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Energy Alternatives II: Non-renewables & renewables

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  • Slide 1
  • Energy Alternatives II: Non-renewables & renewables
  • Slide 2
  • Non-renewables: fossil fuels There is no global shortage of fossil fuels Petroleum: 50+ years left Coal: hundreds of years Natural gas: decades FF are easy to find, mine & consume FF prices are quite low Distributional issues Price issues Environmental issues
  • Slide 3
  • There is still lots of oil around the world
  • Slide 4
  • The problem remains: who has it, who wants it, and how will it get from one to the other
  • Slide 5
  • 1 trillion cu. meters gas = 6.29 billion bbl oil Theres also quite a bit of natural gas: about one trillion barrels of oil equivalent
  • Slide 6
  • 1 billion metric tons coal = 2.45-4.9 billion bbl oil And a lot of coal: 2-4 trillion barrels of oil equivalent
  • Slide 7
  • In principle, fossil fuel supplies are not a serious problem In practice, it appears that they are (or will be)
  • Slide 8
  • Nor can the political implications be ignored Even if oil is not really scarce, perception creates myths, and myths can lead to conflict Even if climate change proves not to be a problem, theres still a lot of pollution from ff And cheap energy fosters growing demand, which has to be supplied somehow Well return to these points next week
  • Slide 9
  • What about energy alternatives? Hydroelectricity Geothermal Fuel cells Ocean energy Fusion Biomass Wind Solar Hydrogen Global oil use = 500 trillion liters/year
  • Slide 10
  • And dont forget how compact & convenient ff are
  • Slide 11
  • What should we look for in energy alternatives? Reduce vulnerability, increase flexibility Be environmentally-friendly or green Be cost-effective & efficient Be sustainable over the long-term Not introduce major lifestyle disruptions Not generate intractable waste problems Not solve one problem only to create others Not introduce intractable social problems
  • Slide 12
  • Hydroelectricity is one very effective & wide- spread renewable energy source
  • Slide 13
  • Its total potential is limited and large dams are not without environmental & social impacts Total global electrical production = 20,000 TWh/yr.
  • Slide 14
  • In theory, geothermal is widespread & could provide heat & electricity Energy in Iceland
  • Slide 15
  • In practice, again, accessible geothermal reservoirs are limited, and recent efforts to fracture bedrock to release geothermal heat appeared to cause earthquakes, leading to cancellation of projects in Switzerland & California
  • Slide 16
  • The oceans offer almost limitless energy potential Wave energy powernote the very high energy potential in the North Atlantic, off the Irish coast: the Saudi Arabia of waves! So far, various technologies have not panned out or proven economicalbut that could change
  • Slide 17
  • It might also be possible to use ocean temperature differences to produce heat much like refrigerators No commercial-scale systems yet
  • Slide 18
  • Fuel cells can generate electricity directly, but require a fuel source to drive electricity production. A few small test plants appear to be in operation
  • Slide 19
  • But fusion is always 50 years in the future And theres always fusion The fuel source is virtually unlimited
  • Slide 20
  • Fusion reactors will involve very complex designs, and they will be very expensive Depending on fuel, they could also generate considerable amounts of radioactive materials
  • Slide 21
  • Biomass conversion involves chemical reduction into liquid fuels, which is already being done on a very large scale in the U.S. & Brazil Depending on source, it might displace food production (as with corn ethanol).
  • Slide 22
  • Solar energy is plentiful but diffuse, and must be collected, concentrated & stored
  • Slide 23
  • It can be used to heat or boil water, the latter to generate steam
  • Slide 24
  • Built onto buildings, on as part of the structure, it can generate electricity
  • Slide 25
  • Global production of solar PV cells is growing, while cost is dropping But solar is diurnal, at best, and some kind of storage system is required for times when it is not available
  • Slide 26
  • There is a lot of wind energy potential, especially out in the oceans
  • Slide 27
  • Wind is variable and diffuse and must be backed up by some other electrical source (could solar & wind back up each other?)
  • Slide 28
  • Wind resources are widely available
  • Slide 29
  • Costs of wind are decreasing, capacity is growing, but so is the average size of turbines. These tend to be quite noisy & to kill birds, and there is growing opposition to them
  • Slide 30
  • What about hydrogen? Solar in the desert could be used to make hydrogen, which could be piped to cities.
  • Slide 31
  • Mtoe Technological progress projection
  • Slide 32
  • This is one optimistic electrical generation projectionnote that it is only electricity; liquids not included

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