Amid growing pressures from ongoing crises and Thailand’s environmental commitments, the clean energy transition extends beyond government policy. It increasingly depends on enabling citizens to play an active role in shaping and participating in the country’s evolving energy landscape.
This shift has supported efforts to promote clean energy adoption at the household level, creating opportunities for citizens to become “prosumers”, both consumers and producers of electricity. One key initiative is the “People’s Solar” programme, launched in 2019, which allows households with rooftop solar installations to sell surplus electricity back to the grid through the Metropolitan Electricity Authority (MEA) or the Provincial Electricity Authority (PEA) at government-determined tariff rates.
A key component of the programme is the use of a net billing mechanism, under which surplus electricity exported to the grid is compensated based on its monetary value. The mechanism was designed to support greater energy self-reliance among households and improve the economic viability of rooftop solar investments by providing an additional revenue stream from excess generation. Rather than serving as a broad-based subsidy to reduce household electricity costs, the scheme aims to encourage distributed renewable energy deployment and strengthen public participation in the energy transition.
In its initial phase, the programme offered a feed-in tariff of up to THB 1.68 per kilowatt-hour (kWh) for surplus electricity exported from participating households, with a guaranteed purchase period of 10 years. In 2021, the scheme was revised, increasing the purchase rate to THB 2.20 per kWh for a 10-year period covering 2021–2030.
At the same time, participation in the programme remained subject to a procurement quota of 90 MW. As interest in rooftop solar continued to grow, applications eventually reached the programme’s capacity limit. As a result, in June 2024, the Energy Regulatory Commission (ERC) suspended new enrolments after the quota had been fully subscribed. In response, government agencies are currently reviewing the scheme and considering the gradual expansion of future procurement quotas to accommodate additional participants.
More recently, additional measures have been introduced to encourage household adoption of clean energy technologies. These include a personal income tax deduction of up to THB 200,000 per household for the installation of residential rooftop solar systems. Available through December 2028, this incentive is designed to reduce upfront investment costs and support the wider deployment of distributed renewable energy across the country.
At the same time, uncertainty in the energy sector since early 2026 has further strengthened public interest in such policies. Rising concerns over energy costs, energy security, and system resilience have prompted more households to explore opportunities to generate their own electricity and reduce reliance on conventional energy sources.
Viewed from a broader perspective, the outlook for residential rooftop solar in Thailand appears increasingly promising. Supportive policies, financial incentives, and growing public awareness have helped create favourable conditions for wider adoption.
However, beneath this positive trajectory, a number of structural constraints and implementation challenges remain. Addressing these issues will be important to ensuring that the benefits of rooftop solar can be accessed more broadly and that its contribution to Thailand’s clean energy transition can be fully realised.
Barriers to Adoption
One of the most significant barriers to residential rooftop solar adoption is the upfront investment required for installation. While the cost of solar technology has declined in recent years, the initial capital expenditure remains substantial for many households.
In Thailand, most installers offer systems with a minimum capacity of around 3 kilowatts (kW), requiring an investment of tens of thousands of baht. For many households, this remains a key obstacle to adoption.1 This means that households must be able to cover the upfront installation cost before they can benefit from rooftop solar. While the tax deduction can help reduce the financial burden, it does not directly reduce the amount of tax owed. Instead, the maximum deduction of THB 200,000 is applied to taxable income, lowering the tax base rather than providing a direct reimbursement. As a result, the value of the incentive varies depending on an individual’s income tax bracket, meaning that the benefits may not be equally accessible to all households.
Another constraint relates to housing conditions. As rooftop solar installations are considered a form of building modification, they are subject to approval and safety requirements set by relevant authorities. In practice, this means that households interested in installing solar panels must have a residence with a structurally sound roof capable of supporting the additional weight of the system. Adequate roof space and suitable orientation for solar exposure are also important factors in determining whether an installation is feasible.
One example of this challenge can be found in urban residential buildings, such as condominiums and apartment complexes. Due to limited roof space, opportunities for installing solar panels are often constrained. Even where rooftop solar installations are technically feasible, the available area may not be sufficient to generate enough electricity to meet the demand of all residents. As a result, many urban households face practical barriers to participating in rooftop solar programmes despite growing interest in clean energy solutions.
One potential approach to addressing this challenge is the implementation of Third-Party Access (TPA), which would allow third parties to use the electricity grid alongside the utilities that operate it. Under such a framework, electricity generated by private producers could be delivered directly to consumers through the existing grid infrastructure, subject to the payment of regulated wheeling charges.
