No, excess electrical energy cannot be directly converted into mechanical energy without the use of storage devices or other intermediary systems. According to the principle of energy conservation, energy cannot be created or destroyed; it can only be converted from one form to another.
In order to convert electrical energy into mechanical energy, some form of energy storage or intermediary mechanism is typically required. One common method is to use electric motors or generators. An electric motor converts electrical energy into mechanical energy by utilizing the interaction between electric currents and magnetic fields. Conversely, an electric generator converts mechanical energy into electrical energy by the same principle but in reverse.
When it comes to excess electrical energy, if there is no means to store or utilize that energy in real-time, it is usually dissipated as waste heat. For example, in an electrical circuit, if the load connected to the power source cannot absorb or use all the electrical energy provided, the excess energy will be dissipated as heat through resistive losses in the circuit components.
However, if you are looking for ways to store or utilize excess electrical energy without batteries or storage devices, alternative methods such as using capacitors, flywheels, or mechanical systems like springs or kinetic energy storage systems could be explored. These mechanisms can store and release energy as needed, but they still involve an intermediary storage device or mechanism to convert and deliver the energy in the desired form.