Quote:
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Originally Posted by dgg9
The fact remains that none of the boutique power sources can produce appreciable amounts of energy. The one form of energy that CAN compete with fossil fuels -- nuclear -- is OPPOSED by the Marxist Greens. Go figure.
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I back safe Nuclear Power Plants...... there are a few which have been in operation for many years..... and with proper safety procedures they are very safe.... though Nuclear is not the only end all and be all replacement of fossil fuels.... check this out
YDROGEN ENERGY SYSTEM:
A PERMANENT SOLUTION TO GLOBAL PROBLEMS
T. Nejat Veziroglu
Clean Energy Research Institute
University of Miami, Coral Gables, FL 33124, USA
Summary:
Fossil fuels (i.e., petroleum, natural gas and coal), which meet most of the world’s energy demand today, are being depleted rapidly. Also, their combustion products are causing global problems, such as the greenhouse effect, ozone layer depletion, acid rains and pollution, which are posing great danger for our environment, and eventually, for the total life on our planet. Many engineers and scientists agree that the solution to all of these global problems would be to replace the existing fossil fuel system with the Hydrogen Energy System. Hydrogen is a very efficient and clean fuel. Its combustion will produce no greenhouse gases, no ozone layer depleting chemicals, and little or no acid rain ingredients and pollution. Hydrogen, produced from renewable energy (solar) sources, would result in a permanent energy system which we would never have to change.
However, there are other energy systems proposed for the post-petroleum era, such as a synthetic fossil fuel system. In this system, synthetic gasoline and synthetic natural gas will be produced using abundant deposits of coal. In a way, this will ensure the continuation of the present fossil fuel system.
The two possible energy systems for the post-fossil fuel era (i.e., solar hydrogen energy system and synthetic fossil fuel system) are compared with the present fossil fuel system by taking into consideration production costs, environmental damages and utilization efficiencies. The results indicate that the solar hydrogen energy system is the best energy system to ascertain a sustainable future.
The paper is presented in a question/answer format.
Question 1: What are the energy related global problems:
Answer 1:
Soon after the invention of the steam engine in the 1860’s, when the Industrial revolution started to replace human and beast toil with nature’s energy sources, a bright future seemed to be certain for humankind. More and more of nature’s energy, initially in the form of wood and coal, and later as oil and natural gas, were being harnessed for the benefit of humans. This resulted in the mass production of goods, with a corresponding reduction in prices and rising living standards.
Communities asked for factories, railroad, highways, seaports and airports. These meant more jobs, income, goods and services. The world’s standard of living was rising. When the Industrial revolution started, the annual gross world product per capita was in tens of dollars; today, it is $6,600 and rising exponentially.
Fossil fuels, which fed this amazing economic growth, were the medicine to cure deprivation. But it was an untested medicine at that. As planet Earth consumed more and more fossil fuels, two important predicaments started to emerge: (1) the fossil fuels would be depleted in a foreseeable future, and (2) the fossil fuels and their combustion products were causing global environmental problems.
Depletion of Fossil Fuels
The demand for energy continues to rise because of two main reasons: (a) the continuing increase in world population, and (b) the growing demand by the developing countries in order to improve their living standards. At the present time, a large portion (about 70%) of the world energy demand is met by the fluid fossil fuels (i.e., petroleum and natural gas) because of their availability and convenient use. However it is expected that the world fluid fossil fuel production will soon peak, and thereafter begin to decrease [1-4]. Figure 1 shows estimates of the production rates of the fossil fuels and the world demand. It can be seen that the fluid fossil fuel (petroleum and natural gas) production worldwide will continue to rise for the next 15 years, and then will start to decrease. The coal production, du to environmental reason, is expected to remain nearly constant for the next decade, and then start to decrease.
In the meantime, as a result of the growing world population and the desire of the people to better their living standards, the world demand for fluid fuels is rising (Fig. 1). It is expected that the world population growth (which is 5.88 billion at the moment and rising at a rate of 1.55 per year) will slow down and reach about ten to twelve billion by the end of the next century [5]. Consequently, the world demand for fluid fuels will slow down and reach around 1.6 x 1012 GJ per year. There will be a growing gap, starting within the next ten years, between the demand and production of fluid fuels.
