|
| Battery storage | None | Yes (Pylontech, BYD, etc.) |
| Works during grid outage? | No | Yes (for battery duration) |
| System cost (1,000 kWp) | BDT 7 to 8 crore | BDT 10 to 14 crore |
| Payback period | 4 to 6 years | 5 to 8 years |
| Best for | Reliable grid areas, daytime loads | Unreliable grid, critical loads |
| Inverter makes used on projects | Sungrow, Huawei, SMA, Solis | Growatt SPH, Solis, Huawei LUNA |
| Complexity | Low | Medium-High |
The cost gap in that table is the whole argument. At 1,000 kWp the battery and its associated switchgear, room, ventilation and protection add several crore, and they do not generate a single extra kWh. What they buy is availability. If your site already tolerates outages with a diesel generator that runs reliably, that money may be better spent on more PV. If your losses during an outage are measured in spoiled stock or halted production, the same money is cheap insurance. Work out the cost of an hour of downtime at your site before you compare the two columns, because that number decides the answer and nobody else can supply it.
The last point deserves emphasis for sites outside the main distribution areas. Where export is not available or is worth little, storing surplus daytime generation and using it in the evening turns a low-value export into a full-value avoided purchase. That changes the arithmetic on batteries considerably, and it is the strongest case for hybrid on a site with an evening-weighted load.
For most garments factories, textile mills and daytime-shift manufacturing in and around Dhaka, Gazipur, Narayanganj and Chattogram, grid-tied is the correct default. The load runs when the sun is up, the grid in those areas is reasonably firm, net-metering is available, and the site almost always has a standby generator already. Adding batteries to that picture mostly duplicates a function the generator already performs.
Nearly every Bangladeshi industrial site of any size has a diesel or gas standby set, and the interaction between solar and that set is the single most commonly mishandled part of the design. A grid-tied inverter that stays connected while the site is running on generator will try to export into the set. A generator cannot absorb reverse power. Depending on the machine, that means reverse power trip, hunting, or damage to the alternator.
A related case is the site where the utility limits or refuses export because the transformer has no headroom. There the plant is designed as grid-tied with zero export: an export limitation device holds generation at or below site consumption in real time. You keep the full value of self-consumed energy, you lose the export credit, and the approval becomes much easier to obtain. On a continuous-process site with strong daytime load, that trade is often barely noticeable, because there was little surplus to export in the first place.
For hybrid systems in Bangladesh, Vvon specifies the Growatt SPH series (3 to 12 kW, single and three-phase), Solis hybrid inverters (3 to 50 kW), and Huawei SUN2000 with LUNA2000 battery for larger commercial installations. All three makes have local service support in Bangladesh and are compatible with Pylontech and BYD battery modules. Service reach in-country is a selection criterion in its own right, not a nice-to-have: a hybrid plant has more failure modes than a grid-tied one, and an inverter or battery module waiting on an overseas RMA takes the backup function offline for as long as it takes to arrive.
Battery siting is where hybrid projects in Bangladesh quietly go wrong, because the room is decided late and by whoever has spare space. Lithium modules lose cycle life quickly at sustained high temperature, and an unventilated first-floor store under a tin roof in Rajshahi in May is a hostile place for them. Plan for a dedicated, ventilated, preferably cooled room at ground or first-floor level, on a slab rated for the weight, away from process heat and away from anything that generates dust or corrosive vapour.