A cursory collection of information by Ken Wear (BSPhysics, MSEE)
commenced Feb. 2001. Whole books may be devoted to any one topic.
The availability of energy is crucially important to our economy
and, indeed, to our world. It is highly selfish and short-sighted if, in the urge to
maintain our civilization through use of the energy on which it depends, we so rape our
environment as to make life sterile, devoid of the natural wonders and pleasures that
feed our souls. At the same time energy is so crucial to our economy that we must
pursue all possible avenues that promise affordable energy. This page is dedicated to
surveying information on the quest for plentiful and affordable energy with only a minimal
impact on the environment we must share with our offspring and their future.
Energy issues will not go away. Neither will environmental concerns disappear. In the
interest of its own survival the United States must become the leader in the search for
alternate means of powering civilization while remaining alert to aesthetic concerns. As
the various sources become strained, as, for instance, development of all hydroelectric
dams our waterways will support -- and there are other needs for that same water -- it
must become a burning national issue to work toward perpetual or renewable resources.
There are two faces to our energy concerns: conservation -- decreasing demand in the short
term in order to stretch the time that (presently) traditional energy sources are adequate --
and bringing new sources on line to offset depletion of existing sources and to allow for
expansion of demand. Here are a few directions for conservation efforts.
1. One of the most wasteful practices of modernity
is location of electricity generation remote from users because the heat rejected by the
generating process both degrades the environment at the generating facility and requires
additional fuel by users who must have heat. Modern designs of generation facilities
remove 98-99% of the obnoxious by-products so generating capacity as part of local
development becomes desirable. (This issue involves state and local regulatory agencies
and therefore has a political component that may require aroused citizens if the practice
is to be corrected.)
2. Home and building construction should take
advantage of present knowledge of designs that have a substantial impact on energy
needs. For instance, joint design in construction can have a significant impact on
energy conservation. Your state's College of Architecture can provide detailed
information.
3. Businesses and industries are often grossly wasteful,
such as lighting when and where it serves no useful purpose. For instance, only very dim
lighting is needed during the wee hours in a company parking lot and lighting is needed
only in selected areas overnight in commercial and industrial buildings.
4. Biofuels make use of agricultural products and algae in
the production of oils as a substitute for petroleum products.
5. Personal commitment, today taking steps as
individuals:
Options for new energy sources are legion. They include:
1. Reopening old oil wells closed because cheap oil
was depleted, or drilling for oil in locations now prohibited.
2. Conversion of products presently considered waste
such as oils from food processing or ethanol from grasses or other cellulosics.
3. Algae will undoubtedly become a dominant source
for both oils and food for humans and animals.
4. Products grown for a combination of food, fiber and
fuel such as marijuana (animal feed).
Energy is simply the potential to do work. To the physicist work and energy
are interchangeable; efficiency of conversion becomes a dominant practical
concern. While energy exists in many forms our practical interest lies entirely
in its potential to assist in our routine requirements.
For discussion of: Petroleum (click here),
Values cited are for the most part handbook values; where conversions were necessary to
presentations, definitions, formulas and conversion factors are included at the end of the
essay. I have attempted to make meaningful comparisons of the efficacy and cost of various
energy sources. While energy sources may be converted from one form to another,
efficiency of conversion is always an issue in determining the desirability of one source
over another.
PETROLEUM (From wells) and alcohols
Liquid petroleum has fueled the growth of the
world's economies and is becoming increasingly difficult to locate. It should be
obvious to all that the current rate of usage cannot be sustained, regardless of
the cost to our environment. Unfortunately Federal research dollars are being
directed toward projects that will continue our heavy dependence on petroleum.
Pipelines to distribute liquid petroleum products have become ubiquitous;
they became widespread during World War II (when patriotism overcame NIMBY
objections). Since, they are very common features of the surface and sub-surface
environment.
Products produced by fractional distillation of petroleum are (in order of increasing
distillation temperature): petroleum gases, naphtha, gasoline, kerosene, diesel oil,
lubricating oil and fuel oil. Asphalt is a residue. (Energy reqired for
distillation is not commonly considered when examining the overall energy efficiencies
involved with consumption of petroleum.) Chemical composition of petroleum varies
considerably, depending on its source. (Helium, often simply bled into the atmosphere
at the oil well, is a by-product of petroleum pumping; we have no other source for this
gas. There have been attempts to capture and store helium against future depletion.
Helium makes no contribution to atmospheric warming.) The table below,
Comparisons of Liquid Fuels, brings together energy properties of several liquid
fuels.
Efficiency in conversion of the energy content of the fuel to useful work is a prime
consideration in choosing a fuel. I am looking at a chart which shows 25% of the energy
input for motive power plus accessories, 5% for friction (which I feel is woefully short),
30% for cooling and 40% out the exhaust. (The same source shows 35% to motive
power plus accessories for diesel.) The same document indicates a U.S. government goal
of 30% (2004 baseline) to 45% by 2012 for passenger vehicles and from 40% (2002
baseline) to 55% by 2013 for commercial vehicles. (Evidently methods of calculation differ
significantly.) But it is obvious that conversion of gasoline-operated equipment,
including cars and light trucks, to diesel, because of its greater efficiency, and
hence number of miles per gallon, would significantly reduce demand for petroleum.
Environmental impact, in the eye of the media and thus the public, of automotive
equipment centers more on gaseous components of exhaust (carbon dioxide) than energy
loss. However, that 30% lost to cooling would heat several houses in a cold climate; that
plus the 40% exhausted increase local environmental temperatures. Seldom considered is
the effect of asphalt pavement on which those vehicles travel in that it absorbs some
90-95% of incident sunlight whereas crops, trees, etc., absorb some 75-85%; thus asphalt
contributes to the heat burden.
Diesel: Since there is no ignitor, compression ratios of 19 to 25
(contrasted to some 9.5 for gasoline engines) are necessary to compress air to
the fuel ignition temperature, so cylinder walls must be stronger and require
more steel; thus diesel engines cost more. But a comparison of automobile mileage
per gallon indicates the higher initial cost will be recovered in three or four
years of moderate usage and quicker with heavy travel. Moreover, diesel engines
are generally more durable and enjoy a longer life cycle. Modern automobile diesel engine
performance characteristics compete well with gasoline engines. Diesel-driven
automobiles are a sound investment both from the standpoint of lifetime
operating expense and reduced demand for petroleum.
Economic efficiency of an automobile or light truck is obviously the cost
per mile, which for most of us equals payment plus insurance plus fuel divided
by miles driven, all figured for the month. It is a comparatively easy calculation
to compare economic efficiency of various vehicles and is undoubtedly part of
your comparison when in the market for a new vehicle.
Entries on the World Wide Web indicate that most modern diesels will operate
equally well on petro- or bio- diesel. (I visited the Auto Show (4-12-05)
in search of information on biodiesel and found that only one car made in the U.S.
is rated for biodiesel, and that was B5 (5% bio in petro). Clearly hobbyists and
experimenters will have to pave the way.) Many people are operating with SVO
(straight vegetable oil), which does require special considerations such as
pre-heating the oil before it reaches the fuel injectors. One approach is use of
two fuel tanks so petro-diesel may be used for the first and last few minutes of
operation (thus cranking and warming on petro-diesel and then clearing the
tubulation and injectors of biodiesel before shut-down; and using a heat
exchanger between waste engine heat and fuel tubulation to pre-heat the SVO).
Various single-tank designs have been used, and some people are running on waste
oils and fats from cruise liners and fast-food outlets (with modest filtering
and conversion). As data on fuels and information on designs becomes
available to me, I will add it to the web page accessed by
clicking here. (Also referenced at the end of this page so you need not link yet.)
There are many applications, such as trucks and fixed power plants, where
constancy of fuel supply is much more valuable than volatility, and flexibility
in oil sources would help assure continuity of supply.
