NATURAL GAS Natural gas, consisting mostly of methane, is often found above reservoirs of crude oil. – When a natural gas-field is tapped, gasses are liquefied

NATURAL GAS

• Natural gas, consisting mostly of methane, is often found above reservoirs of crude oil.– When a natural gas-field is tapped, gasses are

liquefied and removed as liquefied petroleum gas (LPG).

• Coal beds and bubbles of methane trapped in ice crystals deep under the arctic permafrost and beneath deep-ocean sediments are unconventional sources of natural gas.

NATURAL GAS

• Russia and Iran have almost half of the world’s reserves of conventional gas, and global reserves should last 62-125 years.

• Natural gas is versatile and clean-burning fuel, but it releases the greenhouse gases carbon dioxide (when burned) and methane (from leaks) into the troposphere.

COAL

• Coal is a solid fossil fuel that is formed in several stages as the buried remains of land plants that lived 300-400 million years ago.

Figure 16-12Figure 16-12

Fig. 16-12, p. 368

Increasing heat and carbon content

Increasing moisture content

Peat (not a coal)

Lignite (brown coal)

Bituminous

(soft coal)

Anthracite

(hard coal)Heat Heat Heat

Pressure Pressure Pressure

Partially decayed plant matter in swamps and bogs; low heat content

Low heat content; low sulfur content; limited supplies in most areas

Extensively used as a fuel because of its high heat content and large supplies; normally has a high sulfur content

Highly desirable fuel because of its high heat content and low sulfur content; supplies are limited in most areas

Fig. 16-13, p. 369

Waste heat

Coal bunker TurbineCooling tower

transfers waste heat to

atmosphere

Generator

Cooling loop

Stack

Pulverizing mill

Condenser Filter

Boiler

Toxic ash disposal

COAL

• Coal reserves in the United States, Russia, and China could last hundreds to over a thousand years.– The U.S. has 27% of the world’s proven coal

reserves, followed by Russia (17%), and China (13%).

– In 2005, China and the U.S. accounted for 53% of the global coal consumption.

TYPES OF ENERGY RESOURCES

• About 99% of the energy we use for heat comes from the sun and the other 1% comes mostly from burning fossil fuels.– Solar energy indirectly supports wind power,

hydropower, and biomass.• About 76% of the commercial energy we use

comes from nonrenewable fossil fuels (oil, natural gas, and coal) with the remainder coming from renewable sources.


• Nonrenewable energy resources and geothermal energy in the earth’s crust.


Fig. 16-2, p. 357

Oil and natural gasOil and natural gasFloating oil drilling

platform Oil storage CoalCoalContour strip miningOil drilling

platform on legs

Geothermal Geothermal energyenergy

Hot water storageOil well

Pipeline Geothermal power plant

Gas well Valves Mined coal

Pump Area strip mining Drilling

tower

Pipeline

Impervious rock

Underground coal mineNatural gasWaterOil

Water is heated and brought up as dry

steam or wet steamWater

Coal seam Hot rock

Water penetrates

down through the rock

Magma


• Commercial energy use by source for the world (left) and the U.S. (right).


REDUCING ENERGY WASTE AND IMPROVING ENERGY EFFICIENCY• Four widely used devices waste large amounts of

energy:– Incandescent light bulb: 95% is lost as heat.– Internal combustion engine: 94% of the energy in its

fuel is wasted.– Nuclear power plant: 92% of energy is wasted through

nuclear fuel and energy needed for waste management.– Coal-burning power plant: 66% of the energy released

by burning coal is lost.

USING RENEWABLE SOLAR ENERGY TO PROVIDE HEAT AND ELECTRICITY

• A variety of renewable-energy resources are available but their use has been hindered by a lack of government support compared to nonrenewable fossil fuels and nuclear power.– Direct solar – Moving water – Wind – Geothermal


• The European Union aims to get 22% of its electricity from renewable energy by 2010.

