Deep-well heat data point to Thailand’s geothermal potential

Visit Coothongkul, chief executive officer of RT Geothermal Company Limited, told Thansettakij that Thailand’s Power Development Plan 2026, or PDP2026, should not be based solely on energy resources that Thailand currently possesses and has already proven.

It should also provide scope to verify future energy resources that may lie beneath the country, particularly geothermal energy, whose characteristics meet the future needs of the power system.

The key advantage of geothermal energy is that it can generate electricity continuously, 24 hours a day, 7 days a week, without depending on weather conditions as solar and wind power do.

It can therefore function as a stable renewable source, or Clean Firm Power, strengthening power-system stability, reducing reliance on imported fuels and meeting demand for high-quality electricity from data centres, AI and future industries.

Thailand is not starting from zero

Visit said Thailand was not starting from zero in studying geothermal energy, having faced global oil crises in 1973–1974 and 1979–1980 that sent oil prices soaring and severely affected the economy.

At that time, the Electricity Generating Authority of Thailand (EGAT) established the “Special Energy Division” to study domestic energy potential, covering solar, wind and geothermal energy.

The work led to the construction of the 300 kW Fang Geothermal Power Plant in Chiang Mai in 1989, providing important evidence that Thailand can indeed generate electricity from its own underground heat.

Over nearly 50 years, geothermal technology has advanced considerably, particularly through expertise from the shale oil and gas industry. Horizontal drilling and hydraulic fracturing are now being applied to the development of Enhanced Geothermal Systems (EGS).

EGS is important because it extends geothermal development beyond areas with hot springs or near volcanic zones, allowing underground heat to be used in a wider range of geologically suitable areas.

One notable example is Fervo Energy in the United States, which developed EGS at Project Red in Nevada before expanding to Cape Station in Utah.

Cape Station is being developed with 500 MW of generating capacity, while the area has a reported potential of up to 4.3 GW.

Thailand has ‘Proof of Heat’ but needs further proof

Visit noted that Thailand had drilled nearly 10,000 petroleum wells in total over almost 50 years, most of them in the Gulf of Thailand.

Some wells around 3–4 kilometres deep recorded temperatures above 200 degrees Celsius.

Thailand also has an interesting geological setting, including rifted basins, a granite belt extending from northern Thailand to the peninsula and the Gulf of Thailand, and major fault zones that may carry heat upwards from greater depths.

Data from onshore wells in Kamphaeng Saen and Thawi Watthana, together with data from groundwater wells about 1 kilometre deep in Samut Sakhon province, also warrant further study.

However, Visit stressed that these data do not yet constitute “proven reserves”; they amount to “Proof of Heat” sufficient to begin systematic exploration.

From petroleum rules to geothermal rules

Another key issue is that geothermal development cannot rely solely on technology and geological data; it also requires laws and a regulatory system that give investors confidence.

Visit cited lessons from Thailand’s petroleum industry, where the Petroleum Act 1971 was a key mechanism defining exploration and production rights, the concession system, duration, obligations, joint investment arrangements, oversight and the benefits received by the state.

That clarity enabled foreign companies to bring capital, technology, personnel and risk-bearing capacity to participate in exploration in Thailand, while the state gained data, expertise, personnel, revenue and infrastructure that later formed an important foundation for the country’s petroleum industry.

Geology tells us where resources may lie, but clear laws give investors the confidence to begin searching for them.

For geothermal energy, the petroleum law need not be adopted in full, but a clear framework should cover key issues including rights to subsurface resources, exploration and drilling permits, access to sites, reinjection, data use and disclosure, seismic monitoring, and project decommissioning at the end of its operating life.

Crucially, there should be a risk-sharing mechanism between the public and private sectors because the initial risk in geothermal exploration lies in drilling to prove whether commercially producible resources exist.

Visit’s key proposal for PDP2026 is not to set an immediate geothermal target of several thousand megawatts, but to include geothermal as one of the technologies in a Clean Firm Power Technology Track and establish a National Geothermal Proof Program to assess the country’s potential systematically.

His proposed steps include producing a national geothermal resource map, making use of existing data from petroleum and groundwater wells, drilling deep exploration wells and developing pilot projects under a Stage Gate model.

The principles are “Prove first; expand when the data confirm the potential” and “Set the rules first; capital and technology will follow.”

Visit argued that PDP2026 need not rush to determine how many megawatts of geothermal capacity Thailand should have, but should begin by proving the potential.

Lessons from Thailand’s petroleum industry show that subsurface resources are not developed simply because a country knows they exist.

Development comes from a willingness to invest in systematic exploration and from laws that make investors willing to take on risk alongside the country.

Thailand once turned subsurface data into natural gas that served as the backbone of the Thai economy for decades.

PDP2026 could now mark the beginning of doing the same again.

Source: Thansettakij