Encyclopedia of Environmental Science and Engineering, Volume I and II

ENERGY SOURCES—ALTERNATIVES 297

and an advanced conversion system may also be dictated.

Both near- and long-term measures must be discussed to

illustrate the range of selection available among alternatives.

Considering the conventional energy sources, the increasing

environmental problems and all energy sources alternatives,

there can be predicted five essential developments:

1) the conventional energy sources will build also in

the future the hard core of energy activities, substi-

tuting nevertheless as much as possible petroleum

by other energies to strengthen the availability of

petroleum into a longer future

2) the new energy sources—alternatives as weak

energies will substitute partly the short-term

demand on conventional energy sources and take

over in the long-term future an increasing but not

substantial portion of the total energy demand

3) the transportation and traffic systems of the world,

which make a major contribution to environmental

degradation, will be converted to new, or alterna-

tive energy sources, thus fundamentally changing

their nature

4) the protection of environment necessitates for both,

the conventional and the new energy technologies,

high investment costs which will increase the cost

of final energy for the consumer

5) to find out the best combination of conventional

energies and energy sources—alternatives of old

and new energy technologies and necessities as

well as economic possibilities to protect the

environment, the countries—and it can be only a

national way of solution—must elaborate a long-

term planning system like masterplan or energy

strategies with computerized instrumentation, a

typical task for the national energy commissions.

The energy strategies must not be understood as a kind of

legislation, but they will give all industry connected with

energy production, conversion and application the best path

into the future.

ENERGY DEMAND

Energy is utilized in various forms by the demand sectors of

the economy. Household and commercial consumers require

thermal energy for comfort and for the preparation of food,

and electrical energy for lighting and for the operation of

electronic and motor-driven appliances that provide entertain-

ment, communication, and labor-saving functions. Energy in

mechanical form is needed for both public and private trans-

portation. Industry has similar needs with added requirements

involving thermal and chemical energy for materials process-

ing, refining, and the manufacture of synthetic materials and

consumer goods. The use of specific energy resources to sat-

isfy these demands depends on their relative economics and

convenience as well as on the systems that are available for

conversion into the form of energy that is ultimately required.

In principle, especially in the northern countries, the

heat demand is much higher than the demand on mechanical

force. The demand on public and private light varies between

one and fifteen percent. Highly industrialized and densely

populated countries are the biggest consumer of light. The

energies heat, mechanical force and light are called effective,

final or util energies. While in the sixties still all of the energy

demand in the United States was satisfied by consumption of

the fossil fuel resources; coal, oil, and natural gas, the parts

of the individual primary energy agents in the meantime have

changed. Small amounts of power were supplied by hydro-

electric and nuclear power plants and even less by solar, geo-

thermal, tidal, and other energy resources. On the other hand

the part of nuclear energy was increased.

Table 1 shows the direct consumption of energy

resources by demand sector in the United States for the year

1968 with a projection to the year 2000. The consumption

of energy resources in the production of electricity repre-

sents a centralized conversion, and the ultimate disposition

of electrical energy to the various demand sectors is given

in Table 2, again for the year 1968, with a projection to the

year 2000. Since the data presented represent resource con-

sumption, they imply an efficiency of energy conversion and

utilization. Comparing the fuel consumption and electrical

output of utilities in 1968, an average efficiency of about

32% is indicated. Fuels burned for thermal energy in decen-

tralized household, commercial, and industrial applications

Recovery and on-site

treatment of resource

Shipment of fuel

from source

Central refining, treatment

or conversion of fuel

Shipment and distribution

of fuel to energy conversion site

Centralized

energy conversion

Transmission and

distribution of energy

Decentralized

energy conversion,

stationary and mobile

Utilization of energy

FIGURE 2 Simplified energy system flowsheet.

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