1. The light of the Future – Renewable Energy Resources
Chapter 18

2. Solar Energy Heating Systems
Heating houses with solar energy can occur in two ways – passive and active.
A passive solar heating system absorbs and stores heat from the sun directly within a structure
An active solar heating system absorbs energy from the sun by pumping a heat-absorbing fluid through a special collector mounted on a roof facing the sun

3. Benefits of Passive Solar heating
It is not something new – for generations people have been using materials to build their houses to absorb heat from the sun.
By building new houses to face the sun and using energy efficient windows people are thinking about sustainability.
In a life cycle, super-insulated houses may add 5-10% to your housing costs but reduce your cost of operation by 30-40%!!!

4. Benefits of Active Solar Heating
Absorbs the heat in a fluid on a panel that has a black surface (usually) and then has a coil that winds through containing the fluid.
The heat is collected and can be used immediately or is stored for later use in containers found under a house.
They can also provide hot water for a home.

5. Advantages to both Energy is FREE!!!!!!!! NO BETTER KIND
Net energy is moderate (active) to high (passive)
No CO2 emissions
Very low air and water pollution
Very low land disturbances
Moderate costs

6. Disadvantages
For both you need to have access to the sun for 60% of the day
Trees and design of old houses does not allow for modern technology to be added.
You need a heat storage system (if building an active heating system)
Active heating systems need maintenance and repair
They can be unattractive (big deal!)

7. Solar Cells
Solar energy can be converted to electrical energy by photovoltaic (PV) cells also known as solar cells.
Solar cells typically consist of a semiconductor material that is energized by sunlight and creates a flow of electrons generating electricity.
These cells have no moving parts
Require very little maintenance
Produce no pollution
And last as long as conventional fossil fuel or nuclear power plants!

8. Advantages of Solar Cells
You have a fairly high net energy
Work on cloudy days
Quick installation
Easily expand by adding more or can be easily moved
No CO2 emissions
Low environmental impact
Last for years
Low land use (if built on a roof)
Reduces dependence on fossil fuels

9. Disadvantages of Solar Cells
Needs access to sun
Low efficiency
Need electricity storage for backup
High land use (when a power plant) which can disrupt a desert area
High costs (but may be competitive in 5-15 years)
DC current must be converted to AC

10. Producing Electricity from the Water Cycle
Water that flows from high elevations to low elevations in rivers and streams can be controlled by dams and reservoirs and used to produce electricity.
This indirect form of renewable solar energy is called hydropower.

11. Three methods to produce electricity
Large scale hydropower:
A high dam is built across a large river to create a reservoir.
The water flows through and spins turbines to produce electricity
Small scale hydropower:
A low dam with no reservoir is built on a small stream and the water currents spin the turbine and produce electricity without disrupting the movement of fish.
Pumped-storage hydropower:
Uses surplus of water from a lake and pumps to another lake or reservoir at a higher elevation
As it flows back down it spins turbines and generates electricity.

12. Advantages of Large-Scale Hydropower
Moderate to high net energy
High efficiency
Large untapped potential
Low-cost electricity
Long life span
No CO2 emissions
May provide flood control below a dam
Provides water year round for irrigation of cropland
Reservoir is useful for fishing and recreation

13. Disadvantages of large-scale Hydropower
High construction costs
High environmental impacts from flooding land to form a reservoir
High CO2 emissions from biomass decay in shallow waters
Floods natural areas behind dams
Converts land habitat to lake habitat
Uproots people
Decreases fish harvest below the dam
Decreases flow of natural fertilizer (silt) to land below dam.

14. Producing electricity from Wind
This indirect form of solar energy can be captured by wind turbines and converted into electricity.
It is a resource that still remains untapped by most of the world.

15. Advantages of wind power
Moderate to high net energy
High efficiency
Moderate capital cost
Low electricity cost (and still falling)
Very low environmental impact
No CO2 emissions
Quick construction
Easily expanded
Can be located at sea
Land below turbines can be used to grow crops or graze livestock

16. Disadvantages of wind power
Steady wind needed
Backup energy source when wind is low
High land use for wind farm
Visual pollution
Noise when located near populated areas
May interfere in flights of migratory bird and kill birds of prey

17. Producing energy from Biomass
Biomass consists of plant materials and animals wastes that can be burned directly as solid fuel or converted into gaseous or liquid biofuels.
Most biomass is burned directly to spin turbines to generate electricity.
The burning of wood and manure actually provides about 10% of the world’s energy and about 30% of the energy is used in developing countries.

18. Biomass plantations
One way to produce biomass is to plant, harvest, and burn large numbers of fast growing trees.
Crop residues and animal manure can be collected and burned to produce heat for cooking in many poorer nations.
Some ecologists believe it is better to leave the animal manure as a fertilizer and the crop residue to feedstock or prevent soil erosion.
Not doing so may reduce the production of food supplies in that given area.

19. Plantation – (also a wind farm!)

20. Worksheet!

21. Geothermal Energy Systems
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22. How Geothermal Works
Geothermal heat pumps use a pipe and duct system to make use of heat stored in underground rocks and fluids.
The Earth is used as a heat source in winter and a heat sink in summer.

23. Geothermal Exchange
Geothermal exchange, or geoexchange, uses buried pipes filled with fluid to move heat in or out of the ground for heating or cooling needs.
Wells can be used to withdraw wet and dry steam, as well as hot water, for heat, or to produce electricity.
Many energy experts say that geothermal exchange is the most-energy-efficient, cost- effective, and environmentally clean way to heat or cool a building.

24. Geothermal in Canada There are many sources of hot water here.
The amount of geothermal energy available is much greater than that stored in Alberta’s oil and gas reserves.

26. Major Issues There are two problems with goethermal energy.
It is too expensive to tap, except for the most concentrated and accessible sources.
It may be depleted if heat is removed faster than it is renewed.

27. A Sustainable Energy Strategy
A combination of subsidies, tax breaks, and taxes can be used by government to promote or discourage the use of various energy alternatives.
To encourage the shift to sustainable energy use, economic and political strategies can be employed.
Keep energy prices artificially low to encourage use of selected energy resources. Our current system actually encourages energy waste.
Keep energy prices artificially high to discourage use of a resource.
Increase taxes on fossil fuels to reduce air and water pollution, slow greenhouse gas emissions, and encourage improvements in energy efficiency with greater use of renewable energy resources.

28. Continued…
To develop a more sustainable energy future, we must increase energy efficiency, use more renewable energy, and reduce adverse environmental effects from the use of fossil fuels and nuclear energy.
The U.S. is described as a first world nation with a third world electrical grid system.
Implementing policies described in Figure over the next several decades would save money, create a net gain in jobs, reduce greenhouse emissions, and sharply reduce air and water pollution. They might also increase national security by:
reducing the dependence on imported oil, and
decreasing dependence on large, centralized coal and nuclear power plants.

29. Various Ways to Transition to Sustainable Energy

30. The Sustainable Star

31. Assessment
1.What is the major energy source for heating your living space? 
2. What is the major energy source for providing electricity to your living space?
3. How do you feel toward different energy sources?
4. What would be the best alternative energy source in your area?
5. Do you feel a responsibility to use energy wisely? What steps are you willing to take to reduce your energy consumption?
6. How do you feel toward decentralization of the power grid?
7. Do you favour policies that encourage energy conservation and more development of renewable and perpetual energy sources?