Numbers in square brackets refer to references listed at the end of the paper.
"1 GJ of energy is approximately equal to the energy contained in 3.4 gallons of petroleum
Figure 1. Estimates of World Fossil Fuel Production.
Environmental Damage
The second predicament involving the fossil fuels is the environmental damage being caused by the fossil fuels and their combustion products. Technologies for fossil fuel extraction, transportation, processing and particularly their end use (combustion), have harmful impact on the environment, which cause direct and indirect negative effects on the economy. Excavation of coal devastates the land, which has to be reclaimed and is out of use for several years. During the extraction, transportation and storage of oil and gas, spills and leakages occur, which cause water and air pollution. Refining processes also have an environmental impact. However, most of the fossil fuel environmental impact occurs during the end use. The end use of all fossil fuels is combustion, irrespective of the final purpose (i.e., heating, electricity production or motive power for transportation). The main constituents of fossil fuels are carbon and hydrogen, but also some other ingredients, which are originally in the fuel (e.g., sulfur), or are added during refining (e.g., lead, alcohols). Combustion of the fossil fuels produces various gases which are all released into the atmosphere and cause air pollution. Air pollution may be defined as the presence of some gases and particulates which are not a natural constituent of the atmosphere, or even the presence of the natural constituents in an abnormal concentration. Air pollution causes damage to human health, animals, crops, structures, reduces visibility, etc.
Once in the atmosphere, triggered by sunlight or by mixing with water and other atmospheric compounds, these primary pollutants may undergo chemical reactions, change their form and become secondary pollutants, like ozone, aerosols, peroxyacyl nitrates, various acids, etc. Precipitation of sulfur and nitrogen oxides, which have dissolved in clouds and in rain droplets to form sulfuric and nitric acids is called acid rain; but also acid dew, acid fog and acid snow have been recorded. Carbon dioxide in equilibrium with water produces weak carbonic acid. Acid deposition (wet or dry) causes soil and water acidification, resulting in damages to the aquatic and terrestrial ecosystems, affecting humans, animals vegetation and structures.
The remaining products of combustion in the atmosphere, mainly carbon dioxide, together with other so-called greenhouse gases (methane, nitrogen oxides and chlorofluorocarbons), result in thermal changes by absorbing the infrared energy the earth radiates into the atmosphere, and by re-radiating some back to earth, causing global temperatures to increase. The effects of the temperature increase are melting of the ice caps, sea level rise and climate changes, which includes heat waves, droughts, floods, stronger storms, more wildfires, etc.
Using the studies of scores of environmental scientists, the above stated damages have been calculated for each of the fossil fuels[6]. Table 1 presents the results for each type of damage, in 1998, U. S. dollars. It can be seen that the environmental damage for coal in 1998 is $14.51 per GJ of coal consumed; for petroleum in 1998, $12.52 per GJ of petroleum consumed; for natural gas in 1998, $8.26 per GJ of natural gas consumed, and the weighted mean damage in the world is 1998, $12.05 per GJ of fossil fuel consumption. These damage costs are not included in the prices of fossil fuels, but are paid for by the people, directly or indirectly, through taxes, health expenditures, insurance premiums, and through a reduced quality of living. In other words, today fossil fuels are heavily subsidized. If the respective environmental damages were included in the fossil fuel prices, it would force earlier introduction of cleaner fuels, such as hydrogen, with many benefits to the economy and the environment.
In order to see the worldwide dimensions of the fossil fuel environmental damage, Table II has been prepared. It can be seen that 37% of the total damage is caused by coal while the coal consumption is 31% of the total fossil fuel consumption. On the other hand, only 20% of the damage is caused by natural gas, which has a market share of 29%. It is clear that increasing the natural gas consumption, at the expense of coal and petroleum, would be environmentally beneficial. This would also prepare the way for greater public acceptance of gaseous fuels, which would result in a smoother changeover to hydrogen, also a gaseous fuel.
