Fuel diversification for power plants to increase energy balance and reduces imported fuel from overseas is vital to power development plan. Mae Moh Power Plant is an example of EGAT’s achievement in domestic resources development to be used for electricity generation.

With a wide vision of King Rama VII to foresee an opportunity to utilize Mae Moh Mine in the future, he gave a royal command to conserve the lignite source for official use only in 1972. 

From the beginning of the exploration of lignite source in 1817, it led to Mae Moh Mine excavation to utilize lignite for electricity generation, chemicals and cooking charcoal etc.  

In 1954, Lignite Electricity Authority was founded by the government for coal mine operation in order to sell lignite to the tobacco curing houses, State Railway of Thailand and cement factory. Later, Lignite Electricity Authority was changed to be Lignite Authority. In the enactment of EGAT Act B.E. 2511 (1968), the activity of Lignite Authority, Yanhee Electricity Authority and Northeastern Electricity Authority were merged under the Electricity Generating Authority of Thailand (EGAT) which was founded on May 1, 1969. Since then, Mae Moh Mine which is the largest coal mine in Thailand has been under the responsibility of EGAT. The establishment of EGAT has supported the development of economic growth of the Upper North and decreased investment of very long transmission lines from the Central part. The first 3 Units of 75 MW each were constructed followed by the construction of 14 Units respectively. On 7 February 1985, the opening ceremony of Mae Moh Power Plant was performed by His Majesty King Bhumibol. The beginning of the largest thermal power plant using domestic resource as fuel in the North has been implemented and continued until today bringing prosperity to the region and the country endlessly. 

Mae Moh Power Plant consists of 14 Units of thermal power plant as follows : 

• Units 1-3, each of the capacity of 75 MW, total capacity of 225 MW (decommissioned)  
• Units 4-7, each of the capacity of 140 MW, total capacity of 560 MW (decommissioned) 

At present, Mae Moh Power Plant has the total contractual generating capacity of 2,220 MW comprising 

• Units 8-13 with the generating capacity of 1,620 MW 

• Unit 14 with the generating capacity of 600 MW  

(Replacing Units 4-7)