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 TNB charges an operating factory
Under the standard low-voltage industrial category, Tariff D, TNB charges a combined energy, capacity and network rate of RM 0.4868/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 January 2025.
A larger factory drawing power at medium voltage instead sits on an E-series industrial tariff, 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 ICPT surcharge on top of both resets roughly every six months 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 Tariff D, with a side-by-side comparison against a single-shift pattern.
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. 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% | 18,546 kWh | RM 9,028 |
| Two shifts (day + evening) | 80% | 15,139 kWh | RM 7,370 |
Model assumption at ~30% solar penetration, no battery (ARCHETYPE_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
- Low-voltage industrial (Tariff D), RM 0.4868/kWh
- Source: TARIFF_SCHEDULES.D, TNB C&I schedule
- Generation assumption
- 94.6 kWh per kWp per month
- Source: Trexon proposal-engine assumption (30 days × 3.8 sun-hours × performance ratio)
- Two-shift self-consumption
- 80%
- Source: ARCHETYPE_PROFILES factory-2shift, ~30% solar penetration, no battery
- Monthly generation: 200 kWp × 94.6 kWh per kWp = 18,924 kWh/month
- Self-consumed energy (two shifts): 18,924 kWh × 80% = 15,139 kWh/month
- Monthly saving: 15,139 kWh × RM 0.4868/kWh = RM 7,370/month
- Annual saving: monthly saving × 12 = RM 88,437/year
- Simple payback: Your quoted installed cost ÷ annual saving = quoted cost ÷ RM 88,437 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.
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 PPA
A factory can fund rooftop solar the same four ways any commercial site can — the difference is who ends up owning the asset, and therefore who can claim the tax benefits in the next section.
| 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 |
| Power Purchase Agreement (PPA) | The PPA provider | RM0 | Generally not the factory — see PPA financing | Buyers who prefer to pay only for the electricity produced |
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 approval — 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. 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/MIDA approval, applicable tax law and confirmation by the customer’s licensed tax adviser. Official GITA Asset window ends 31 December 2026.
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 a commercial lead and Deal Room.
- Site assessment — an engineer reviews the roof, switchboard, single-line diagram and shutdown constraints; a physical walk-through is available as the RM100 priority visit, fully credited if you proceed — see book a site visit.
- 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.
Solar kilang: ringkasan untuk pengurus kilang
Kilang yang beroperasi di Malaysia boleh memasang solar atas bumbung untuk mengurangkan bil TNB bulanan, tertakluk kepada had Solar ATAP dan corak syif pengeluaran kilang berkenaan. Bagi pelanggan industri voltan rendah di bawah Tarif D, kadar tenaga (gabungan tenaga, kapasiti dan rangkaian) ialah RM 0.4868/kWh, ditambah levi KWTBB sebanyak 1.6% ke atas jumlah bil bulanan — rujukan jadual tarif TNB bertarikh 1 Januari 2025.
Skim Solar ATAP (GP/ST/No. 60/2025) mengehadkan saiz sistem solar bukan domestik kepada 100% daripada permintaan maksimum (kWac) tapak, dengan had mutlak 1,000 kW bagi setiap pemasangan. Syarikat yang layak boleh memohon Elaun Cukai Pelaburan Hijau (GITA) bersamaan 60% daripada perbelanjaan modal yang layak, diimbangi terhadap sehingga 70% pendapatan berkanun tahun taksiran, tertakluk kepada kelulusan MGTC, dalam tempoh yang kini berakhir pada 31 Disember 2026.
Trexon Energy, berdaftar dengan SEDA (lesen SEDA-RPVSP-2026/373) dan nombor syarikat 201301044881 (1074704-D), menawarkan lawatan tapak keutamaan bernilai RM100 yang dikreditkan sepenuhnya jika projek diteruskan. Hubungi pasukan kami melalui WhatsApp untuk semakan tenaga jarak jauh yang percuma.