What size solar system does a factory need?
Size follows twelve months of TNB kWh and your shift pattern, capped by usable roof area or the Solar ATAP limit — whichever binds first. A single day-shift plant uses almost all of a correctly sized system's output; two or three shifts move load outside sun hours, so the same roof is sized to self-consumption instead. Solar ATAP caps a non-domestic system's inverter output at 100% of maximum demand in kWac, up to 1,000 kW per installation (GP/ST/No. 60/2025 §8.3 and §8.5). The worked example below shows the method.
Industrial solar panels for factories: system types
Industrial solar panels on a factory are not one product. The same Jinko N-type modules can sit on the production-hall roof, over the staff car park, on spare land inside the fence, or feed a hybrid inverter with a battery behind it. Which layout fits depends on how much load-bearing roof the plant has, whether there is yard space it can give up, and whether the bill carries a maximum-demand charge worth attacking. Most factories start with the roof and add the other layouts only where the roof runs out or the tariff rewards storage.
| System type | Where it goes | When it suits a factory | Main trade-off |
|---|---|---|---|
| Rooftop (grid-tied) | Production hall, warehouse or office block roofs | Sound metal-deck or RC roof with most of its warranty left; daytime production load | Roof condition and penetrations decide the design |
| Solar carport | Staff or lorry car park | Roof too small, too old or under a void-if-penetrated warranty | Steel canopy adds cost, but staff get shade and the roof is left alone — see solar carport |
| Ground-mount | Spare land inside the factory fence | Large unused yard and no plans to build on it | Gives up land the plant may need for expansion |
| Hybrid solar + battery (BESS) | Inverter and battery cabinet beside the main switchroom | Medium-voltage bill with a maximum-demand charge, or evening and night shifts | Battery capital cost; sized from half-hourly data, not the monthly bill — see BESS |
Who this route is for
This page is for a single operating factory in Malaysia deciding whether — and how — to put rooftop solar on that one site: a plant manager, facility engineer or owner weighing shift-driven savings against a real roof, a real switchboard and a live production line. For the tariff mechanics that apply across a whole medium-voltage manufacturing group, see Industrial Solar Malaysia; for storage sitting behind the same meter, see BESS Malaysia.
If your factory sits in one of these industrial parks, the park guide covers its manufacturing profile and grid context:
How does GITA work for solar in Malaysia in 2026?
Current rules, until 31 December 2026. A company that owns a solar system for its own use can claim GITA Asset at Tier 2: an allowance of 60% of qualifying capital expenditure, set against up to 70% of statutory income. Under the current MGTC guideline the capex must be incurred, the system commissioned and the GITA Asset application received by MGTC by 31 December 2026 — the application can only be filed after commissioning. A system the company does not own does not qualify, because the claimant must own the asset.
From 1 January 2027 — proposed under Budget 2027, subject to legislation. The Budget 2027 tax measures propose extending GITA Asset to purchases verified by MGTC up to 31 December 2030, with two changes that matter for solar: a standalone solar system is no longer listed, and solar integrated with battery storage (BESS or ESS) moves to Tier 1 at 100% of qualifying capital expenditure, still set against up to 70% of statutory income. Companies would have to apply to MGTC within 24 months of purchase. These are announced proposals, not yet gazetted, and MGTC has not published its updated guideline or asset list. How a 2026 purchase verified in 2027 will be treated has not been published either, so plan to commission and apply in 2026. Source: MOF Budget 2027 Tax Measures, Appendix 25.
For a factory, pairing rooftop solar with a battery also targets the maximum-demand charge — see BESS battery storage. The claim mechanics are in the GITA guide for companies.
How TNB charges an operating factory
Under the Non-Domestic Low Voltage tariff (formerly Tariff D), TNB charges a combined energy, capacity and network rate of RM 0.5068/kWh, plus a RM 20.00 monthly retail charge and a 1.6% KWTBB (renewable-energy fund) levy on the total bill — per the TNB Commercial & Industrial Pricing & Tariffs schedule stamped 1 July 2025.
A larger factory drawing power at medium voltage instead sits on a medium-voltage tariff (formerly the E-series industrial tariffs), where a maximum-demand charge (RM per kW of the highest 30-minute demand in the billing month) and, on the time-of-use tariffs, a peak/off-peak energy split are layered onto the same structure — see Industrial Solar Malaysia for how that changes the economics. The Automatic Fuel Adjustment (AFA) on top of both is set monthly and is left out of the figures on this page because it moves independently of the base rate.
How much can rooftop solar save at a factory?