OPEC (Organization of Petroleum Exporting Countries) has been successful
several times in curtailing production, apportioning it among member states, to
cause a rise in petroleum prices. Each time one or several members, after a
time, felt pressure for additional income and cheated on their allotment. It is
a poor national policy to rely on the greed of OPEC members. However, I can
think of nothing that would have a more beneficial effect on the greed driving
OPEC than a serious effort in this country at conservation of petroleum and
development and use of alternate fuels. 8-21-06
My recollection is that petroleum prices peaked in the late 1970s but the specter
of increased production from Middle East oil wells discouraged development
of other resources. 9-11-06 For the past year or so we
have experienced unconscionable oil prices. Remarkably, the announcement of
discovery of immense quantities of oil under the Gulf of Mexico has led to an
immediate drop in petroleum prices. This has led me to a discussion (and
suggested legislation) of how to shield the U.S. from OPEC's greed. This may
be seen by clicking here.
Shale and oil sands: I was shocked to
learn that many shales are so oil-rich that they can be burned as fuel, leaving an ash
that has been the basis for cement manufacture. Both the shale and its over-burden
resulted from geological processes of deposition and compaction of silt; the chemical
composition reflects surface conditions at the time, plant and animal life , erosion
products added to the silt and leaching by ground water during compaction.
Studies show there is enough oil-bearing shale in our country and Canada alone to satisfy
our petroleum needs for 200-300 years -- larger than any known liquid petroleum reserve
anywhere in the world. There are also extensive oil-bearing sands in Canada. There must
surely be a price level for petroleum that makes it economical to develop shale. The U.S.
could be independent of foreign oil for decades. 8-21-06 The
Green River Formation in Utah, Wyoming and Colorado is estimated to hold, under 1000
feet of over-burden, more recoverable oil than all known liquid petroleum reserves combined
-- 16,000 square miles containing some one barrel of oil per ton of shale. Oil sands in
Alberta, Canada, contain about half that much. China has been exploiting its shale since
1929 and Estonia's chief export is electricity generated from shale oil. Brazil has
produced since 1991 100,000 tons of oil per year from its shale. Some oil
companies claim they can harvest shale oil from the Green River Formation at $10
per barrel while present production is at $25 per barrel by pumping heated
liquid into the shale to release oil from the rock. I understand a 2005 Federal law
is intended to encourage production of oil from Green River shale.
Developing oil from shale: 06-06-08 With 1000 feet of
over-burden, and the recognition that maximum petroleum production requires shale be
brought to the surface for extraction of its oil, the question presents itself: what to do
with the residue once its oil is extracted? Such questions beg for examination. Of
course, once production moves to a new pit, filling the earlier pit would account for
a major portion of the residue.
What is the nutrient content of the shale and its over-burden? It should be similar to top
soil that is the basis for farming. Since it cannot be readily compacted to its present
volume, alternative uses must be found beyond parks and lakes (commonly used today to
leave abandoned mines in a state that is attractive to the public). Intensive farming has
left much farm land depleted of nutrients in the soil and there may be enough demand for
use of over-burden to replenish depleted soil to justify transporting it to farming
operations. Something government leadership ought to consider!
One would think petroleum interests would give priority to learning how extraction of oil
from shale can be made attractive to the public, including "green" interests. Once oil is
extracted those huge holes resulting from mining must be filled. Rather than that
producing eye sores, parks and cultivatable land could result.
Alternates to liquid petroleum: The popularity of
automobiles has driven our choices toward petroleum and its controlled volatility. But we
should examine possibilities for other sources of fuel-tankable power. (The next two
sections discuss biodiesel and vegetable oils as well as compressible gaseous fuels.)
7-23-07 I have just examined tabular data from the U.S.
Dept. of Energy. Regrettably, biodiesel from vegetable oils is not added into their data
as biodiesel, which I regard as gross dishonesty in favor of ethanol, likely due to
lobbying effort by ethanol interests. (Political chicanery?)
Ethanol (ethyl alcohol, the potable stuff) takes the
same corn from which corn oil may be extracted, converts it to sugar and then produces
ethanol (aprx 2.5 gal/bu), a fuel whose energy content is some 62% that of petroleum. It
would be interesting to compare the energy production per acre using, first, corn oil, and
second, ethanol. I say with tongue in cheek that, in the quest for sustainable seed oil
production, the corn subsidy might usefully be switched to cannabis subsidy. USDA
estimates that energy from corn ethanol is only 34% more than energy required to produce
it. (Engine lubrication using ethanol may be a concern; I have no information.)
(July '07)Applications are coming on line to produce ethanol and
methanol from municipal garbage. Research is underway to produce ethanol from cellulosic
crops, such as switch grass from our Great Plains; it crosses my mind that the residue from
production of oil from algae ought also be explored.
In using ethanol to fuel automobiles, "E85" is 85% ethanol, 15% gasoline.
1-12-06: I have learned that Brazil has taken advantage of its tremendous
sugar cane industry to produce ethanol and encourage its use in automobiles. Over time the
cost advantage of gasoline versus ethanol has varied, but recently they have introduced
cars that run on flex-fuel, a continuously variable mixture of gasoline and ethanol so
the cars can take advantage of whichever fuel is currently cheaper per mile. Over
three decades Brazil has improved productivity of sugar to 6000 liters of ethanol per
hectare of crop land (aprx 4800 kg/ha). The history of Brazil's development of ethanol is
an interesting mix of Brazilian politics, world oil prices and research on sugar cane's
DNA as well as uses for the remaining pulp.
Methanol (methyl alcohol, the poisonous stuff)(energy content
75% that of ethanol): I lack data other than the table below.
Denatured (fuel) alcohol I lack data other than the table below.
Comparisons of Liquid Fuels
*Handbook values are presented in a variety of units, so it is difficult
to compare fuels in useful terms. I have undertaken some conversions for comparison.
Conversion units are listed at the end of this essay.
[I have recently become aware that my life-long assumption, that
dinosaurs and other creatures of our long past produced our petroleum, has been
cast into question. Perhaps methane existing at great depths -- part of the
primordial soup from which Earth condensed -- was acted on by the immense
temperatures and pressures to produce petroleum and that "known" oil reserves
are minuscule compared with petroleum at these greater depths. I am forever the
skeptic and have scant confidence that significant quantities of deep petroleum
even exist, much less can be recovered. In my quest for acceptance of such
possibilities, I am hopeful of finding information on the laboratory production
of petroleum from methane. Whatever the results of research on this fountain of
petroleum, I would urge the advocates of untamed consumption to be honest in
their notions of our civilization's ability to mine and thereby harness these
reserves. Science has been and likely will continue to be limited in the depth
of drilling by the immense temperatures existing toward Earth's core.
[Our civilization's greed and disregard for the effects of unfettered
exploration, exploitation and uses of petroleum, especially transportation of
raw petroleum, are an international disgrace and a shameful lack of concern for
tomorrow and its citizens. Adequate safeguards for the environment must be
erected to assure that the esthetics and practical functionality are not
destroyed. At the very least our technology must learn and apply techniques that
prevent oil spills altogether, while in the interim avoiding the waste and
environmental destruction of spills.
[I remember when the beach at Fort Walton, Florida, was clean -- sand almost
white -- and the waters slapping onto the beach were so clean and clear you
could see the bottom way out; now the sand is a dingy gray and has lumps of
residue from a Mexican oil well that sprung a leak and remained uncapped for
weeks. I have not read much of the oil dumping and well fires ordered by Saddam
Hussein in the throes of the Iraqi war of the early 1990's. But the Exxon-Valdez
spill in Alaska also comes to mind. Such environmental disasters simply
must be precluded by evolving technology -- such as locating and
pumping dry sunken oil tankers. It is often an international issue and the
boundaries between private development and governmental regulation come into
play.]