Table 1. Environmental Damage Caused by Each of the Fossil Fuels
Type of Damage (n)
Environmental Damage 1998 $ per GJ
Coal
Petroleum
Natural Gas
Itemized
Damage
Sub-
Totals
Itemized
Damage
Sub-
Totals
Itemized
Damage
Sub-
Totals
Effect on Humans 5.16 4.19 3.09
Premature deaths 1.75 1.42 1.05
Medical expenses 1.75 1.42 1.05
Loss of working efficiency 1.66 1.35 0.99
Effect on animals 0.75 0.63 0.45
Loss of domestic live stock 0.25 0.21 0.15
Loss of wildlife 0.50 0.42 0.30
Effect on Plants and Forest 1.99 1.61 1.20
Crop yield reduction – ozone 0.25 0.21 0.15
Crop yield reduction – acid rains 0.13 0.10 0.07
Effect on wild flora (plants) 0.77 0.62 0.46
Forest decline (economic value) 0.27 0.22 0.16
Forest decline (effect on biological diversity) 0.53 0.43 0.33
Loss of recreational value 0.04 0.03 0.03
Effect on aquatic ecosystems 0.26 1.55 0.16
Oil spills 0.26 1.55 0.16
Underwater tanks leakages 0.90
Liming lakes 0.04 0.03 0.03
Loss of fish population 0.04 0.03 0.03
Effect on biological diversity 0.18 0.15 0.10
Effect on man-made structures 1.66 1.34 0.983
Historical buildings and monument degradation 0.18 0.15 0.10
Detriment to building and houses 0.37 0.30 0.22
Steel construction corrosion 0.99 0.80 0.59
Soiling of clothing, cars, etc. 0.12 0.09 0.07
Other air pollution costs 1.45 1.16 0.88
Visibility reduction 0.30 0.23 0.18
Air pollution abatement costs 1.15 0.93 0.70
Effect of strip mining 0.73
Effect of climactic changes 2.04 1.66 1.22
Heat waves – effects on humans 0.27 0.22 0.16
Droughts
Agricultural losses 0.16 0.13 0.10
Livestock losses 0.13 0.10 0.07
Forest losses 0.16 0.13 0.10
Wild flora and fauna losses 0.93 0.75 0.56
Water shortage and power production problems 0.25 0.21 0.15
Floods 0.07 0.06 0.04
Storms, hurricanes, tornadoes 0.07 0.06 0.04
Effect of sea level rise 0.47 0.38 0.28
TOTALS 14.51 12.52 8.26
Table II. Worldwide Fossil Fuel Consumption and Environmental Damage for 1998.
Fossil Fuel Consumption
World coal consumption
World petroleum consumption
World natural gas consumption
World fossil fuel consumption
(1018 J per year)
112
148
105
365
Environmental Damage Estimate
Damage due to coal
Damage due to petroleum
Damage due to natural gas
Total Damage
(1998 billion $)
1,625
1,853
867
4,345
Demographic and economic data
World population (in billions)
Damage per capita
World GWP (billion $)
GWP per capita
Damage/GWP
5.96
$ 730.00
$39.340.00
$ 6,600.00
0.11
It can also be seen from Table II that the annual worldwide environmental damage caused by fossil fuels in 1998 is $4,345 billion, or equal to 11% of the gross world product. This is a very large figure. Conversion to a cleaner fuel, such as hydrogen, would enable the world to save this enormous sum, and perhaps use it to improve the quality of life worldwide.
Question 2: What is the Hydrogen Energy System?
Answer 2:
Because of the foregoing, energy researchers are looking at the possible sources of energy to replace the fossil fuels. There are quite a number of primary energy sources available, such as thermonuclear energy, nuclear breeders, solar energy, wind energy, hydropower, geothermal energy, ocean currents, tides and waves.
At the consumer, end, about one-quarter of the primary energy is used as electricity and three-quarters as fuel. The above mentioned primary energy sources must, therefore, be converted to these energy carriers needed by the consumer. In contrast with the fossil fuels, none of the new primary energy sources can be used directly as a fuel, e.g., for air transportation, land transportation. Consequently, they must be used to manufacture a fuel or fuels, as well as to generate electricity.
Since we need to manufacture a fuel for the post fossil fuel era, we are in a position to select the best possible fuel. There are many candidates, such as synthetic gasoline, synthetic natural gas (methane), methanol, ethanol and hydrogen. The fuel of choice must satisfy the following conditions [7]:
It must be convenient fuel for transportation.
