Biomass Energies: Resources, Links, Constraints

468 Pages·1983·10.17 MB·English

by  Vaclav Smil (auth.)

BIOMASS ENERGIES
Resources, Links, Constraints
MODERN PERSPECTIVES IN ENERGY
Series Editors: David J. Rose, Richard K. Lester, and John Andelin
ENERGY: The Conservation Revolution
John H. Gibbons and William U. Chandler
STRUCTURAL MATERIALS IN NUCLEAR POWER SYSTEMS
J. T. Adrian Roberts
BIOMASS ENERGIES: Resources, Links, Constraints
Vaclav Smil
BIOMASS ENERGIES
Resources, Links, Constraints
VACLAV SMIL
The University of Manitoba
Winnipeg, Manitoba, Canada
PLENUM PRESS · NEW YORK AND LONDON
Library of Congress Cataloging in Publication Data
Smil, Vaclav.
Biomass energies.
(Modern perspectives in energy)
Bibliography: p.
Includes index.
1. Biomass energy. I. Title. II. Series.
TP360.sS4 1983 662'.8 83-9611
ISBN -13 :978-1-4613-3693-8 e-ISBN-13:978-1-4613-3691-4
DOl: 10.1007/978-1-4613-3691-4
©1983 Plenum Press, New York
Sof tcover reprint of the hardcover I st edition 1983
A Division of Plenum Publishing Corporation
233 Spring Street, New York, N.Y. 10013
All rights reserved
No part of this book may be reproduced, stored in a retrieval system, or transmitted
in any form or by any means, electronic, mechanical, photocopying, microfilming,
recording, or otherwise, without written permission from the Publisher
SETTING THE STAGE
Men occupy a very small place upon Earth .... All humanity could be
piled up on a small Pacific islet.
The grown-ups, to be sure, will not believe you when you tell them
that. They imagine they fill a great deal of space. They fancy themselves as
important as the baobabs. You should advise them, then, to make their own
calculations. They adore figures, and that will please them. But do not
waste your time on this extra task. It is unnecessary. You have, I know,
confidence in me.
-ANTOINE DE SAINT-ExUPERY
The Little Prince
This book originated with a letter from David Rose, editor of Plenum's
"Modern Perspectives in Energy" series, suggesting that I contribute a
volume on energy in the poor countries. As I had just finished editing a
book and writing a string of papers on that topic, I proposed doing a
book on biomass energy instead. Professor Rose agreed-and soon I
was putting in order a jumble of writing, thinking, and research I had
done previously on some aspects of biomass energy, and laying out
plans for the systematic coverage of such a fascinating, multifaceted
topic.
I may have some appropriate pro-biomass credentials-ranging
from more lectures on plant morphology and physiology than I would
care to take, to the membership in the Biomass Energy Institute; from
spending my adolescent summers splitting huge piles of wood to feed
our stoves through the snowy winters in the Bohemian Forest, to more
recent scholarly pursuits-but I have voiced largely doubting and critical
opinions: this book is their considered interdisciplinary summation.
Being interdisciplinary, it stresses limitations, complexities, uncer
tainties, links, and consequences. I believe that these considerations,
rather than detailed descriptions of experimental technologies or repeat
ed comparisons of dubious cost estimates, are fundamental to answer
ing the key questions: Is it worth it? To what the extent should it be
used? What would be the real cost? Where should we concentrate our
efforts? Where should we abstain?
A better understanding of these opportunities, options, and limita
v
vi PREFACE
tions is not possible without first putting the problem into a wider con
text. Consequently, before proceeding with detailed critical topical cov
erage of individual biomass energy sources, uses, and effects, I will
extend this preface with a few pages of rather personal reflections (I will
use the same device in closing the book: after providing concise topical
summaries in Chapter 8, I will conclude with some essayistic musings
on renewable energetics, plants, people, and a scientist's responsibility).
