1.2 Energy storage

Why is energy stored?

To use electricity later when demand is higher

Name three energy storage methods

Batteries, capacitors, pumped storage

How does pumped storage store energy?

Pumps water uphill to store gravitational potential energy

How is energy released in pumped storage?

Water flows downhill through turbines to generate electricity

Give one advantage of pumped storage

Very fast response to changes in demand

Give one disadvantage of pumped storage

Requires suitable geography

What is a flywheel?

A spinning wheel that stores rotational kinetic energy

What reduces flywheel efficiency?

Friction and air resistance

What is clockwork energy storage?

Energy stored by deforming a spring (elastic potential energy)

What does a capacitor store?

Electrical energy in an electric field

Give one advantage of capacitors

Very fast charging and discharging

Give one disadvantage of capacitors

Low energy density

How do batteries store energy?

As chemical energy converted to electrical energy

What are the two main types of batteries?

Primary (single-use) and secondary (rechargeable)

Give one advantage of batteries

High energy density

Give two disadvantages of batteries

Degrade over time and have limited charge cycles