The honest answer is that panel price is not what decides a factory's payback — how much of the generation your line consumes at the moment it is generated is. Solar only produces in daylight, so the question is how much of your load sits in daylight hours. A single day-shift factory draws most of its power while the sun is up and uses almost everything the panels produce; a two- or three-shift factory spreads the same consumption across the evening and night, so at the same solar share of its annual consumption a larger part of midday output exceeds what the line is drawing at that moment and is exported at the lower credit rate.
The worked example below walks through the method — sizing, self-consumption and the resulting saving — for an illustrative two-shift, 200 kWp system on the Non-Domestic Low Voltage tariff, with a side-by-side comparison against a single-shift pattern.
Cutting maximum demand: solar alone vs solar + battery
On a medium-voltage bill the maximum-demand (MD) charge is often the line a plant manager most wants to cut. Since 1 July 2025 TNB charges RM89.27/kW on Medium Voltage General and RM97.06/kW on Medium Voltage Time of Use, where it applies to the highest demand recorded in the weekday peak window (see the medium-voltage tariff guide). The charge is set by the single highest 30-minute average demand in the billing month, so it rewards removing one spike, not trimming consumption in general.
Solar alone rarely moves that number. A cloud passing over the roof during a production peak drops solar output to a fraction within minutes, and that one half-hour sets the month's MD as if the panels were not there. Trexon therefore counts no MD saving for a solar-only design at any shift pattern; the solar saving is on the energy charge. A battery is different: its discharge is controlled, so it can hold grid demand under a target for the length of the peak whatever the weather. The illustrative example below shows the arithmetic for one plant.
Worked example: shaving 200 kW off a 1,000 kW peak on MV General
Illustrative example — labelled assumptions, not a quotation
- Recorded monthly MD (illustrative)
- 1,000 kW
- Source: illustrative — a mid-size plant on an 11 kV supply
- MD rate
- RM89.27/kW (Medium Voltage General)
- Source: TNB tariff in force from 1 July 2025, capacity + network charge
- Peak to remove
- 200 kW for up to 2 hours
- Source: illustrative — read from half-hourly meter data in a real design
- Battery usable energy
- 400 kWh
- Source: shave power × peak duration
- MD charge before: 1,000 kW × RM89.27/kW = RM 89,270/month
- Solar alone: one cloudy half-hour during the peak sets the MD = no MD saving counted
- Solar + battery: MD reduction: 200 kW × RM89.27/kW = RM 17,854/month
- Annual MD saving: monthly MD saving × 12 = RM 214,248/year
Illustrative only — not a quotation. It assumes the battery holds the target in every half-hour of every month; if a peak lasts longer than the battery can cover, that month's MD is set anyway. It excludes the energy-charge saving from solar, battery losses, KWTBB and AFA. A real design starts from 12 months of half-hourly data and is modelled before it is quoted — see maximum demand peak shaving.
How much does solar for a factory cost in Malaysia?
Cost is priced per project, not per watt. Each quote is built from 12 months of TNB bills (minimum 6), a roof plan, the single-line diagram and a meter and switchboard photo, because roof structure, cable runs and switchboard work move the price more than panel count. A booking of 20% of the system price, capped at RM20,000 locks in your slot and engineering review and is credited in full against the project. See commercial solar panel cost Malaysia.
Sizing solar from your shifts and your bill
Trexon sizes a factory system from three real inputs: your last twelve months of TNB bills, or an interval load profile where you have one; your shift pattern; and the smaller of your usable roof area or the Solar ATAP maximum-demand ceiling for the site. Multi-tenant premises are not eligible for Solar ATAP (§6.1(d) of the guidelines); single-occupier premises with their own TNB account can apply. Trexon designs around Jinko 620W N-type modules with Solis, Huawei, Sungrow or GoodWe string or hybrid inverters, selected per site. The worked example below shows that method end to end.
| Shift pattern | Self-consumption assumption | Self-consumed energy | Monthly saving |
|---|---|---|---|
| One shift (day only) | 98% | 20,580 kWh | RM 10,430 |
| Two shifts (day + evening) | 80% | 16,800 kWh | RM 8,514 |
Model assumption at ~30% solar penetration, no battery (Trexon factory load profiles). A three-shift, 24-hour factory sits lower again — see the shift FAQ below. Real self-consumption depends on your actual production calendar.