It must be versatile or convert with ease to other energy forms at the user end.
It must have high utilization efficiency.
It must be safe to use.
In addition, the resulting energy system must be environmentally compatible and economical.
Transportation Fuel
Surface vehicles and airplanes must carry their fuel for a certain distance before replenishing their fuel supply. In the case of space transportation, the space vehicles must carry their fuel, as well as the oxidant necessary for their scheduled range. Therefore, ti is important that the transportation fuel be as light as possible and also take as little space as possible. We can combine these requirements in a dimensionless number, termed the motivity factor [8]:
(1)
where E is the energy generated by the fuel, M the mass of the fuel, V the volume of the fuel, and subscript h refers to hydrogen. The higher the motivity factor, the better the fuel for transportation. Table III lists the pertinent properties of some fuels, as well as the motivity factors calculated using Equation (1). It can be seen that among the liquid fuels, LH2 has the best motivity factor, while methanol has the lowest motivity factor. Among the gaseous fuels, GH2 has the best motivity factor.
Consideration of the utilization efficiency advantage of hydrogen further improves hydrogen’s standing as the best transportation fuel. Of course, this is one of the reasons why hydrogen is the fuel of choice for the space programs around the world, even though presently, it is more expensive than fossil fuels.
Versatility
At the user end, all fuels must be converted through a process (such as combustion) to other forms of energy, e.g., thermal energy, mechanical energy and electrical energy. If a
fuel can be converted through more than one process to various forms of energy at the user end, it becomes more versatile and more convenient to utilize. Table IV lists various fuels and processes by which they can be converted to other forms of energy at the user end. It can be seen that all the fuels, except hydrogen, can be converted through one process only; that of combustion. Hydrogen, however, can be converted to other forms of energy in five different ways; i.e., in addition to flame combustion, it can be converted directly to steam, converted to heat through catalytic combustion, act as a heat source and/or heat sink through chemical reactions, and converted directly to electricity through electrochemical processes [9]. In other words, hydrogen is the most versatile fuel.
Table III. Energy Densities (HHV) and Motivity Factors for Liquid and Gaseous Fuels
Fuel
Chemical
Formula
Energy per unit
Mass
J/kg
Energy per unit
Volume
J/m
Motivity Factor
f M
Liquid fuels
Fuel oil
Gasoline
Jet fuel
LPG
LNG
Methanol
Ethanol
LH2
C£ 20 H£ 42
C5-10 H12-22
C10-15H22-32
C3-4H8-10
~CH4
CH3OH4
CH2H5OH
H2
45.5
47.4
46.5
48.8
50.0
22.3
29.9
141.9
38.65
34.85
35.30
24.40
23.00
18.10
23.60
10.10
0.78
0.76
0.75
0.62
0.61
0.23
0.37
1.00
Gaseous Fuels
Natural gas
GH2
~CH4
H2
50.0
141.9
0.040
0.013
0.75
1.00
Table IV. Versatility (convertibility) of Fuels
Conversion Process Hydrogen Fossil Fuels
Flame combustion
Direct steam production
Catalytic combustion
Chemical conversion (Hydriding)
Electrochemical conversion (Fuel Cells)
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
Utilization Efficiency
In comparing the fuels, it is important to take into account the utilization efficiencies at the user end. For utilization by the user, fuels are converted to various energy forms, such as mechanical, electrical and thermal. Studies show that in almost every instance of utilization, hydrogen can be converted to the desired energy form more efficiently than other fuels [6].
Table V presents the utilization efficiency factors, defined as the fossil fuel utilization efficiency divided by the hydrogen utilization efficiency, for various applications. It can be seen that hydrogen is the most efficient fuel. This results in conservation of resources, in addition to conserving energy.
