Chapter 4 - Renewable Energy Flashcards
Main source for most energy on earth
which sources do not originate from sun
radiation from the Sun is the main source of energy for all our energy resources
except geothermal, nuclear and tidal
how does the sun produce energy
nuclear fusion of hydrogen to give helium
Can we perform nuclear fusion on earth right now?
no. but we’re actively researching how to.
2 classifications of energy
renewable
non-renewable
Define non-renewable energy
Energy sources that once used, cannot be regenerated
Sources of non renewable energy
Chemical energy from fossil fuels
Nuclear energy
Define fossil fuel
renewable or non-renewable?
come from the sun?
Fuel that were formed from remains of plants and tiny sea creatures that lived millions of years ago
non-renewable
sun: yes
What are the problems with fossil fuel
Waste gas pollute the atmosphere when burnt
High lvls of CO2 which contribute to global warming
What is an advantage of using coal (and fossil fuels in general)?
relatively cheap and available widely
How do we harvest nuclear energy
renewable or non-renewable?
come from the sun?
Fission - Nuclei of uranium atoms are split
non-renewable
sun: no
Problems with nuclear fuels + energy
High lvl of safety standards are needed
Waste from nuclear fuels remains radioactive for 1000s of years.
Nuclear power stations are expensive to build
Nuclear power stations are expensive to decomission
Define renewable energy
Energy sources that are continuously regenerated
What are the renewable energy sources
Tidal
Wave
Hydroelectric
Wind
Solar
Geothermal
Biofuels
What energy sources that use water to generate energy
Tidal
Wave
Hydroelectric
What is hydroelectric energy
renewable or non-renewable?
come from the sun?
A lake is filled behind a damn. The water that flows down from this lake turns generators.
renewable
comes from the sun
What is tidal energy
renewable or non-renewable?
come from the sun?
Lake is filled when tide comes in and empties when tide leaves. Generators are turned by movement of water
renewable
don’t come from the sun
Problems with hydroelectric and tidal energy
Expensive to build
Few areas of the world are suitable
What is wave energy
renewable or non-renewable?
come from the sun?
Generators driven by up-and-down motion of waves at sea.
renewable
come from the sun
Problem with wave energy
Difficult to build - few devices have been successful
What is wind energy
renewable or non-renewable?
come from the sun?
Generators are driven by wind turbines
renewable
comes from the sun
Problems with wind energy
Large, remote, and windy landscapes are required
noisy
can spoil landscape
What is geothermal energy
renewable or non-renewable?
come from the sun?
Water is pumped down to hot rocks deep underground and then rises as steam to push generators
renewable
sun: no
Problems with geothermal energy
Deep drilling is difficult
it is also expensive
What is solar energy
renewable or non-renewable?
come from the sun?
Energy radiated from sun is absorbed by solar panels.
Heat energy - heat water up.
Light energy - Have solar cells that deliver an electric current when they absorb energy in light.
renewable
sun: yes
Problems with solar energy
Variable amounts of sunshine means variable amount of energy produced
Solar cells are expensive
What are biofuels
renewable or non-renewable?
come from the sun?
Fuels made by plant and animal matter
renewable
sun: yes
What are biofuels
renewable or non-renewable?
come from the sun?
Fuels made by plant and animal matter
renewable
sun: yes
Problem with biofuel
Huge amount of land needed to grow plants for biofuel
Few ways to be less wasteful with energy:
Less use of vehicles
recycling materials
Better insulation in buildings - less need for heating in cold countries and vice versa
process for generating electricity at a hydroelectric power station
vapour rises
rain falls
collects in lake
water falls
water turns turbine
electricity is generated
PE in water to KE in turbine movement
KE in turbine movement to electrical for turbine
Process for generating electricity at a thermal power station
Water is heated in a boiler to produce steam, which pushes turbines that turn generators.
The thermal energy that is used to heat the water comes from either nuclear energy, or from burning fuel such as coal, oil or natural gas.
After the steam passes through the turbines, it is cooled and condensed back into water, so that it can go back to the boiler and the process repeats.
