Engineers at UT Austin are working to solve that problem. The space station's orbit around the earth is 90 minutes long, cycling rapidly from the light to the shadow side of the planet. The station runs on power from batteries during these dark periods. Chemical batteries used currently on the space station need to be replaced about every five years. Engineers at the Center for Electromechanics are doing research that could lead to replacing the chemical batteries needed to operate the space station when it is in the dark with flywheel batteries.
Flywheel batteries store and release energy on a continuous basis.
I am proud that The University of Texas at Austin is in the forefront of this effort. A flywheel battery, designed to fit in the existing space provided for a chemical battery, has a greater capacity and could last the lifetime of the space station itself. Current batteries weigh about 300 pounds and fit in a box about 12 cubic feet in size. Flywheel batteries are a cleaner and more economical source of battery power than chemical models. The flywheel that would be used in the battery on the space station is about 1.5 feet in diameter and nearly three feet long.