Macrogeneration

Question 1

What are the mains stages for the generation of electricity in a fossil fuel power plant?

Answer 1

1. Combustion of fossil fuel.
2. Evaporation of water.
3. Steam used to turn turbine.
4. Condensing in cooling towers.

Question 2

What is involved in the first stage of the generation of electricity in a fossil fuel power plant?

Answer 2

Fossil fuel combusted in furnace to release chemical energy.

Question 3

What is involved in the second stage of the generation of electricity in a fossil fuel power plant?

Answer 3

Thermal energy produced used to increase temp of water in furnace until turns to steam.

Steam ejected from furnace into steam engine.

Question 4

What is involved in the third stage of the generation of electricity in a fossil fuel power plant?

Answer 4

Steam turbine turns when high-pressure steam forced through it.

Turbine connected to generator which turns to produce electricity.

Question 5

What is involved in the fourth stage of the generation of electricity in a fossil fuel power plant?

Answer 5

Hot steam enters cooling towers where loses substantial energy and condenses back into water.

Cold liquid recirculated back to furnace.

Question 6

What is the efficiency of a fossil fuel power plant and why?

Answer 6

Approx 40%.

Condensing steam takes considerable energy from steam which reduces efficiency of plant.

Question 7

What are direct renewable energy sources?

Answer 7

Take energy from renewable source and can convert into electrical energy directly.

Question 8

What are some examples of direct renewable energy sources?

Answer 8

Wind
Hydroelectric
Wave
Tidal

Question 9

What are indirect renewable energy sources?

Answer 9

Take energy from renewable source using physical characteristic of material being used, and convert this energy into electrical energy.

Question 10

What are some examples of indirect renewable energy sources?

Answer 10

Solar PV
Biomass

Question 11

What are the energy changes involved in wind power?

Answer 11

Wind - KE of wind;
Hub - KE of blades / hub and main shaft (thermal and sound losses);
Gearbox - KE of high speed shaft ( thermal and sound losses);
Generator - Electrical energy (thermal and sound losses).

Question 12

What are the energy changes involved in solar power?

Answer 12

Sun - Radiant energy;
PV panel - Electrical energy (thermal losses).

Question 13

What are the energy changes involved in hydroelectric power?

Answer 13

Dam - Gravitational potential energy;
Moving water - KE (thermal and sound losses);
Turbine - KE as it rotates (thermal and sound losses);
Generator - Electrical energy (thermal and sound losses).

Question 14

What are the energy changes involved in tidal power?

Answer 14

Behind tidal barrier - Gravitational potential energy;
Moving water - KE (thermal and sound losses);
Turbine - KE as it rotates (thermal and sound losses);
Generator - Electrical energy (thermal and sound losses).

Question 15

What are the energy changes involved in wave power?

Answer 15

Sun - Radiant energy from Sun produces wind with KE;
Waves - KE of wind causes KE of waves;
Wave generator - KE of waves causes tube sun surface if ocean to gain KE (thermal and sound losses);
Generator - KE from oscillation tubes turns generator forming electrical energy (thermal and sound losses).

Question 16

What are the energy changes involved in biomass power?

Answer 16

Biomass fuel - Chemical energy;
Burning fuel - Thermal energy;
Steam - Thermal energy (thermal losses);
Turbine - KE (thermal and sound losses);
Generator - Electrical energy (thermal and sound losses).

Question 17

What are the 4 stages involved in the distribution of electricity through the National Grid?

Answer 17

1. Producing electricity in power plant.
2. Step-up transformer.
3. Transmission lines.
4. Step-down transformer.

Question 18

What is involved in the first stage of the distribution of electricity through the National Grid?

Answer 18

Electricity produced in power plant at 22kV.

Question 19

What is involved in the second stage of the distribution of electricity through the National Grid?

Answer 19

Voltage if electricity stepped up from 22kV to 275-400kV.

Question 20

What is involved in the third stage of the distribution of electricity through the National Grid?

Answer 20

Stepped-up electricity sent across National grid through transmission lines.

Question 21

What is involved in the fourth stage of the distribution of electricity through the National Grid?

Answer 21

Voltage of electricity stepped down to levels required by consumer.

