The Grid Code is a regulatory instrument used to coordinate various electricity supply activities of the electricity producer, operator, distributor and the consumer.

The Grid Code for Peninsular Malaysia was first issued by the Energy Commission based on the approval made by the Commission on 8 June 2010 and by the Minister on 21 December 2010. Pursuant to Section 42 of the Electricity Supply (Amendment) Act 2015 [Act A1501], the Code shall continue in full force and effect from the date of registration.

The Grid Code is a technical specification which defines the parameters electricity generating plants and grid system networks have to meet to ensure proper functioning of the electrical grid. It is used by utility companies such as TNB and IPPs in Peninsular Malaysia as the main guidelines in electricity supply operation and helps to ensure the reliability of electricity supply in Peninsular Malaysia.

The Grid Code set the regulations and technical requirements to be followed by all parties involved in the planning, managing and maintenance of the grid system to ensure security, safety and reliability. They provide detailed roles and responsibilities of parties involved in managing or using the system, including generators, grid system operators, distribution system operators, single buyers and large power consumers.

The Energy Commission of Malaysia as the regulatory body of the energy industry, will chair the Grid Code Committee (GCC) with members from the energy industry. The GCC is tasked to oversee the implementation of the Grid Code. The Committee shall ensure the relevancy of the Grid Code, review and make amendments to the Grid Code and provide guidance in relation to implementation, performance and interpretation of the Code.

Amongst other things, the Grid Code contains a Planning Code describing the process by which the Grid Owner undertakes the planning and development of the grid system, including timescales, and the provision of certain information by Users and the Grid Owner to enable this process; a Connection Code specifying the minimum technical, design and operational criteria which must be complied with by Users connected or seeking connection or seeking to modify their connection to the grid system; an Operation Code dealing with all processes associated with operational planning and control operation of the system in real time and obligations of the Users to provide and supply information to the Grid Owner and Grid System Operator (GSO) to enable those processes; a Scheduling and Dispatch Code containing preparation of an indicative least cost generation schedule indicating which generating units may be instructed or dispatched, the issuance of control, scheduling and dispatch instructions to generating units, and the procedures and requirements in relation to control of system frequency control and interconnector power transfers; a Data Registration Code setting out a unified listing of all data required by the Grid Owner and GSO from Users, and by Users from the Grid Owner and GSO and, a Metering Code dealing with transmission metering at the connection points and at the interface with the generation, distribution and user systems.