While space-based solar power does not need any reserve power in theory, since it can operate 24 hours throughout the year, there is still the need to withstand rises and drops in demand, as well as backup during occasional partial system failures (though we would want to avoid that as much as possible with built-in redundancy). One way is to use a small portion of the power from space during typical operating hours to be able to split water into hydrogen and oxygen, which can be stored in high-pressure, cryogenic conditions in deep-sea capsules suspended underneath the oceanic power stations, taking advantage of the naturally high pressures and cold temperatures to prevent the gases from escaping. Afterwards, when power is needed, the oxygen and hydrogen gas can be drawn back up to the surface and burnt, which produces only water: $ \ce{2H2(g) + O2(g) \to 2H2O(g)} $ The steam generated can then drive conventional steam turbines, producing backup electricity. And since water is the only by-product, it can then be cooled, purified and dumped back into the ocean, or be used to heat the station in cold climates. Lastly, extra hydrogen and oxygen has a possible use in **rocket fuel**. > **Note:** We can use fuel cells too, although they are likely less efficient.