Pipes are placed into the ground to absorb the heat from the rocks in the Earth. This heat is used to generate steam to turn turbines
24.1
Heat → kinetic → electricity
z
Fig. 24.1.6
A geothermal power station takes heat from the Earth’s core to heat steam and turn turbines
Wave energy
When ocean waves crash against a machine called a Pelamis, their kinetic energy is converted to electricity
z Fig. 24.1.7
A Pelamis is a device that converts the energy from ocean waves into electricity
Biomass
Plants are burned as a fuel source in power stations. Cars may run on the biofuels created from such plants; for example, biodiesel and bioethanol. These fuels can also be produced from other biological materials, including algae and faeces
z Fig. 24.1.8
Miscanthus, also known as elephant grass, being grown as a biofuel
Although the energies listed in the table above are renewable, they are not entirely free of carbon emissions. The energy needed to build these devices and plant biomass crops produce a certain amount of carbon dioxide.
Debating renewable energy
Renewable energy sources make us less dependent on fossil fuels. However, these energy sources can also have an impact on the environment.
1. In groups, create posters on the environmental impact of one of the following: z z
zz zz
Wind farms in Ireland. River damming in China. Building solar cells.
2. Present your findings to the class. 415
Learn more about types of energy in Physical World 16.1