Worked example: sizing a 200 kWp system for two-shift production
Illustrative example — labelled assumptions, not a quotation
- Illustrative system size
- 200 kWp
- Source: illustrative — a mid-size two-shift factory
- Tariff
- Non-Domestic Low Voltage (formerly Tariff D), RM 0.5068/kWh
- Source: TNB C&I tariff schedule (Non-Domestic Low Voltage)
- Generation assumption
- 105.0 kWh per kWp per month
- Source: Trexon yield basis (30 days × 3.5 peak-sun-hours)
- Two-shift self-consumption
- 80%
- Source: Trexon two-shift factory load profile, ~30% solar penetration, no battery
- Monthly generation: 200 kWp × 105.0 kWh per kWp = 21,000 kWh/month
- Self-consumed energy (two shifts): 21,000 kWh × 80% = 16,800 kWh/month
- Monthly saving: 16,800 kWh × RM 0.5068/kWh = RM 8,514/month
- Annual saving: monthly saving × 12 = RM 102,171/year
- Simple payback: Your quoted installed cost ÷ annual saving = quoted cost ÷ RM 102,171 per year
Illustrative only — not a quotation. Excludes the monthly retail charge, KWTBB levy and export credit for any unconsumed generation. Actual self-consumption depends on your real shift pattern, weekday/weekend production and any planned expansion, and the system must still fit inside the Solar ATAP maximum-demand cap for your site (see the FAQ below). Confirmed pricing and payback come from a metered site assessment, not this example.
Roof, switchboard and shutdown planning
The roof carries the project before the panels do. Trexon's assessment records roof material — metal deck, concrete or fibre-cement — its age and remaining warranty, existing penetrations and skylights, and safe maintenance access; a structural sign-off on an older metal-deck roof is a normal, expected step, not a red flag. Where the roof is inadequate, under a manufacturer's void-if-penetrated warranty, or simply too small for the target size, a ground-mount or carport array on spare yard space is the alternative — the trade-off is land use and racking cost against a straightforward, unpenetrated roof.
On the electrical side, the assessment reviews the single-line diagram, the incoming switchboard and available breaker capacity, and the protection settings the inverter has to coordinate with. Connecting a rooftop system safely usually needs one or more planned shutdown windows on the main switchboard — timed around your production calendar, not imposed on it — plus, for the Solar ATAP interconnection, a metering change coordinated with TNB.
Factory roof types: metal deck, Klip-Lok and RC slab
Most Malaysian factories sit under one of three roofs, and each changes how the array is fixed and what the structural engineer has to sign off. A plant built in stages often has two or three of them across different blocks, so the design is done block by block. The Solar ATAP guidelines require the mounting structure to comply with the Registration of Engineers Act 1967.
| Roof | How the array is fixed | What the engineer checks | Factory watch-out |
|---|---|---|---|
| Trapezoidal metal deck (through-fastened) | Rails screwed through the sheet into the purlins, every hole sealed | Purlin size and spacing, sheet gauge, rust at laps and fixings | Older halls often need corroded sheets replaced first; plan that into the shutdown calendar |
| Klip-Lok or other concealed-fix deck | Clamps that grip the ribs, with no holes through the sheet | Clamp tested for that exact rib profile; uplift on wide spans | Keeps the roof warranty intact; clamps from the wrong profile can slip |
| Reinforced-concrete (RC) slab | Ballasted or chemically anchored tilt frames | Slab design load against ballast weight; falls to drains | Leave clear paths around rooftop chillers, cooling towers and exhaust fans |
Fibre-cement and translucent skylight sheets cannot carry modules; arrays are laid out around them, or that part of the site moves to a carport or ground-mount.
Production continuity and safety coordination
Installation is normally phased by roof zone or by electrical section so the plant keeps running: cabling and racking on one zone while another stays fully operational, with switchboard shutdown windows agreed in advance and kept as short and as few as the design allows. This page does not quote a generic installation timeframe — the phasing plan, and how many shutdown windows it needs, is set from your actual roof size, switchboard layout and production calendar during the assessment, not before it.
Work on and around a live switchboard follows a lock-out/tag-out isolation process, authorised and agreed with your site safety team before any isolation happens, and roof access follows your existing site safety rules alongside the installation crew's own fall-protection procedures. This page does not claim any particular safety certification — ask your assessment engineer for the standards and documentation relevant to your site and industry.
Own, borrow, instalment or hire purchase
A factory can fund rooftop solar in four ways, and in each one the factory owns the system — which is what lets it claim the tax benefits in the next section. Trexon does not offer arrangements where a third party owns the panels on your roof.
Cash or hire purchase. Paying cash gives the full saving from day one. A plant that would rather keep its capex budget for production equipment can use a 2 to 5 years hire-purchase plan from Mitsubishi HC Capital Malaysia Sdn Bhd, arranged by Trexon. The plan is quoted at 3.6–3.95% flat p.a.; because a flat rate is charged on the original amount for the whole term, the true cost is about 6.8–7.4% a year, and that effective figure is the one your finance team should compare with a term loan. The final rate and any deposit come with credit approval, and ownership passes to the factory when the term ends. Hire purchase is open to commercial and industrial customers only.