Interest in biomass energies is just a part of a broader global trend
toward renewable energetics, a trend which has evolved speedily after
the crude oil price escalation started in 1973. Yet one must be reminded
that for the rich countries fossil fuels are, and for a long period shall
remain, the foundation of an affluent civilization, while throughout the
poor world the reliance of most people on biomass energies for everyday
subsistence has brought many damaging environmental and social ef
fects; that the reality of sharp price rises for crude oil (actually not so
sharp once adjusted for inflation) should not be misconstrued as an
"energy crisis"; that the rise of renew abies and the claims made on their
behalf by countless enthusiasts look so much better on paper than in
reality; and that the potential of biomass energies, an essential ingre
dient of renewable scenarios, has been judged more with proselytizing
zeal than with critical detachment.
Solar energy stored in fossil fuels-organic mineraloids with minor
quantities of inorganic contaminants-is the mainstay of modern indus
trial civilization. Global, and most national, quantities of fossil fuels are
not known with any satisfactory degree of certainty: their accounting,
comprising the basic division into resources and reserves and their sub
categories, involves an often-confusing array of internationally nonstan
dardized terminology.
By far the largest amount of past photosynthesis has been se
questered in solid fuels, predominantly in different varieties of coals.
Total global coal resources are well over 10 trillion metric tons (t) and
recoverable reserves are no smaller than 60 billion t (World Energy Con
ference, 1974). Estimates of ultimately recoverable world resources of
crude oils range very widely, from lows of less than 200 billion t to highs
of nearly 2 trillion t (Albers et a1., 1973). Here the rapid postwar expan
sion of crude oil reserves-more than tenfold since 1945--illustrates well
the process of "making" reserves out of resources through exploration
and development, as well as the hazards inherent in estimating the
economically available deposits.
Whatever the global crude oil resources might be, there is no doubt
that even greater masses of oils are locked in nonfluid hydrocarbons
with a wide variety of organic content. However, oil shales and oil sands
SETTING THE STAGE vii
typically yield only small amounts of oil per unit of raw material and
their always-difficult processing is still economically prohibitive. As
with the crude oils, estimates for ultimately recoverable quantities of
natural gas display a wide range, from a low of some 100,000 km3 to a
high of more than 1 million km3 (Albers et al., 1973).
When the best currently available data on recoverable resources of
all fossil fuels are converted to a common energy equivalent, the total is
nearly 3.5 x 1022 L with solid fuel storing roughly half of this energy,
crude oil and natural gas about one-fifth, and nonfluid hydrocarbons the
rest (World Energy Conference, 1974). Spatially, most of this recoverable
energy is stored in North America (about half) and Asia (one-third,
including the USSR). North America's primacy is due to its vast deposits
of coat natural gas, oil shales, and tar sands, while Asia (including the
USSR) contains about two-thirds of the world's crude oil reserves.
Although all kinds of fossil fuels have been known and locally uti
lized since antiquity, their large-scale commercial recovery dates only
from the 19th century. Global production of coal exceeded 100 million t
in the 1850s and 500 million t during the 1890s; by that time coal still
supplied 95% of all fossil energies; its dominance slipped only slightly
during the first decades of this century, from about 90% at the outbreak
of World War I to about 75% at the beginning of World War II. After
ward the rise of hydrocarbons was swift: by the late 1950s crude oil and
natural gas supplied as much energy as coat and by 1970 they provided
two-thirds of the total flow; this share remained about constant during
the 1970s.
In absolute terms there has been an order-of-magnitude increase in
fossil fuel consumption during the past century-and another order-of
magnitude rise since then, from about 2.2 x 1019 J in 1900 to some 2.6 x
1020 J in 1980. Coal consumption grew about 3.5 times, but crude oil use
rose more than 150 times and natural gas flow expanded about 180
times.
