This Topic expands on what you thought about and learned in Topic 1 about USING
Energy. Much of the energy use for cooking and heating was found to be natural gas and electricity. These sources
of Energy can undergo transformations before they are used for cooking and heating. There may also be environmental
concerns in using each source of energy.
Chemical Energy can be transformed into Thermal Energy when wood, or coal is burned.
(Environmental Impacts: pollution caused by the burning
of these fossil fuels)
Electricity is produced in many ways. Hydro-electric dams use the force of gravity which pulls the water over the dam to turn turbines, which are attached
to generators, which produce the electrical energy from the mechanical energy of the generators.
Electricity can also be produced at thermo-electric
(fuel-burning) generating stations that burn fossil fuels.
(Environmental Impacts: wildlife in the area of the dam
lose valuable habitat, plants may perish when the river which was blocked overflows its banks to create the reservoir
for the dam, commercial enterprises may be adversely affected, pollution by the burning of fossil fuels, heated
waste water can affect organisms in lakes where this waste water is dumped.)
Mechanical forces that push or pull objects often release thermal energy, as do Frictional forces.
Volcanoes, hot springs and geysers are sources of geothermal energy - energy from the interior of the earth. The thermal energy from these events can produce hot
water or steam, which can be then piped to a power plant at the surface. This can be used to run turbines which
produce electrical energy. HRD (hot, dry rock) can be used as another technique to generate thermal energy. (Water
is pumped into cracks in the earth's crust. It returns to the surface as steam, which can be used to generate electricity.
(Environmental Impacts: more extensive use
of this clean and environmentally friendly technique, could reduce the threat of oil spills, the pollution caused by burning fossil fuels and the wastes from
mining fossil fuels.)
Solar Energy (A Solar Energy Information Resource)
Solar energy is clean and is guaranteed not to run out. It is not available all the time
(nighttime, less in winter/ than in summer).
There are two techniques that can help to overcome these issues. (See Figure 3.32, page 243)
Passive solar heating - uses the materials in the structure to
absorb, store and release the solar energy.
Active solar heating - uses mechanical devices to collect and distribute
the thermal energy.
(Environmental Impacts: none)
Wind energy is the energy of moving air, and is a result of solar energy and convection.
As the sun heats up the air, the warm air rises and cools off. The cooler air falls, creating the convection currents
called thermals. These convection currents on a global basis, form the Earth's wind systems. The windmill is a turbine (a wheel with fan blades), which is connected to a generator.
When the windmill spins the generator produces electricity.
(Environmental Impacts: aesthetics)
More Sources of Thermal Energy
The living organisms burn food (chemical energy) in their bodies to generate body heat
A composter is another source of thermal energy. Decomposers break down food and as these chemical
changes occur, thermal energy is produced, which in turn helps speed up the process of decomposition.
(Environmental Impacts: waste management)
An energy resource is anything that can provide energy in a useful form. Most energy
supplies come from fossil fuels (in Alberta and throughout the world). Fossil Fuels are chemicals from plants and
other organisms that died and decomposed millions of years ago and have been preserved underground.
(Environmental Impacts: global warming, changing
climate zones around the world, plant growth, depleted water resources and thermal pollution)
Fossil Fuels: Two Problems
The widespread use of fossil fuels has created 2 primary problems.
1- these energy sources are non-renewable
and their supplies are running out
2- they produce toxic chemicals which can harm the environment by producing a greenhouse
effect resulting in global warming
Co-generation uses some of the two-thirds of the energy
release by the burning of fossil fuels as thermal energy, to heat a building, or a fuel, to generate electrical
Topic Review p. 247