VEGETABLE or SEED OILS and ALGAE (for biodiesel)
Most automobiles on roads in the U.S. are powered by gasoline, with some formulations
containing a small percentage of ethanol. Many trucks and mobile equipment requiring
greater power rely on engine designs that use diesel fuel. There has been some
experimenting in Europe with gasoline engines converted to biodiesel but I will not
speculate on the possibility of a fuel igniter that will make it possible to ignite diesel
fuel at the lower compression ratios typical of gasoline engines. (Data on design for
biodiesel is shown by clicking here.)
Use of by-products and leavings of oil production will become major issues
and may in fact determine which crops may best be utilized for fuel production.
Cattle feed from cottonseed oil production. Fiber from hemp. Tillage.
Fertilizers. Pests.
It should be obvious that, politically on the international stage, our
nation's reliance on liquid petroleum makes us vulnerable to political events
beyond our shores and beyond our control. The lack of alternates is not a
suitable or sustainable national policy. An obvious direction for agricultural
research is genetic engineering for seed oil production. I am disheartened at
the obvious influence of petroleum interests (and the so-called "war on drugs")
in failing to direct research interest toward projects that have hope for relieving
our dependence on foreign oil.
Nor should the environmental impact of seed oils as a fuel be overlooked. The
USDA has pointed out that 10,000 acres planted in hemp will yield as much paper
as 40,000 acres planted in trees and requires far less caustic chemicals in its
manufacture than paper from wood pulp. Biomass (seed oil) fuels release fewer
pollutants into the atmosphere and the plant source spends its growing season
removing carbon dioxide from the atmosphere through photosynthesis. As a fiber
source hemp has an enormous potential and is perhaps the world champion
photosynthesizer of solar energy, with more than four times the biomass/cellulose
potential of corn or kneaf.
Seed oils have an energy content per gallon of some 85% that of
petroleum distillates. And early diesel engines were operated on peanut or hemp seed oil,
where one acre of plant could reportedly produce 800 or more gallons. Energy
content of the fuel used is not a factor in diesel engine design since
lower-energy-content oils simply need a greater depression of the power pedal in
order to produce the same horsepower, so cost and volume (miles per fill in
travel applications) become limiting factors. (Engine lubrication is reportedly better
with seed oils than with petroleum distillates.)
* I am suspicious of this data: compare 18 gal/acre
with the earlier data of 2.5 gal/bu of ethanol from corn.; yet in 2006 the average yield of
corn was 149 bu/acre.
Algae as a potential source for oils
supposedly far exceeds (estimated at a factor of more than 100) any of the above oils.
With some 18000 known strains of algae with oil content 2% to 40%, a separate table is
appropriate; searching the Web for data on algae is for me a new (8/07) project and data
collected is in a separate section; you may view a summary of research efforts as well as
data on algae by clicking here.
So long as octane ratings can be maintained (and pollution is reduced with
most oils) there seems little reason to avoid mixing other oils with petroleum
distillates. Ignition has apparently dictated spark plugs and gasoline; but a
well-warmed-up engine should allow an increased percentage of less volatile
fuel, and two injectors per cylinder (one controlled by engine temperature)
should allow mixing fuels with no loss of engine performance. Two fuel tanks,
and two fuel gauges on the dash, should not be a severe penalty for the
projected benefits of dual fuel use. Today a mixture of petroleum-derived oil
and soy oil are offered for diesels: I do not know the proportions. [B20 is 20%
biodiesel in petroleum distillates; B100 is 100% biodiesel.]
Viscosity of any fuel oil (which becomes less at higher temperatures) is of concern since
it must traverse tubulation and some form of injection into the combustion chamber. In
many cases waste heat may be used to warm the fuel to a desired temperature.
Home heating and hot water require constancy of energy supply. Seed oils will compare
favorably with petroleum once cost per gallon can be brought reasonably close.
The volatility of petroleum prices should be an incentive to accept somewhat
higher prices for seed oil installations. While I am not familiar with ignitor
designs, there should be so little difference in designs for the various seed
oils that one seed oil may be freely substituted for another; in fact petroleum
and seed oils are likely interchangeable so blends could and should become part
of the fuel mix.
I am seeking information on costs of seed oil production and utilization of
by-products; it has been a frustrating search. I offer this much:
Jet aircraft burn kerosene-like petroleum distillates. There is a penalty in weight in use
of seed oils, but so long as ignition can be sustained at acceptable temperatures there
should be no other advantage of petroleum over alternate oils.
Hemp: Hemp, a member of the mulberry family, is similar to flax, kenaf,
jute and ramie with long slender fibers in the outer stalk, a fibrous core that has a
number of uses and seeds rich in oil. When raised for high quality fiber it is harvested
when it flowers; for seeds harvest is 4-6 weeks later, when fiber is a lesser quality. Few
varieties contain enough THC (the psychoactive ingredient) to be of interest to smokers.
Although the USDA is encouraging production of hemp, this country's drug policy may be
a barrier to research but, should hemp oil become a viable alternative to petroleum, then
our drug policy must of necessity be reexamined. Hemp agriculture was required of early
Virginia farmers, and was encouraged by the U.S. government during World War II, as a
source for fiber. I am not familiar with the history of hemp use and competitive products,
but I have heard the story that a commercial process for using hemp fiber in the manufacture
of newsprint motivated newspaper interests (who at the time owned large pulpwood forests
that would lose value) to try to produce a public hysteria against marijuana and succeeded
in 1937 in inducing the Congress of the United States to make marijuana illegal. While I
doubt that the developers of that process are still living, there should be patent records
of the process. Should this source of fiber be economically competitive today then that,
in combination with the fuel usage of hemp seeds, will make a powerful argument for
controlling marijuana use by taxation as a recreational drug (after the fashion of alcohol).
A search (2-2-05) of the World Wide Web has yielded this much: Hemp produces
some 4 tons of seeds per acre, and 30% of seed weight is oil, for up to 300
gallons of oil per acre (compared with 60 gal/acre for sunflower and safflower).
300 gallons per acre, considering costs of production, yields $0.77 per gallon.
USDA strongly encourages hemp agriculture. To my mind we ought as a nation
embark on efforts to genetically engineer hemp to maximize its potential as a
substitute for petroleum. (Use of fiber from hemp stems is reportedly used for
over 10,000 different products so there is the potential for great industrial
development.)
During World War II, Henry Ford developed a car that could run on hemp-based
fuel.
The National Biodiesel Board offers this: Biodiesel (blended of unspecified
vegetable oils -- soy suspected -- and put through their process) has been
successful at 20% in #2 (petroleum) heating oil; 100% is usable without
equipment modification, but they encourage delay until testing protocols can be
established. In diesel-electric application in California 100% produced notably
decreased atmospheric emissions. 2-5% concentration improves lubricity. Most
diesel engines built since 1994 can use biodiesel without modification although
transportation and storage require special management. Some biodeisels are more
aggressive than petroleum so rubber parts should be of Viton or a similar
compound. Their web page declines to discuss costs; there are relatively few
outlets but they can deliver anywhere. The infrastructure is underway.
The Biodiesel WWW Encyclopedia links to many contemporary topics regarding
biodiesel. Their URL is http://www.bdpedia.com/.
COMBUSTIBLE GASES -- hydrocarbons and hydrogen
Production and consumption of hydrocarbon gases are often great distances apart and
transport is crucial. Internationally there are thousands of miles of pipelines, but many
of these end at the loading dock. But it isn't economical to transport them in the gaseous
state so liquifaction is essential. So of engineering concern are the properties of
critical temperature and critical pressure. At temperatures higher than critical
the gas cannot be liquified regardless of pressure, and at pressures lower than
critical the gases cannot be liquified regardless of temperature. Therefore
transport requires pressure containers that are well insulated. Gases of primary
interest are tabulated below; LNG (Liquid Natural Gas) and liquified hydrogen
also appear in the table for liquid fuels. (It should be evident from the critical
temperature for hydrogen that ordinary insulations are not adequate to even
short term storage; there must be a search for an absorbent
that will hold large quantities of hydrogen at high densities.)
