In a rare move for Apple, the company filed for a patent for a wind turbine, in 2011.
That wind turbine would uniquely generate electricity from stored heat energy, not by rotating blades, which would solve the problem of intermittency.
In its filing, Apple notes that current turbines rely on a constant supply of wind because of the way they are constructed. Instead, they propose “a system that converts rotational energy from the turbine into heat, which is then stored in a low-heat-capacity fluid. From storage, heat can be selectively transferred to a working fluid that’s used to generate electricity during lulls in wind activity.
Apple describes the process in the patent application:
“Once sufficient heat is transferred to working fluid, the heat may be used to generate electricity. In particular, the heat may boil working fluid (e.g., due to the low boiling point of working fluid), generating vapor that is used to rotate a turbine. Turbine may then be used to drive an electric generator that supplies electricity to a load, such as a motor vehicle, home, business, building, and/or electrical grid. Transfer of heat from low-heat-capacity fluid to working fluid, as well as the resulting generation of electricity from the transferred heat, may be ceased once the energy stored in low-heat-capacity fluid is no longer needed to meet electrical demand.”
This would make wind energy available “on-demand”, reducing costs related to that form of energy. It can also be used to replace other energy storage devices, such as batteries.