New Rooftop Solar Rules for 2026: What Homeowners in Thailand Need to Know

New Rooftop Solar Rules for 2026: What Homeowners in Thailand Need to Know

The rooftop solar market in Thailand is rapidly maturing. Until recently, bureaucratic barriers discouraged many homeowners from installing solar systems. But in 2024–2025 the country launched a major reform of residential solar energy. The government has approved a draft law aimed at supporting rooftop solar, reducing administrative hurdles and expanding financial incentives. Installing solar systems is now becoming significantly easier and more attractive for homeowners.

Thailand’s first law specifically designed to support rooftop solar is now in the final stages of adoption. In the meantime, regulators have already updated several related regulations and simplified a number of procedures.

Here are the key changes.

Installing solar panels for self-consumption is no longer treated as a licensed activity.

Homeowners are no longer required to obtain an industrial license to install a solar system, regardless of its capacity. Previously, the exemption applied only to systems up to 1,000 kW, but this limit has now been lifted.

Building modification permits are no longer required.

Under the previous regulations, installing solar panels was classified as a “building modification.” Property owners had to conduct a structural inspection, obtain a certification, and notify the authorities. The only exception applied to residential buildings smaller than 160 m², with a roof load not exceeding 20 kg per square meter.

The exemption has now been extended to all types of buildings, regardless of installation size. The only remaining requirement concerns roof load limits. However, liability for non-compliance has become stricter. If a solar installation is deemed unsafe, authorities may require it to be dismantled at the owner’s expense.

There is no longer a need to notify the Energy Regulatory Commission (ERC) separately.

Submitting an application through the utility’s website is now sufficient. Previously, system owners first had to obtain approval from the electricity utility (MEA in Bangkok or PEA in other provinces) and then submit a separate notification to the Energy Regulatory Commission (ERC) to register the exemption from licensing. Under the new rules, for residential systems up to 10 kVA, the utility automatically forwards the necessary information to the ERC.

Power Generation Licensing

In 2024, the requirement to obtain a factory license for rooftop solar installations on industrial facilities was abolished. In addition, the Energy Regulatory Commission (ERC) simplified the procedure for registering power generation. Systems with a capacity of up to 10 kVA are now exempt from licensing, and applications can be submitted online.

According to the ERC’s 2022 report, homeowners can register for the licensing exemption through the ERC website or mobile application, while all 13 regional ERC offices provide consultations for residential system owners. The program specifically applies to solar systems with a capacity of up to 10 kVA.

Connection of solar systems to the public grid (PEA or MEA) has also been simplified.

If a system meets the approved criteria, including equipment safety certification and an engineering assessment of the roof structure, no separate grid-connection permit is required. Applications can be submitted online through the utilities’ portals at www.myenergy.mea.or.th or www.ppim.pea.co.th. For systems up to 10 kVA, the Energy Regulatory Commission (ERC) has automated the data transfer process, so a separate notification to the ERC is no longer required.

New Safety Standards: Mandatory Certification for Panels and Inverters

The government has strengthened equipment quality requirements. In 2025, the Thai Industrial Standards Institute (TISI) introduced mandatory TIS standards, equivalent to IEC 61215 and IEC 61730, for all solar panels.

At the same time, the Provincial Electricity Authority (PEA) updated its inverter approval criteria. Each inverter must now be tested and included in the official approved equipment registry.

For homeowners, mandatory certification is ultimately a positive development. It means that only high quality and reliable solutions will remain on the market. Siriteja Energy works exclusively with leading global brands such as Huawei, Growatt and Deye. All equipment we install is fully certified. We also closely monitor regulatory developments in Thailand’s solar energy sector and assist our clients with preparing and submitting all required documentation at every stage of the project.

New Feed in Tariff

Access to the program allowing households to sell electricity to the grid was previously closed after the annual quota of 100 MW had been exhausted. In 2025, the quota was increased to 400 MW, allowing thousands of additional households to begin selling surplus electricity to the state.