Comparisons of Gaseous Fuels
Methyl hydrates have been estimated to contain enough methane
in known deposits to power our civilization for many decades, possibly
centuries. Deposits exist in vast quantities at shallow ocean depths in the
polar regions, inside the Siberian permafrost, underneath the sea floor, off
the Oregon coast at 1/2 mile. Reportedly it is formed by expulsion of water
and gases from tectonic plates at the sea bed. The technology to recover methane
from methyl hydrates presently limits this source of
energy. With economical recovery technology there would become the matter of
pipelines from sites such as ocean bottom or tundra to distribution centers.
Hydrogen may be used in an internal combustion engine just as hydrocarbons or
in a fuel cell (in which oxidation is accomplished without high temperature combustion,
with the resultant electricity being used to drive electric motors). (In hybrid cars,
additional energy comes from capacitor storage of energy captured during braking. Since
I studed electrical engineering in college I am curious about such things as size, voltage
and duration of storage.) In examining energy inventories, one must realize that hydorgen
requires considerable energy for its production; it is doubtful there can be any energy
advantage to its use. Considering that generation of electricity (except nuclear) releases
substantial carbon dioxide into the atmosphere, use of hydrogen is not likely to alleviate
concerns for atmospheric effects of energy used.
Comparing CNG (Compressed Natural Gas) with gasoline for motor vehicle fuel:
Both have comparable operating characteristics, but natural gas costs considerably less per
mile. (Tapping the gas line that heats your home brings cost to about half.) CNG has less
carbon monoxide emissions. A CNG car requires a considerably larger fuel tank; even so
miles per fill-up drops from ~400 to ~250.
Scientists in Denmark have succeeded in absorbing ammonia
(NH3) in tablets of sea salt where the equivalent of 360 miles of gasoline can
be stored in a comparably-sized tank. When the ammonia is depleted, simply expose the
tablets to more ammonia. A catalyst is used to recover hydrogen from the ammonia; how
the ammonia is recovered from the sea salt was not disclosed although the
ammonia-charged tablets may be safely carried in a pocket without safety precautions.
The alga chlamydomonas reinhardii (a green alga) has been used to produce hydrogen when
deprived of sulfur in an anaerobic atmosphere. Moeweesi also produces hydrogen.
10kW generators for emergency back-up using hydrogen stored in cylinders is
offered by APC; they may be used when regulations prohibit pollution from
traditional generators such as diesel.
Automobiles using hydrogen fuel cells are being built in Japan and
operated in the U.S. as a trial (as of July 2005); refill stations are being built; present
limit is 150 miles per fill. It is questionable if hydrogen power can improve pollution
since hydrogen is produced from natural gas or coal (or by electrolysis of water
using electricity, itself a source of pollution, as a power source).
I have learned that nine European cities operate buses in public transportation using
fuel cells with hydrogen as energy source. And some fork lifts in this country are
powered by hydrogen fuel cells. Evidently, where a vehicle can be filled daily,
long-term storage in the vehicle is not a problem as it is with automobiles.
Internal combustion engines burning hydrogen are in cars built by BMW on an
experimental basis. They use liquefied hydrogen from a fuel tank (at -423o
F) "made of 70 layers of fiberglass and aluminum." I assume they have to be fueled
daily since the temperature is maintained in the face of penetration of heat by
evaporation of fuel. Hydrogen is produced by electrolysis of water using solar power.
Range is somewhat over 200 miles per fill. Refill is by a robotic arm so users are
protected from handling hydrogen at that temperature.
Methane from cow dung has been captured by one California farmer, and researchers
are working with microorganisms in a cow's digestive tract to produce methane for
generation of electricity.
In my humble opinion, petroleum interests in the U.S. advocate hydrogen technology
because of the improbability of it becoming a practical automotive fuel. When
I reflect on the critical temperature and visualize an automobile sitting in the sun
for hours, I cannot conceive of any insulation adequate to prevent heating the
hydrogen above its critical temperature although liquid helium (at a still lower
temperature) has been used in space vehicles (doubtless shielded from the sun and
relying on the cold of outer space).
(I await description of an accident that ruptures a hydrogen fuel tank, with
the rocket propulsion of gas escaping at several thousand psi. It has become
obvious to me that my preoccupation with automotive applications has blinded
me to many niche markets where hydrogen is a practical source.)
ELECTRICITY
Nearly all energy sources are used to generate electricity. Its greatest peculiarity,
perhaps I should say strength, is that generation and consumption may occur at widely
different locations, with transmission lines providing the connection. Those lines are
fixed in their termination in the home or business and do not lend to portability.
Initially generation of electricity was direct current. Because of transmission (iR or
current times electrical resistance) losses -- and power=current times voltage -- much
greater power levels can be transmitted without significant power loss, by using
transformers so transmission is at voltage levels of hundreds of kilovolts; thus
alternating current has become dominant.
Transmission losses: "NIMBY:" 'Not In My Back Yard' has become the cry
of home owners. Considering the losses of transmission, generation must be within a
reasonable distance from consumption. That flurry of public concern about the health
hazards created by radiation effects from those overhead high-voltage lines should have
made it obvious that there are significant losses. The strength of electric field
diminishes as the square of the distance from the transmission line, and every erg of
energy felt at the ground represents loss from the lines. Doubling the height of power
lines, while creating other hazards and likely being uneconomical as well as unsound
engineering, would only quarter the energy felt at the ground. I am searching for numbers
but expect loss to be measured as a percentage of power transmitted per mile of line. The
closer generation is to the user, the greater the useful utilization of the electricity
generated. Excepting failure of local utilities and reliance on a national grid (with its
increased losses) transmission losses have been estimated at 10-15%.1 (To view footnote, click here.)
There seems to be a tendency to rely increasingly on massive
interconnections between power grids; not only are transmission losses increased, but
phase difference between generators far apart becomes an increasing concern with longer
transmission lines.
Energy content of fuels is determined by calorimetry; efficiency in
converting fuel to heat has been dramatically improved in recent decades;
efficiency in utilization of that heat to produce electricity has been improved
even more dramatically; efficiency in consumers' utilization of purchased
electricity is a separate consideration. As generation and distribution of
electricity have evolved, efficiency in fuel use has improved from 7% (Thomas
Edison's early generators) to a possible 65-97% due to technological (and
regulatory) advances. In today's practice generation is centralized in locations
remote from users so heat cannot be efficiently transported to users; in thus
converting fuel to electricity, only about one third of the energy content of
the fuel results in electricity in transmission lines; some two-thirds is wasted
by dumping it into the air or into waterways. While efficiency and economy of
scale may have driven early generation capacity to remote locations requiring
transmission -- and government regulations have largely locked the generating
industry into that philosophy -- new equipment has removed the efficiency of
scale so new capacity may be located in the midst of users, allowing heat that
is presently being wasted to be used by local industry and residences as an
alternative to consumption of additional fuel.
Government policy in most localities grants a monopoly to generation and
local distribution of electricity, guaranteeing to the utility company a
reasonable return on investment. Advances in technology have resulted in
reducing emissions of greenhouse and noxious gases (and soot) to 1-2% of their
former value, which ought, in reason, remove local objections to locating
generating capacity within the local industrial community, where heat that is
now wasted could be used. Despite demonstration1
(To view footnote, click
here.) of the improved economy of distributed (or local)
generation of electricity, despite the lack of incentive of monopoly to seek
improved methods, despite the increased consumption of irreplaceable fuels and
growing concern for environmental issues, and despite the potential for failue
of mammoth distribution grids, governments have chosen to listen to interests
vested in the status quo; monopoly and centralized generation continue.
