On-Grid vs Off-Grid vs Hybrid Solar How They Differ & Which to Choose
About to install solar but unsure what on-grid, off-grid and hybrid actually mean, how they differ, and which one your home or business should pick? This page condenses the official explanations from PEA (PEA Solar) and MEA: how each works, pros and cons, a 3-system comparison table, who fits which type, what grid-connection request and permits apply, whether you can sell the surplus, and what moves the price of a 5 kW package. Payback years live on a separate page.
The three solar types differ on two questions: “is it connected to the utility grid?” and “does it have a battery?” — On-grid runs in parallel with the MEA/PEA grid with no battery; it is the cheapest and most common choice for homes and businesses that use power in the daytime, but it shuts down when the grid goes down · Off-grid has no grid connection at all and must have a battery; right for places the grid does not reach, but battery cost is high · Hybrid is grid-connected *and* has a battery, so it covers night-time use and outages, at a higher price than on-grid. Any grid-connected system (on-grid/hybrid) must file a connection / parallel-operation request with MEA or PEA even if you never sell a unit; selling the surplus is only possible for homes that join the Solar Phak Prachachon program (2.20 THB/unit, ≤5 kW). For payback years see the payback calculation page.
What Is On-Grid Solar and How Does It Work?
PEA Solar defines it plainly: on-grid is “a solar generating system connected to the utility's network (whether or not you sell power back)”. Its advantage is guaranteed supply — grid power flows in by itself whenever the panels cannot produce, such as under cloud or at night; its drawback is that when the utility supply fails, the solar system goes dark too. MEA summarises on-grid as “economical, uses solar power in the daytime — suitable for homes, offices, schools or any site that consumes electricity during the day”. The kit is just panels + inverter (string / micro / optimizer) + switchboard, breakers and surge protection; the utility swaps the meter during the connection step if you join the sell-back program.
On-Grid vs Off-Grid vs Hybrid — How Do They Differ? Pros & Cons
| Aspect | On-grid | Off-grid | Hybrid |
|---|---|---|---|
| Grid connection | Yes — parallel with MEA/PEA | No — fully independent | Yes — parallel with the grid |
| Battery | None | Required (sized to the load) | Yes (sized by design) |
| Works during a grid outage? | No — the system shuts down too | Yes — as long as the battery lasts | Yes — backup mode, per battery size / backed-up circuits |
| Night-time supply | Bought from the grid as usual | Battery only | Battery first, then the grid |
| Grid-connection request needed? | Yes — always, even with no sale | No parallel request (not connected); other size-based permits still apply | Yes — same as on-grid |
| Can the surplus be sold? | Only Type-1 homes ≤5 kW in the program (2.20 THB/unit) | No (not connected) | Yes, under the same terms (ERC does not bar BESS pairing) |
| Cost / complexity | Lowest — panels + inverter | High — the battery is the big item | Above on-grid (hybrid inverter + battery) |
| Best for (per PEA/MEA) | Homes, offices, schools, daytime-use sites | Remote sites the grid does not reach | Homes with heavy day-and-night use / needing backup |
On-grid / Off-grid / Hybrid comparison (condensed from PEA Solar and MEA explanations)
On-grid — pros / cons
- Pro: guaranteed supply — grid power flows in by itself when the panels cannot produce (PEA)
- Pro: lowest cost and fastest payback of the three because there is no battery — the more daytime use, the better it pays (MEA)
- Con: if the utility supply fails, the solar system goes dark too (PEA) — it is not a backup system
- Con: nights are still bought from the grid, and daytime surplus earns little (2.20 THB/unit, program homes only) — so size the system to daytime use
Off-grid — pros / cons
- Pro: right for remote areas the utility network has not reached (PEA) — farm houses, fields, water pumps, telecom masts
- Pro: no grid-connection request, since nothing is connected, and no utility bill for whatever the system covers
- Con: must be paired with a battery, which is costly (PEA), and batteries wear out before the panels do
- Con: not available 24/7 — it depends on battery size (PEA); several rainy days in a row can drain it
Hybrid — pros / cons
- Pro: combines both — grid-connected with a battery reserved for night-time use (MEA); suits homes with heavy day-and-night consumption
- Pro: backup during outages, per battery size and the circuits you back up — answers homes with frequent outages or critical loads
- Con: costs more than on-grid because of the hybrid inverter + battery — payback stretches if the battery is under-used
- Con: still needs the connection request and utility inspection like on-grid, and the battery must meet the contracting utility's engineering standards (per ERC)
The on-grid/off-grid wording above follows the PEA Solar FAQ and MEA's “Which Solar Rooftop type should you choose?” article (4 Jun 2026) — links at the end of the page.
How Much Does a 5 kW On-Grid System Cost, and Why Do Quotes Differ?
5 kW is the popular home size for two reasons: it is the per-meter cap of the residential sell-back program, and it is a size PEA packages for both 1-phase and 3-phase homes (about 10–12 panels at current module ratings). To judge whether a quote is fair, do not stop at the total — compare baht per installed watt (฿/Wp) and units generated per year. How to turn a price into payback years is on the solar payback page; the itemised cost stack (panels / inverter / mounting / BOS / labour / paperwork) is on the installation cost breakdown page.
