9.10 CHAPTER 9. THE LITHOSPHERE
- Biofuels
In many parts of the world, ethanol is currentlybeing used as a substitute for crude petroleum.
Ethanol can be produced through the fermentation of sugar-containingproducts such as sugar
cane. One of the problems with this however, isthe vast areas of land that are needed to cultivate
the necessary crops. Crops such as maize canalso be used in the process. In South Africa, a
company called ’Ethanol Africa’ has been set upby commercial farmersto convert their surplus
maize into environmentally-friendly biofuel, andplans are underway to establish ethanol plants
in some of the maize-producing provinces. - Hydropower
Hydropower producesenergy from the actionof falling water. As water falls from a height,
the energy is used to turn turbines which produce electricity. However, for hydropower to be
effective, a large dam isneeded to store water. The building of a dam comes with its own set of
problems such as the expense of construction, as well as the social andenvironmental impacts
of relocating people (if the area is populated),and disrupting a natural river course. - Solar energy
Solar energy is energy from the sun. The sun’sradiation is trapped in solar panels and is then
converted into electricity. While this process isenvironmentally friendly, and solar energy is a
renewable resource, thesupply of radiation is not constant (think for example of cloudy days,
and nights), and the production of electricity isnot efficient. Solar energy can however meet
small energy needs suchas the direct heating of homes. - Geothermal energy
This type of energy comes from the natural heatbelow the Earth’s surface. If hot underground
steam can be tapped and brought to the surface, it has the potential to produce electricity.
Activity: Using energy wisely
The massive power cutsor ’load shedding’ that South Africans began to experience at the
beginning of 2008, werea dramatic wake-up callto the growing energy crisis that the country
faces.There are alternative energy sources available,but they will take yearsto become func-
tional, and many of themhave their own problems. Another way to lookat the problem, is to
put the focus on reducing how much energy is used rather than focusing only on ways to meet
the growing demand.- In your groups, discuss ways that each of the following groups ofpeople could save
energy.
(a) industries
(b) domestic users
(c) farmers - Discuss creative incentives that could be used to encourage each ofthese groups to re-
duce their energy consumption.
Chapter 9 — Summary
See the summary presentation ( Presentation: VPjxi at http://www.everythingscience.co.za)