Governments need to hear from advocates of free enterprise as well as advocates
for our descendants.
Environmental impact: Approximately 2/3 of the caloric content of the
fuel used to generate electricity is waste heat rejected to the environment.
Moreover, each kilowatt-hour generated by burning fossil fuel adds some six
pounds of carbon dioxide to the atmosphere. As I find informamtion on efficiencies of
specific fuels I will include that data here.
I should note that batteries and hydrogen fuel cells provide electric power for
many applications.
NUCLEAR
Of the two nuclear processes for the release of energy, fission and
fusion, only fission has been controlled. In fission heavy radioactive atoms split to
produce lighter atoms; in fusion light atoms join together to make heavier atoms. Both
processes involve rearrangement of the constituent parts of atoms with the release of
excess energy over that required for stability of the end products of the process.
Our Sun is powered by fusion and research continues, in our laboratories, to contain
the immense temperatures and pressures of the fusion process.
In common with coal- and oil-fired generation of electricity, heat from the reaction
produces steam, which is used to drive the turbines that produce the electricity. Of
course the steam could be used for motive power as in nuclear-powered submarines or
aircraft carriers; in time it will undoubtedly be harnessed in trains.
Politics: Like so many scientific advances, war motivated progress. The
public is well aware of the destructive potential of the atom bomb (a fission reaction),
where primitive versions were exploded over Japan to end the war, and has heard
predictions of the vastly more powerful hydrogen bomb (a fusion reaction). After World
War II scientific effort was dedicated to harnessing the immense potential for constructive
purposes such as generation of electricity, and several processes were developed, each
with its own safety requirements. And concern for public safety has driven politics.
Barring accidental releases from a nuclear reactor there are no local environmental
degradation issues other than temperature increase in cooling water that is released into
a waterway. Of course, the public is aware of the Chernobyl (Russia) and Three Mile Island
(U.S.) incidents, which resulted from failure of control devices and a resultant melt-down
of the radioactive core; it became obvious that initial design and construction must deal
with the possibility of accident. In the Three Mile Island incident, there has been no
reported leakage of radiation from the containment building or into the river; evidently
design of that reactor facility was adequate.
We are continually bombarded with background (naturally occurring) radiation from both
space (gamma radiation which produces nuclear events when it strikes molecules) and
sub-surface (radon) sources. In evaluating radioactive leakage the concern is for increase
in radiation beyond this natural background -- in the increases we can control -- rather
than in total radiation. It is unfortunate that the public fear of accident and the resultant
outcry against nuclear power generation has produced a near-hysteria and has curbed
further research efforts. As various possibilities for problems became obvious, designs
became more elaborate, resulting in the cost of nuclear power plant construction being so
greatly increased by safety concerns that nuclear power is marginally uneconomical and
initial investment has become a limiting factor in development of nuclear generation of
electricity. (To my knowledge, no new installations have been undertaken in this country
for years -- decades, in fact.)
There are concerns for public safety in three aspects of nuclear generation of electricity:
(1) failure of a nuclear reactor that releases radioactive products into the
environment, (2) accident in transporting hazardous wastes (by-products
of nuclear reaction) through populated areas, and (3) long term storage of those
wastes since half-lives of some wastes are thousands of years and geological stability
of storage sites is difficult to guarantee. Failure and construction costs are twin problems;
hopefully new designs and new realizations will both reduce risk and lower costs.
Accidents happen; containment vessels must be adequate to prevent rupture in all but the
most grotesque accidents. Long term storage embraces several technical and scientific
concerns, each of which can be addressed if there is will and foresight.
It is also unfortunate that research on breeder reactor technology -- that is, generation
of more fissionable material than is consumed in the course of expending fissionable
material -- ceased. If power demands continue to escalate, nuclear will become a
necessity, and breeder reactors will be a feature of the future. Simply put, if the United
States does not maintain a lead in this technology, someone else will, to our probable
disadvantage.
Disposition of radioactive wastes presents several challenges. Some concerns,
such as protection of reprocessing and research personnel, are common to all. Processing
spent fuel rods, which is the source of all concerns about waste, can separate
non-radioactive from radioactive products. Researchers should strive to turn waste from
one process into a resource for another. Many radioactive products have half-lives on a
hour-days-weeks time scale; unfissioned radium and plutonium plus other heavy elements
can be recycled back into new fuel rods; elements of intermediate half-lives may be
irradiated in a nuclear reactor to transform them into non-radioactive or stable, non-toxic
elements. Thus the volume of waste can be reduced by 95-99% and what remains may be
encapsulated and stored; information available to me shows that encapsulated wastes -- and
here we deal with isotopes (such as strontium-90, cesium-137, technetium-99 and iodine-129)
one by one -- will decay and lose toxicity over the course of a few hundred years (rather
than the many tens of thousands of years presently postulated).
Technical: We are familiar with the orbital description of atoms, with electrons
orbiting around a nucleus consisting of protons and neutrons and the number of electrons
equal to the number of protons. Chemically, the number of electrons governs. Of course
protons, being all positively charged, repel each other, so neutrons are necessary to
prevent the nucleus from flying apart. And as the number of protons increases, there is an
increasing possibility for extra neutrons, which gives rise to isotopes of the elements, such
as carbon-12 (normal) with six each and carbon-14 with six protons and eight neutrons.
And the nucleus of carbon-14 is unstable with a half-life of 5700 years, that is, in a
sample of carbon-14 atoms, on average half will decay within 5700 years.
So we go on up the scale of elements through iron-56 (Fe56) with 20 protons
and 36 neutrons, through strontium-88 (Sr88) with 38 protons and 50 neutrons
to uranium-238 (U238) with 92 protons and 146 neutrons and plutonium-242
(Pu242) with 94 protons and 148 neutrons, the imbalance between protons and
neutrons increases. As atomic weights (the '242' or '238) increase, fewer isotopes are
stable although half lives may be exceeding long. The most common naturally-occurring
isotope of uranium is U238 (over 99%) with the remainder U235,
which is sufficiently unstable to be fissionable by ejection of an alpha particle (helium-4,
with 2 protons and 2 neutrons). U235 may fission to U231
which may in turn fission to U227, which may in turn fission to a lighter
atom.
Ejected protons and neutrons may escape to the surrounding space and thus not participate
in a chain reaction, but if they strike another atom, that atom may in turn eject a particle.
When more particles escape than strike other atoms, the reaction is 'sub-critical' and no
chain reaction occurs; if more particles strike other atoms than escape, the reaction is
'critical' and there is a chain reaction. In reactors for power production the degree of
criticality is controlled by inserting or removing absorbing materials between fuel rods.
However, other reactors may be designed for sub-critical operation so materials may be
inserted to be bombarded by neutrons, thereby increasing the number of particles in their
nuclei in order to create a heavier chemical and, depending on the stability of that nucleus,
perhaps creating a different chemical.
We recognize the probability a spent fuel rod will contain a variety of chemicals and
isotopes, including Pu242 (U238 absorbing one alpha).
Exact mixture of isotopes will obviously depend on the energetics of the various reactions
with nuclei in the fuel rod, which must depend on composition of the fuel rod and power
level of reactor operation. For a light-water reactor, enrichment of U238
with U235 is only 3-5%; spent fuel rods contain about 94% uranium, 1%
of transuranic elements (Plutonium and heavier) and fission products.
I understand that, in the U.S., uranium ore is sufficiently plentiful there has been little
incentive to extract uranium from spent fuel rods, so entire rods become waste. Were the
uranium extracted, what remains may be treated as radioactive wastes.
A fascinating statistic: A typical coal-fired generating plant consuming 10K
tons of coal per day is liberating 100 kg of uranium per day, either up the smokestack or
in the ash that is dumped into a landfill. The energy content of the uranium in the coal is
greater than the energy yielded by burning the coal.
