1 / 49

ALTERNATIVE ENERGY SOURCES STEM Carib 2012

Mike Cowdery, Corporate Electric & UCCI. ALTERNATIVE ENERGY SOURCES STEM Carib 2012. CONTENTS. Introduction Why engineering a sustainable future matters Energy sources Where does energy come from? Energy alternatives Renewable energy options Other alternative energy sources?

chandler
Download Presentation

ALTERNATIVE ENERGY SOURCES STEM Carib 2012

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Mike Cowdery, Corporate Electric & UCCI ALTERNATIVE ENERGY SOURCESSTEM Carib 2012

  2. CONTENTS • Introduction • Why engineering a sustainable future matters • Energy sources • Where does energy come from? • Energy alternatives • Renewable energy options • Other alternative energy sources? • Conclusions Some material courtesy Tom Murphy UCSD

  3. INTRODUCTION Why engineering a sustainable future matters

  4. Fossil fuels… • Our per capita energy consumption is many times that of the rest of the world • Most energy comes from fossil fuels - a short, finite lifetime • What will our future hold? • Will it be back to a simple life? • Or will we find new ways to produce all the energy we want? • Or will it be somewhere in the middle? Fossil fuels Nuclear, geothermal, solar energy OR People, animals, firewood energy usage People, animals, firewood 2000BC 1000BC 0 1000 3000 4000 5000 6000 2000 year

  5. Global Energy: Where Does it Come From? * Ultimately derived from our sun Courtesy David Bodansky (UW)

  6. The Great Energy Divide Cayman Many countries in the world lie in this quarter-circle!!

  7. Economic Growth and Energy Use Energy usage Energy use is directly correlated with economic prosperity

  8. Why sustainability matters – price of oil

  9. Why sustainability matters – security of supply

  10. Why sustainability matters – climate change Pasterze Glacier, Austria, 1874 Pasterze Glacier, Austria, 2000

  11. What are we going to do? We are borrowing money from China to buy oil from the Gulf -and it all goes up in smoke!

  12. Energy: sources and uses

  13. Kinetic energy & wind • Kinetic Energy: the energy of motion K.E. = ½mv2 • KE of wind can be used (e.g. windmills, sailing boats, etc.) • Example: wind passing through a square meter at 8 meters per second (18mph) • Each second we have 8 cubic meters • Air has density of 1.3 kg/m3, so (8 m3)(1.3 kg/m3) = 10.4 kg of air each second • ½mv2 = ½(10.4 kg)(8 m/s)2= 333 J • 333J every second 333W per square meter (but to get all of it, you’d have to stop the wind) • Stronger winds  more power (~ v3) 13

  14. Challenges for small islands?

  15. Gravitational energy • Raising a Weight W through height h against gravity requires an energy input (work) of E = W = F ·h = mgh • Rolling a boulder up a hill gives it gravitational potential energy • The higher the cliff, the more kinetic energy the boulder will have when it reaches the ground mgh Conservation of energy: ½mv2 = mgh v2= 2gh becomes h ½mv2 15

  16. Energy of the hydrologic cycle • Evaporating 1g of water takes 2,250J • Raising 1g of water to top of the troposphere (10,000 m, or 33,000 ft): mgh = (0.001 kg)(10 m/s2)(10,000 m) = 100 J • A tiny bit of PE remains, IFrain falls on suitable terrain (e.g. higher than sea level) • hydroelectric plants use this tiny left-overenergy • damming concentrates PE in one location • 401015 W of solar power goes into evaporation • Gravitational PE given to water vapor in the atmosphere (per second): mgh = (1.61010 kg)(10 m/s2)(2000 m) = 3.21014 J = 320 TW • US uses only 1.25% of that available

  17. Gravitational energy - water Pumped storage

  18. Waves: global distribution of annual mean wave power A GLOBAL WAVE ENERGY RESOURCE ASSESSMENT. Andrew M. Cornett. Proceedings of the Eighteenth (2008) International Offshore and Polar Engineering Conference Vancouver, BC, Canada, July 6-11, 2008.

  19. Chemical Energy • Electrostatic energy (associated with charged particles, like electrons) is stored in the atomic bonds of substances. • Rearranging these bonds can release chemical energy (some reactions require energy to be put in) • Typical numbers: 100–200 kJ per mole • a mole is 6.0221023 molecules/particles • typical molecules are tens of grams per mole  several thousand Joules per gram

  20. Chemical Energy Examples • Burning a wooden match: • releases about 1055 Joules • a match is about 0.3 grams • Energy release >3kJ/g (3kJ/g) • Burning coal releases about 20kJ/g of chemical energy • Burning gasoline yields about 39kJ/g • Very few substances yield over about 45kJ/g 20

  21. Power generation from diesel power plant • CUC's power system comprised of 17 generating units (15 diesel and two gas turbine) - capacity 151.2 MW • Electricity price heavily dependent upon fuel cost

