Energy sources can be classified into two main categories.
Renewable Energy Sources
- Abundantly found in nature
- Able to replenished continually
- Usually non-polluting
- Free but storage equipment or conversion into electricity can be costly
| Solar energy | Energy from the sun converted into electricity by solar cells.
Requires large areas for installation of panels. |
| Wind energy |
Movement of air can drive wind turbines to produce electricity. Endanger flying animals. |
| Hydropower |
Movement of water (tides and waterfalls) turn turbines to generate electricity. Can lead to floods and affects ecosystem. |
| Geothermal | Thermal energy causes water to boil. The steam produced will turn turbines to generate electricity. |
| Biomass | Combustion of organic materials will release the stored chemical energy as thermal energy to the surroundings. |
Non-renewable Energy Sources
- Limited and will be used up
- Takes a long time to be replenished
- Usually polluting
- High efficiency in energy conversion into electricity
| Fossil fuels | Burning of fossil fuels produces steam to drive turbines.
Produces CO2, which increases the greenhouse effect. Produces SO2, which may result in the occurrence of acid rain. |
| Nuclear energy |
Thermal energy is released when the uranium atom splits due to a small loss in mass. The thermal energy is used to produce steam to drive turbines. Produces radioactive waste, which needs to be disposed carefully. |
Cost of Electricity
Multiple factors contribute to the cost of electricity
- Initial capital costs
- Operation and maintenance costs
- Fuel costs (raw materials)
For example:
- nuclear energy has low running costs, but incurs high costs from building the plant, waste disposal, and shutting down.
- Solar energy is practically free in terms of fuel costs, but is expensive due to the production of solar cells.
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| https://www.eia.gov/energyexplained/what-is-energy/sources-of-energy.php |