By enabling access to renewable electricity from off-site generation sources, TPA could expand opportunities for consumers who are unable to install rooftop solar themselves. This could benefit residents of condominiums and apartment buildings, as well as communities facing physical or technical constraints that limit the deployment of on-site solar systems, allowing them to participate more fully in the clean energy transition.
Recent developments in this area include the approval of a pilot Direct Power Purchase Agreement (Direct PPA) scheme by the National Energy Policy Council (NEPC) in 2024. The pilot allows electricity producers to supply power directly to consumers through a TPA framework, with a total capacity of up to 2,000 MW.
However, the pilot programme is primarily designed for large electricity consumers, particularly data centres and other energy-intensive businesses. At present, it does not extend to residential consumers. As a result, while the initiative represents an important step towards greater electricity market participation and renewable energy access, its benefits are not yet available to households, including residents of condominiums and other multi-unit residential buildings.2
These considerations raise broader questions about the extent to which current policies for promoting residential rooftop solar are able to meet the diverse needs of households. While existing measures have helped expand opportunities for some consumers to participate in the clean energy transition, questions remain as to whether the benefits are being distributed broadly enough and whether the policy framework adequately addresses the varying circumstances faced by different groups of citizens.
Economic Viability of Rooftop Solar
While rooftop solar offers clear benefits in the form of clean energy generation and reduced electricity bills, the upfront investment required for installation also means that households are likely to consider the economic viability of such an investment. For many prospective adopters, the decision to install rooftop solar depends not only on environmental considerations, but also on the expected financial returns and the length of time required to recover the initial costs.
Factors such as household electricity consumption patterns, the size and quality of the solar system, and the availability of government support measures can all influence the payback period of a rooftop solar installation. As a result, the economic returns from rooftop solar can vary considerably across households, depending on their individual circumstances.
This is particularly relevant given that solar panels can only generate electricity when sunlight is available. Households that wish to use solar-generated electricity during the evening or at night may need to invest in battery storage systems to store excess electricity for later use. While battery storage can increase energy self-sufficiency and flexibility, it also adds to the overall cost of installation, affecting the project’s economic viability and payback period.
For example, a 3 kW rooftop solar system, the smallest size commonly available on the market and capable of generating approximately 300–400 kWh of electricity per month, typically has a payback period of around six to seven years. The actual payback period may vary depending on household consumption patterns, installation costs, and the extent to which the electricity generated can be used on-site. 3 This represents a relatively long investment horizon for many households. As a result, policies that allow households to sell surplus electricity back to the grid have attracted considerable interest, as they can provide an additional source of revenue and help shorten the payback period of rooftop solar installations.
However, as noted earlier, participation in the surplus electricity purchase programme is limited by a quota system, and no additional applications have been accepted since the available quota was fully subscribed in 2024. Beyond this constraint, another area of discussion relates to the purchase rate itself. While surplus electricity is currently purchased at THB 2.20 per kWh, households typically purchase electricity from the grid at a higher retail tariff. This difference affects the overall economics of rooftop solar investments, as electricity exported to the grid is valued at a lower rate than electricity consumed from it. As a result, the payback period may be extended, potentially reducing the financial attractiveness of installing rooftop solar systems for some households.
The economics of rooftop solar are also influenced by the billing mechanism used for electricity trading. As noted earlier, Thailand currently applies a net billing system, under which households can sell surplus solar electricity back to the grid. However, the purchase price for exported electricity is lower than the retail tariff paid by households for electricity consumed from the grid. This difference can lengthen the payback period for rooftop solar investments.
At the same time, the net billing approach provides flexibility for policymakers to set compensation rates that reflect the costs associated with operating, maintaining, and ensuring the stability of the electricity grid. As a result, the mechanism seeks to balance incentives for distributed renewable energy deployment with broader system management considerations.
An alternative approach that is often discussed is net metering, which is based on the exchange of electricity units rather than monetary value. Under a net metering system, electricity generated by a rooftop solar system can be directly offset against electricity consumed from the grid on a one-to-one basis. In effect, each unit of electricity exported to the grid carries the same value as a unit purchased from the utility. This can improve the economics of rooftop solar and shorten the payback period for households compared with a net billing arrangement.4
Given the different advantages and trade-offs associated with each approach, discussions around the most appropriate billing mechanism have continued. At the same time, any assessment of these options must also consider their implications for the broader electricity system.
Electricity generated by rooftop solar and exported to the grid can provide important benefits, such as reducing the need for conventional power generation during periods of high demand. However, it can also introduce operational challenges due to the variable nature of solar generation, which depends on weather conditions and the availability of sunlight. As the share of distributed solar increases, maintaining grid reliability and system stability becomes an increasingly important consideration in the design of support mechanisms and market arrangements.