COLD (nuclear) FUSION excited a great deal of public interest some
years ago. It has been suggested that loading deuterium
into palladium (by electrolysis) will produce the gas helium plus an excess of
output energy over input energy. Development has been hindered by lack of
federal interest and the apparent unwillingness of private sources to fund
research. Graphs I have seen show insignificant power levels although
there seems a modest amplification in power. Production of helium in the process
suggests fusion is indeed occurring. The use of palladium, an extremely
expensive precious metal, militates against widespread application; less
expensive metals must be sought if there is to be hope for this technology. My
personal estimate is that practical application is so far in the future as to be
unworthy of heavy investment at this time, though a modest level of
experimentation should be continued.
(There was a suggestion years ago that useful energy could be derived from a
simple arrangement, using electrolysis of water in the presence of finely
divided nickel. Demonstrations reportedly produced 1 kilowatt of heat energy for
each 1 watt expended in operating the system, a multiplication of 1000. The
author of this statement has offered no reference, and I have found none in
following links at his web site. If such an experiment were successful I would
think it would be a widely-used high school chemistry demonstration.)
SOLAR
Solar energy may be used directly as a heat source, or it may illuminate
photovoltaic cells to generate electricity. Constancy is the greatest question to
the user. The promise of solar energy is of course greatest nearer the equator (or
between the Tropics of Cancer and Capricorn) and where clouds do not obscure
the sun. And with ground-based collection, sufficient energy must be captured
and stored during daylight hours to provide the needs of the overnight hours. In
European installations huge arrays of solar panels produce megawatts of electric
power. Every kilowatt-hour and every barrel of oil or cubic foot of
gas that is saved is that much gain for the useful life of our resources.
It has been suggested that huge solar collectors in space could collect and
concentrate solar energy and beam it to the ground. There may be promise in such
technology, but we must be extraordinarily careful that the transmission of
power to the ground does not sterilize the ground nor cook everything in the
intervening atmosphere (including birds who may have a pathway during
migrations).
In residential application, water heated by incident solar energy is an obvious
application, especially since short term storage can overcome the irregularities in
collection and usage. Home heating should be feasible in many regions; for comfort's
sake it may be necessary to provide back-up equipment although some level of
temperature discomfort during periods of extreme weather should be acceptable as a
trade-off for conservation. On average about a quarter of the home energy budget is
for hot water, with most of the rest for heating and cooling of the living space. I
estimate that in most homes the cost of equipment for solar energy collection for
hot water would be recovered in a year or two. I further estimate that, in using
circulating hot water for space heating, solar energy could, in the northern United
States, supply over 50% (and in the south over 90%) of total needed heat (with minimal
auxiliary equipment for use in extreme weather). I have seen house designs for using
solar heat only, using window location and massive walls (and other ballast) for
heat collection and retention. (I am, in fact, surprised that federal subsidies have not
been offered for retrofitting existing residences and for initial equipment in new housing.)
Commercial and industrial applications should not be overlooked. Certainly for hot water
and heat in commercial buildings, solar energy should be part of their energy
considerations. In industrial and commercial application it should not be a barrier to
exploitation that there may be brief periods during the year when solar plus auxiliary
heaters allows space heating to fall below ordinary comfort levels. In Spain it is now
required by law that new buildings use solar energy for a portion of their needs.
And solar energy has been successfully applied to recovering potable drinking
water -- and water for other home needs -- from the ocean on a commercial scale.
It dumbfounds me that local solar distillation has not been massively
applied in the Third World and in areas with adequate but contaminated water.
In Spain new commercial buildings are required to use solar energy for a high percentage
-- wish I had kept the reference -- of their energy requirement.
A solar chimney is planned in Australia where a chimney some 0.4 miles high
will be heated by the sun and rising air trapped within will drive turbines.
To deal arithmetically with solar energy, we measure a solar constant (amount
of energy received atop Earth's atmosphere on a square meter that is normal to
the sun) at Earth's average distance from the sun. It is about 1.3 kilowatts
with a variation of some 2% due to solar activity. As the sunlight penetrates
our atmosphere, some 20% is absorbed by atmospheric constituents and some 30% is
reflected from clouds, aerosols, glaciers, water, sand, vegetation, etc. (not as
infrared energy but at the same wavelengths as are incident). So some half
reaches the ground and is absorbed there. Of this half some 40% rises into the
atmosphere as water vapor (including the heat of vaporization) and convection
currents; the balance heats Earth and the warmer Earth radiates energy into the
atmosphere as infrared energy, some of which penetrates to space while some is
absorbed and heats certain atmospheric constituents (the so-called "greenhouse
gases"). Of this absorbed heat about half is reradiated into space and the other
half is reradiated to the ground, raising ground temperature further. A
temperature balance (or, more accurately, a balance of energy flows) is reached
between incoming and outgoing radiation.
The effect of solar radiation on any specific unit of Earth's surface varies
according to angle with incident radiation, distance energy travels through the
atmosphere, intervening clouds, and the radiative nature of the surface (both
reflective, absorptive and reradiative). Evidently, numbers describing local
reception of solar energy are highly dependent on local conditions so averages
for Earth are not predictive of local reception. It is estimated that, on average,
240 watts reaches every square meter of surface.
I had at one time wanted to pursue application of solar energy to distilling
ethanol from fermented vegetables. It was not at the time interest in economy
but interest in technology because vacuum distillation would be involved and my
specialty had been vacuum technology; I did not pursue it.
8-18-05 From a report dated in 1997: Solar cells
of polycrystalline silicon of 12-15% efficiency are on the market with promise
of 18% upon removal of impurities. Photovoltaic cells vary in response to
wavelengths of incident radiation; maximum theoretical efficiency of conversion
has been estimated at more than 70% using the entire spectrum, which would
require multi-layer construction, while a two-layer cell may reach 50%
conversion efficiency. It is estimated that an efficiency of 14% is the
boundary for commercial competitiveness. 12-12-05
Researchers at Ohio State University claim 97% capture of the solar spectrum
in solar cells designed for satellite experiments. BATTERIES
convert chemical energy to direct current electricity; many are discarded when their
chemicals are consumed; many may be recharged. Generally they are limited to small
appliances such as flashlights and wrist watches, although there are battery-powered
automobiles (recharged from electric mains). Hybrid automobiles recharge
their batteries using excess kinetic energy and use the battery to then augment power
produced by a liquid fuel. There is a great deal of research underway to improve ratios
of weight to energy storage and/or power output. Batteries are unlikely to become major
sources of prime power but will remain important accessories, and, from researach
currently underway, may provide overnight power in residential solar energy applications.
HYDROELECTRIC
I have heard that every waterway that can be profitably exploited, in this country and,
indeed, in the world, has been dammed. Tides have also been harnessed in locations
where it was economically advantageous to do so. As efforts in the old Soviet Union,
in Egypt (Aswan) and in modern China demonstrate, there are population and agricultural
costs in almost any dam that is undertaken.
Atmospheric consequence: Methane is produced by the anaerobic decay of
plants submerged in creating the dam, and methane is 21 times as powerful in the
greenhouse effect as CO2. On balance a dam
may produce as much atmospheric consequence as burning the fossil fuel it replaces.
Levies on the Mississippi have demonstrated that Nature will work its way and that there
are practical limits on man's ability to control Nature.
COAL
Coals differ considerably in energy content as well as environmental effect.
For instance, anthracite (hard coal) yields some 11,620 BTU/lb; bituminous (soft
coal) yields from 10,240 to 14,630 BTU/lb; lignite (coal in process of
formation) yields some 6,000 BTU/lb; peat (lignite in process of formation). The
sulfur content varies from 0.3% to 6.2%, so there is evidently great variation
in noxious waste gas resulting from burning coal.
