P2 - Sustainable Energy Flashcards
what are the 8 energy stores?
thermal, kinetic, gravitational potential, elastic, chemical, nuclear, electromagnetic, electrostatic.
when is energy transferred?
when a system changes
what are the 2 ways energy can be transferred from heating?
conduction and convection
energy can be transferred by heating and??
work done
what are the ways of “working”
mechanically and electrically
what does the conservation of energy principle say?
energy can be transferred usefully, stored or dissipated, but can never be created or destroyed
how can you work out the efficiency of any energy transfer?
efficiency = useful energy / total energy
how can we reduce energy losses in buildings?
thermal insulation
thickness and thermal conductivity of walls
what are the main non-renewable energy sources on earth?
fossil fuels; (coal, oil, and gas)
nuclear fuels
advantages of non-renewable sources?
enough to meet the current demand
extracted from the earth at a fast enough rate
disadvantages of non-renewable sources?
adds to the greenhouse effect, and contributes to global warming
what are renewable energy sources?
is one that will never run out
don’t provide as much energy as the non-renewable energy sources
e.g sun, hydroelectricity
most power stations use steam to drive a turbine
- as the fossil fuel heats up, the water is heated
- the water boils to form steam, which moves and turns a turbine
- turbine is connected to an electrical generator, which generates a potential difference
- the current produced by the generator flows through the national grid
how does wind power / wind turbines work?
each wind turbine has a generator inside it. the rotating blades turn the generator to produce electricity
- only work when windy
- spoil the view
- no pollution
Solar cells
energy is free
can’t make at night
most suitable for sunny countries
Biofuels
are made from plants and waste
renewable as we can grow more
can be burnt to produce electricity
costs to make biofuels is high
Hydroelectricity
usually involves flooding a valley by building a big dam
flooding // potential loss of habitat
Tidal barrages
big dams built across river estuaries with turbines in them
at the tide comes in it fills the estuary. The water is let our through the turbines at a set speed and they alter habitat
suggest 2 reasons why a government might choose to invest in nuclear power?
it’s efficient
it provides more jobs
what is the national grid?
transfers energy electrically from power stations anywhere on the grid where it’s needed
what are transformers?
are used to increase the generated electricity to a very high potential difference before it is transmitted through the network of the national grid
what are alternating supplies?
the current is constantly changing direction. Alternating currents are produced by alternating voltages in which the positive and negative ends of potential difference keep alternating
what is direct current?
is a current that is always flowing in the same direction.
what colour is the live wire?
brown
what is the live wire?
carries the voltage. It alternates between a high positive and negative voltage of about 230V
what colour is the neutral wire?
blue
what is the neutral wire?
completes the circuit
0V
what colour is the Earth wire?
green and yelow
what is the earth wire?
for safety
carries the current away if something goes wrong
what is the voltage between the live wire and the neutral wire?
230V
what is the voltage of the live wire and the earth wire?
230V
what is the voltage between the neutral wire and the earth wire?
0V
