Energy

• World energy consumption projected to rise > 70% from 2003 to 2030

• OECD

Energy

• Bulk of increase expected to come from non-OECD nations

• Energy demand in Asia, Central and South America expected to more than double by 2030

Energy

A. Conventional1. Fossil Fuels

a. Oil• Transportation, electricity generation, heating• World’s dominant source of energy for past

several decades• Expected to remain important for next 20 years

- Estimated ~35-40% of total energy consumption through 2020

• Greatest consumption by OECD nations, but gap closing

• 1999 – Non-OECD nations consumed 58% as much as OECD nations

• 2030 – Projected to use ~90% as much• Most of increase from transportation sector

(few alternative fuel sources)

Energy

A. Conventional1. Fossil Fuels

a. Oil• Benefits

• Readily available• High energy density• Inexpensive• Existing technology & infrastructure

• Concerns• Combustion releases pollutants (CO2, NOx,

SOx, PM)• Extraction harms environment• Accidental releases, especially in ocean• Long-term availability• Energy security - US imports 60% of oil

Energy

A. Conventional1. Fossil Fuels

b. Coal• Electricity generation (65% of global coal use)• Main fuel source in China for industry• Use expected to grow slowly, mostly fueled by Asia,

especially China and India• Benefits

• Inexpensive• Abundant, easy to recover• Requires minimal processing• Existing technology & infrastructure

• Concerns• Environmental degradation from mining• Requires extensive transportation system (rail)• Combustion generates pollutants (CO2, PM, Hg, NOx,

SOx), including components of brown smog

Energy

A. Conventional1. Fossil Fuels

c. Natural gas (methane)• Fastest growing source of energy over next 20 years

(projected to double)• Equaled coal (BTU basis) in 1999• Increase fueled by price, environmental concerns,

energy security issues, market deregulation• Benefits

• Inexpensive• Abundant, easy to recover• Existing technology & infrastructure• Burns relatively cleanly (little PM, etc.), almost no

solid waste• High efficiency (90% vs. 27% for electricity)• Energy security – US produces 85% of demand vs.

40% for oil• Concerns

• Greenhouse gas• Adequate long-term supply

Energy

A. Conventional1. Fossil Fuels

d. Gas (methane) hydrates• Worldwide reserves estimated at up to 100,000

trillion cubic feet of gas (10,000 Gt carbon), twice the carbon in all other fossil fuel reserves on earth

• Located beneath marine sediments at 300-500 m depth

• Common off SE US, Siberia, Alaska• Benefits

• Extremely abundant• Existing infrastructure for distribution• Burns relatively cleanly (little PM, etc.), almost no

solid waste• High efficiency (90% vs. 27% for electricity)• Energy security – US has extensive reserves

• Concerns• Greenhouse gas• Damage to sea floor• Catastrophic effects of massive release

Energy

A. Conventional2. Nuclear

• Derived from splitting ("fissioning“) of uranium atoms• Uranium mined, processed to increase fissionable material,

made into fuel rods• Uranium atoms split inside reactor, generate heat steam

electricity• World capacity projected to rise from 362 GW in 2003 to 437 GW

in 2030• Highest growth projected for developing world, especially Asia

• Benefits• Clean (few pollutants or GHGs)• Relatively inexpensive• Existing technology & infrastructure• Compact fuel & waste (high energy density – 1 lb of U =

3.5 million lbs of coal)• Energy security – US has extensive reserves

• Concerns• Safety – Possibility of accidents• Strategic risks – Material stolen and used to create weapon• Waste disposal – Contamination of ground water, soil,

animals, plants, people• GHG production from mining & transportation of uranium

Energy

B. Renewable• Sources either can’t be used up or are replenished

quickly through natural processes• In CA, eligible renewable energy sources include

1) Biomass and waste2) Geothermal3) Solar4) Small hydroelectric5) Wind energy

• Use expected to increase by 65% worldwide between 2003 and 2030; current 8% share of total energy consumption projected to rise slightly to 9% by 2030

• Growth in renewable energy resources expected to be constrained by moderate fossil fuel prices

• Energy consumption expected to be driven by new, large-scale hydroelectric projects, esp. in China, India, Malaysia, other developing Asian countries