Table V. Utilization Efficiency Comparisons of Fossil fuels and Hydrogen
Application
Utilization Efficiency Factor
Thermal Energy
Flame Combustion
Catalytic Combustion
Steam Generation
1.00
0.80
0.80
Electric Power, Fuel Cells
0.54
Surface Transportation
Internal Combustion Engines
Fuel Cells/Electric Motor
0.82
0.40
Subsonic Jet Transportation
0.84
Supersonic Jet Transportation
Weighted Average
Hydrogen Utilization Efficiency Factor
Fossil Fuel Utilization Efficiency Factor
0.72
0.72
1.00
0.72
Safety
The safety aspects of fuels involve their toxicity on one hand and the fire hazard properties on the other. In addition to the toxicity of their combustion products, the fuels themselves can be toxic. The toxicity increases as the carbon-to-hydrogen ratio increases. Hydrogen and its main combustion product, water or water vapor, are not toxic. However, Nox, which can be produced through the flame combustion of hydrogen (as well as through the combustion of fossil fuels) displays toxic effects.
Table VI lists the characteristics of fuels related to fire hazards. Lower density makes a fuel safer, since it increases the buoyancy force for speedy dispersal of the fuel in case of
a leak. For the same reason, higher diffusion coefficients are helpful. Higher specific heat causes a fuel to be safer, since it slows down the temperature increases for a given heat input. Wider ignition limits, lower ignition energies, and lower ignition temperatures make the fuels less safe, as they increase the limits in which a fire could commence. Higher flame temperature, higher explosion energy, and higher flame emissivity make a fuel less safe as well, since its fire would be more damaging.
Table VII compares the safety of fuels. For each of the toxic element and fire hazard characteristics, it ranks the fuels from 1 to 3; 1 being the safest and 3 the least safe. These rankings have been summed up for each fuel in order to arrive at an overall ranking. The total rankings have been prorated to obtain the safety factors, defined as the ratio of the total ranking for hydrogen to that of a given fuel. It can be seen that hydrogen becomes the safest fuel, while gasoline is the least safe; methane being in between the two.
Table VI. Characteristics Related to Fire Hazard of Fuels
Property
Gasoline
Methane
Hydrogen
Density3 (Kg/M
Diffusion Coefficient In Air3 (Cm2/Sec)
Specific Heat at Constant Pressurea (J/Gk)
Ignition Limits In Air (vol %)
Ignition Energy In Air (Mj)
Ignition Temperature (oC)
Flame Temperature In Air (oC)
Explosion Energyb (G TNT/kj)
Flame Emissivity (%)
4.40
0.05
1.20
1.0 – 7.6
0.24
228 – 471
2197
0.25
34 -43
0.65
0.16
2.22
5.3 - 15.0
0.29
540
1875
0.19
25 -33
0.084
0.610
14.89
4.0 - 75.0
0.02
585
2045
0.17
17 -25
a At normal temperature and pressure.
b theoretical maximum; actual 10% of theoretical.
The Best Fuel
When we look at the fuel options critically under the criteria given above, it becomes clear that hydrogen is the best transportation fuel, the most versatile fuel, the most efficient fuel and the safest fuel. In summary, hydrogen is the best fuel.
Hydrogen Energy System
As a result of the above discussion, it becomes clear that it would be expedient to manufacture hydrogen using any and al primary energy sources, in order to make up for their shortcomings. Such an energy system is then called the "Hydrogen Energy System".
Table VII. Safety Ranking of Fuels
Charactristic
Fuel Ranking3
Gasoline
Methane
Hydrogen
Toxicity Of Fuel
Toxicity Of Combustion
Density
Diffusion Coefficient
Specific Heat
Ignition Limit
Ignition Energy
Ignition Temperature
Flame Temperature
Explosion Energy
Flame Emissivity
3
2`
1
3
2
2
3
2
1
3
2
1
3
2
1
1
2
3
2
1
3
3
2
Q
3
1
2
3
2
1
3
2
1
Totals
30
20
16
Safety factor f s
0.53
0.80
1.00
a 1, safest; 2, less safe; 3, least safe.
Figure 2. A Schematic Diagram of Hydrogen Energy System.