  22. Alternative fossil fuel source: shale gas & oil • Shale gas = natural gas formed trapped within shale formations. • An increasingly important source of natural gas in the US & rest of the world. • In 2000 shale gas provided 1% of U.S. natural gas production; by 2010 it was over 20% • U.S. government's Energy Information Administration predicts by 2035, 46% of the US NG from shale gas. Source: New York Mercantile Exchange

  23. Is peak oil a myth? - The path to US energy independence • Are fossil fuel resources finite/known?? • May be too much fossil fuel - prices may be too low, not too high • Availability, not cost • Abundant low-cost “conventional” oil (Middle East) has limited other sources • The revolution in shale gas/shale oil has been transformational in the US • Is there another way forward, using cheaper gas without increasing emissions? • Yes –for the next couple of decades • Switching from coal to gas is cheap – & cuts emissions by roughly half! • Does not solve climate change but gets emissions down much faster and cheaper than wind farms Source: BP energy outlook 2030, Jan 2012

  24. Energy from crops - food • Human energy derived from food (stored solar energy in the form of chemical energy). • Energy sources recognized by our digestive systems: • Carbohydrates: 17kJ/g (4 Cal per g) • Proteins: 17kJ/g (4 Cal per g) • Fats: 38kJ/g (9 Cal per g - like gasoline) • A 2000 Calorie per day diet means 20004184 J = 8,368,000 J per day, corresponds to 97 Watts of power • This product has 150 Calories = 636 kJ: enough to climb about 1000 meters (64 kg person) 24

  25. Biomass • Biomass: any living organism • 40x1012W out of the 174,000x1012W incident on the earth from the sun goes into photosynthesis • 0.023% • this is the fuel for virtually all biological activity • half occurs in oceans • Compare this to global human power generation of 12x1012W, or to 0.6x1012W of human biological activity • Fossil fuels represent stored biomass energy 1.5% Solar Energy Conversion Efficiency 25

  26. How much land? How much land to replace US oil? • Cornfield ~ 1.5% efficient at turning sunlight into stored chemical energy • Conversion to ethanol is 17% efficient • Growing season is only part of year (say 50%) • Net efficiency ~ (1.5% x 17% x 50%) = 0.13% • Need 4x1019J/yr to replace petroleum - this is 1.3x1012 W • thus need 1015 W input (at 0.13%) • at 200 W/m2 insolation, need 5x1012m2, or (2,200 km)2 of land • that’s a square 2,200 km on a side

  27. Mass-energy • Einstein theory of relativity: E = mc2 • Relates mass to energy • one can be transformed into the other • physicists speak generally of mass-energy • Seldom experienced in daily life directly • Happens at large scale in the center of the sun, and in nuclear weapons and reactors • Happens in all energy transactions, but the effect is tiny! 27

  28. E = mc2 Examples • The energy equivalent of one gram of material (any composition!!) is (0.001 kg)(3.0108 m/s)2 = 9.01013 J = 90,000,000,000,000 J = 90 TJ ≡ 568,000g gasoline • If one gram of material undergoes a chemical reaction, losing about 9,000 J of energy, how much mass does it lose? 9,000 J = mc2, so m = 9,000/c2 = 9103/91016 = 10-13kg 28

  29. E = mc2 in Sun • Helium nucleus is lighter than the four protons! • Mass difference is 4.029  4.0015 = 0.0276 a.m.u. • 1 a.m.u. (atomic mass unit) is 1.660510-27 kg • difference of 4.5810-29 kg • multiply by c2 to get 4.1210-12 J • 1 mole (6.0221023 particles) of protons  2.51012 J • typical chemical reactions are 100-200 kJ/mole • nuclear fusion is ~20 million times more potent! 4 protons: mass = 4.029 energy 4He nucleus: mass = 4.0015 29

  30. Utilising solar energy: PV types • Energy reaching the Earth’s atmosphere is 174 x 1015W → 89 x 1015W at surface • Compare to total energy production on earth of 3.31012 W • Even a small fraction of could solve world energy problems! • Single-crystal silicon: η~15–18% • expensive (grown as big crystal) • Poly-crystalline silicon: η~ 12–16% • cheaper (cast in ingots) • Amorphous silicon (non-crystalline) • η~ 4–8% • “thin film”, easily deposited on a wide range of surface types • Max. Si PV efficiency around 23%

  31. Alternative energy options?

  32. The main energy alternatives • We’ve now seen all the major energy alternatives: • kinetic energy (wind, ocean currents) • gravitational PE (hydroelectric, tidal, wave) • chemical energy (batteries, food, biomass, fossil fuels (incl. shale gas)→ heat energy (power plants)) • mass-energy (nuclear sources, sun’s energy) • radiant energy (solar energy) • WHAT WORKS HERE? 32

