Deck 18: Energy Storage

Question 1

A superconducting magnetic energy storage coil has 10,000 turns of wire,

Answer 1

Question 2

A steel flywheel in the form of a solid disk has a radius of 0.2 m and a

Answer 2

(a) From equation (18.10) so

Question 3

Consider the possibility of constructing a vehicle that operates on

Answer 3

From equation (18.4),

Question 4

Energy is extracted from a flywheel with an initial rotational frequency of

Question 5

Question 6

Compare the following energies
(a) The rotational energy of the earth (rotating on its axis)
(b) The kinetic energy of the earth (in its orbit around the sun)
(c) The rotational energy of the sun (rotating on its axis)
(d) The kinetic energy of the moon (in its orbit around the earth)
Consider all bodies as solid spherical objects with uniform density, and consider all orbits
as circular. Masses, diameters, orbital dimensions, and rotational periods are readily
available on the web.

Question 7

It is common for homeowners to store thermal energy (e.g., from solar

Question 8

A pumped hydroelectric storage reservoir has an area of 1 km2 and an
average depth of 30 m. The water flows to a lower reservoir with a head of 150 m.
(a) What is the total energy available in MWhe? Assume a generator efficiency of 85%.
(b) What is the average power available (in megawatts) if the upper drains through the
turbines over a period of 12 hours?

Question 9

Consider solid cylindrical flywheels with the diameter equal to the length.

Question 10

Other materials (in addition to those given in Table 18.3) have properties

Question 11

The total volume of the upper reservoir of a pumped hydroelectric facility

Question 12

When the Bath County Pumped Hydroelectric Facility is generating
electricity at maximum output, what is the velocity of the water flowing through the
penstocks?

Question 13

A pumped hydroelectric facility has an upper reservoir with an area of 2

Question 14

(a) Assuming that the earth is a solid sphere of uniform density, calculate

Question 15

The requirements for an ideal location for a pumped hydroelectric storage

Question 16

Design a steel flywheel-based electricity backup system to provide 1 day of
typical electricity use for a single-family home (no electric heat). Assume that 70% of the
maximum theoretical energy storage capacity is available and can be converted to
electricity at 90% efficiency.

Question 17

A compressed air energy storage facility operates between a pressure of

Question 18

The world's largest pumped hydroelectric facility in Bath County, Virginia,

Question 19

A small pumped hydroelectric facility has a mean head of 50 m. The

Question 20

For large-scale electric storage for the grid, a capacity in the order of 1 GWh