For residential systems up to 10 kW, the feed in tariff is now 2.2 THB per kWh, up from 1.68 THB previously. However, the tariff remains significantly lower than the retail price households pay for electricity. Many homeowners hope for the introduction of full net metering, where exported electricity would be credited at the same rate as consumed electricity. The government has considered transitioning to such a system, but the proposal has been postponed due to technical limitations.

Community Solar Program

In 2025, Thailand approved a “community solar” program for municipalities, cooperatives, and schools, with an annual quota of 400 MW. The program allows participating projects to sell electricity to the grid under dedicated tariff schemes. This direction is particularly important for developers, as it opens opportunities to participate in larger scale solar projects.

Tax Deduction for Homeowners

Starting March 3, 2026, homeowners can deduct up to 200,000 THB, including VAT, from their taxable income for the installation of a rooftop solar system. The deduction applies to individuals who install a grid connected solar system of up to 10 kW on their own residence and will remain available until December 31, 2028.

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What Documents Are Still Required

• Power of attorney, if the application is submitted by the installation company
• Photos of the solar panels and inverter
• Mounting structure plan certified by a licensed engineer
• Electrical diagram also certified by a licensed engineer
• Technical specifications of the panels and inverter
• A list of safety measures for the installation

How to Connect a Rooftop Solar System: Step by Step Guide

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Roof Audit

Order an inspection by a certified engineer to confirm that the roof can safely support a load of up to 20 kg per square meter and does not require structural reinforcement. For commercial projects, the engineer will also assess the feasibility of connecting the system to the grid.

Equipment Selection

Choose solar panels certified under TIS standards (equivalent to IEC 61215 and IEC 61730) and inverters listed in the MEA or PEA approved equipment registry. Some suppliers, such as Huawei, Growatt, and Deye, already provide equipment that meets these certification requirements. Also verify that the inverter is suitable for your electrical connection type: single phase systems typically up to 5 kW, or three phase systems up to 10 kW.

Application Submission to PEA

Submit the application through ppim.pea.co.th or via the PEA Smart Plus platform. The system will automatically transmit the required information to the Energy Regulatory Commission (ERC), so no separate notification is necessary.

You will also need to specify whether you plan to sell surplus electricity under the net billing program (for systems up to 10 kW) or use the solar energy exclusively for self consumption.

Grid Connection Approval

PEA reviews the application, assesses the technical feasibility of grid connection, and issues a power purchase agreement if the system is eligible. According to the ERC, the connection process has been shortened to approximately 30 working days. Once the agreement is signed, you will receive a net billing account under which exported electricity is compensated at 2.2 THB per kWh.

System Installation

After approval, the system is installed, including solar panels, inverter, protection devices, and metering equipment. It is recommended to work with a certified EPC contractor that can deliver a turnkey project and provide guarantees for both equipment and grid connection.

Inspection and Final Agreement

A representative from MEA or PEA will inspect the installation, test the inverter, and connect the system to the grid. After synchronization with the grid, the system becomes operational and you can begin receiving compensation for surplus electricity exported to the network.

Conclusion

2025 marked the most significant liberalization of the rooftop solar market in Thailand to date.

Why this matters for property owners

• Less bureaucracy. Installing solar panels is no longer classified as a building modification, and small systems can now be registered online. This shortens approval timelines and reduces the risk of penalties.
• Access to incentives and subsidies. The government is encouraging the transition to solar energy through tax incentives, surplus energy buyback programs, and BOI initiatives. Homeowners benefit from reduced taxable income and potential revenue from selling excess electricity.
• Higher property value. Energy efficient homes are increasingly attractive to both buyers and tenants. A grid connected solar system can increase the market value of villas and commercial properties.
• Control over energy costs. As electricity prices rise, self generation allows homeowners to offset a portion of their consumption and earn income from surplus power exported to the grid.

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Get a free Solar Rooftop assessment from Siriteja Energy. Our engineering EPC team in Phuket designs and installs turnkey solar and smart home systems, from energy audits and system design to installation and long term service support.

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