Thailand Introduces Tax Incentives for Solar Rooftop Installation and Energy-Efficient Machinery

Royal Decree No. 805 (B.E. 2569), published in the Royal Gazette on 2 March 2026, introduces two tax incentives supporting Thailand’s energy transition. Individual taxpayers can claim up to THB 200,000 in personal income tax deductions for residential solar rooftop installations, while companies and qualifying individuals receive a 150% tax deduction on certified energy-saving machinery. Both measures run from 3 March 2026 through 31 December 2028.

Personal Tax Deduction for Solar Rooftop Systems

Section 3 of the decree grants individual taxpayers a personal income tax exemption equal to the actual cost of purchasing and installing an on-grid rooftop solar system on a residential building, including VAT, subject to a cap of THB 200,000. The deduction applies once per taxpayer and is claimed in the tax year in which the system receives grid connection approval from the Metropolitan Electricity Authority (MEA) or the Provincial Electricity Authority (PEA).

Parameter	Details
Eligible taxpayers	Individual PIT taxpayers (excluding ordinary partnerships, non-juristic groups, and undivided estates)
Maximum deduction	THB 200,000 (actual cost including VAT)
Eligible systems	On-grid solar systems installed on rooftops or terraces of residential buildings, up to 10 kWp
Grid connection	Must connect to MEA or PEA grid
Supplier requirement	VAT-registered operator; valid e-Tax Invoice required
Claim period	3 March 2026 to 31 December 2028

The claimant’s name on the e-Tax Invoice must match the electricity meter registration. No retroactive claims are permitted for systems installed before the effective date. Thailand’s existing net billing scheme also allows residential solar systems to sell surplus electricity back to the grid at approximately THB 2.20 per kWh, providing an additional return alongside the tax benefit.

150% Corporate Tax Deduction for Energy-Saving Machinery

Section 4 creates a separate incentive directed at corporate and professional investment in energy-efficient equipment. The structure of the incentive is a tax exemption equal to 50% of qualifying expenditure, layered on top of standard depreciation. In effect, the taxpayer deducts the full cost through normal depreciation (100%) and claims an additional 50% bonus, for a total deduction of 150% of actual expenditure. At the standard 20% CIT rate, a THB 1,000,000 investment in qualifying equipment yields THB 100,000 in additional tax savings from the bonus deduction alone.

Parameter	Details
Eligible taxpayers	Companies, juristic partnerships, and individuals earning under Sections 40(5)–40(8)
Total deduction	150% of actual expenditure (100% depreciation + 50% bonus)
Certification	Level 5-star energy efficiency label from DEDE and EGAT
Equipment condition	Must be new, used in Thailand, and operational by 31 December 2028
Supplier requirement	VAT-registered operator; valid e-Tax Invoice required
Claim period	3 March 2026 to 31 December 2028

The Level 5-star label currently covers over 40 product categories including air conditioning, refrigeration, lighting, and industrial motors. Businesses should verify that specific equipment models carry the required certification before committing to procurement.

Compliance Requirements and Anti-Stacking Rules

Both measures share several conditions that shape how the incentives function in practice. All qualifying expenditure must be paid to a VAT-registered supplier, and the supplier must issue a valid e-Tax Invoice under the Revenue Code. Purchases from non-VAT-registered vendors, or transactions supported only by paper invoices, do not qualify.

The anti-stacking provisions are where foreign businesses need to exercise particular care. Expenses claimed under Royal Decree No. 805 cannot be claimed again under any other Royal Decree or Ministerial Regulation granting tax exemptions, whether in whole or in part. More significantly, the equipment must not be used in any business activity already receiving corporate income tax exemptions under the Investment Promotion Act (BOI), the Act on Enhancing Competitiveness for Target Industries, or the Eastern Economic Corridor (EEC) Act. This exclusion is consequential. BOI-promoted companies with active CIT exemption periods will, in most cases, derive greater value from their existing promotional certificates than from the 150% deduction under this decree for the same assets.

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