All the advances of industrial civilization have been bound, directly
or indirectly, to the ready availability of relatively inexpensive fossil
fuels-but it must not be forgotten that for most of the world's people
fossil fuels are neither easily accessible nor cheap. In fact the bulk of the
global population, living in the poor countries, is largely untouched by
modern energy flows and continues to rely on the animate energies of
human muscle and draft animals for motive power (in places supple
mented by water and wind), and on a variety of plant fuels for the
thermal energy needed in households and local manufacturing.
No precise figures on the consumption of forest fuels (stem and
branch wood, bark, roots, leaves, shrubs), crop residues (cereal straws,
viii
PREFACE
corn stover, cane bagasse, cotton and jute stalks, tuber and legume
vines), and dry animal dung are available-and probably never will be,
as most of the collection is done by the users themselves and only a part
of these fuels enters some commercial exchanges.
My estimates, based on a wide variety of the best current evidence,
suggest that these fuels burnt annually in the poor countries contain
energy equivalent to nearly 900 million t of crude oil (Smil, 1979a). As
the poor world's consumption of modern commercial energies now sur
passes 1.3 billion t of oil equivalent, two-fifths of its total fuel use is
supplied by wood, straw, and dung, and in most of the poor countries,
and for most of their inhabitants, this dependence is much higher than
the global average.
Among the most populous poor nations the share of traditional
fuels in the total consumption is nearly nine-tenths in Bangladesh, four
fifths in Nigeria, two-thirds in Indonesia, and about half in India; on the
other hand in Brazil and in China the share is around one-third. But
because all these values are national averages they do not convey the
distinction between urban and rural energy consumption: the latter is
almost solely dependent on traditional fuels, not only in the world's
poorest areas (Bangladesh, Ethiopia, the Sahel), but also in China, India,
Indonesia, or Brazil. And in most of the poor world's countryside, daily
consumption of biomass fuels is only between 5 and 20 MJ per capita,
barely enough to cook two simple meals and perhaps to warm a room
for a few hours.
An approximate division of the poor nations shows that the primary
energy supply in some 60 countries with nearly 700 million people (42 of
these countries, with over 300 million inhabitants, are in Africa) still
comes predominantly from traditional fuels and that less than a tenth of
the poor world's population lives in the nations that have shifted into
fossil-fueled energetics. In terms of absolute numbers, wood, crop resi
dues, or dung remain the principal or sale fuels for just over 2 billion
people, or half the global population.
Modern energies, especially the convenient and versatile liquid
fuels, started to make discernible contributions to the poor world's pri
mary energy supply only in the early 1950s, but the subsequent growth
was rapid: consumption of refined oil products increased by an order of
magnitude within just two decades. Similarly, between the early 1950s
and the early 1970s the rich world's consumption of crude oil grew
nearly fivefold and it provided about three-fifths of all the new supplies.
But these trends were not destined to continue throughout the 1970s.
Abrupt reversal of the price trend for crude oil after the Yom Kippur
War of October 1973 was the beginning of unprecedented rapid changes
SETTING THE STAGE ix
in the global energy market. For decades preceding the early 1970s the
real price of crude oil had been decreasing: in terms of 1970 dollars Saudi
Arabian light crude oil cost around $4.00 per barrel in the early 1950s; it
sank below $3.00 a decade later, and was a mere $1.60 in 1970 (Odell and
Vallenilla, 1978). Posted prices of Middle Eastern oil still stood at just
$3.01 per barrel in September 1973.
The first sudden wave of OPEC price increases, coupled with inef
fective but worrisome export embargoes by Arab oil exporters, brought
the official average annual sale price to $11.28 in 1974. This nearly four
fold rise ushered in the years of "energy crisis" manifested by economic
recessions, deteriorating balances-of-payments, and temporary fuel
shortages in oil-importing nations, by the rising might of OPEC, and by
ceaseless worries about the future of a global civilization running out of
energy. These trends were only reinforced by the second period of sud
den crude oil price increases, prompted by the collapse of the imperial
regime in Iran, that brought the average OPEC sale price to $30.87 in
1980 and $34 in 1982.