Energy

B. Renewable1. Hydroelectric

• Currently supplies ~20% of electricity production worldwidea. Small (<30 MW)

• Less impact but less power than large facilitiesb. Large (>30 MW)

• Includes immense dams with potentially large impacts• Ex – Itaipu Dam (Brazil, Paraguay, Argentina) = 12,600 MW• Ex – Three Gorges Dam (China) = 18,200 MW

• Benefits• Inexpensive, once facility exists• Minimal environmental impact – Little pollution, no GHGs• Many facilities already in place• May permit flood control• Relatively efficient and nondestructive

• Concerns• Limited use geographically• Environmental degradation in flooded areas• Environmental degradation downstream• Detrimental to some aquatic animals (Ex – salmon)• Collapses can be catastrophic• Rainfall variation can reduce reliability

http://www.nwd-wc.usace.army.mil/report/colmap.htm

Energy

B. Renewable2. Wind

• Power captured with wind turbines• The Dakotas and Texas have sufficient wind capacity to

supply energy needs of entire United States• Benefits

• “Free”• Minimal environmental impact – Little pollution, no

GHGs• Can produce electricity without being connected to

power grid• Multiple uses of land

• Concerns• Limited use geographically• Inconsistent energy source• Expensive to maintain• May be dangerous to birds• Low power density• Weather effects?

Energy

B. Renewable3. Solar

• Can be generated bya. Focusing heat of sun on central point that heats up; heat used to

produce steam, which turns turbineb. Photovoltaic (PV) cells – Convert energy from sun directly to

electricity; each PV panel typically produces small amount of electricity, but panels can be grouped

• Benefits• Abundant – “The amount of solar radiation striking the

earth over a three-day period is equivalent to the energy stored in all fossil energy sources.”

• “Free”• Minimal environmental impact – Little pollution, no GHGs• PV systems have no moving parts, require little

maintenance• Can produce electricity without being connected to power

grid• Concerns

• Limited use geographically• Inconsistent energy source• Expensive – $0.22-0.40/kWh vs. $0.13/kWh on my latest bill• Requires special materials to harvest energy• Low power density; long-term storage of energy

Energy

B. Renewable4. 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 not yet well developed

Energy

B. Renewable5. Geothermal

• Heat from deep within earth captured and used to turn an electric generation turbine

• Benefits• Inexpensive• Minimal environmental impact – Little pollution, no

GHGs• 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 CO2 and H2S, as

well as various toxic compounds• Not economically viable in most areas

Energy

B. Renewable6. 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

Energy

B. Renewable7. Other

• Tidal energy• Wave energy• OTEC (Ocean Thermal Energy Conversion)• Fusion

Energy

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California Net System Power Mix

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 m3 person-1 year-1 800 m3 person-1 year-1

• Global water use increased fourfold

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

Fresh Water

A. Current Status1. 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 m3 per person per year vs. 4700 m3 per person per year in Asia

• <10% of Mexico supplies >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

Fresh Water

A. Current Status2. 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; water used heavily for agriculture

• Personal use tracks standard of living• Africa – 17 m3 year-1 (47 l d-1)• Asia – 31 m3 year-1 (85 l d-1)• UK – 122 m3 year-1 (334 l d-1)• US – 211 m3 year-1 (578 l 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

Fresh Water

A. Current Status3. 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. 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 km2 in 30 years Link• Aral Sea – Diversion for agriculture has caused severe

shrinkage, with environmental & health problems L1 L2

Fresh Water

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

Fresh Water

B. Possible Solutions1. 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. 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

Fresh Water

B. Possible Solutions3. 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. More water efficient industry• Practiced in industrialized nations.• Amount of water needed to produce a ton of steel ranges

from 23 to 56 m3 in China, compared to an average of less than 6 m3 in US, Japan, and Germany

5. Desalination• 1990 – Just over 13 million m3 of fresh water produced

daily in 7,500 facilities worldwide• Provides 0.1% of global fresh water use

• Current methods of desalination driven almost entirely by combustion of fossil fuels

• Solar powered desalination plants are currently produce only 5,240 cubic m3d-1