Chapter 2 - Energy and the environment Flashcards
How is coal formed?
Huge forests grew millions of years ago that covered most of the earth. The vegetation died and formed peat. The peat was compressed between layers of sediments to form lignite which is a low-grade coal. This lignite is further compressed to form coal.
How is crude oil and natural gas formed?
Small animals and plants die and fall to the bottom of the ocean. Sediment covers their remains. As the sediment starts forming layers, they start to change into sandstone as the temperature and pressure increase. The heat and pressure turn the remains into crude oil and natural gas. They separate and rise through sandstone, filling the pores. The rock above the oil and gas layer is impermeable so they get trapped underneath it.
What are the three reasons that the demand for energy is increasing worldwide?
The demand for energy is increasing worldwide due to increasing population, increasing industrialization and urbanization and improvements in standards of living and expectations.
What are two characteristics of non renewable energy sources?
limited and takes millions of years to be replenished
What are two characteristics of renewable energy sources?
can be used over and over again and can be replenished in a short period of time
What are two examples of non renewable energy sources?
fossil fuels (coal, oil and natural gas) and nuclear power using uranium
What are seven examples of renewable energy sources?
geothermal, hydroelectric, tidal, wave, wind, solar and biofuels (bioethanol, biogas and wood)
What is a turbine?
A turbine is a machine, often containing fins, which is made to revolve by gas, steam or air and is connected to a generator.
What is a generator?
A generator is a machine that coverts mechanical energy into electric energy.
What are fossil fuels?
Fossil fuels produce massive amounts of energy during combustion that is used to heat water and convert it into steam, which therefore drives the turbine includes coal oil and natural gas
What is nuclear power?
Nuclear power generates energy by using nuclear fission of uranium. This energy is used to heat the water, produce steam, and rotate the turbines.
What is geothermal power?
Geothermal power generates electricity as cold water is pumped under pressure into a layer of hot rocks, the rocks heat the water, the hot water returns to the surface under pressure and heats the second supply of water using a heat exchanger and then the steam produced in the second supply of water moves the turbine therefore generating electricity.
What is hydroelectric power?
Hydroelectric power uses a dam or a river to store water in a reservoir. Water is then released from the reservoir that flows through a turbine causing it to rotate which is attached to a generator that generates electricity.
What is tidal power?
Tidal power uses the natural rise and fall in the level of water in an area. When the water levels drop, water is help back by a tidal barrage which is a small dam that releases water back through a turbine.
What is wave power?
Wave power uses the smaller differences in water levels that are caused by the wind to push water through a turbine which is connected to a generator.
What is solar power?
Solar power uses photovoltaic cells that produced a small electric charge when exposed to light. A bank of cells organised into solar panels produces a significant amount of electricity.
What are biofuels?
Biofuels produce a massive amount of energy during combustion that is used to heat water and convert it into steam, where thereby drives the turbine. biowood, biogas and bioethanol
What are three advantages of fossil fuels as an energy source?
Plentiful supply in some locations. Extraction provides jobs. Existing technology as the fuel is available for most countries to use.
What are three disadvantages of fossil fuels as an energy source?
Carbon dioxide and toxic gases are produced during combustion which impacts climate change. Extraction causes damage to local area. Limited supply meaning prices will rise as the supply gets smaller.
What are three advantages of nuclear power as an energy source?
Does not produce carbon dioxide (impact on climate change). Small amount of fuel produces large amounts of energy. Power plants employ lots of people.
What are three disadvantages of nuclear power as an energy source?
Risk of radiation leakage which impacts human health and the environment.
Waste products cannot be recycled as radiation is active for centuries.
There is a limited supply.
What are three advantages of biofuels as an energy source?
A renewable source: bioethanol and wood are both obtained from growing plants, and biogas is obtained from the recycling of waste products.
Growing more plants uses carbon dioxide.
Potentially a plentiful supply.
What are three disadvantages of biofuels as an energy source?
Carbon dioxide and other toxic gases are produced during combustion. A lot of land is needed to grow crops for fuel. Potential removal of natural ecosystems to grow fuel crops.
What are two advantages of geothermal power as an energy source?
Does not produce carbon dioxide. Unlimited supply as uses the heat from the earth as a power source.