• Costa Rica gets 92% of its energy from renewable resources.

• China aims to get 10% of its total energy from renewable resources by 2020.

• In 2004, California got about 12% of its electricity from wind and plans to increase this to 50% by 2030.


• Denmark now gets 20% of its electricity from wind and plans to increase this to 50% by 2030.

• Brazil gets 20% of its gasoline from sugarcane residue.

• In 2004, the world’s renewable-energy industries provided 1.7 million jobs.

Solar

• Types – photovoltaic cells (convert sunlight directly to electricity with a 10% efficiency) and solar thermal systems (sun’s heat is used to heat bodies of water enough to produce steam that can be used to make electricity)

• Energy conversion – radiant/heat to electrical, heat or mechanical

• Benefits – pollution-free, unlimited source• Costs – not useful in cloudy areas or at night, we do

not have the technology needed to use very efficiently

Producing Electricity with Solar Cells

• Photovoltaic (PV) cells can provide electricity for a house of building using solar-cell roof shingles.


Fig. 17-17, p. 398

Single solar cellSolar-cell roof

–

Boron enriched silicon

+

Junction

Phosphorus enriched silicon

Roof options

Panels of solar cells

Solar shingles

Producing Electricity with Solar Cells

• Solar cells can be used in rural villages with ample sunlight who are not connected to an electrical grid.


Core Case Study: The Coming Energy-Efficiency and Renewable-Energy

Revolution

• It is possible to get electricity from solar cells that convert sunlight into electricity.– Can be attached like shingles on a roof.– Can be applied to window glass as a coating.– Can be mounted on racks almost anywhere.

Core Case Study: The Coming Energy-Efficiency and Renewable-Energy

Revolution

• The heating bill for this energy-efficient passive solar radiation office in Colorado is $50 a year.


Passive Solar Heating

• Passive solar heating system absorbs and stores heat from the sun directly within a structure without the need for pumps to distribute the heat.


Fig. 17-13, p. 396

Direct Gain

Summer sunHot air

Warm air

Super-insulated windows

Winter sun

Cool air

Earth tubes

Ceiling and north wall heavily insulated

Fig. 17-13, p. 396

Greenhouse, Sunspace, or Attached Solarium

Summer cooling vent

Warm air

Insulated windows

Cool air

Fig. 17-13, p. 396

Earth Sheltered

Reinforced concrete, carefully waterproofed walls and roof

Triple-paned or superwindowsEarth

Flagstone floor for heat storage

Fig. 17-14, p. 396

Trade-Offs

Passive or Active Solar Heating

Advantages Disadvantages

Energy is free Need access to sun 60% of time

Net energy is moderate (active) to high (passive)

Sun blocked by other structures

Need heat storage system

Quick installation

No CO2 emissions

Very low air and water pollution

High cost (active)

Very low land disturbance (built into roof or window)

Active system needs maintenance and repair

Moderate cost (passive)

Active collectors unattractive

Cooling Houses Naturally

• We can cool houses by:– Superinsulating them.– Taking advantages of breezes. – Shading them.– Having light colored or green roofs.– Using geothermal cooling.

Wind

• Energy conversion – kinetic to electrical

• Benefits – pollution-free, source is free (used in West Texas, Hawaii, California, and more)

• Costs – can only be used in places with lots of wind

PRODUCING ELECTRICITY FROM WIND

• Wind power is the world’s most promising energy resource because it is abundant, inexhaustible, widely distributed, cheap, clean, and emits no greenhouse gases.

• Much of the world’s potential for wind power remains untapped.

• Capturing only 20% of the wind energy at the world’s best energy sites could meet all the world’s energy demands.


• Wind turbines can be used individually to produce electricity. They are also used interconnected in arrays on wind farms.



• The United States once led the wind power industry, but Europe now leads this rapidly growing business.– The U.S. government lacked subsidies, tax breaks and

other financial incentives.

