Which entity is responsible for formulating the Philippine Energy Plan?

The Department of Energy (DOE) is responsible for formulating the Philippine Energy Plan because it serves as the primary government agency tasked with overseeing the energy sector in the Philippines. The DOE is mandated to create and implement energy policies and plans that ensure the country's energy security, sustainability, and development. This includes strategic planning for energy supply, demand management, renewable energy development, and infrastructure improvements. Given its role and expertise, the DOE collaborates with various stakeholders to develop a comprehensive energy strategy for national development, making it the appropriate entity for formulating the Philippine Energy Plan.

While the other entities, such as the Energy Regulatory Commission (ERC) and the National Grid Corporation (NGCP), have significant roles within the energy sector—such as regulating energy prices and maintaining grid stability—they do not have the authority to create the overarching energy policy framework. The Office of the President may influence energy policy and support the DOE's initiatives but does not directly formulate the energy plan. Therefore, the DOE is the correct answer for this question, as it holds the specific mandate to develop the Philippine Energy Plan.