Fig 2 presents a schematic diagram of the proposed hydrogen energy system. In this system, hydrogen (and oxygen) is produced in large industrial plants where the energy source (solar, nuclear, and even fossil) and water (H2O), the raw material, are available. For large scale storage, hydrogen can be stored underground in ex-mines, caverns and/or aquifers. Hydrogen is then transported, b means of pipelines or super tankers, to energy consumption centers. It is then used in electricity, transportation, industrial, residential and commercial sectors as a fuel and/or an energy carrier. The by-product is water or water vapor. If flame combustion of hydrogen is used, then some NOx is also produced. Water and water vapor is recycled back, through rain, rivers, lakes and oceans, to make up for the water used in the first place to manufacture hydrogen.
The oxygen produced in the industrial plant making hydrogen could either be released into the atmosphere, or could be shipped or piped to industrial and city centers for use in fuel cells (instead of air) for electricity generation. This would have the advantage of increasing the utilization efficiency. The oxygen could be used by industry for non-energy applications, and also for rejuvenating the polluted rivers and lakes, or speeding up sewage treatment.
It should be noted that in the hydrogen energy system, hydrogen is not a primary source of energy. It is an intermediary or secondary form of energy, or an energy carrier. Hydrogen complements the primary energy sources, and presents them to the consumer in a convenient form at the desired location and time.
Details of the hydrogen energy system, including production, storage, transportation, distribution, utilization, environmental impact and economics, can be found in the proceedings of the THEME and the World Hydrogen Energy Conferences [10-21].
Question 3: Which are the competing energy systems?
Answer 3:
Essentially, there are three contending energy systems: (1) the present fossil fuel system, (2) the coal/synthetic fossil fuel system, and (
the solar hydrogen energy system, which is a special case of the hydrogen energy system.
Fossil Fuel System
A simplified version of today’s energy system is shown in fig. 3. Fossil fuels are used for transportation (mostly petroleum products), for heat generation in residential, commercial and industrial sectors, and for electric power generation. For transportation, mostly petroleum products are used (gasoline, diesel fuel, jet fuel, etc.). Heat generation includes space heating, domestic water heating, cooking steam generation and direct heating and/or drying in various industrial processes. All three forms of fossil fuels are used for these purposes. In electric power generation, coal is used mainly for the base load generation, and natural gas and heating oil are used for peak load. Part of the electric power is produced by hydro and nuclear power.
Figure 3. Fossil Fuel System
In comparing hydrogen with other energy systems, it can be assumed 40% of primary energy (in fossil fuel equivalent units) will be used for thermal energy generation. Thirty percent of electric power generation, and 30% for transportation 92/3 for surface transportation and 1/3 for air transportation) [22]. Energy supplied by hydro and nuclear power plants (mostly in the form of electric power) and by other non-fossil fuel sources do not have to be taken into account, since it is assumed that it will be the same for all three considered systems. Actually, it is reasonable to expect that in the future even more electrical energy will be supplied by these sources.
When one considers the early 2000’s, it can be expected that about one half of the thermal energy will be supplied by natural gas, and the rest by petroleum fuels (fuel oil and residual oil) and coal. Coal is assumed to be the main energy source for electricity generation, gasoline for surface transportation and jet fuel for air transportation. This is, of course, a simplified version of the fossil fuel energy system, but it is close enough to the present patterns of energy consumption, and can be used as the basis for comparisons.
Coal/Synthetic Fossil Fuel System
Reserves of fossil fuels are finite, particularly those of oil and natural gas. Known reserves of oil and natural gas are about 8,000 EJ (1EJ-1018J), which would be enough for the next 40 years at the current consumption rate [12]. If the exponential population growth and the demand growth were taken into account, they would only last about 25 years. Even if the estimated additional undiscovered resources were added, this would satisfy energy needs for fluid fuels only an additional 30 years or so. Coal reserves are much larger; known reserves are about 20,000 EJ, but estimated, ultimately recoverable resources add up to 150,000 EJ. These large amounts of coal could eventually be used to produce synthetic liquid fuels, allowing society to continue employing the present energy system. Such a system is called the coal/synthetic fossil fuel system, since coal is to be used to manufacture synthetic fossil fuels, as well as to be directly used for electricity generation.
