1. I. I.Energy B. B.Renewable 4. 4.Biomass and Waste Biomass fuels include residues from logging; mill operations; processing of wood, pulp, paper, fiberboard; agricultural crops; livestock and poultry operations; food processing; demolition (urban wood waste) Waste fuels include combustible residues from industrial processes, municipal solid & liquid wastes Currently supplies ~15% of electricity production worldwide, more in developing countries Benefits Readily available fuel Inexpensive Reduces waste stream Concerns Emissions – Especially for waste combustion Low fuel density Technology still being developed (mainly emissions)

2. I. I.Energy B. B.Renewable 5. 5.Geothermal Heat from deep within earth captured and used to turn an electric generation turbine Benefits Inexpensive Minimal environmental impact – Little pollution Energy security – US has extensive resources Concerns Limited use geographically Not truly renewable (water injection can prolong life of geyser field) Geothermal emissions may include CO 2 and H 2 S, as well as various toxic compounds Not economically viable in most areas Geological risks

3. I. I.Energy B. B.Renewable 6. 6.Fuel Cells Many types All have membrane that only allows positively charged particles to cross and external shunt that channels electrons Have been used for decades (powered manned space flights) Benefits Low emissions Highly efficient (up to 85% in some cases) No moving parts – Enhances durability, simplifies maintenance Energy security – Can be produced anywhere Concerns Technology still in its infancy Energy input during processing Risks of handling hydrogen and other fuels Currently very expensive www.fuelcells.org

4. I. I.Energy B. B.Renewable 7. 7.Biofuels Bioalcohols Biodiesel Biogas Benefits Renewable Energy security Reduced waste stream for raw materials Reduced environmental impacts vs. other energy sources Concerns “Food vs. Fuel” – Elevated food prices Not carbon neutral or carbon negative Growing crops & processing for fuel requires land and water Pesticides may contaminate local aquifers Emissions from biofuels (air pollution)

5. Gibbs et al. 2008

6. Righelato and Spracklen 2007

7. US EIA

8. I. I.Energy B. B.Renewable 8. 8.Other Tidal energy Wave energy OTEC (Ocean Thermal Energy Conversion) Fusion

9. II. II.Fresh Water Historically limiting factor in arid regions 1940-1990 World population more than doubled 2.3 billion  5.3 billion Per capita water use doubled 400 m 3 person -1 year -1  800 m 3 person -1 year -1 Global water use increased fourfold 2000: USA ~2000 m 3 person -1 year -1 (~1450 gal day -1 ) A. A.Current Status In 1996, world human population using estimated 54% of all accessible fresh water in rivers, lakes, aquifers Many people predict disastrous consequences for world’s fresh water supply in coming years This potential disaster may have several causes

10. II. II.Fresh Water A. A.Current Status 1. 1.Distribution Uneven compared to population 75% of annual rainfall in areas containing less than one-third of global population Amazon River carries 20% of global runoff through area containing 10 million people Congo River carries 30% of Africa’s runoff through area containing 10% of population Uneven in space North America contains 19,000 m 3 per person per year vs. 4700 m 3 per person per year in Asia 50% of annual runoff Uneven in time India gets 90% of annual rainfall during summer monsoon season (Jun-Sep); runs off too rapidly for efficient use

11. II. II.Fresh Water A. A.Current Status 2. 2.Usage patterns Agriculture – 69% Industry/Energy – 23% Domestic – 8% Varies among regions and with development Africa – 88% for agriculture (irrigation) Europe – >50% for industry Japan – Industrial but uses lots of water for growing rice Spain/Portugal – Arid; use water heavily for agriculture Personal use tracks standard of living Africa – 17 m 3 year -1 (12.3 gal d -1 ) Asia – 31 m 3 year -1 (22.4 gal d -1 ) UK – 122 m 3 year -1 (88.3 gal d -1 ) US – 211 m 3 year -1 (153 gal d -1 ) By 2020, water shortages likely in Ethiopia, India, Kenya, Nigeria, China (parts of China already face problems) Mexico City uses groundwater for 80% of municipal water supply Depletion exceeds aquifer recharge rate by 50-80% Sinking of land in some areas  Damage to buildings City imports water to meet demand

12. II. II.Fresh Water A. A.Current Status 3. 3.Contamination Numerous examples worldwide Biggest source = Agriculture Europe – Over 90% of rivers have elevated nutrient levels from agrochemicals Hungary – Nearly 40% of well fields contaminated Developing countries – On average, 90% to 95% of all domestic sewage and 75% of all industrial waste discharged into surface waters without treatment 4. 4.Impacts Nile River – Diverting water + retention of sediment behind dams has caused fertile delta to shrink Rhine River – Lost 8 of 44 fish species; 25 more endangered Lake Chad – Diversion + drought has caused shrinkage from 25,000 to 2,000 km 2 in 30 years LinkLink Aral Sea – Diversion for agriculture has caused severe shrinkage, with environmental & health problems L1 L2L1L2

13. II. II.Fresh Water B. B.Possible Solutions World may have enough fresh water but inadequate distribution mechanism Long pipelines and movement of icebergs have been proposed Excessively expensive Technological limitations

14. II. II.Fresh Water B. B.Possible Solutions 1. 1.Improved irrigation efficiency Drip irrigation reduces losses from evaporation Cuts water use by 40-60% compared to conventional systems Used on <1% of irrigated land worldwide but used extensively in some countries (Ex – Israel uses DI on 50% of irrigated land) Low-energy precision application (LEPA) methods apply water directly to plants Can lower use of water and energy (20-50%) 2. 2.Municipal conservation Infrastructural losses can be substantial Ex – 40-70% of water lost in transit in 15 major Mexican cities (similar rates in India) Ex – Djakarta, Indonesia could cut water losses an estimated 20% by fixing leaky distribution pipes; would save ~12 billion gallons of water a year, enough to supply 800,000 people Higher price could encourage conservation Ex – Bogor, Indonesia increased water prices 3-4x; average household water use dropped by 30% in less than one year

15. II. II.Fresh Water B. B.Possible Solutions 3. 3.Reuse of urban wastewater Use of treated wastewater for irrigation Today, at least half a million hectares in 15 countries are being irrigated with “gray water” 4. 4.More water-efficient industry Practiced in industrialized nations. Amount of water needed to produce a ton of steel ranges from 23 to 56 m 3 in China, compared to an average of less than 6 m 3 in US, Japan, and Germany 5. 5.Desalination 2010 – Over 20 billion gallons of fresh water produced daily in ~15,000 facilities worldwide Minimum cost = 0.2¢ gal -1 Current methods of desalination driven almost entirely by combustion of fossil fuels Solar powered desalination plants produced only 1.4 million gal d -1 in 2009