Atmospheric consequence: Coal is pure carbon plus impurities; burning
it produces CO2 plus compounds of the
impurities, such as sulfur dioxide (SO2),
which combines with water in the air to produce sulfurous or sulfuric acid which may
in turn decompose to aerosols.
BIOMASS: Wood and Wastes (including agricultural)
Oak 3.99 kcal/gm; pine 4.42
There is tremendous waste of combustible wood, such as roadside burning of
trees felled for highway development. Or of trees cut for beautification or for
safety reasons. And clear-cutting of forests for agricultural land. I am unaware
of any organized effort to collect these (otherwise waste) woods for use in
electricity generation or other energy applications -- not even for home
fireplaces. I am unaware how wood chips, produced for tree management or
clean-up of storm debris, are disposed of.
The National Bioenergy Center is testing various organisms that can digest woody
cellulose to produce methane or methanol. And it is claimed that switchgrass, native to
the American prairies and presently used for animal food, if converted to methanol
could produce 1/2 to 2/3 of demand for U.S. transportation fuel.
Despite their ubiquity I do not see the collection and burning of leaves and
pine straw as commercially viable energy businesses or fuel choices although it
may be possible to ferment either to produce alcohol. Where household organic
wastes are composted as a means of waste disposal, should the heat generated
find useful application, then organized collection of leaves, straw and yard
waste could become justifiable.
I have learned of two landfills in the State of Georgia where the methane produced by
(anaerobic) decomposition of waste is captured and used to generate electricity. A sketch
of one installation shows a liner underneath waste and a cover of dirt, with wells used to
collect the gas. (Landfills emit some 34% of the methane released into the atmosphere.)
In my own practice I am composting leaves and lawn clippings. This should provide
fertilizer for what gardening efforts I undertake.
I recall there was at one time talk of collecting hyacinth from northeast
Florida waterways for use as fuel. This as a means of controlling unwanted
vegetation in navigable waterways; use as fuel was incidental.
A study of 62 kinds of biomass in 1985 reported 17.5-18.75 mJ/kg for corn,
13.75 for weathered rice star (straw?) and 23.28 for prune pits. That equates to
4.3, 3.3 and 5.6 kcal/gm, respectively. One estimate is that, should biomass become the
principal transportation fuel source, it would require doubling the amount of land
committed to agriculture. (See comments on seed oils.)
ANIMAL FATS
Mean 9.5 kcal/g; tallow 9.50; sperm oil 10.0
Manufacturing plants are currently on line to produce the equivalent of
crude oil from agricultural waste such as waste from a turkey processing facility.
WIND and WAVES
Like solar energy, constancy is the essential problem. There are regions with
prevailing winds of a constancy and velocity where turbines may be used to
generate electricity on a competitive basis. Where there is for the most part
sufficient wind to power industry, there seems the possibility of suspending
industrial output during periods of calm so extended as to exceed the limits of energy
storage (batteries). While I cannot foresee a likelihood that whole communities could
be developed with the possibility of extended discomfort, I can see a local dual-energy
economy with wind as a primary energy source with only nominal back-up, perhaps solar,
for home heating and hot water.
I have not followed the installation of wind farms on the Oregon coast for
the generation of electricity, but I am heartened at efforts to tame the winds. But I have
recently read (National Geographic, Aug. '05) that wind turbines are generating significant
quantities of electricity, in Denmark some 20% of the nation's needs, significant
installations in Germany and some in Britain. I have no idea how widespread has been the
study of wind velocities and constancy at various regions of the planet; New Hampshire's
White Mountains has reportedly the highest velocities in this country, and such locations
as the Himalayan mountains should hold possibilities for exploitation although
transportation would become a question. (I can visualize whole nations being supported
-- as in the case of petroleum -- by production of electricity by mountain winds.)
A wave generator is being developed at England's cliffs to convert the ocean's wave
motion into electricity. A number of patents have been filed for various devices to use
wave motion to generate electricity, and other developments are presently under way.
A Dutch firm has anchored a wind turbine off the coast of Italy, expecting to generate
nearly 10 megawatts per turbine.
GEOTHERMAL
There are applications aplenty in regions where volcanic heat lies just below
the surface and has been used as an apparently inexhaustible source of heat. And
there is no doubt that, with some innovation, volcanic heat may be tapped, in
selected locations, at increasing depths.
GROUND HEAT
Just a foot or so below ground surface commences a reservoir that is
relatively unaffected by variations in weather, and temperatures increase at
about 2-3o per meter, or 33-50o per mile (which has
limited the depth for mining). Moreover, underground water, whether streams or
aquifers, are at a reasonably constant temperature. Withdrawals of underground
water for air conditioning purposes has long been practiced. However,
considering the difficulty in extracting large quantities of heat energy at
useful temperatures, it seems likely ground heat must be limited to local
applications requiring only modest quantities of energy; it seems unlikely that
there can be commercial developments as an energy source.
I have just learned (Jan 07) of heat pump applications of commercial and industrial
size using loops of buried liquid (antifreeze)-carrying tubing to use ground heat for
both heating and cooling. Electric energy cost has been determined to be half to a
third that of conventional petro heat, with no other fuel required.
Undoubtedly homes of the future will take advantage of ground heat, with
sub-surface temperatures near 55oF throughout the year. A home
partially submerged, and using the displaced earth for thermal insulation, would
need only nominal energy to increase its internal temperature
10-15oF, well within the bounds available from ground-level solar
collectors or collection of ground heat.
The mountain home I did not build contemplated using a subterranean tunnel
for air entry over heat transfer surfaces using ground heat for cooling and
heating, with supplemental heat. I never got around to designing the heat
exchange device for rejecting heat to that immense underground heat sink but did
contemplate something akin to a septic tank leach field. Due to low thermal
conductivity of soil, collection surface area would be large.
COMPRESSED AIR
VENTILATION
Whether for personal comfort, process control or air quality, circulation of
outdoor air is one of the simplest -- least polluting and most cost effective --
uses of energy. Of course outdoor air varies in temperature and quality
throughout the day and with the seasons, so that alternate means of heating or
cooling must be available. But I suspect that one of the most effective possible
conservation programs would be maximizing the use of ventilation for personal
comfort at home.
Obviously if air is to be drawn in from outdoors there must be ports for both
entry and exhaust.
At one time our home used a large exhaust fan, primarily in lieu of air
conditioning in the summer but occasionally for heating when indoor and outdoor
temperature conditions allowed. It required operator intervention in selecting
the times when it would be cost effective and in opening windows or other
inlets; of course the process could have been automated but we did not undertake
controls beyond on-off and opening selected windows. This seems a fertile
application for home computers and "smart homes" as the products of the
digital revolution become more widespread.
Automatic ventilation of attics to retard penetration of heat collected by
the roof has long been common.
ENVIRONMENTAL IMPACT
There are concerns at each step along the way from prospecting to production
to transporting to refining to consumption to disposal of residue. I will
undertake to record here some concerns that are common to all or most fuels. And
I will try to include under each topic above concerns that are peculiar to that
energy source. However, expansion of this section is a luxury that demands on my
time may limit. Environmentalists -- troublemakers, bless their hearts -- are
trying to get the public's attention for the benefit of the future; they need to
soften their rhetoric and we need to give them greater heed.
Ultimately nearly all the energy available to us comes from the sun and is,
after taking part in various energy interchanges, radiated into space. A simple
calculation equating energy received from the sun with radiation into space (by
the fourth-power law) yields an average world-wide temperature of 0oF.
(I won't get into computation of world-wide average; that is a study unto
itself.) The measured average is 59oF. Over geologic time it is
estimated that changes producing ice ages were less than 5oF,
a small change for such a significant result. The only reason that can be postulated
for the difference between the theoretical average of 0o and the
measured 59o is trapping heat in Earth's atmosphere and its
reradiation to the ground before ultimately escaping into space. So there is a
natural greenhouse effect that has made Earth habitable.
