Thailand is stepping up efforts to expand its solar power infrastructure as part of a broader drive towards clean energy and reduced reliance on fossil fuels. With abundant sunshine throughout much of the year and increasing pressure to decarbonise its economy, the Southeast Asian nation has identified solar energy as a key pillar in its energy transition strategy.

Currently, Thailand boasts the largest solar capacity in the ASEAN region, with more than 3 gigawatts (GW) of installed solar photovoltaic (PV) capacity as of 2024. This marks a steady increase from under 2.5 GW five years ago. The country was one of the early movers in the region to embrace solar technology, and its government continues to encourage investment through incentives and revised energy plans.

At the heart of this push lies the Power Development Plan (PDP) 2024, which sets out an ambitious vision for the nation's energy future. Under the PDP, Thailand aims to generate 50% of its electricity from renewable sources by 2040. Of that, solar is expected to contribute a significant share, with a target of over 14 GW of installed solar capacity within the next 15 years.

To meet this goal, the government is encouraging both utility-scale solar farms and distributed rooftop installations. Rooftop solar has gained particular traction among businesses and households seeking to reduce their electricity bills and carbon footprint. The Ministry of Energy has also rolled out net metering schemes, allowing small-scale producers to sell excess power back to the grid, a move designed to incentivise adoption across the private sector.

Notably, state-owned utilities such as the Electricity Generating Authority of Thailand (EGAT) and the Provincial Electricity Authority (PEA) have increased their investments in solar infrastructure. EGAT recently announced a pilot floating solar farm on the Sirindhorn Dam in Ubon Ratchathani, combining solar PV with hydropower in a hybrid model. The project, among the largest of its kind in the world, represents a new approach to renewable energy integration in Thailand.

International investors are also taking notice. Japanese, Chinese, and European companies have all partnered with Thai firms to develop large-scale solar farms across provinces such as Lopburi, Nakhon Ratchasima and Chonburi. In addition, Thailand’s well-developed grid infrastructure, compared to many of its neighbours, makes it a more attractive destination for solar developers looking for regional hubs.

However, issues remain. Land availability for large-scale projects is limited in densely populated or agriculturally important areas, and regulatory hurdles can still slow implementation. Critics also point to the slow pace of policy reform and bureaucratic processes, calling for more streamlined permitting and clearer long-term incentives.

Still, with rising energy demand, pressure to reduce emissions, and declining costs of solar technology, Thailand’s solar prospects appear bright. The country is positioning itself not only as a regional leader in solar deployment but also as a potential exporter of renewable energy expertise.

As Southeast Asia grapples with the twin pressures of economic growth and climate change, Thailand’s solar expansion offers a glimpse into what a low-carbon future might look like for the region.