Encyclopedia of Environmental Science and Engineering, Volume I and II

312 ENERGY SOURCES—ALTERNATIVES

America various sites on the Bay of Fundy have a total poten-

tial for the production of about 29,000 MW of electrical power,

although little of this can be developed economically.

The use of wave power of the oceans was proposed

repeatedly and in different systems, firmly installed at the

beach or near the beach swimming. Theoretically it is pos-

sible to use the wave power and this can be demonstrated on

models. But in great quantities it will not be economical, and

as the aim is the production of electrical energy, it would be

necessary to install enormous conventional stand-by plants

because of its irregular turn.

Biomass

In the ecology the entire living components of ecological

systems are called biomass. Biomass is subject to dynamic

changes because phases of production follow phases of con-

sumption and decomposition. As this runs by law of nature

but principally is controllable by suitable production terms,

there arose already before the productional ecological

research out of practice the agricultural production oriented

economy which is, under several aspects, only a synonym for

productional ecology. The productional ecology integrates the

biological energy flow. As with each productional process a

portion of the absorbed energy at living organisms is used to

maintain metabolism, there remains from the gross production

only a fraction as usable net production. We must consider the

turnover which makes the production, and this turnover is not

comparably high competed with the hard energy.

Another problem is that the use of biomass as industrial

initial position for energy production at equal conditions for

the protection of the environment can easily become uneco-

nomical. The conclusion is that biomass will reach only a

small percentage of the total energy volume, should be used

in small plants of conversion only, brings principally advan-

tages only for decentralized small consumers, and has no

economic basis should the regulations for the protection of

the environment be valid also for big biomass systems.

Sun 37,38,39,40,41^

The rate at which solar energy intercepts the diametral plane

of the earth is about 17.7 
 10 10 MW. At the surface of the

earth the average solar power is about 1820 Btu/ft^2 -day but

this figure can vary widely depending upon the location and,

of course, is only available during sunny periods.

The principle difficulty in utilizing solar thermal energy

for endothermic reactions is thus not so much matching the

technology of the power plant to the solar-specific condi-

tions, but to tie in the processes for which the power demand

is usually constant to the fluctuating conditions of insola-

tion. The problem of intermittent energy supply originat-

ing in the day/night cycle has therefore to be countered by

the development of storage devices, hybrid strategies or by

selecting interruptable processes, before large-scale utiliza-

tion of solar energy can be considered.

Possibilities which show promise for the future are the

development of technically efficient devices suitable for

commercial exploitation, and a similarly attractive proposi-

tion appears to be a method of storing the fluctuating solar

energy in processes which are interruptable, or at least can

be modified over time. Conversion of such processes to solar

power appears conceivable, and likewise simultaneous uti-

lization of thermal and photochemical energies could result

in advantages that up to now have not been fully exploited.

Possibly hydrogen produced by solar power will play a

part in the storage and transportation of energy from solar

plants. In all solar thermal power plants, the low radiation

flux density of the incoming solar radiation is collected and

concentrated by a field of mirrors, referred to as collectors

or heliostats. As much as possible of the radiation energy

is absorbed and converted to energy. The balance of plant

elements correspond to the conventional components of a

normal power plant, but they have to be matched to the solar-

specific mode of operation.

Figure 5 shows the general arrangement of a cen-

tral receiver system power plant, which shall be briefly

TABLE 14

Foreign crude oil production by area and sulfur content category

Area and sulfur content 1996 production

range, weight % 106 bbl %

Africa:

0.00–0.25 637 63.7

0.26–0.50 144 14.4

0.51–1.00 216 21.6

1.01–2.00 — —

>2.00 3 0.3

Canada:

0.00–0.25 112 35.3

0.26–0.50 18 5.7

0.51–1.00 107 33.8

1.01–2.00 40 12.6

>2.00 40 12.6

Middle East:

0.00–0.25 — —

0.26–0.50 — —

0.51–1.00 — —

1.01–2.00 1509 44.8

>2.00 1862 55.2

South America:

0.00–0.25 24 1.6

0.26–0.50 19 1.3

0.51–1.00 52 3.5

1.01–2.00 225 15.2

>2.00 1161 78.4

Source: McKinney, C. M., and E. M. Shelton, Sulfur Content of Crude Oils

of the Free World, US Dept. of the Interior, Report of Investigations 7059,

1967, Washington, DC.

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