Each gas and each kind of particulate matter in the air makes its
contribution to the greenhouse effect, nitrogen and oxygen essentially none,
water vapor, methane and carbon dioxide being the principal contributors to
trapping heat (water vapor on a short time cycle, methane on an intermediate
time cycle and carbon dioxide on a time cycle of many decades. Carbon
dioxide concentration in the atmosphere was measured at 270
parts per million in the year 1750 and is some 350 now; and presumably the
increase is primarily the result of the activities of our species. Scientists
have undertaken to learn the carbon cycles worldwide -- the sources of carbon
such as carbon dioxide and the sinks where it is removed from the atmosphere and
bound up in vegetable matter, etc. This information is far from complete, but it
is obvious that massive reductions in rain forest and destruction of kelp beds
removes substantial sinks and may be a major contributor to the rise in
atmospheric carbon dioxide. It is the increase in atmospheric carbon dioxide
(and to a lesser extent methane) that causes environmentalists such concern
about a generally increasing average temperature of Earth.
A more extended discussion of global warming may be seen by
clicking here.
Of Earth's total energy budget, about 90% comes from fossil fuels, about 1/3
each from petroleum, coal and natural gas. Of these, for each kilowatt-hour of electric
power generated, methane produces about 1.0 lb., petroleum about 1.6 lb and coal
some 2.5 lb of carbon dioxide.
You undoubtedly have information or comment that should be incorporated here.
To offer it please use as Subject - I read your post about energy - exactly as
you see it here and click here for
the e-mail form.
http://www.oilgae.com/energy/energy.html seems a good source for links to research in
many aspects of energy production.
To examine information on biodiesel, click here.
Definitions, formulas and conversion
factors:
biodeisel or seed oils (click here),
combustible gases (including hydrogen) (click here),
electricity (click here),
nuclear (click here),
solar (click here),
with others (including animal fats) grouped toward the end (
click here).
Environmental impact is both mixed with discussion of specific energy sources and
in a section that may be accessed by clicking here.
Fuel* kcal/gm % of _KBTU in a_ lb/gal Formula ____Per mole__ gas pound gallon gm kcal kJ Gasoline 11.528 100 20.750 128 6.152 Kerosene 11.006 95.5 19.810 135 6.822 Ethanol 7.12 61.8 C2H5OH 46 327.6 1366.8 Methanol 5.34 46.3 CH3OH 32 170.9 726.1 Denatured 6.456 56.0 11.620 79.4 6.836 Alcohol LNG 22.8 30.8 1.35 Hydrogen .0339 29.8 0.26 H2 2 285.8
If your computer does not produce a readable table, try clicking
here. Your BACK button will return you here.
Source of oil - Energy kcal/g - - - Source of oil - Energy kcal/g Cottonseed 9.50 Olive 9.40 Linseed 9.43 Rape seed 10.00
Of these, jojoba is native to the deserts of California and Mexico. Oil palm is native to
West Africa and grown on South Sea islands (such as Fiji) where immense tracts of land
are being cleared to plant palms.) Hemp, flax, kenaf and jute are commercial sources of
fiber; opium production should be convertible to oil.
Source of oil - US gal/acre - - - Source of oil - US gal/acre - - - Source of oil - US gal/acre> corn (maize) 18* oats 23 kenaf 29 cotton 35 hemp 39 soybeans 48 linseed (flax) 51 mustard 61 safflower 83 rice 88 cocoa (cacao) 110 peanuts 113 opium poppy 124 rapeseed 127 jojoba 194 avocado 282 coconut 287 oil palm 635
soybean oil on
the commodity market sells by the pound;
at a specific gravity
(15o/15o) of .924-.927 and using water at 8.328
lb/gal(15o) as reference, there is 7.695-7.720 lb/gal -- use 7.71 as
an average.
At today's (5/10/04) $0.34/lb that is $2.62/gal, compared with
(wholesale) $1.00/gal for #2 heating oil and $1.33/gal for unleaded gasoline.
Clearly costs must be greatly reduced to make soybean oil competitive with petroleum
distillates. (I have received information during a web search that hemp seed oil should
be available at some $0.77 per gallon.) A recent TV program indicated 1.4 gallons
of oil may be produced from a bushel of soy seeds.
**Handbook values are presented in a variety of units, so it is difficult
to compare fuels in useful terms. I have undertaken some conversions for comparison.
Conversion units are listed at the end of this essay.Note critical temperatures and pressures, esp 1st 3 fuels Fuel** Critical Formula ___Per mole___ BTU per vapor_pres oC psi gm kcal kJ cuft 760 mm @ Natural gas* -82.5 673
Hydrogen -240 188 H2 2 285.8 319 Methane -83 667 CH4 16 211 890.8 ~950 -161.5oC Ethane +32 706 C2H6 30 1560.7 1700 -88.6oC Propane 97 616 C3H8 44 526.3 2465 Butane 152 551 C4H10 58 2877.6 3200 *Per cent methane varies well by well, some are rich in propane; vehicles typically charged to 3000-3600 psi
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In the international scheme, energy (or work or heat) is measured in joules (J) and
power is measured in watts (W). Both units being small, it is easier in practice
to use the prefix "kilo (k)," which is 1000 times larger. As a unit of energy
the calorie (cal) has been so widely used that it is included (as kcal).
Power is the rate at which energy is expended, so energy is power expended
multiplied by duration of its expenditure.
Arithmetically, anything multiplied or divided by unity (or 1) is unchanged.
To use these conversions, make a fraction of two equal values (carrying along the
units); multiply the quantity being converted by that fraction, cancelling
units to be sure you have an accurate conversion
1 kJ = 1 kW-sec = 0.948 BTU = 0.239 kcal
1 kW = 1 kJ/sec = 1.341 hp = 293 BTU/hr = 0.239 kcal/sec
1 kcal = 3.967 BTU = 4.186 kJ = 0.001163 kW-hr
1 kW-hr = 3412 BTU = 3600 kW-sec
1 liter = 1.057 qt = 0.264 gal = 0.0284 bu, or 1 gal = 3.788 liters = 0.1337 cuft = 0.1076 bu
1 cuft = 7.481 gal or 1 cu m = 1000 liters
1 lb = 454 g or 1 kg = 2.203 lb
1 mi = 1.609 km or 1 in = 2.54 cm or 1 m = 39.37 in
1 acre = 0.4047 hectare (ha)
1 quad = 1015 BTU
Specific gravity (SpGr) is the ratio of weight of a
liquid to that of water, measured at one temperature but reported at a reference
temperature. Water at 15oC of 8.328 lb/gal is taken as reference.
SpGr times density of water yields density of the liquid. Thus
SpGr(Xo/15oC) times 8.328(15oC) yields
weight per gallon in pounds of the liquid at 15oC.
Mole: For each element
in the formula, multiply its atomic weight by the number of atoms in the formula;
add them together. That number of grams is one gram-mole; and that number of
pounds is one lb-mole.
STP: Standard Temperature and Pressure: At a temperature of the ice point of
water (0oC) and a pressure of 1 atm (14.7 psi)
A perfect gas at STP occupies 22.4 liters per gram-mole. While few gases are
perfect near their boiling points, it is a useful approximation and, well above the boiling
point is quite correct.
Absolute temperatures: To degrees Fahrenheit add 460 to get degrees Rankin. To
degrees Celsius (or Centigrade) add 273 to get degrees Kelvin.
Critical temperature: The temperture above which a gas cannot be liquified
regardless of pressure
Critical pressure: Equilibrium pressure at critical temperature so gas and liquid
can coexist; at lower pressure it cannot exist as a liquid
Critical temperature and pressure: For the gas to exist in the liquid state, it must
be at a temperature below critical and a pressure above critical.