Energy Storage

Question 1

State one problem associated with generating electricity from ocean waves

Answer 1

Intermittency of wave energy sources

Reliability of wave energy sources

Question 2

Renewable energy sources have the potential to deliver significant proportion of our energy needs in the future. State one main reason why storage facilities are needed in order for us to make optimum use of renewable energy sources such as wind, solar wave and tidal

Answer 2

Energy supplies from renewable energy sources tend to be unreliable or intermittent

Question 3

The figure below is a diagram of a hydropower scheme. Complete the figure by labelling X and Y

Answer 3

X = lower reservoir

Y = dam

Question 4

Identify the type of energy storage facility shown in the figure above and describe how the system operates

Answer 4

Pumped hydro storage

It utilities renewable energy to pump water up to the high dam/ reservoir

It uses gravity fed water supply to turn turbines whenever there is a lull in renewable power

Question 5

State one other method of energy storage

Answer 5

Compressed air energy storage (CAES)

Question 6

The flow diagram shown in the figure below illustrates the stages of a typical Compressed Air Energy Storage (CAES) system. In the space provides, outline the operation of the system making reference to each stage

Answer 6

Energy from a renewable energy resource can be stored during periods of low energy demand (off peak)

Air is compressed by an electrically powered compressor

And stored in mass quantity in an underground cavern

For use in meeting periods of higher (peak load)

When there is a demand the compressed air is released to drive a turbine connected to a generator to produce electricity

Question 7

The figure below shows a schematic diagram of an energy storage facility. Name the energy storage facility shown in the diagram above and describe how the system operates.

Answer 7

Pumped Hydro Energy Storage

During off peak times, renewable electricity from the grid is used to power pumps

Which pump water from a lower reservoir to an upper reservoir

When demand increases the water from the upper reservoir is released down a pipe under high pressure

This then spins turbines which drive generators to produce electricity

Question 8

State three factores that would make a potential location both beneficial as well as cost effective for the type of energy storage facility shown below

Answer 8

Availability of existing lakes/reservoirs

Suitable topography- good height difference between lower and upper reservoirs

Proximity to high voltage power transmission network

Accessibility for construction, operation and maintenance

Lack of environment concerns/objections