Next Generation Computing Research and Development Act of 2021 This bill provides for the support of advanced scientific computing programs and activities at the Department of Energy (DOE). The DOE Office of Science shall carry out a research and development program to advance computational and networking capabilities to analyze and predict complex phenomena relevant to the development of new energy technologies and U.S. competitiveness. DOE shall establish a program to implement a strategy for achieving computing systems with capabilities beyond exascale computing systems; support a program of fundamental research and development of energy efficient computing technologies relevant to advanced computing applications in high performance computing, artificial intelligence, and scientific machine learning; and provide for an upgrade to the Energy Sciences Network user facility in order to meet federal research needs for highly reliable data transport capabilities optimized for the requirements of large-scale science. The DOE Office of Advanced Scientific Computing Research shall support the development of a computational science workforce. The DOE Office of Science shall maintain a balanced portfolio within the advanced scientific computing research and development program that supports robust investment in applied mathematical, computational, and computer sciences research needs relevant to DOE's mission; and associated high-performance computing hardware and facilities.