Ratnavadi’s shares in Thailand’s third largest power producer, Gulf Energy Development Pcl, surged 50 percent after announcing last August that he would invest in solar and power ventures in Vietnam.

He owns about 73 percent of Gulf Energy. With a net worth of $4.8 billion, he is the third richest man in Thailand, according to the Bloomberg Billionaires Index.

The surge in Gulf Energy’s share price since August 15 is the second-biggest among the 36 companies in the Bloomberg Asia Pacific Electric Index.

"Vietnam has a vast potential as higher economic growth and foreign direct investments will boost future electricity demand," Sarath said in an interview with Bloomberg.

At a meeting with authorities in Ninh Thuan Province in central Vietnam last month, Gulf Energy expressed interest in building a $7.8-billion liquefied natural gas (LNG)-fired power complex in Ca Na, a coastal commune in the province.

It will have four LNG-fired power plants with a combined capacity of 6,000 MW to be built under build-operate-transfer (BOT) or other modes.

Ninh Thuan recently sent to the Ministry of Industry and Trade a proposal to add the Ca Na power complex to its development plans for appraisal. The proposal will be submitted to competent authorities for approval later.

Pham Van Hau, the province’s Vice Chairman, said that once the proposal is approved, Ninh Thuan would release the criteria for choosing investors, with Thailand’s Gulf Energy being one of the candidates.

In addition to Ca Na, Gulf Energy is also eyeing a 5,000 MW gas power complex in the southern province of Dong Nai and said it is ready to supply gas-fired power technologies to companies in Vietnam.

Under the country's gas industry development plan by 2025, with vision to 2035, Vietnam plans to have six LNG terminals at a total cost of more than $6 billion.

The World Bank has estimated Vietnam’s electricity demand to grow by around 8 percent a year for the next decade, and said it would need to invest $150 billion by 2030 to develop its energy sector.