1.7.3 Energy resources (3)
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1.
Describe how useful energy may be obtained, or electrical power generated, from: (f) light from the Sun to generate electrical power (solar cells)
Solar cells, also known as photovoltaic (PV) cells, directly convert light energy from the Sun into electrical energy. The process relies on the photovoltaic effect. Solar cells are typically made from semiconductor materials, such as silicon. When photons (light particles) strike the solar cell, they transfer their energy to electrons in the semiconductor material. This excites the electrons, causing them to move and create an electric current.
A solar panel consists of multiple solar cells connected together. The electricity generated by the solar panel is direct current (DC). An inverter is used to convert the DC electricity into alternating current (AC), which is the type of electricity used in homes and businesses. Solar panels can be installed on rooftops or in large solar farms.
The efficiency of solar cells varies depending on the material and the design of the cell. Factors such as cloud cover, the angle of the Sun, and the temperature of the solar cells can affect the amount of electricity generated. Solar power is a renewable and clean energy source, but it is intermittent and requires energy storage solutions (e.g., batteries) to provide electricity when the Sun is not shining.
2.
Compare and contrast the advantages and disadvantages of hydroelectric power and tidal power as methods of generating electricity, considering renewability, availability, reliability, scale and environmental impact. Present your answer in a table format.
Here's a comparison of hydroelectric and tidal power:
| Feature | Hydroelectric Power | Tidal Power |
| Renewability | Advantage - Water cycle ensures continuous supply. Disadvantage - Dams can alter river ecosystems. | Advantage - Tides are predictable and renewable. Disadvantage - Limited number of suitable sites. |
| Availability | Disadvantage - Dependent on rainfall and river flow. Advantage - Can be stored in reservoirs. | Advantage - Tides are predictable (high and low). Disadvantage - Limited to coastal locations with significant tidal ranges. |
| Reliability | Advantage - Relatively reliable with reservoir storage. Disadvantage - Can be affected by droughts. | Disadvantage - Intermittent, dependent on tidal cycles. Advantage - Predictable cycles allow for some level of planning. |
| Scale | Advantage - Can be large-scale (large dams). Disadvantage - Significant land area required for reservoirs. | Disadvantage - Typically smaller scale than hydroelectric. Advantage - Can be integrated into existing coastal structures. |
| Environmental Impact | Disadvantage - Dams can disrupt river ecosystems, affecting fish migration and water quality. Advantage - Provides flood control and water storage. | Disadvantage - Can impact marine ecosystems and coastal habitats. Advantage - Minimal greenhouse gas emissions. |
3.
Describe how useful energy may be obtained, or electrical power generated, from: (g) infrared and other electromagnetic waves from the Sun to heat water (solar panels) including references to a boiler, turbine and generator
While solar panels primarily convert visible light to electricity, the Sun also emits infrared radiation and other electromagnetic waves that can be used to heat water. This heat can then be used to generate useful energy, typically in the form of electricity. This process is often referred to as solar thermal energy.
The infrared radiation from the Sun is absorbed by a solar collector, which is typically a dark-colored absorber plate. This collector heats water that circulates through tubes within the collector. The heated water is then pumped to a boiler, where it is further heated to produce steam. The steam is directed to a turbine, which is connected to a generator. The turbine's rotation drives the generator, producing electricity via electromagnetic induction. The electricity is then transmitted.
Solar thermal systems are a renewable energy source, but their efficiency depends on the intensity of the sunlight and the design of the collector and boiler. They are particularly effective in sunny climates. The system can be used for domestic hot water heating or for generating electricity on a larger scale. The efficiency of the system is affected by factors such as insulation and heat loss.