In this case, it can be assumed that the present fossil fuel system will be continued by he substitution of synthetic fuels derived from coal wherever convenient and/or necessary. Patterns of energy consumption are also assumed to be unchanged (see Fig. 4). Coal will be used extensively for thermal power generation and for electric power generation because it is less expensive than synthetic fuels. However, some end-uses require fluid fuels. Therefore, it has been assumed that synthetic natural gas (SNG) will be used for some thermal energy generation (primarily in the residential sector) and also as fuel for surface transportation, where it will share the market with synthetic gasoline. Synthetic jet fuel will be used in air transportation.
Figure 4. Coal/Synthetic Fossil Fuel System
Solar Hydrogen Energy System
If solar energy in its direct and/or indirect forms (e.g., hydro, wind, etc.), is used to manufacture hydrogen, then the resulting system is called "solar hydrogen energy system". In this system, both the primary and secondary energy sources are renewable and environmentally compatible, resulting in a clean and permanent energy system. Fig. 5 presents a schematic of the solar hydrogen energy system.
In this case it is assumed that the conversion to the hydrogen energy system will take place, and one-third of the hydrogen needed will be produced from hydropower (and/or wind power) and two-thirds by direct and indirect (other than hydropower) solar energy forms. The same percentage of energy demand sectors as the above systems will be
assumed. It will further be assumed that one half of the thermal energy will be achieved by flame combustion, one quarter by steam generation with hydrogen/oxygen steam generators, and the last quarter by catalytic combustion. Electric power will be generated by fuel cells; one-half of the surface transportation will use gaseous hydrogen burning in internal combustion engines, and the other half will fuel cells. In air transportation, both subsonic and supersonic liquid hydrogen will be used.
Question 4: How do the environmental effects of the different energy alternatives compare?
Answer 4:
It may be best to divide the answer to this question into three parts, viz., pollution, vapor generation and environmental damage.
Pollution
Table VIII lists the pollutants for the three energy systems described. It can be seen that the coal/synthetic fossil system is the worst from the environmental point of view, while the solar-hydrogen energy system is the best. The solar-hydrogen system will not produce any CO2, C, Sox, hydrocarbons or particulates, except some NOx. However, the solar-hydrogen-produced NOx is much less than that produced by the other energy systems. This is due to the fact in the solar hydrogen energy system only the flame combustion of hydrogen in air will generate NOx. The other utilization processes (such
as direct steam generation, use of hydrogen in fuel cells, hydriding processes, etc.) will not produce any NOx .
Table VIII. Pollutants Produced by Three Energy Systems
Pollutant
Fossil fuel
System
(kg/GJ)
Coal/Synthetic
Fossil System
(kg/GJ)
Solar-Hydrogen
System
(kg/GJ)
CO2
CO
SO2
NOX
HC
PM*
72.40
0.80
0.38
0.34
0.20
0.09
100.00
0.65
0.50.
0.32
0.12
0.14
0
0
0
0.10
0
0
*Particulate Matter
Vapor Generation
There is a notion that the hydrogen energy system would produce more water vapor than the other energy systems, since the fuel is pure hydrogen. When one considers the problem in detail, this is not so.
Only the flame combustion of fuels in air or in oxygen will produce water vapor. In the case of hydrogen, those other processes mentioned earlier will not produce any water vapor. Consequently, contrary to the popular belief, the solar-hydrogen energy system will produce less water vapor than the other systems.
Global warming, which is caused by the utilization of fossil fuels, also causes an increase in water vapor generation. Assuming that earth’s mean temperature has increased by 0.5o C since the beginning of the Industrial Revolution [24], this additional water vapor generation and that produced by the combustion of fuels have been calculated. The results are presented in table IX. It can be seen that (1) the two fossil fuel systems generate much more additional (above normal) water vapor than the solar hydrogen energy system, (2) the additional water vapor generated by global warming is much greater than that produced by the combustion of fuels, (
the amount of water vapor generated by fuels is minimal compared to that generated normally, and (4) the solar-hydrogen system causes the smallest increase in vapor generation. Again, when the additional vapor generation is considered, the solar-hydrogen system becomes environmentally the most compatible system.
