Encyclopedia of Environmental Science and Engineering, Volume I and II

ENERGY SOURCES—ALTERNATIVES 315

Centralized Power Plants

To take advantage of economies of scale, electrical energy

is generated in large centralized facilities for distribution

to consuming activities. The demand for electrical energy

varies on a daily, weekly, and seasonal cycle. Since this form

of energy cannot be conveniently stored, the installed gen-

erating capacity must match the peak demand and some of

this capacity must be idle during periods of low demand. The

more economic plants in the system, which may be fossil

or nuclear facilities operating on a steam power cycle or

hydroelectric plants, are usually operated as much as pos-

sible in a so-called baseloaded condition, while the older

and less efficient plants and special gas-turbine installations

are utilized only during periods of peak demand. The use of

pumped storage can serve to flatten out the demand curve by

using excess power produced during periods of low demand

to pump water uphill where it can be used during later

periods of high demand by recovering its potential energy.

Transmission ties between electric utility systems in differ-

ent regions of the country can be used to take advantage of

load diversity since the timing of seasonal and daily peak

demands varies depending on location.

Electric generating plants with an output of over 1000

MW are not uncommon and stations of up to 10,000 MW

capacity are anticipated by the year 2000, perhaps involving

an energy center concept where the power source is inte-

grated on the same site with industrial, agricultural, and/or

desalination operations. The concentrated environmental

effects of large central station power plants are receiving

increased attention and have been the subject of congressio-

nal hearings.^40 Natural gas and low-sulfur residual oil may

be used in steam-electric plants with minimal air pollution

but these fuels are limited in their availability. The provision

From

To

Electro-

magnetic

Chemical Nuclear Thermal

Kinetic

(mechanical) Electrical Gravitational

Electro-

magnetic

Chemical

Nuclear

Thermal

Kinetic

Electrical

Gravita-

tional

Chemilumin-

escence

(fireflies)

Photosynthe-

sis (plants)

Photochemistry

(photographic

film)

Gamma-

neutron

reactions

(Be^9 +

Be^8 + n)

Solar absorber

(hot sidewalk)

Radiometer

Solar cell

Radio

antenna

Solar cell

Unknown

Combustion

(fire)

Muscle

Fuel cell

Batteries

Unknown Unknown Unknown Unknown Unknown

Gamma Unknown

reactions

(Co^60

source)

A-bomb

Radiation

catalysis

(hydrazine

plant) Ioniza-

tion (cloud

chamber)

Fission (fuel

element)

Fusion

Radioactivity

(alpha par-

ticles)

A-bomb

Nuclear

battery

Thermal

radiation

(hot iron)

Boiling

(water/steam)

Dissociation

Power cycles

(thermal expansion

turbines,

combustion

engines)

Thermoelec-

tricity, Therm-

ionics, Thermo-

magnetism,

Ferroelectri-

city

Accelerating

charge (cyclo-

tron) Phosphor

Dissociation

by radiolysis

Friction

(brake shoes)

MHD

Conventional

generator

Piezoelectricity

Rising object

Electro-

magnetic

radiation

Electrolumin-

escence

Electrolysis

(production of

aluminum)

Resistance-

heating

(electric stove)

Motors

Electrostric-

tion (sonar

transmitter)

Unknown

Unknown

Falling object

(water)

Unknown

Source: Adapted from USAEC matrix.

FIGURE 6 Energy conversion matrix.

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