topic 5 (macrogeneration) Flashcards
main stages in large scale electricity production
Combustion of fuel {1} to produce steam {1}.
Steam driving a turbine {1} which is connected to a generator to produce
electricity {1}.
furnace to boiler energy form?
Heat energy
turbine to generator energy form?
Kinetic energy
e outline
the phases which happen between turbine, condenser and boiler.
The steam from the turbine passes to the condenser which may be a cooling
tower or lake {1} and this changes it back to water before returning it to the
boiler to be reheated {1}.
Give one example of their use to generate
electricity directly and one example of their use to generate electricity indirectly.
Direct use
Indirect use
One from Wind, Hydroelectric, Wave or Tidal.
One from Solar Photovoltaic or Biomass.
Explain what is meant by the term indirect renewable energy source.
An indirect renewable source of energy will take energy from a renewable
source [1] such as the sun and using a physical
characteristic of the material being used, convert this energy into electrical
energy. [1]
Identify the main energy transformations that take place in
the wind turbine.
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.
{1}
This results in electromagnetic induction. On other words kinetic energy of
relative motion is transferred into inducted electrical energy.
describe how electricity is distrubuted through the
National Grid.
Power stations generate electricity at 22kV
This is stepped up to high voltage (275 kV or 400 kV) by transformers.
{5}
{1}
{1}
Electricity is transmitted at high voltage to reduce energy losses in wires. {1}
Voltage is stepped down by transformers close to consumers.
{1}
Electricity is distributed to homes at 240V.
1.5.6
LO6 Y;
{1}
explain
how a smart grid facilitates the incorporation of electricity generated from
renewable sources.
The energy produced from renewable sources varies over time.
{1}
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.
{1}
In doing so the ‘SMART grid’ enables the amount of pollutant / carbon dioxide
produced to be minimised.
Explain the concept of a smart grid.
A computer-controlled electricity network that switches input from one energy
source to another {1} as demand for energy varies on the grid {1}
Outline one way in which a smart grid can facilitate
the efficient supply and distribution of electricity.
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}
; Identify another name by which Combined Heat and Power
(CHP) is also known.
Cogeneration
Discuss the role of Combined Heat and Power in improving
energy efficiencies in traditional power plants.
Combined Heat and Power (CHP) integrates the production of usable heat and
power (electricity)
{1}
In one single, highly efficient process
{1}
CHP generates electricity whilst also capturing usable heat that is produced in
this process
{1}
This contrasts with traditional ways of generating electricity where vast amounts
of heat are wasted.
Discuss how CHP can improve energy efficiencies in the production of heat and
power and contrast this with the processes in traditional power plants.
Combined Heat and Power (CHP) integrates the production of usable heat and
power (electricity) [1], in one single, highly efficient process [1]. CHP generates
electricity whilst also capturing usable heat that is produced in this process [1].
This contrasts with traditional ways of generating electricity where vast amounts
of heat are wasted [1].
