1.8.1Motion, Forces and Energy
Energy from the Sun — Cambridge IGCSE Physics 0625 Revision Notes & Topical Questions
5 min read 9 parts Lesson 84 of 91 1 quiz
Lesson summary
1.8.1 Energy from the Sun — IGCSE PHYSICS notes: Describe how solar cells, solar panels and wind use energy from the Sun and compare their advantages and disadvantages.Almost all energy resources are driven by the Sun, which transfers energy by electromagnetic radiation produced …
- Solar heating panels are different
- Power produced
- Energy chain
- Non-renewable
- Wind turbine
- Intermittent
Part 1 of 7The Sun as the main energy source
1
Almost all energy resources are driven by the Sun, which transfers energy by electromagnetic radiation produced by nuclear fusion.
2
The energy warms the atmosphere and oceans, evaporates water, drives the winds and is captured by plants in photosynthesis.
3
Fossil fuels are remains of ancient plants and animals that stored the Sun's energy.
4
Resources that do not depend on the Sun are nuclear fission, geothermal and tidal energy.
5
Renewable resources are replaced as fast as they are used and non-renewable resources have a finite supply.
6
Solar and wind energy are renewable.
Part 2 of 7Solar cells and panels
1
Solar cells (photovoltaic cells) convert light energy directly into electrical energy.
2
Many cells joined together form solar panels that supply homes, calculators, satellites and remote devices.
3Solar heating panels are different
- Solar heating panels are different sunlight heats water flowing through pipes in a dark panel, transferring energy to the thermal store of the water.
4Power produced
Power produced intensity × area × efficiency.
- Intensity at the ground on a clear day can reach about 1000 W/m², but the daily average is much lower.
Part 3 of 7Solar energy — advantages and disadvantages
| Advantages | Disadvantages |
|---|---|
| Renewable | Output depends on weather and is zero at night |
| No fuel cost | Large areas are needed for large power |
| No carbon dioxide or pollutant gases in operation | High initial cost per unit of power |
| Useful in remote places with no grid | Manufacture uses energy and materials |
| Long life and low maintenance | Storage for night use needs batteries |
Part 4 of 7Wind energy
Uneven heating of the air by the Sun creates wind.
Energy chain
- Energy chain kinetic energy of moving air, then kinetic energy of the turbine blades, then electrical energy from the generator.
The wind turns the blades, and the rotating shaft drives a generator.
Power rises rapidly with wind speed because the kinetic energy of air depends on v² and the volume of air arriving each second is proportional to v.
Longer blades sweep a larger area and capture more energy.
Part 5 of 7Wind energy — advantages and disadvantages
| Advantages | Disadvantages |
|---|---|
| Renewable | Works only when the wind is at a suitable speed |
| No fuel cost | Noise and visual impact |
| No emissions in operation | Can harm birds |
| Can be built offshore or on hills | High building cost |
| Land between turbines can still be farmed | Energy cannot easily be stored |
Part 6 of 7Reliability and the energy mix
1
Solar and wind output changes with weather and time of day, so they are intermittent.
2
Other sources or storage are needed to cover calm or dark periods.
- Gas power stations can be switched on quickly.
- Pumped storage saves energy as gravitational potential energy.
3
A mix of sources lowers the risk of shortages.
4
Compare resources by reliability, cost, environmental impact and whether they are renewable.
Part 7 of 7More from the specification
More from the specification
Solar Energy as the Primary Energy Source
- Most renewable energy resources on Earth—including wind, waves, biofuels,
- and hydroelectric power—originate from solar radiation driving atmospheric winds and the hydrologic water cycle.
Hydroelectric and Tidal Power Generation
- In a hydroelectric power station, gravitational potential energy of stored reservoir water drives turbines connected to electrical generators without emitting greenhouse gases or sulfur dioxide.
Environmental Comparison of Fossil Fuels and Renewables
- Burning fossil fuels releases sulfur dioxide and carbon dioxide (a greenhouse gas that traps thermal radiation to contribute to global warming),
- (causing acid rain)
- whereas solar and wind power do not emit atmospheric pollutants.
Solar Photovoltaic vs Solar Thermal Systems
- Solar photovoltaic cells directly convert incident solar light into electrical current,
- while solar thermal collectors absorb radiation to heat water into steam to heat domestic supplies or generate electricity.
Hydroelectric
- Electricity from water flowing down from a high reservoir.
Biofuel
- Fuel made from recently living plant or animal material.
Global warming
- Rise in the average temperature of the Earth.
Hydroelectric power
- Electricity generated from water flowing down from a reservoir.
Key terms
| Term | Meaning |
|---|---|
| Renewable | A resource replaced as fast as it is used. |
| Non-renewable | A resource that will run out because it is not replaced quickly. |
| Solar cell | Device that converts light energy directly into electrical energy. |
| Wind turbine | Machine in which wind turns blades that drive a generator. |
| Intermittent | Available only some of the time. |
| Photovoltaic | Producing a voltage from light. |
Avoid these mistakes
1
Saying renewable energy has no environmental effect — building and siting affect land and wildlife.
2
Mixing up solar cells (electricity) and solar heating panels (thermal energy).
3
Thinking wind turbines work in all weather — they need a suitable wind speed.
4
Saying "it is free" without noting the equipment is costly.
5
Forgetting that the Sun is itself powered by fusion.
Marked practiceQuizzes for this lesson
Last updated:
\n