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The Philippines' first geothermal power generation in Cale, Tiwi, Albay
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The setting: Tiwi at the Foot of a Volcano
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Tiwi is a coastal town in Albay province, located near the geothermal fields around Mount Malinao and in the broader volcanic landscape dominated by Mayon Volcano. Long before modern power plants were built, the area was known for its hot springs and fumaroles, visible signs of the intense heat stored beneath the ground. These natural features made Tiwi a logical choice for early government‑backed experiments in harnessing geothermal energy for electricity.
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Dr. Arturo P. Alcaraz and the COMVOL team
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The work in Tiwi was led by Dr. Arturo P. Alcaraz, a Filipino volcanologist who headed a research team under the Commission on Volcanology (COMVOL), the predecessor of today's Philippine Institute of Volcanology and Seismology (PHIVOLCS). Assigned as chief volcanologist, Alcaraz had been studying Philippine volcanoes since the early 1960s, not only to understand eruptions but also to explore the possibility of using their stored heat as an energy resource. Because of his pioneering role in these efforts, he is widely recognized as a leading figure - often called a pioneer - in Philippine geothermal energy development.
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<h2>
Building the First Geothermal Demonstration Plant
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COMVOL began focused geothermal investigations in Tiwi around 1962, conducting geological and geophysical surveys to locate promising zones for drilling shallow wells. After identifying suitable sites in the Cale area, the team drilled exploratory wells that produced steam hot enough to turn a small turbine. Using this steam, they assembled a modest 2.5‑kilowatt (2.5 kWe) demonstration plant that could drive a small turbo‑generator, making it the first installation in the country to generate electricity directly from geothermal steam.
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<h2>
April 12, 1967: The Historic Lighting of the Bulbs
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On April 12, 1967, Alcaraz's team piped steam from one of the shallow exploratory wells in Barrio Cale to their small turbine‑generator set. When the generator was brought online, it successfully produced enough electricity to light several electric bulbs in the barrio, an event remembered as the first use of geothermal energy to power electric lights in the Philippines and Southeast Asia. Contemporary accounts describe it as a milestone in the country's energy history, demonstrating in a very concrete way that "earth‑heat" from a Philippine volcano could be converted into modern electric power.
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Symbolism and Impact of the Experiment
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In technical terms, the output of the pilot plant was small - a few kilowatts were enough only for light bulbs and basic loads - but its symbolic value was enormous. For policymakers and engineers, the experiment showed that geothermal steam in Tiwi had sufficient temperature and pressure to sustain power generation, justifying more detailed feasibility studies for larger plants. For the residents of Cale and nearby communities, the sight of bulbs lit by steam from the ground helped turn an abstract scientific idea into a visible sign of national progress and self‑reliance.
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Philippines' First Geothermal Light Bulb Was Lit on April 12, 1967