ALTERNATIVE ENERGY SOURCES STEM Carib 2012

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