Can we use up all of our sunlight?
No, we have a limitless supply of sunlight. That makes it a renewable resource. Products derived from fossil fuels, like the gasoline we use to drive our cars, are not renewable resources. We will eventually run out of fossil fuels.
Renewable Resources and Alternative Energy Sources
A resource is renewable if it is remade by natural processes at the same rate that humans use it up. Sunlight and wind are renewable resources because they will not be used up (Figure below). The rising and falling of ocean tides is another example of a resource in unlimited supply. A sustainable resource is a resource that is used in a way that meets the needs of the present without keeping future generations from meeting their needs. People can sustainably harvest wood, cork, and bamboo. Farmers can also grow crops sustainably by not planting the same crop in their soil year after year. Planting the same crop each year can remove nutrients from the soil. This means that wood, cork, bamboo, and crops can be sustainable resources.
Alternative Energy Sources
A nonrenewable resource is one that cannot be replaced as easily as it is consumed. Fossil fuels are an example of nonrenewable resources. They take millions of years to form naturally, and so they cannot be replaced as fast as they are consumed. To take the place of fossil fuel use, alternative energy resources are being developed. These alternative energy sources often utilize renewable resources. The following are examples of sustainable alternative energy resources:
- Solar power, which uses solar cells to turn sunlight into electricity (Figure below). The electricity can be used to power anything that uses normal coal-generated electricity.
- Wind power, which uses windmills to transform wind energy into electricity. It is used for less than 1% of the world’s energy needs. But wind energy is growing fast. Every year, 30% more wind energy is used to create electricity.
- Hydropower (Figure below), which uses the energy of moving water to turn turbines (similar to windmills) or water wheels, that create electricity. This form of energy produces no waste or pollution. It is a renewable resource.
- Geothermal power, which uses the natural flow of heat from the Earth’s core to produce steam. This steam is used to turn turbines which create electricity.
- Biomass is the mass of biological organisms. It is usually used to describe the amount of organic matter in a trophic level of an ecosystem. Biomass production involves using organic matter ("biomass") from plants to create electricity. Using corn to make ethanol fuel is an example of biomass generated energy. Biomass is generally renewable.
- Tides in the ocean can also turn a turbine to create electricity. This energy can then be stored until needed (Figure below).
Turning Trash Into Treasure
Scientists at the Massachusetts of Technology are turning trash into coal, which can readily be used to heat homes and cook food in developing countries. This coal burns cleaner than that from fossil fuels. It also save a tremendous amount of energy. See http://youtu.be/GzhFgEYiVyY?list=PLzMhsCgGKd1hoofiKuifwy6qRXZs7NG6a for more information.
- Renewable resources can be replaced by natural processes as quickly as they are used.
- Alternative energy sources include wind power, solar power, hydropower, and geothermal power.
- What is a renewable resource? Give two examples.
- What does sustainable mean?
- What are three ways that renewable resources can be used to generate energy?