The main topics of this chapter can be summarized as follows:
|9.1 Solar and Wind Energy
|Almost everything we grow depends on solar energy, but we can also convert solar into useful electricity, either through solar-thermal processes, or using solar photo-voltaic technology. Solar technologies are now cost-effective almost anywhere. Wind energy is more restricted to specific sites, and is most viable offshore, in near-coast regions, or on interior plains. In some regions it should be possible to power entire countries with a combination of wind and solar energy.
|9.2 Hydro Energy
|Hydro is the most mature of the renewable energy technologies, and has reached saturation in many regions. The public acceptance of large dams and reservoirs is waning for environmental and social reasons, but smaller run-of-river projects may still be an option in some areas.
|9.3 Wave and Tidal Energy
|Waves and tidal currents represent a significant energy resource, but the technologies to capture that energy have been slow to develop for logistical, social and environmental reasons.
|9.4 Geothermal and Geo-Exchange Energy
|Although the flow of heat from within the Earth is small compared with the flux of energy from the sun, there are many places where it can be converted into a reliable, clean and cost-effective source for heating and electricity generation. Geo-exchange, on the other hand, is a technology for using the near-surface ground as a heat source during cold periods and a heat sink during hot periods.
|9.5 Nuclear Energy
|Nuclear fission energy is produced when large atoms—like uranium—are split apart. Nuclear fusion energy is produced when small atoms—like hydrogen—are fused together. Nuclear fission represents a significant proportion of our current energy supply, but because of some serious past accidents it is widely unpopular. Viable nuclear fusion energy is still several decades away
|9.6 Our Energy Future
|We have no choice but to reduce our dependence on fossil-fuel energy, dramatically and quickly. Thankfully, there are many strategies for living without fossil fuels. The first and most important is for those of us in developed countries is to reduce our energy demand. The second is to continue to research and develop sustainable energy sources of all of the types described here. The third is to even out the supply and demand using energy storage systems at both small and large scales, and electricity sharing across wide regions.
Answers for the review questions can be found in Appendix 1.
- Why does southern Saskatchewan have better solar resources than southern British Columbia?
- A typical process in a solar-thermal plant is to heat up molten sodium, and then use the heat in the sodium to run a steam turbine. In what way is that a significant advantage over using the solar heat to create steam directly?
- Why might a run-of-river hydro project have a lower environmental impact than a dam and reservoir hydro project?
- Describe two ways to capture tidal energy.
- List two ways that geothermal heat can be used, apart from generating electricity.
- What is the source of the thermal energy that is used in a geo-exchange system?
- Explain the advantages of nuclear fusion over nuclear fission.
- Solar and wind are both mature energy technologies and are rivals for the cheapest installation costs per kWh produced. Using Figures 9.1.1 and 9.1.5 (or other maps relevant to your region), decide which of these technologies might be most suitable for the location (city or surrounding district) where you live.
- Explain why either energy storage or efficient regional electrical grids can help to solve our energy needs.