Another consideration relates to equity among electricity consumers. Thailand’s electricity sector operates under a cost-recovery model, whereby the costs of investing in, operating, and maintaining the electricity network are recovered through electricity tariffs paid by consumers.
As households with rooftop solar reduce the amount of electricity they purchase from the grid, utility revenues may decline while many network-related costs remain unchanged. This has led to discussions about how the costs of maintaining the electricity system should be allocated and whether a greater share of these costs could ultimately be borne by households that do not have access to rooftop solar. Balancing incentives for distributed renewable energy with broader considerations of cost recovery and fairness therefore remains an important policy consideration. 5
Equally important is whether the current structure of the electricity sector is prepared to support a transition towards a more decentralised energy system with a growing number of small-scale electricity producers. As distributed renewable energy continues to expand, policymakers may need to consider how the electricity system can evolve to accommodate changing patterns of generation and consumption while maintaining reliability, cost recovery, and fairness.
End-of-Life Management of Solar Equipment
A final consideration is the management of solar equipment at the end of its operational life, an issue that will become increasingly important as Thailand continues to expand the deployment of solar energy.
Solar panels typically have a lifespan of around 25–30 years. Beyond this period, their electricity generation efficiency gradually declines, and they may need to be decommissioned and replaced. As solar installations continue to grow, the volume of end-of-life solar panel waste is expected to increase significantly. Estimates suggest that cumulative solar panel waste in Thailand could reach approximately 9,900–57,200 tonnes by 2030 and 17,900–78,100 tonnes by 2032, reflecting the rapid expansion of installations between 2010 and 2020.
In addition to the challenge of waste management, there are also environmental and public health considerations associated with the accumulation of certain materials contained in solar panels. Projections indicate that, by 2040, end-of-life solar panels in Thailand could contain approximately 3.0–17.2 tonnes of lead and 6.9–40.0 tonnes of antimony. These projections highlight the importance of developing effective collection, recycling, and disposal systems alongside efforts to expand solar energy deployment.6
At present, Thailand does not yet have a comprehensive framework for managing end-of-life solar panels. Existing guidance focuses primarily on disposal options such as landfilling, incineration, and export for treatment abroad. While these approaches provide pathways for handling solar waste, they have also raised concerns regarding the potential release of hazardous materials and the long-term environmental and public health implications associated with improper disposal.
Taken together, Thailand’s experience with rooftop solar highlights that the key challenges facing the sector are no longer primarily related to the technical viability of solar technology itself. Over the past decade, a range of policies and support measures have been introduced to encourage greater adoption of solar energy, reflecting growing confidence in the technology’s maturity, reliability, and role in the country’s energy transition.
Instead, many of the remaining challenges are linked to the structure of the electricity sector, which was not originally designed to accommodate a growing number of diverse, small-scale electricity producers. While policies that encourage rooftop solar deployment can help stimulate adoption, they may not on their own be sufficient to support a comprehensive and long-term energy transition.
Alongside continued support for solar deployment, there is also a need to consider how the electricity sector can evolve to better integrate distributed energy resources and enable broader participation in the energy system. This includes examining whether existing market arrangements remain fit for purpose as the number of small-scale producers increases and as electricity generation becomes more decentralised.
In this context, discussions on electricity sector reform have increasingly focused on how to create greater flexibility and consumer choice within the market. Thailand’s current electricity system is largely based on a single-buyer model, in which electricity generated by private producers is purchased centrally before being supplied to end users through the distribution utilities. Alternative market designs, including more liberalised arrangements that allow consumers to purchase electricity directly from a wider range of suppliers, are often discussed as potential pathways for accommodating a more diverse and distributed energy landscape.
Such a model could help address multiple challenges. It could increase competition in the electricity market and allow consumers to choose clean electricity from their preferred sources, whether they are households that do not have sufficient space to install solar panels on their premises or businesses exporting products to the European Union, such as the steel industry, which is subject to import charges under the Carbon Border Adjustment Mechanism (CBAM) based on the greenhouse gas emissions associated with their products, a measure that came into effect on 1 January 2026. 7
Furthermore, if small-scale electricity producers are able to sell surplus electricity freely, the payback period for rooftop solar installations could be shortened, creating stronger incentives for households and businesses to invest in solar energy systems.
Another important priority is preparing for the growing volume of end-of-life solar equipment. As Thailand is still in the relatively early stages of expanding solar deployment, there is an opportunity to develop the policies, systems, and technologies needed to manage solar waste in a safe and effective manner before it becomes a larger challenge.
