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Chapter

chapter notes


Department
Environmental Science
Course Code
EESA01H3
Professor
Carl Mitchell

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Chapter 17
- Tidal: sluice/gates
- energy from the Sun/wind/ Earths geothermal heat/ movement of ocean water
o not yet used on a wide scale in our modern industrial society
o harnessed by using technologies that are still in a rapid phase of development
o will play a larger role in energy use in the future
1. power generation (using wind, solar, tidal, and other energy sources)
2. space heating (using solar and terrestrial energy sources to heat buildings, factories, and
communities)
3. fuel (using alternatives, such as hydrogen or crops, crop residues, or waste materials to
manufacture ethanol and biodiesel for use in transportation)
- 0.5% worldwide obtained from new renewable energy sources
- Wind power grew by 50% annually since 1970
- Expanding quickly because of growing concerns of diminishing fossil fuel supplies (Æ high prices
and national security concerns) & environmental impacts of fossil fuel combustion
- Advances in technology Æ less expensive and easier
- Can create new employment opportunities, sources of income, property tax
- 44 landfill gas-to-electricity (LFGTE) systems in Canada in 2003
- Research and development projects for renewable sources are underfunded least subsidy
Solar energy
- 1 m2 on Earths surface receives ~1kW of solar energy [17 times a light bulb]
- Mainly used for:
o Heating and cooling air
o Heating water (aquaculture, swimming pools, home & industrial uses
o Drying crops (tea, coffee, timber, fruit, etc)
o Generating electricity for off-grid & distributed energy applications
o Detoxifying water and air
o Cooking
o Daylighting
Passive solar energy collection: buildings/building materials are made to maximize direct absorption of
sunlight in winter
- Low, south-facing windows to maximize sunlight capture in the winter (in North)
- Use of heat-absorbing construction materials (thermal mass straw, brick, concrete, or other
materials) that absorb heat, store it, and release it later
- Can involve planting vegetation around a building
Active solar energy collection: makes use of technological devices to focus, move, or store solar energy
- Solar panels/flat-plate solar collectors: often on rooftops, dark-coloured heat-absorbing metal
plates mounted in flat boxes with covered glass panels
- water/air/anti-freeze solutions are run through tubes through collectors transferring heat
- common in China, Europe, and isolated locations
- does not have to be expensive or confined to regions that are always sunny
- can magnify the strength of solar energy by gathering sunlight from a wide area & focusing on a
single point
- mirrors concentrate sunlight onto a receiver Æ heat is transported by fluids (molten salts) Æ
piped to a steam-driven generator to create electricity
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