Solar installations require a Factory License Amendment (รง.4).
The procedures for the application are as follows
- Document Preparation: The entrepreneur prepares all necessary application documents for the solar system installation.
- Submission: Submit the application to the Provincial Industry Office (PIO).
- Verification: The PIO reviews the documentation and officially accepts the application.
- Public Notice: A public announcement must be posted for at least 15 days to gather community feedback and opinions.
- Public Opinion Summary: The PIO summarizes the results of the public hearing process.
- Fee Payment & Approval: The PIO instructs the entrepreneur to pay the required fees and issues the formal Certificate of Factory Expansion.
Key Requirements to Note
- Threshold for Solar Expansion: A factory is required to apply for an expansion permit if the solar installation capacity is 1 MW or higher.
- Definition of a “Factory” (Ror.Ngor. 4): Under current regulations, a facility is classified as a factory requiring a license if it utilizes machinery exceeding 75 horsepower and employs more than 75 workers.


