; (2) conduct independent oversight of the execution of a demonstration project once funding has been awarded for such project; and (3) ensure a balanced portfolio of investments in clean energy technology demonstration projects. (b) Demonstration project management employees (1) Authority In carrying out the program under subsection (a), the Under Secretary for Science shall appoint at least 2 full time employees to achieve the purposes of the program outlined in subsection (a) in coordination with relevant staff at Department program offices. (2) Hiring authority To carry out the program authorized in this section, the Under Secretary for Science may hire personnel using the authorities in section 306 of this Act. (c) Duties In carrying out the program in subsection (a), employees under this section shall work with relevant staff from Department program offices to— (1) evaluate demonstration project proposals, including the scope, technical specifications, maturity of design, funding profile, estimated costs, proposed schedule, proposed technical and financial milestones, and potential for commercial success based on economic and policy projections; (2) develop independent cost estimates of demonstration project proposals, when appropriate; (3) recommend to the director of a program office whether to fund a demonstration project proposal; (4) oversee the execution of the demonstration projects that receive funding from the Department under this section and conduct reviews of ongoing projects, which may include reconciling estimated costs as compared to actual costs and evaluating progress of the project based on the proposed schedule and technical and financial milestones, and provide such reviews to the Secretary