6 factors that move a 5 kW package price
Panel / inverter brand and grade — Tier-1 panels and utility-registered inverters (PEA: smartlist.pea.co.th / MEA: per its connection standard) cost more but pass inspection and carry warranties (PEA/MEA cite 10-year inverter, ≥80% panel performance at 25 years)
Inverter type — PEA's packages come in 4 variants: Standard (string) / +Rapid Shutdown / +Power Optimizer / Micro Inverter — micro inverters and optimizers cost more but help with shading and safety
Roof type and condition — PEA uses 4 standard roof designs: metal sheet / CPAC tile / flat deck / corrugated tile — flat decks need tilt frames; tall, steep or reinforced roofs add labour
1-phase vs 3-phase service and cable runs — 5 kW fits both, but on different inverter models, and longer runs from roof to switchboard/meter add cable, trunking and labour
Add-ons — a battery (if you go hybrid), monitoring, reverse-flow prevention (zero export) and lightning/surge protection
Paperwork and acceptance — filing the connection request / ERC exemption notice / local notice, the utility's inspection fee, insurance, and post-install cleaning & maintenance (PEA includes 2 years, once a year)
Note: this page deliberately prints no price figure, because package prices move with equipment models and promotions — check PEA Solar's current pricing at peasolar.pea.co.th or collect quotes from utility-registered installers, then use our payback page to turn them into years.
Which Type for a Home, Shop, Farm or Factory?
Answer two questions first: “when do you use the most power?” and “do you already have stable grid supply?” — MEA's own summary is that homes with heavy daytime use (retirees at home, pets, working from home) see the fastest results. Then pick from the table:
| Situation | Usual fit | Why / watch-outs |
|---|---|---|
| Home with meaningful daytime use (WFH, retirees, daytime air-con) | On-grid 3–5 kW | Lowest cost, fastest payback; at ≤5 kW on a Type-1 tariff you can also enrol to sell the surplus |
| Home with heavy night use, frequent outages or critical loads | Hybrid (on-grid + battery) | Cuts daytime bills and backs you up; the battery raises cost and lengthens payback — check the battery really earns its keep |
| Shops, offices, clinics, schools (daytime operation) | On-grid for self-consumption | Load coincides with production, so it pays well, but businesses cannot sell into the program — size to avoid large surplus, or set zero export |
| Farms, garden houses, pumps, sites without (or with unstable) grid | Off-grid (no grid) or Hybrid (grid present but unstable) | Off-grid needs no connection request but the battery must cover rainy days; a daytime pump may need no battery at all |
| Factories, warehouses, large commercial buildings | Large on-grid (near-100% self-consumption) | High daytime load, fast payback; ≥1,000 kWp needs a generation licence; BESS only for peak-shaving cases — see the factory solar guide |
Do You Need a Grid-Connection Request or Permits, and Can You Sell Power Back?
Why file when you sell nothing? Because an inverter running in parallel with the grid must disconnect the instant the grid fails (anti-islanding), or it endangers line crews — MEA states that customers “must obtain permission to connect to the network and install equipment to MEA's standard, subject to inspection by qualified officers”, and the inverter must be a registered model (PEA's list is at smartlist.pea.co.th). For the factory-side connection and transformer steps see grid interconnection & transformers, and for the full legal frame Thai rooftop solar regulations.
The 4 permit groups by size (PEA Solar's summary)
Electricity generation licence (ERC): below 1,000 kWp — exemption notice · 1,000 kWp and above — licence required
Factory licence Ror Ngor 4 (item 88): up to 1,000 kWp — not required · above 1,000 kWp — required
Building permit Or 1 + certificate Or 6: array area ≤160 m² and weight ≤20 kg/m² — no permit, but notify the local official · beyond that — permit required
Controlled-energy production licence Por Kor 2: total inverter capacity below 200 kVA — not required · 200 kVA and above — required
So a 3–10 kW home normally ends at “connection request with the utility + ERC exemption notice + local notification” — registered installers usually file the whole set (PEA says PEA Solar “handles every permit with the relevant agencies”).
Can you sell the surplus, and for how much?
Popular Sizes Compared: 3 / 5 / 10 / 15 / 20 kW up to Factory Scale
PEA offers 5 package sizes (1-phase: 3 and 5 kW · 3-phase: 5–20 kW) with its own monthly-saving estimates — every figure in the table is PEA Solar's, and is an estimate under the assumptions PEA states below the table:
| Size (service) | Panels (PEA) | Est. saving / month (PEA) | Typically fits |
|---|---|---|---|
| 3 kW (1-phase) | 6–8 | ~1,500 THB | Small home, 1–2 daytime air-cons |
| 5 kW (1- or 3-phase) | 10–12 | ~2,500 THB | Typical home — the ≤5 kW sell-back cap |
| 10 kW (3-phase) | 17–24 | ~5,000 THB | Large home / small shop or office (self-use) |
| 15 kW (3-phase) | 25–36 | ~7,500 THB | Shops, clinics, offices |
| 20 kW (3-phase) | 33–48 | ~10,000 THB | Small businesses, small warehouses |
| 100 kW and up (factories) | Hundreds of panels | Per actual load and TOU rate | Factories, warehouses — see the factory solar guide |
PEA's stated basis for the saving figures: “assumes the panels generate 5 hours per day at 80% system efficiency, multiplied by an average tariff of 5 THB per unit”, and “actual savings also depend on weather and the customer's usage behaviour” — so your result hinges on how much of the daytime output you actually consume (see how to calculate payback yourself).
About the Author
Compiled by the CapSolar team under Frank Lee (Founder). CapSolar is a commercial & industrial solar EPC/PPA provider in Thailand that designs and connects large on-grid systems with MEA/PEA as routine work, and condenses the utilities' official explanations so households and businesses pick the right system type from the start.
FAQ
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