Table 20.3: (continued)Where Energy is Used How We Can Use Less En-
ergyHow We Can Use Energy
More Efficiently
Commercial (businesses,
shopping areas, etc.)- Turn off appliances
and equipment when
not in use- Use fluorescent light-
ing - Set thermostats to au-
tomatically turn off
heat or air condition-
ing when buildings are
closed
- Use fluorescent light-
Using less energy or using energy more efficiently will help conserve our energy resources.
Since many of the energy resources we depend upon are non-renewable, we need to make
sure that we waste them as little as possible.
Lesson Summary
- It takes energy to get energy. We use the term ’net energy’ to refer to the amount of
energy left for use after we expend energy to get, transport and refine other forms of
energy. - Once the energy is available, we use it for some purpose, but sometimes do so ineffi-
ciently. - We can conserve energy resources by reducing energy use.
- We can also use energy more efficiently by getting more work out of the energy that
we use. - Examples of this include driving smaller cars and using fluorescent light bulbs.
Review Questions
- Define net energy?
- Why does solar power have a higher net energy ratio than coal-fired electricity?
- Coal-fired electricity has a net energy ratio of 0.40. Explain why this means that
getting electricity from burning coal is an undesirable option for energy use. - What are two ways you can use less energy in your home?
- Why is it especially important to not waste energy from fossil fuels?
- Trains are much more efficient than trucks in transporting items around. Why do you
think this might be so?