• European companies manufacture 80% of the wind turbines sold in the global market– The success has been aided by strong government

subsidies.

Biomass• Description – any type of organic matter (forest products, crop

wastes, animal wastes, people wastes, etc.) that can be used to produce energy; currently used for about 5% of U.S. energy

• Energy conversion – chemical to electrical or heat• Benefits – cheap, less toxic pollutants, using wastes effectively,

currently used in Rio Grande Valley with the burning of sugar cane residue, also produces food, feed, and fiber

• Costs – we don’t have all the technology needed to use this well right now, not useful in every location, some pollution is produced

PRODUCING ENERGY FROM BIOMASS

• Plant materials and animal wastes can be burned to provide heat or electricity or converted into gaseous or liquid biofuels.


PRODUCING ENERGY FROM BIOMASS

• The scarcity of fuelwood causes people to make fuel briquettes from cow dung in India. This deprives soil of plant nutrients.


Fig. 17-25, p. 405

Trade-Offs

Solid Biomass


Large potential supply in some areas

Nonrenewable if harvested unsustainably

Moderate costsModerate to high environmental impact

No net CO2 increase if harvested and burned sustainably

CO2 emissions if harvested and burned unsustainably

Low photosynthetic efficiencyPlantation can be located on semiarid land not needed for crops

Soil erosion, water pollution, and loss of wildlife habitat

Plantation can help restore degraded lands

Plantations could compete with cropland

Often burned in inefficient and polluting open fires and stoves

Can make use of agricultural, timber, and urban wastes

Water• Energy conversion – kinetic to electrical or heat• Benefits – already have the technology to do this,

pollution free, dams are also useful as water sources and flood controls; world’s largest source of electrical power

• Costs – there are environmental costs to building new dams, there are not rivers located everywhere

• Read James Bay Watershed Transfer Project Miller Page 304

PRODUCING ELECTRICITY FROM THE WATER CYCLE

• Water flowing in rivers and streams can be trapped in reservoirs behind dams and released as needed to spin turbines and produce electricity.

• There is little room for expansion in the U.S. – Dams and reservoirs have been created on 98% of suitable rivers.

Fig. 17-20, p. 400

Trade-Offs

Large-Scale Hydropower


Moderate to high net energy High construction costs

Large untapped potential

High environmental impact from flooding land to form a reservoir

High efficiency (80%)

High CO2 emissions from biomass decay in shallow tropical reservoirs

Low-cost electricity

Long life span

No CO2 emissions during operation in temperate areas

Floods natural areas behind dam

May provide flood control below dam

Converts land habitat to lake habitat

Danger of collapse

Provides water for year-round irrigation of cropland

Uproots people

Decreases fish harvest below dam

Reservoir is useful for fishing and recreation

Decreases flow of natural fertilizer (silt) to land below dam

Geothermal

• Description – heat from deep within the earth is used to produce electricity

• This is the only energy source that doesn’t come from the sun!

• Energy conversion – thermal to electrical and heat

• Benefits – pollution-free, used near Waco and in Iceland

• Costs – not available everywhere, we don’t have all the technology needed to use it

GEOTHERMAL ENERGY• Geothermal energy consists of heat stored in

soil, underground rocks, and fluids in the earth’s mantle.

• We can use geothermal energy stored in the earth’s mantle to heat and cool buildings and to produce electricity.– A geothermal heat pump (GHP) can heat and cool a

house by exploiting the difference between the earth’s surface and underground temperatures.

Geothermal Heat Pump• The house is heated

in the winter by transferring heat from the ground into the house.

• The process is reversed in the summer to cool the house.


Tidal Power

• Energy conversion – kinetic to electrical

• Benefits – pollution-free, cheap, renewable

• Costs – only two places in the U.S. have tides needed to do this

Wave Power

• Energy conversion – kinetic to electrical• Benefits – pollution-free, cheap, renewable• Costs - only suitable in areas facing the

open ocean (especially on the West Coasts of continents); tend to be destroyed in storms

PRODUCING ELECTRICITY FROM THE WATER CYCLE

• Ocean tides and waves and temperature differences between surface and bottom waters in tropical waters are not expected to provide much of the world’s electrical needs.

• Only two large tidal energy dams are currently operating: one in La Rance, France and Nova Scotia’s bay of Fundy where the tidal amplitude can be as high as 16 meters (63 feet).

NUCLEAR ENERGY

• When isotopes of uranium and plutonium undergo controlled nuclear fission, the resulting heat produces steam that spins turbines to generate electricity.– The uranium oxide consists of about 97%

nonfissionable uranium-238 and 3% fissionable uranium-235.

– The concentration of uranium-235 is increased through an enrichment process.

Fig. 16-16, p. 372

Small amounts of radioactive gases

Uranium fuel input (reactor core)

Control rodsContainment shell

Heat exchanger

Steam Turbine Generator

Waste heat

Electric power

Hot coolant

Useful energy 25%–30%Hot

water outputPumpPump

Coolant Pump Pump

Moderator

Cool water input

Waste heat

Shielding Pressure vessel

Coolant passage

Water CondenserPeriodic removal and storage of radioactive wastes and spent fuel assemblies

Periodic removal and storage of radioactive liquid wastes

Water source (river, lake, ocean)

NUCLEAR ENERGY

• After three or four years in a reactor, spent fuel rods are removed and stored in a deep pool of water contained in a steel-lined concrete container.


NUCLEAR ENERGY

• After spent fuel rods are cooled considerably, they are sometimes moved to dry-storage containers made of steel or concrete.


What Happened to Nuclear Power?• After more than 50 years of development and

enormous government subsidies, nuclear power has not lived up to its promise because:– Multi billion-dollar construction costs.– Higher operation costs and more malfunctions than

expected.– Poor management.– Public concerns about safety and stricter

government safety regulations.

Case Study: The Chernobyl Nuclear Power Plant Accident

• The world’s worst nuclear power plant accident occurred in 1986 in Ukraine.

• The disaster was caused by poor reactor design and human error.

• By 2005, 56 people had died from radiation released.– 4,000 more are expected from thyroid cancer and

leukemia.

NUCLEAR ENERGY

• A 1,000 megawatt nuclear plant is refueled once a year, whereas a coal plant requires 80 rail cars a day.


Fig. 16-20, p. 376

Coal vs. Nuclear

Trade-Offs

Coal Nuclear

Ample supply Ample supply of uranium

High net energy yield Low net energy yield

Very high air pollutionLow air pollution (mostly from fuel reprocessing)

High CO2 emissions Low CO2 emissions (mostly from fuel reprocessing)

High land disruption from surface mining Much lower land disruption

from surface mining

Low cost (with huge subsidies) High cost (even with huge subsidies)

High land use Moderate land use

NUCLEAR ENERGY

• Terrorists could attack nuclear power plants, especially poorly protected pools and casks that store spent nuclear fuel rods.

• Terrorists could wrap explosives around small amounts of radioactive materials that are fairly easy to get, detonate such bombs, and contaminate large areas for decades.

NUCLEAR ENERGY• When a nuclear reactor reaches the end of its

useful life, its highly radioactive materials must be kept from reaching the environment for thousands of years.

• At least 228 large commercial reactors worldwide (20 in the U.S.) are scheduled for retirement by 2012.– Many reactors are applying to extent their 40-year

license to 60 years.– Aging reactors are subject to embrittlement and

corrosion.

NUCLEAR ENERGY

• Building more nuclear power plants will not lessen dependence on imported oil and will not reduce CO2 emissions as much as other alternatives.– The nuclear fuel cycle contributes to CO2 emissions.

– Wind turbines, solar cells, geothermal energy, and hydrogen contributes much less to CO2 emissions.

NUCLEAR ENERGY

• Scientists disagree about the best methods for long-term storage of high-level radioactive waste:– Bury it deep underground.– Shoot it into space.– Bury it in the Antarctic ice sheet.– Bury it in the deep-ocean floor that is geologically

stable.– Change it into harmless or less harmful isotopes.

Nuclear

• Description – using fission to split large uranium atoms into smaller products and releasing tremendous amounts of heat energy which is used to make steam that turns turbines to create electricity

• Energy conversion – nuclear to electrical and heat• Benefits – pollution-free, very, very efficient• Costs – risk of accidents (spread of radioactivity);

transportation and disposal of radioactive wastes (Nimby!) It also produces a ton of thermal pollution!

WAYS TO IMPROVE ENERGY EFFICIENCY

• We can save energy in building by getting heat from the sun, superinsulating them, and using plant covered green roofs.

• We can save energy in existing buildings by insulating them, plugging leaks, and using energy-efficient heating and cooling systems, appliances, and lighting.

Strawbale House

• Strawbale is a superinsulator that is made from bales of low-cost straw covered with plaster or adobe. Depending on the thickness of the bales, its strength exceeds standard construction.


Living Roofs• Roofs covered with

plants have been used for decades in Europe and Iceland.

• These roofs are built from a blend of light-weight compost, mulch and sponge-like materials that hold water.


Saving Energy in Existing Buildings

• About one-third of the heated air in typical U.S. homes and buildings escapes through closed windows and holes and cracks.


Approximate Energy Efficiencies:

• Photosynthesis: 1%• Incandescent light bulbs: 95%

Definition

• Any fuel that meets certain emissions standards; i.e. they give off a certain amount of pollution (or less)

Alternative Fuels

Laws Involved

• Clean Air Act amendments of 1990• Energy Policy Act (EPACT) in Texas of

1992• Such laws have led to more research and

development of these fuels

Examples of Alternative Fuels• Biodiesel – made of vegetable oils and alcohols;

expensive

• Diesel – cleaner than “normal” gasoline, being more refined

• Biogas – by-product of decaying vegetation; need technology

• Hydrogen – expensive and we need more technology

Ethanol/Methanol – alcohols; not as efficient (Miles per gallon) and we don’t have all the technology ; also, if our grain supplies are used to make fuel, will we have enough to feed the world?Natural Gas – expensive and we need more technologyReformulated Gasoline (RFG) – regular gas that has been further refined to remove some of the more toxic pollutants

Propane – most usable form of alternative fuel; not as efficient (mpg)

Syngas – manmade gas made of hydrogen and carbon monoxide; need more technology to use it

HYDROGEN• Some energy experts view hydrogen gas as the

best fuel to replace oil during the last half of the century, but there are several hurdles to overcome:– Hydrogen is chemically locked up in water an organic

compounds.– It takes energy and money to produce it (net energy is

low).– Fuel cells are expensive.– Hydrogen may be produced by using fossil fuels.

Energy Laws• Public Utility Holding Company Act (PUHCA) –

1935; regulated the interstate flow of energy; 1st law of its kind; a law designed to protect consumers from corporate abuse of electricity markets

• (so electric companies can’t price gouge.) This was happening during the great depression.

Corporate Average Fuel Economy Act (CAFÉ) –1975; focused attention on efficiency of cars; mpg stickers requiredPublic Utility Regulatory Policies Act (PURPA)–1978; higher utility rates for increased electricity use

Converting Plants and Plant Wastes to Liquid Biofuels: An Overview

• Motor vehicles can run on ethanol, biodiesel, and methanol produced from plants and plant wastes.

• The major advantages of biofuels are:– Crops used for production can be grown almost

anywhere.– There is no net increase in CO2 emissions.

– Widely available and easy to store and transport.

Case Study: Producing Ethanol

• Crops such as sugarcane, corn, and switchgrass and agricultural, forestry and municipal wastes can be converted to ethanol. Switchgrass can remove

CO2 from the troposphere and store it in the soil.


Case Study: Producing Ethanol

• 10-23% pure ethanol makes gasohol which can be run in conventional motors.

• 85% ethanol (E85) must be burned in flex-fuel cars.

• Processing all corn grown in the U.S. into ethanol would cover only about 55 days of current driving.

• Biodiesel is made by combining alcohol with vegetable oil made from a variety of different plants..

Case Study: Biodiesel and Methanol

• Growing crops for biodiesel could potentially promote deforestation.

• Methanol is made mostly from natural gas but can also be produced at a higher cost from CO2 from the atmosphere which could help slow global warming.– Can also be converted to other hydrocarbons to

produce chemicals that are now made from petroleum and natural gas.


• Average fuel economy of new vehicles sold in the U.S. between 1975-2006.

• The government Corporate Average Fuel Economy (CAFE) has not increased after 1985.


Fig. 17-5, p. 388

Cars

Both

Ave

rag

e fu

el e

con

om

y (m

iles

per

gal

lon

, o

r m

pg

)

Model year

Pickups, vans, and sport utility vehicles


• General features of a car powered by a hybrid-electric engine.

• “Gas sipping” cars account for less than 1% of all new car sales in the U.S.


Fig. 17-7, p. 389

Regulator: Controls flow of power between electric motor and battery bank.

Fuel tank: Liquid fuel such as gasoline, diesel, or ethanol runs small combustion engine.Transmission:

Efficient 5-speed automatic transmission.

Battery: High-density battery powers electric motor for increased power.

Combustion engine: Small, efficient internal combustion engine powers vehicle with low emmissions; shuts off at low speeds and stops.

Electric motor: Traction drive provides additional power for passing and acceleration; excess energy recovered during braking is used to help power motor.

Fuel Electricity

Hybrid Vehicles, Sustainable Wind Power, and Oil imports

• Hybrid gasoline-electric engines with an extra plug-in battery could be powered mostly by electricity produced by wind and get twice the mileage of current hybrid cars.– Currently plug-in batteries would by generated by coal

and nuclear power plants.– According to U.S. Department of Energy, a network of

wind farms in just four states could meet all U.S. electricity means.

Fuel-Cell Vehicles

• Fuel-efficient vehicles powered by a fuel cell that runs on hydrogen gas are being developed.

• Combines hydrogen gas (H2) and oxygen gas (O2) fuel to produce electricity and water vapor (2H2+O2 2H2O).

• Emits no air pollution or CO2 if the hydrogen is produced from renewable-energy sources.

Fig. 17-8, p. 390

Body attachments Body attachments Mechanical locks that secure the Mechanical locks that secure the body to the chassisbody to the chassis

Air system management

Universal docking connection Connects the chassis with the

drive-by-wire system in the bodyFuel-cell stack Converts hydrogen fuel into electricity

Rear crush zone Absorbs crash energy

Drive-by-wire system controls

Cabin heating unit

Side-mounted radiators Release heat generated by the fuel cell, vehicle electronics, and wheel motors

Hydrogen fuel tanks

Front crush zone Absorbs crash energy

Electric wheel motors Provide four-wheel drive; have built-in brakes

National Appliance Energy Act – 1987; energy efficiency stickers on all appliances

• Renewable Energy and Technology Competitiveness Act – 1989; effort to develop renewable energy nationally

• Clean Air Act Amendments – 1990; set standards for cities and emissions

• Energy Policy Act – 1992; comprehensive effort to find renewable energy resources

Hydrogen Future Act – 1996; develop hydrogen as an energy source

PROBLEM – FEW of these actually provide the money needed to research renewable resources

Documents

NATURAL GAS Natural gas, consisting mostly of methane, is often found above reservoirs of crude oil. – When a natural gas-field is tapped, gasses are liquefied