In the eight years between fall 1973 and fall 1981 crude oil prices
thus rose a bit over elevenfold. Rich countries have had their economic
growth rates cut sharply-double-digit inflation became a norm and
unemployment rose-while most poor countries have devoted rapidly
rising shares of their often-meagre foreign earnings to oil purchases and
have cut down modernization plans predicated on the availability of
reasonably priced liquid fuels. Uncertainties about the future (especially
in contrast with the fast-growth decades of the 1950s and 1960s) grew,
and the need for solutions became urgent.
And solutions have been offered, hastily, repeatedly, enthusi
astically-and uncritically, too often with scant regard for realities that
do not resemble the overwhelmingly mislabeled and misunderstood
developments of the 1970s. Indeed developments of that decade pre
sented perhaps more a challenging opportunity than a regrettable col
lapse of stability. To begin with, the crude oil price rises have not been
as large as figures in current monies indicate: after the initial increases in
1973 and 1974 the average official OPEC sale price actually fell, when
adjusted for inflation, by about 13% between 1974 and 1978; the eleven
fold rise between 1973 and 1982 shrinks to (a still considerable) less
than-sevenfold increase.
Mistaking temporary oil supply difficulties in some rich nations for
an impending exhaustion of energy resources is an overreaction not
worthy even of Sunday newspaper magazines. Bemoaning the end of an
era in countries whose inhabitants continue to consume several metric
tons of liquid fuels a year per capita-wasting most of it in the process-
x PREFACE
is a damning commentary on irrational behavior rather than a sympa
thy-evoking cry. For the rich world there is, without any doubt, no
energy crisis: energy conservation potentials in our wasteful societies
are, without exaggeration, fabulous (Gibbons and Chandler, 1981, give a
fine account); beyond them lie abundant resources of fossil fuels other
than crude oil-and even crude oil resources are undoubtedly far greater
than many conservative estimates would lead us to believe (Grossling,
1976).
For poor countries the situation is fundamentally different in the
sense that most of them have to expand their total energy consumption
substantially to improve the lives of their growing populations and to
modernize their economies. However, as most of the hydrocarbon
basins in the poor countries are yet to be drilled for oil and gas with an
intensity approaching the rich countries' exploration efforts, the output
of these highest quality fossil fuels can be greatly expanded in many
nations that were producing little or no oil and gas before 1973 (coun
tries such as Mexico, Malaysia, Egypt, and the Philippines have moved
into this category during the 1970s), and coal resources, largely unap
praised, are by no means negligible. Reduction of wasteful oil consump
tion in the rich countries would also make more liquid fuels available to
the poorer importers, and the energy conservation potential in the poor
countries is relatively no smaller than in the rich societies.
Yet in spite of the fact that the developments of the 1970s had
nothing to do with absolute scarcity of fossil energy resources, they
were misunderstood precisely in that way by much of the public and by
more than few ruling bureaucracies. The response has been predictable:
if we are "running out" of fossil fuels, especially oil, we must act quickly
and decisively to replace them with renewable energies. At a more so
phisticated level, the huge investments needed to develop new hydro
carbon and coal resources and technologies, and the adverse environ
mental effects of fossil fuel combustion (the CO problem and acid rain,
2
above all), have been added to the depletion threat to stress the inev
itability of turning toward the renewables.
A veritable downpour of renewable energy wonders descended on
scientific publications and the public media alike: direct solar radiation
was to be captured by contrivances ranging from simple black boxes on
roofs for heating bath water, to computerized mirror arrays that reflect
the sun's rays to a central tower for electricity generation by steam; tides
and waves showing impressive theoretical potential were to be tapped
by dual-flow turbines and innovative conversion devices; wind was to
turn egg-beaters, blade rotors, and sail mills atop hills or proposed mon
strous towers; thermal differences in the warm ocean were to generate