Over a dozen high-ranking positions at three energy state enterprises and energy policymakers are open to alternative resources, marking a sea change in the sector.
Mr Kulit takes over as energy permanent secretary.
PTT Plc, the national oil and gas conglomerate, expects to elect four high-ranking executives to replace retirees at the end of last month.
Chansin Treenuchagron was appointed president and chief executive by PTT's board of directors in April to replace Tevin Vongvanich. Mr Chansin started his new position last Friday.
The four open positions are expected to be selected by the PTT board tomorrow, said a source who is familiar to this matter.
Mr Chansin is the new head of PTT, starting last Friday.
"These new appointments will be the biggest changes in PTT's human resources since establishment in December 1978," the source said.
As of Aug 31, there were 90 people at PTT in middle and operating levels entering retirement, including five at the highest level.
Three in middle management are Nitima Thepvanangkul, chief financial officer, Sriwan Eamrungroj, senior executive vice-president for corporate strategy and Boobpha Amornkiatkajorn, senior executive vice-president for international trading business.
Furthermore, two PTT Group subsidiaries will select new chief executives to replace Toemchai Bunnag at Global Power Synergy Plc, PTT's power business, and Somporn Vongvuthipornchai at PTT Exploration and Production Plc (PTTEP).
For PTTEP, Phongsthorn Thavisin will start as president and chief executive from Oct 1.
On the policymaking front, seven positions will be vacated as officials reach retirement.
In the Energy Ministry, Customs Department director-general Kulit Sombatsiri will replace Thammayot Srichuai as permanent secretary when the latter retires at the end of September.
The ministry's chief inspector Suchalee Sumamal will retire in the same period and Mr Kulit will need to select a replacement for him.
Mr Kulit will also select two director-generals at two departments, replacing retirees Veerasak Puengrasamee in the Mineral Fuels Department, an upstream petroleum regulator, and Witoon Kulcharoenwirat at the Energy Business Department, a downstream petroleum regulator.
Three commissioners at the Energy Regulatory Commission will need to be appointed -- Duongmanee Komaratat and Vachara Kunawatanawuti have taken early retirement while Kraisi Karnasuta is retiring at age 70.
At the Electricity Generating Authority of Thailand, the cabinet appointed May Viboon Rerksirathai as the new governor in May to replace Kornrasit Pakchotanon as the latter retires.
The Metropolitan Electricity Authority and the Provincial Electricity Authority will each have vacant governorships as Chaiyong Puapongsakorn and Sermsakool Klaikaew are going to retire soon. The Interior Ministry will select their replacements.
Mr Phongsthorn is the new head of PTTEP starting Oct 1.