P3 Flashcards
Guve 5 examples of renewable energy resources
- Hydroelectric - Wind - Tidal - Wave - Solar - Geothermal
Give four examples of non-renewable energy resources
- Coal - Oil - Natural gas - Nuclear
How does a fossil fuel burning power station work?
A fuel burns to heat water and produce steam. The steam drives a turbine, which is a bit like a big fan. The turbine drives a generator to create electricity.
How does a nuclear power station work?
Nuclear fission occurs as atoms are shot at eachother at extreme speeds, creating a chain reaction, resulting in lots of heat. This heat heats water which produces steam as it evaporates. The steam drives a turbine and the turbine drives a generator to create electricity.
Why are biofuels carbin neutral?
They are carbon-neutral which means that the carbon released when biofuels are burnt is the balanced by the carbon they absorbed as they grew.
Why aren’t fossil fuels carbon neutral?
Because when they are burnt to produce energy through heat, they release more carbon dioxide into the atmosphere than was orignially there as fossil fuels don’t absorb carbon dioxide like biofuels do.
What are the problems associated with biofuels and their production?
- We can’t make enough by diesel to replace regular diesel because there are not enough vegetable oil crops. - Biodiesel can also be made from used fish oil but there isn’t enough of that either. - Bio diesel is expensive.
Why are wind turbines, wave generators, hydroelectric systems, and tidal systems renewable energy resources?
The use of resources for energy that are replenished at a higher rate than they are consumed.
How does wind energy work?
As wind pushes the blades of the wind turbine around a rotor which spins a generator, creating electricity.
compare the operation of hydroelectric, wave, and tidal systems in terms of reliability, potential power
Hydroelectic energy is reliable as there is a constant renewable source of energy. Furthermore, energy can be stored, the water cam be re-used and it meets energy demans quickly. On the other hand, wave and tidal systems are much less reliable as it isn’t constantly wavy and the tide only changes approximately twice a day, limiting the amount of energy produced. Furthermore, tidal energy only produces substantial energy when the tide differs at least 5m in height. However, wave systems have a lot of potential power if it were to be extremelly windy, causing large waves, producing lots of energy.
What are the advantages of renewable energy?
- Doesn’t have any carbon emmisions or negative effect on the environment - Difersifying energy supply - Reduces dependance on fossil fuels and nuclear power - Often lower energy costs
What are the disadvantages of renewable energy?
- Often unreliable - Expensive set up cost - Often produces far less energy than non-renewable energy sources - Doesn’t produce enough energy for society to mainly rely on
How does the hydroelectic system opperate and produce energy?
Before water, from the resevoir above the dam, flows down, it has potential energy. As it flows down it spins on turbine. As a result, it drives generator which produces electricity. The water can then be re-used again to create electricity.
What is the purpose, operation, and advantages of a pumped storage system?
Pumped-storage hydroelectricity allows energy from intermittent sources (such as solar, wind) and other renewables, or excess electricity from continuous base-load sources (such as coal or nuclear) to be saved for periods of higher demand. When there is excess power on the grid and demand for electricity is low, the power is used to pump water from the lower to the upper reservoir using reversible turbines. This can be useful as it means for when demand increases suddenly, the energy demands can be met quickly without a long start-up time. This can also be useful as it allows the resources to be re-used to create further electricity.
What energy resource has the quickest start-up time?
Natural gas power station
How much energy is released per kg of fuel between a fossil fuel power station and nuclear power station?
- Fossil fuel power station: 30MJ - Nuclear power station: 300,000 MJ
How does a solar cell operate?
When the semiconductor is exposed to light, it absorbs the light’s energy and transfers it to negatively charged particles in the material called electrons. This extra energy allows the electrons to flow through the material as an electrical current.
Compare and contrast the operation of solar cells (photovoltaic cells) with solar heating panels.
Solar cells (photovoltaic cells) systems convert sunlight directly into electricity, using the extra electricity towards electrons to create an electrical current, whilst thermal systems produce thermal energy for residential heating systems such as hot water or space heaters, using solar energy to heat a fluid (either liquid or air).
What are the power outputs of different energy sources?
- Wind: Very low - Hydroelectricity: Medium - Geothermal: Medium - Tidal: Potentially very high, but unreliable
What are the differences between solar cells and solar heating systems?
Solar heating systems are used to collect sunlight and and use the solar energy to heat a fluid (either liquid or air) and produce thermal energy for residential heating systems such as hot water or space heaters. Solar panels, on the other hand, utilise PV technology to capture sun rays and directly convert the sunlight into electricity.
How does a solar power tower work?
The setup includes an array of large, sun-tracking mirrors known as heliostats that focus sunlight on a receiver at the top of a tower. In this receiver, a fluid is heated and used to generate steam. This steam then powers a turbine generator to generate electricity.
How do you calculate the energy provided by a solar heating system by using the increase in water temperature?
Energy = rate of flow (in kilograms/s , kg/s) x Specific heat capacity of water x Change in temperature of the water (°C)
Why is radioactive decay the source of heating in geothermal systems?
Certain elements, known as radioactive elements such as potassium, uranium, and thorium, break down through a process known as radioactive decay, and release energy as heat. Heat from the core is constantly radiating outward and warming rocks, water, gas, and other geological material, which become the source of heating in geothermal stystems
How does a geothermal power plant work?
Geothermal power plants use steam to produce electricity. Hot watee is pumped from resevoirs underground through a well under high pressure. When the water reaches the surface, the pressure is dropped and it turns to steam. The steam rotates a turbine that activates a generator, which produces electricity. The hot water can also be directly circulated into homes for heating and hot water.
