L6 - Energy for Electricity 2

objectives

Pollution Problems

• Thermal power stations can cause pollution in a variety of ways:
  • Fuel-burning power stations put extra carbon dioxide gas into the atmosphere.
  • This traps die Sun's energy and may be adding to global warming.
  • Coal-burning power stations emit almost twice the amount of carbon dioxide per kJ output compared with those burning natural gas.
  • Unless low-sulfur coal is used, or desulfurization (FGD) units are fitted, coal-burning power stations emit sulfur dioxide, which is harmful to health and causes acid rain.

• Transporting fuels can cause pollution. For example, there may be a leak from an oil tanker,
  • The radioactive waste from nuclear power stations is highly dangerous. It must be carried away and stored safely in sealed containers for many years - in some cases, thousands of years.
  • Nuclear accidents are rare. But when they do occur, radioactive gas and dust can be carried thousands of kilometres by winds.

Power from Water and Wind

• Some generators are turned by the force of moving water or wind.
• There are three examples below.
• Power schemes like this have no fuel costs, and give off no polluting gases.
• However, they can be expensive to build, and need large areas of land.
• Compared with fossil fuels, moving water and wind are much less concentrated sources of energy: