Energy Now and in the Future

Part 1 Energy Now:Nonrenewable Energy

Core Case Study: How Long Will the Oil Party Last?

The world may have 40-90 years of oil left.

Peak oil will most likely occur within 20 years

We need to replace oil for transportation energy within 50 years.

Figure 16-1

Fig. 16-3b, p. 357

Hydropower geothermal, solar, wind

3%

Nuclear power 8

%R

EN

EW

AB

LE

8%

Coal 23%

Natural gas 23%

Oil 39%

Biomass 4%

NO

NR

ENEW

AB

LE 93%

United States

CRUDE OIL Crude oil (a.k.a. petroleum) is a thick liquid

containing hydrocarbons that we extract from underground deposits and separate into products such as gasoline, heating oil and asphalt.

OIL Refining crude oil:

Based on boiling points, components are removed at various layers in a giant distillation column.

The most volatile components with the lowest boiling points are removed at the top.

Figure 16-5

Fig. 16-5, p. 359

Gases

Gasoline

Aviation fuel

Heating oil

Diesel oil

Naptha

Grease and wax

Asphalt

Heated crude oil

Furnace

NATURAL GAS

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

be liquefied and removed as liquefied petroleum gas (LPG).

Some analysts see natural gas as the best fuel to help us make the transition to improved energy efficiency and greater use of renewable energy.

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 16-12

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-Fired Power Plant

COAL

Coal reserves in the United States, Russia, and China could last 225 to 900 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.

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 (ore) consists of about 97% nonfissionable uranium-238 and 3% fissionable uranium-235.

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

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.

Plutonium is one of the most harmful substances on Earth

Figure 16-17

NUCLEAR ENERGY

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

Figure 16-17

Yucca Mountain, NevadaNational Nuclear Waste Disposal Site

Yucca Mountani is “ready” to store US nuclear waste, but Nevada and states through which the waste must pass have blocked it’s use.

Part 2 The Future of Energy

Energy Efficiency and

Renewable Energy

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.

Fig. 17-3, p. 386

Solutions

Reducing Energy Waste

Prolongs fossil fuel supplies

Reduces oil imports

Very high net energy

Low cost

Reduces pollution and environmental degradation

Buys time to phase in renewable energy

Less need for military protection of Middle East oil resources

Creates local jobs

Reducing energy waste (a.k.a. increasing energy efficiency) is the easiest and most powerful step humans can take toward a sustainable energy future.

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: cars and trucks

lose 75-80% of their energy as heat. Nuclear power plant: 92% of energy is wasted

as heat through nuclear fuel enrichment and the energy needed for waste management.

Coal-burning power plant: 66% of the energy released by burning coal is lost as heat.

WAYS TO IMPROVE ENERGY EFFICIENCY- Hybrid Engines (Prius)

Has a small internal combustion engine AND an electric motor.

Battery is recharged by braking.

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

Figure 17-7

Fuel-Cell Vehicles

Electric 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 Mechanical locks that secure the body 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

WAYS TO IMPROVE ENERGY EFFICIENCY

We can save energy in buildings 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.

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.

Figure 17-11

Producing Electricity with Solar Cells

Photovoltaic solar cells convert sunlight to electricity.

Their costs are high, but dropping quickly.

Figure 17-16

Fig. 17-19, p. 399

Trade-Offs

Solar Cells

Advantages Disadvantages

Fairly high net energy Need access to sun

Work on cloudy daysLow efficiency

Quick installation

Need electricity storage system or backup

Easily expanded or moved

No CO2 emissions

High land use (solar-cell power plants) could disrupt desert areas

Low environmental impact

Last 20–40 years

Low land use (if on roof or built into walls or windows)

High costs, but dropping rapidly

Reduces dependence on fossil fuels DC current must be converted

to AC

PRODUCING ELECTRICITY FROM WIND

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

Figure 17-21

PRODUCING ELECTRICITY FROM WIND

Wind power is a very 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.

PRODUCING ELECTRICITY FROM WIND

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

Full development of all US wind sites could produce 3 times the total current US electricity demand.

Fig. 17-22, p. 403

Trade-Offs

Wind Power

Advantages Disadvantages

Moderate to high net energy Steady winds needed

Backup systems needed when winds are low

High efficiency

Moderate capital cost

Low electricity cost (and falling)High land use for wind farm

Very low environmental impact

No CO2 emissions Visual pollution

Quick constructionNoise when located near populated areasEasily expanded

Can be located at sea

Land below turbines can be used to grow crops or graze livestock

May interfere in flights of migratory birds and kill birds of prey

PRODUCING ENERGY FROM

BIOMASS

Plant materials (like tree bark) and animal wastes can be burned to provide heat or electricity or converted into gaseous or liquid biofuels.

Figure 17-23

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.

Figure 17-26

Georgia may become a leader in the production of switchgrass.

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.

Fig. 17-34, p. 413

Wood

Coal

Natural gas

Oil

Hydrogen Solar

NuclearCo

ntr

ibu

tio

n t

o t

ota

l en

erg

y co

nsu

mp

tio

n (

per

cen

t)

Year

Fig. 17-35, p. 414

Small solar-cell power plantsBioenergy power

plantsWind farm

Rooftop solar cell arrays

Fuel cells

Solar-cell rooftop

systems

Transmission and distribution system

Commercial

Small wind

turbineResidential

Industrial Microturbines

Fig. 17-37, p. 416

What Can You Do?

Energy Use and Waste

• Get an energy audit at your house or office.

• Drive a car that gets at least 15 kilometers per liter (35 miles per gallon) and join a carpool.

• Use mass transit, walking, and bicycling.

• Superinsulate your house and plug all air leaks.

• Turn off lights, TV sets, computers, and other electronic equipment when they are not in use.

• Wash laundry in warm or cold water.

• Use passive solar heating.

• For cooling, open windows and use ceiling fans or whole-house attic or window fans.

• Turn thermostats down in winter, up in summer.

• Buy the most energy-efficient homes, lights, cars, and appliances available.

• Turn down the thermostat on water heaters to 43–49°C (110–120°F) and insulate hot water heaters and pipes.