Potential measures could include examining regulatory approaches that clarify responsibility for solar panels at the end of their useful life, whether through Extended Producer Responsibility (EPR) schemes that assign responsibility to manufacturers or through the Polluter Pays Principle (PPP), under which users bear responsibility for disposal and treatment costs. In parallel, developing systems to collect and track information on solar installations could provide an important evidence base for monitoring, planning, and managing future solar waste streams.
There is also a need to establish collection and processing systems for decommissioned solar panels, including mechanisms to identify panels that remain suitable for continued use and to promote their reuse where technically and economically feasible. Such measures could help reduce waste volumes, extend the useful life of solar equipment, and support the development of a more circular solar economy. 8
The story of solar energy demonstrates that, while solar power has significant potential in the Thai context and the technology itself is already commercially available and widely proven, practical barriers can still arise when the broader energy sector framework is not fully aligned with the requirements of the transition. Combined with support measures that do not yet address the entire lifecycle of the technology, these challenges can limit the effectiveness of deployment efforts and contribute to public concerns.
At the same time, this experience reinforces an important lesson: a successful and sustainable energy transition depends on more than technological readiness alone. It also requires policy frameworks that are designed in a comprehensive manner, taking into account economic, social, environmental, and institutional considerations, while ensuring that the interests of all stakeholders are appropriately balanced.
This lesson also raises a broader question for emerging energy technologies. If a technology as familiar and established as solar power continues to face these challenges, what might this mean for technologies that are still at an earlier stage of development, such as hydrogen and small modular reactors (SMRs)? Will they represent new opportunities, new challenges, or a combination of both for Thailand? And what role could they play in the country’s future energy landscape?
These are some of the questions that will be explored in the next article of the Energy Transition Series.
Thailand’s Solar Journey: From Early Adoption to the Energy Transition
The energy transition is a key mechanism for helping Thailand achieve both its environmental objectives and long-term energy security goals.
Over the years, a wide range of clean energy technologies have been developed and deployed. These technologies have contributed to reducing greenhouse gas emissions from energy production and have become important technical enablers of the energy transition.
Among them, one of the most prominent technologies—and one that is particularly well aligned with Thailand’s geographic potential—is solar energy.
Solar energy is derived from the sun’s radiation. While sunlight has traditionally been viewed primarily as a source of light and heat, technological advances have enabled solar radiation to be converted into electricity through solar panels. These panels are made from semiconductor materials, most commonly silicon, which possess the properties required to generate the photoelectric effect—a process through which sunlight striking the surface of a solar panel is converted into electrical energy.
The electricity generated can then be converted into a form that can be used directly by households and electrical appliances. Alternatively, it can be stored in battery systems for later use when solar radiation is unavailable, such as during the evening or periods of low sunlight.
In Thailand, electricity generation from solar panels is not a new concept. As early as 1976, agencies under the Ministry of Public Health and the Princess Mother’s Medical Volunteer Foundation began deploying approximately 300 solar panels for electricity generation. At the policy level, solar energy was also incorporated into Thailand’s national development planning through the Fourth National Economic and Social Development Plan (1977–1981).9 Since then, the development and promotion of solar energy have continued steadily. Today, solar technologies are deployed in a variety of forms, depending on their intended application and the characteristics of each location, and are being promoted across multiple levels of the energy system.
These applications range from large-scale projects led by the government to smaller distributed systems. One example is floating solar, which involves installing solar panels on floating structures in reservoirs or dam impoundments. This approach helps increase the electricity generation capacity of existing hydropower facilities, creating what is known as a hybrid floating solar-hydropower plant. A key advantage of this model is its ability to generate electricity from both solar energy during daylight hours and hydropower from existing dam infrastructure during periods when solar generation is unavailable or when additional electricity is needed to meet peak demand. The Electricity Generating Authority of Thailand (EGAT) launched its first pilot project at Sirindhorn Dam in Ubon Ratchathani Province in October 2021 and has since outlined plans to expand similar projects across major dams. The combined generation capacity of these developments is targeted to reach 2,725 MW by 2030. 10
At the same time, households and businesses have increasingly adopted rooftop solar systems to generate electricity on-site. These systems produce direct current (DC) electricity, which is then converted by an inverter into alternating current (AC) electricity for use in buildings and with conventional electrical appliances.
Thailand’s solar journey over the past five decades reflects the growing role of solar energy within the country’s electricity system. More broadly, it highlights an important reality: sunlight is not only a natural resource available in abundance, but also an opportunity to shape a cleaner, more secure, and more sustainable energy future.