  33. Renewable Resources • Renewable = anything that won’t be depleted • sunlight (the sun will rise again tomorrow) • biomass (grows again) • hydrological cycle (will rain again) • wind (sunlight on earth makes more) • ocean currents (driven by sun) • tidal motion (moon keeps on producing it) • geothermal (heat sources inside earth not used up fast)

  34. Solar energy economics • Current electricity cost in GC is about CI$0.35 per kWh • PV output: assume 5 hours peak-sun equivalent per day = 1800 h/y • one Watt delivers 1.8 kWh in a year • installed cost is CI$5 per peak Watt capability • panel lasts at least 25 years, so 45 kWh for each Watt of capacity • CI$0.111/kWh • Assuming energy inflation a few % per year, payback is ~ 6 years • thereafter: “free” • $$ up front = loss of investment capability • Cost today is what matters to many

  35. The downside of solar • The sun is not always shining! • 100% energy availability is not fully compatible with direct solar power • Hence large-scale solar implementation must address energy storage techniques • small scale: feed solar into grid & let other power plants take up slack • Methods of storage: • conventional batteries (lead-acid) • exotic batteries (need development) • hydrogen production (consume later, transport) • Pumped storage/global electricity grid? (not for Cayman)

  36. Ocean Thermal Energy Conversion • OTEC uses heat stored in ocean waters • The temperature of the water varies: • top layer normally warmer than that nearer the bottom • Works best when there is at least 20°C difference • This ΔT often found in tropical areas • Closed cycle uses low-boiling point fluid (e.g. ammonia) • Warm ocean water is pumped through a heat exchanger to vaporize the fluid • Energy extracted in a turbine • Cold water pumped through a second heat exchanger to condense vapor to be recycled through the system

  37. Transportation • About 1/3 of US annual energy usage for transportation • Gasoline is a good fuel • Around 40kJ/g • engine efficiency only around 20% • Problems with ethanol (from corn) • Solar cars are impractical, at 1–2 horsepower • Electric cars need batteries (but can use solar as a source of electricity) • batteries store only 0.14 to 0.46 kJ/g • some gain in fact that conversion to mechanical is 90% efficient • Desperately need a replacement for portable gasoline

  38. Working design 2012: Legislation changed • HSEVs now available (e.g. Wheego) meeting US crash-test standards • 14 businesses have signed letters of intent for solar-panel powered EV stations • Cayman Automotive + UGO Stations + Corporate Electric working on installation plan

  39. How the EV charger works • Equipment required: • Solar panels, inverter and charger etc. • Mounting, installation & infrastructure • Energy exchange with electricity grid • Sunshine = power generation to car charger or send electricity grid • Car charging: from solar electricity or grid • Vehicle energy costs (Grand Cayman experience): • Gasoline: 22mpg @ $6/gallon = 27c/mile = $2430/y • Mains electricity: 14kWh, 40 miles = 12c/mile = $1080/y • Electric (solar): 0c/mile = $0/y

  40. Engineering considerations • Technical • Type 1, 2 or 3 – charge times • Power source • CUC • Renewable – solar/wind • Mechanical/structural • Withstand to natural and man-made hazards • Aesthetics • Local or remote PV array • Harmonisation with surroundings

  41. Motor vehicles in the future?

  42. Another alternative energy option: Go Nuclear? • Nuclear energy • Fission • Fusion • Fission energy release: • 85%: kinetic energy of fission products (heat) • 15%: ke of neutrons + radiation energy (γ) • Energy release: E = mc2 • 1g equivalent: • 21.5 kilotons of TNT • 568,000 USG of gasoline

  43. Nuclear energy: atomic structure • Structure of the atom • Nucleus • Protons • Neutrons • Electrons

  44. How a reactor works

  45. Nuclear waste: Oklominesite, Gabon West Africa

  46. Small modular reactor: Hyperion • Modern small reactors: • Simple design; • Mass production economies; • Reduced siting costs. • High level of passive or inherent safety • Many safety provisions necessary in large reactors are not necessary in the small designs. • Hyperion: Uranium-nitride fuelled, lead-bismuth cooled small reactor • 70 MWt, 25 Mwe • Claimed to be modular, inexpensive, inherently safe, and proliferation-resistant. • Could be used for heat generation, production of electricity, and desalination.

  47. Conclusions

  48. What are the alternative-energy options? • Do nothing • Maintain dependence on diesel, gasoline • Use more natural gas - rely on shale gas/oil from overseas • Global warming? • Become more energy-independent • Economy benefits • Renewables: solar, OTEC • Transportation: electric vehicles • Solar-assisted? • Nuclear: Small modular reactor technology

  49. What do you think? • Energy cost • Energy security of supply • Environment & climate change • Land use • Safety • Waste • Employment

More Related