| Route | Who owns it | Upfront | Who claims GITA/CA | Best for |
|---|---|---|---|---|
| Outright purchase | Factory (customer) | Full amount | Factory (customer) | Balance-sheet buyers wanting the full saving and the full tax benefit |
| Green or bank loan | Factory (customer) | Depends on the bank's terms | Factory (customer) | Owners who want the asset now but prefer to repay from the savings it generates |
| 0% card instalment plan (IPP) | Factory (customer) | Paid over up to 24 months on a participating bank card | Factory (customer) | Smaller systems where the owner wants the asset without a bank loan |
| Hire purchase (2-5 yrs) | Factory (customer), outright once the term completes | Financed through Mitsubishi HC Capital at 3.6–3.95% flat p.a. (effective about 6.8–7.4% a year); deposit set at credit approval | Factory (customer) | Owners who want the asset and its tax position but would rather not pay in one go — see hire purchase |
Tax incentives for factory solar
Solar equipment installed on a factory roof can qualify for the Green Investment Tax Allowance (GITA Asset), subject to MGTC verification — currently an allowance equal to 60% of qualifying capital expenditure on the solar system, which can be offset against up to 70% of the company's statutory income in a year of assessment, under a window that currently runs to 31 December 2026. The system must be commissioned and the GITA Asset application received by MGTC by 31 December 2026. Read the full mechanics in the GITA tax incentive guide.
Separately, solar equipment can also qualify as plant and machinery under the standard capital allowance rules — an Initial Allowance of 20% in the first year of assessment plus an Annual Allowance of 14% in each year after. See the capital allowance guide for how the two interact.
Indicative only. Subject to MGTC verification, applicable tax law and confirmation by the customer’s licensed tax adviser. The system must be commissioned and the GITA Asset application submitted to MGTC by 31 December 2026.
GITA 2027 for manufacturers: why solar + battery matters
For a manufacturer the Budget 2027 proposal changes what is worth planning after this year. If it is legislated as announced, standalone solar drops off the GITA Asset list from 1 January 2027, while solar integrated with a battery moves to Tier 1 at 100% of qualifying capital expenditure for purchases verified by MGTC up to 31 December 2030 — proposed under Budget 2027, subject to legislation, as set out in the GITA section above. That lines the tax up with the engineering: on a medium-voltage plant the battery is also the part that cuts the maximum-demand charge.
In practice: a solar-only project should aim to be commissioned, with its application received by MGTC, by 31 December 2026; a plant that will add storage anyway can design the hybrid inverter and battery space in now. The GITA deadline guide for manufacturers covers the timing in more detail.
Factory solar by industrial park
Each park guide covers the manufacturing mix, the grid context and what that means for a rooftop or hybrid design on a factory in that park:
From project brief to commissioning
The route from brief to a commissioned system, without promising a duration for any stage:
- Project brief — you send your bill, shift pattern and site details below; Trexon opens your commercial project file and contacts you.
- Site assessment — an engineer reviews the roof, switchboard, single-line diagram and shutdown constraints; Reserve the project with a booking of 20% of the system price, capped at RM20,000, credited in full to the system price; an engineer then verifies roof, switchboard and access on site, and we confirm whether commissioning and an MGTC application received by 31 December 2026 are achievable for your site before you pay anything further.
- Engineering and documentation — system design, the Solar ATAP application and TNB interconnection paperwork, and structural sign-off where the roof needs it.
- Phased installation — racking and cabling by roof zone or electrical section, with switchboard shutdown windows agreed with your team in advance.
- Commissioning and TNB metering change — testing, hand-over documentation and the export-meter change that brings the system onto Solar ATAP.
Factory solar: a summary for factory managers
Factories operating in Malaysia can install rooftop solar to reduce the monthly TNB bill, subject to the Solar ATAP limits and the factory's production shift pattern. For industrial customers on the Non-Domestic Low Voltage tariff (formerly Tariff D), the combined energy, capacity and network rate is RM 0.5068/kWh, plus a 1.6% KWTBB levy on the total monthly bill — per the TNB tariff schedule stamped 1 July 2025.
The Solar ATAP scheme (GP/ST/No. 60/2025 §8.3 and §8.5) limits a non-domestic solar system to 100% of the site's maximum demand (kWac), with an absolute cap of 1,000 kW per installation. Eligible companies can apply for the Green Investment Tax Allowance (GITA) equal to 60% of qualifying capital expenditure, offset against up to 70% of statutory income for the year of assessment, subject to MGTC verification, under a window that currently runs to 31 December 2026. The system must be commissioned and the GITA Asset application received by MGTC by 31 December 2026.
Trexon Energy, registered with SEDA (registration SEDA-RPVSP-2026/373) under company number 201301044881 (1074704-D), starts projects with a booking of 20% of the system price, capped at RM20,000, credited in full to the system price. Contact our team on WhatsApp for a free quote.