As Thailand continues its energy transition, solar energy is expected to remain an important part of the conversation—not only because of its technical potential, but also because of the broader questions it raises about how energy systems, markets, and policies can evolve to support a more resilient and inclusive energy future.
- สายะเสวี, ม. (ผู้ดำเนินรายการ). (2569, เมษายน). Install – ใครอยากใช้พลังงานทางเลือก และใครกันแน่ที่เข้าถึงได้จริง. Healthstation Talk. YouTube. https://www.youtube.com/watch?v=eDmwYi7yuEc ↩︎
- สำนักงานคณะกรรมการกำกับกิจการพลังงาน. (2568, ตุลาคม). รายงานการรับฟังความคิดเห็นเรื่อง เรื่อง ร่างหลักเกณฑ์ โครงการนําร่องการซื้อขายไฟฟ้าพลังงานหมุนเวียนในรูปแบบการทํา
สัญญาซื้อขายพลังงานไฟฟ้าได้โดยตรง (Direct Power Purchase Agreement: Direct PPA) ผ่านการขอใช้บริการระบบโครงข่ายไฟฟ้าให้แก่บุคคลที่สาม (Third Party Access: TPA) สําหรับศูนย์ข้อมูล (Data Center). https://www.erc.or.th/th/listen-to-opinions/580 ↩︎ - PEA ENCOM SMART. (ไม่ระบุวันที่). บ้านแบบไหนที่ติดตั้งโซลาร์เซลล์แล้วจึงคุ้ม? / คืนทุนในกี่ปี? https://www.encomsmart.com/post/post_4_whichhome_need_solarcell_break-even ↩︎
- กลุ่มวิชาการ กองพัฒนาทรัพยากรบุคคลด้านพลังงาน กรมพัฒนาพลังงานทดแทนและอนุรักษ์พลังงาน กระทรวงพลังงาน. (2567, มกราคม). ความแตกต่างระหว่างระบบขายไฟ Net Billing และ Net Metering. https://enhrd.dede.go.th/ความแตกต่างระหว่างระบบ/ ↩︎
- จุลกาญจน์, ส. (2566, พฤษภาคม). ทำความรู้จัก Net Metering และ Net Billing และประเด็นขบคิดเพื่อการพัฒนากลไกที่ยั่งยืน. ข่าวสด Online. https://www.khaosod.co.th/pr-news/news_7659547 ↩︎
- บัวแย้ม, ณ. และคณะ. (2568, ธันวาคม) สถานการณ์ขยะโซลาร์เซลล์และแนวทางพัฒนานโยบายการจัดการแผงโซลาร์เซลล์หลังสิ้นอายุขัยของประเทศไทย. สถาบันวิจัยเพื่อการพัฒนาประเทศไทย (TDRI). https://tdri.or.th/2025/12/pv-eol-situation-white-paper/ ↩︎
- ศูนย์วิจัยกสิกรไทย. (2568, ธันวาคม). มาตรการปรับราคาคาร์บอนข้ามพรหมแดน (CBAM) ของสหภาพยุโรปที่จะเริ่มบังคับใช้ 1 ม.ค. 2569 อาจทำให้อุตสาหกรรมเหล็กของไทยสูญเสียความสามารถในการแข่งขันเร็ว ๆ นี้. Econ Digest. https://www.kasikornresearch.com/th/analysis/k-social-media/Pages/CBAM-EU-Steel-CIS3629-FB-2025-12-08.aspx ↩︎
- บัวแย้ม, ณ. และคณะ. (2568, ธันวาคม) สถานการณ์ขยะโซลาร์เซลล์และแนวทางพัฒนานโยบายการจัดการแผงโซลาร์เซลล์หลังสิ้นอายุขัยของประเทศไทย. สถาบันวิจัยเพื่อการพัฒนาประเทศไทย (TDRI). https://tdri.or.th/2025/12/pv-eol-situation-white-paper/ ↩︎
- บูรณสิงห์, ณ. (2558, เมษายน). เซลล์แสงอาทิตย์พลังงานทดแทนที่ยั่งยืน. สำนักวิชาการ สำนักงานเลขาธิการสภาผู้แทนราษฎร. https://old.parliament.go.th/ewtadmin/ewt/parliament_parcy/ewt_dl_link.php?nid=28468&filename=index ↩︎
- Green Network. (2558, ตุลาคม). กระทรวงพลังงาน เร่งเดินหน้าโครงการ Floating Solar ของ กฟผ.. Green Network Thailand. https://www.greennetworkthailand.com/energy-egat-floating-solar/ ↩︎
