The northeastern part of Thailand is the large region and the most populated in the country. The region has an increasing demand for electricity every year. To meet the demand, EGAT has applied advanced technology, specifically a pumped-storage hydropower plant.

The pumped-storage hydropower plant was constructed near Lamtakong Dam. EGAT has considered developing the first pumped-storage hydropower plant project of Thailand in the northeastern region. The power plant is operated by pumping water from the reservoir of Lamtakong Dam of the Department of Royal Irrigation to store in the upper reservoir on Khao Yai Thiang during the time of off-peak or from night time to morning. When the peak demand occurs during daytime to evening, water will be released from the upper reservoir for electricity generation before being released into Lamtakong reservoir again.

The construction of the project began in 1994. The upper reservoir on Khao Yai Thiang is a rockfill covered with asphalt to prevent seepage. The reservoir capacity is 10.3 million cubic meters. Lamtakong Jolabha Vadhana Power Plant was built about 350 meters below the ground. It is the first and the only underground power plant in the country. Two generators with the total capacity of 500 MW with water turbines of Vertical Shaft Francis Type were installed. After the construction, the power plant has supplied electricity to the system since 2004. This power plant plays an important role in supporting the power system during the peak period and strengthens security of the power system in the Northeast, a vital factor to enhance industrial development in the region.            

On July 17, 2009, His Majesty King Bhumibol Adulyadej The Great graciously named the power plant “Lamtakong Jolabha Vadhana” meaning “Lamtakong Power Plant is the place of developing electric light by water.” On June 13, 2013, the opening of the power plant was inaugurated by Her Royal Highness Princess Maha Chakri Sirindhorn representing the King. Lamtakong Jolabha Vadhana Power Plant is the last power plant during the reign of King Bhumibol Adulyadej The Great which was auspiciously named by the king.

Presently, Lamtakong Jolabha Vadhana Power Plant has the contractual generating capacity of 1,000 MW

• It is the pumped-storage hydropower plant which is the first and the only underground power plant in Thailand.