Title: Mechanical Energy Storage

Q: What is a mechanical energy storage system?
- A system that stores energy through a medium's position, chemical state, and/or its speed.
- A system that stores energy through a medium's heat, thermodynamic state, and/or its position.
- A system that stores energy through a medium's position, thermodynamic state, and/or its speed. (correct)
- A system that stores energy through a medium's position, chemical state, and/or its temperature.

HINT: Ask yourself - what is mechanical energy?

Q: Pumped-storage plants (PSPs) store energy by
- using an upper and lower reservoir that are artificially constructed. Water in the lower reservoir is pumped to the upper reservoir during low-load hours. They are considered high pressure facilities. (correct)
- using an upper and lower reservoir that are artificially constructed. Water in the lower reservoir is pumped to the upper reservoir during high-load hours. They are considered high pressure facilities.
- using an upper and lower reservoir that are artificially constructed. Water in the lower reservoir is pumped to the upper reservoir during low-load hours. They are considered low pressure facilities.

Q: On the other hand, Storage power plants operate similarly to PSP's but
- the upper reservoir is formed by damming a river, creating a natural intake of water. (correct)
- the lower reservoir is formed by damming a river, creating a natural intake of water.
- the upper reservoir is formed artifically, creating an intake of water.

Flywheel Energy Storage - Fill in the Blanks

Fill in the missing words

Q: Flywheel energy storage stores mechanical energy in the form of [...] energy.

This is done by rotating a flywheel [...] at a constant speed. To drive the rotor to a high speed, a [...] is used - when energy is recuperated, the flywheel decelerates and it then acts as a [...] and the mechanical energy is turned back into electrical energy.
A: kinetic; rotor; motor; generator

Compressed Air Storage - Drag Text

Drag the words into the correct boxes

Q: Compressed Air Systems (CAS) store energy by compressing a [...], typically air.

The working principle is based on 4 main components. A [...], driven by an electric grid system, is used to drive ambient air to a high pressure.
The compressed air is then sent to a [...] - typically made of porous caverns or salt mines.
When the energy is recuperated, the compressed air is then sent to a [...] where it is burned, converting the energy to heat. Heat is then converted to mechanical energy in a [...] which turns a generator thus converting the energy back into electrical energy.
A: gas; compressor; gas storage system; combustion chamber; turbine