Ppq Macrogeneration And Microgeneration

Question 1

Give one example of how renewable energy sources are used to generate electricity directly

Answer 1

One from wind, hydroelectric, wave or tidal

Question 2

Give one example of how renewable energy sources are used to generate electricity indirectly

Answer 2

One from Solar Photovoltaic or Biomass.

Question 3

Identify the main energy transformations that take place in the wind turbine.

Answer 3

Kinetic energy transferred from the shaft (connected from the rotor, through gearbox, to the generator), to relative rotational motion (kinetic energy) between a metal coil and a magnetic field in the generator.
This results in electromagnetic induction. On other words kinetic energy of relative motion is transferred into inducted electrical energy.

Question 4

below shows a typical power generation and distribution system such as the National Grid.
With reference to describe how electricity is distrubuted through the National Grid.

Answer 4

Power stations generate electricity at 22kV
This is stepped up to high voltage (275 kV or 400 kV) by transformers. Electricity is transmitted at high voltage to reduce energy losses in wires.
Voltage is stepped down by transformers close to consumers. Electricity is distributed to homes at 240V.

Question 5

Using the information in the figure below, explain how a smart grid facilitates the incorporation of electricity generated from renewable sources.

Answer 5

The energy produced from renewable sources varies over time.
A ‘SMART’ grid systems computer measures the amount of electricity that is being produced at any point in time and then increases of decreases the amount of non-renewable that needs to be generated to meet the requirements.
In doing so the ‘SMART grid’ enables the amount of pollutant / carbon dioxide produced to be minimised.

Question 6

Question; Explain the concept of a smart grid.

Answer 6

Answer; A computer controlled electricity network that switches input from one energy source to another as demand for energy varies on the grid.

Question 7

Question; Outline one way in which a smart grid can facilitate the efficient supply and distribution of electricity.

Answer 7

Question; Outline one way in which a smart grid can facilitate the efficient supply and distribution of electricity. {1}
Answer;
Any one from;
• By using a network of intelligent meters located throughout the grid to
accurately predict demand {1}
• By incorporating electricity generated by a wide range of energy sources, including renewables, in order to meet demand {1}
• By incorporating energy generated from international energy sources {1}

Question 8

Question; Identify another name by which Combined Heat and Power (CHP) is also known.

Answer 8

Answer;

Cogeneration.

Question 9

Question; Discuss the role of Combined Heat and Power in improving energy efficiencies inn traditional power plants. {4}

Answer 9

Answer;
Combined Heat and Power (CHP) integrates the production of usable heat and power (electricity)
In one single, highly efficient process
CHP generates electricity whilst also capturing usable heat that is produced in this process.
This contrasts with traditional ways of generating electricity where vast amounts of heat are wasted.