Question 22

Why must the electricity be stepped up before it can be sent across the National Grid?

Answer 22

To minimises heat losses occurring in cables.

To provide enough push to reach destination.

Question 23

What value must the electricity be stepped down to for use in factories?

Answer 23

33kV

Question 24

What value must the electricity be stepped down to for use in towns and villages?

Answer 24

11kV

Question 25

What value must the electricity be stepped down to for use in homes, schools and shops?

Answer 25

240V

Question 26

How was electricity distributed in the traditional National Grid?

Answer 26

Distributed in one direction from power plant to end consumer.

Question 27

What is a SMART Grid?

Answer 27

Computer-controlled electricity network that switches input from one energy source to another as demand for energy varies on grid.

Question 28

Why is a SMART Grid needed instead of the National Grid?

Answer 28

To incorporate renewable sources of electricity and plan and manage intermittent nature of these source.

Question 29

What are the 4 requirements of the SMART Grid?

Answer 29

1. Predict demand 2. Measuring output from renewables. 3. Adapting non-renewable power outputs. 4. Exporting or importing to other nations.

Question 30

What is involved in predicting demand in a SMART Grid?

Answer 30

Have network of intelligent meters to accurately predict demand.

Question 31

What is involved in measuring output from renewables in a SMART Grid?

Answer 31

Have intelligent meters to detect output from renewables.

Question 32

What is involved in adapting non-renewable power outputs in a SMART Grid?

Answer 32

Provider must establish demand throughout day and night, output monitored so additional contributions from fossil fuel power can be calculated.

Question 33

What is involved in exporting or importing to other nations in a SMART Grid?

Answer 33

Nation can export excess energy to other nations. If nation needs extra energy, importing renewable energy from other nations can be more cost effective than using fossil fuel power.

Question 34

What are the 3 benefits of a SMART Grid?

Answer 34

1. Maximises renewables. 2. Minimises fossil fuels. 3. Control electricity demand.

Question 35

How does a SMART Grid help maximises renewables?

Answer 35

Maximises proportion of renewables providing energy for nation, increases fuel security.

Question 36

How does a SMART Grid help minimise fossil fuels?

Answer 36

Minimises proportion of electricity from fossil fuel power plants, lower GHG emissions.

Question 37

How does a SMART Grid help control electricity demand?

Answer 37

Providers can offer different electricity prices during day, can move consumers away from peak times of power demand, e.g. morning and evening. Results in National Grid not having to be upgraded.

Question 38

What are interconnectors?

Answer 38

Electrical cable joining 2 nations together, over land or sea. Facilities exporting energy to one another.

Question 39

What is the name of the joined electricity markets of NI and ROI?

Answer 39

Single Electricity Market (SEM).

Question 40

When did SEM become operational?

Answer 40

2007

Question 41

What are two examples of interconnectors between Ireland and Great Britain?

Answer 41

Moyle from Antrim to Scotland. EirGrid from Meath to Wales.

Question 42

What are the environmental benefits of interconnectors?

Answer 42

1. Electricity energy from renewables from one nation can be exported to other nations when in excess, importing nation consumes less fossil fuels. 2. Connections to nations such as Norway facilitates energy storage through pumped hydro, can be used when required to reduce fossil fuels used.

Question 43

What are the economic benefits of interconnectors?

Answer 43

1. Interconnected European Grid enables nations to import energy from other nations, increased competition will drives down costs fro consumers. 2. Nation’s and region’s fuel security increased greatly and less reliant on volatile fossil fuel prices.

Question 44

What is combined heat and power (CHP)?

Answer 44

Method that seeks to increases effectiveness of overall electricity production process.

Question 45

What is CHP also referred to as?

Answer 45

Co-generation

Question 46

How does CHP increase the effectiveness of the overall electricity production process?

Answer 46

Making use of thermal energy in steam lost to surrounding in cooling towers, condensed into hot water and sent to local homes to heat.

Question 47

What are the advantages of CHP?

Answer 47

1. Efficiency can exceed 30%? 2. CHO plant typically located close to end user so transmission losses reduced. 3. Carbon emissions reduced as less fuel required. 4. Energy bills can be minimised for consumers.