The Earth — with its myriad shifting atmospheric, oceanic, land and ice components — presents an extraordinarily complex system to simulate using computer models.

Nuclear power plants typically run either at full capacity or not at all. Yet the plants have the technical ability to adjust to the changing demand for power and thus better accommodate sources of renewable energy such as wind or solar power.

Entrepreneurs from Illinois, California, New York, Texas and Missouri have won spots in an elite national program at the Department of Energy’s (DOE) Argonne National Laboratory to grow startup technologies.