Table IX. Comparison of Vapor Generation by Three Energy Systems
Item
Unit Fossil
Fuel
System
Coal/Synthetic
Fossil System
Solar-Hydrogen
System
Annual Vapor Generation by Energy System
1012kg
8.9
9.300
6.0
Annual Vapor Generation Due to
Global Warming
1012kg
3,900
3,900,000
0
Total Vapor Generation Due to
Energy System & Global Warming
1012kg
3,900
3,900,00
6.0
Total vapor generation as fraction of that
Produced naturally
%
0.782
0.782
0.001
Note: Annual vapor generation due to solar heating is 5 x 1017 kg.
Environmental Damage
Table X presents the environmental damage per gigajoule of the energy consumed for each of the three energy systems considered and also for their fuel components in 1998, in US dollars, as well as environmental compatibility factors, defined as the ratio of the environmental damage due to the hydrogen-energy system to that due to a given energy system. The environmental damage for the solar-hydrogen energy system is due to the Nox produced. It can be seen that the solar-hydrogen energy system is environmentally the most compatible system.
It should be mentioned that hydrogen also has the answer to the depletion of the ozone layer, mainly caused by chlorofluorocarbons. Refrigeration and air-conditioning systems based on the hydriding property of hydrogen do not need chlorofluorocarbons, but need hydrogen, and any hydrogen leak would not cause ozone layer depletion. Such refrigeration systems are also very quiet, since they do not have any moving machinery.
Question 5: How do the economics of the different energy alternatives compare?
Answer 5:
The economical comparison between the competing energy systems should be based on the effective costs of the services that these fuels provide. The effective costs include the utilization efficiency, the cost of the fuel, and the costs associated with fuel consumption, but which are not included in its price (so-called external costs). External costs include the costs of the physical damage done to humans, fauna, flora and the environment due to harmful emissions, oil spills and leaks, and coal strip mining, as well as governmental expenditures for pollution abatement and expenditures for military protection of oil supplies.
Table X. Environmental Damage and Environmental Compatibility Factors
Energy System and Fuel Environmental Damage
(1998 $/GJ)
Environmental
Compatibility Factor, f E
Fossil Fuel System
Coal
Oil
Natural Gas
12.47
14.51
12.52
8.26
0.055
Coal/Synthetic Fossil System
Syn-Gas
SNG
15.46
20.34
13.49
0.044
Solar-Hydrogen Energy System
Hydrogen
0.68
0.68
1.000
In economic considerations, it is also important to compare the future costs of hydrogen (which will be considerably lower than they are today because of the assumed market and technology development), with fossil fuels, both internal and external, which, unavoidably, will be higher than today’s prices due to depletion, international conflicts and the environmental impact).
The effective cost of a fuel can be calculated using the following relationship:
(2)
Where Ci is the internal cost or the conventional cost of the fuel, Ce the external cost, including the environmental damage caused by the fuel h fk the fossil fuel utilization efficiency for application k, and h sk the synthetic fuel (including hydrogen) utilization efficiency for the same application, or the end use.
In order to evaluate the overall cost (Co) to society, the three scenarios considered earlier will be used. This cost can be calculated from the relationship
(
where a n is the fraction of energy used by the energy sector n, such as electricity generating, heat producing, surface transportation, subsonic air transportation, and supersonic air transportation. Since – is a fraction, their sum is
(4)
Substituting Eq. (2) for Eq. (
, one obtains
(5)
Using Eqs. (2)-(5), Tables XI-XIII have been prepared for the three energy scenarios, i.e., the fossil fuel system, the coal/synthetic fossil fuel system, and the solar-hydrogen energy system in 1998, in U.S. dollars. Comparing the results, it becomes clear that the solar-hydrogen energy system is the most cost-effective energy system, and results in the lowest effective cost to society.
Table XI. Effective Cost of Fossil Fuel System
Application Fuel Energy Consumption
Fraction
Effective Cost
(1998 U.S. $/GJ)
Thermal Energy
Natural Gas Petroleum Fuels
Coal
0.20
0.10
0.10
17.46
27.56*
17.75
Electric Power
Coal 0.30 17.25
Surface Transportation
Gasoline 0.20 31.61
Air Transportation
Jet Fuel 0.10 25.98
TOTAL OF FRACTIONS
1.00
OVERALL EFFECTIVE COST
22.11
*Average for residential and industrial sector.
Table XII. Effective Cost of Coal/Synthetic Fuel System
Application Fuel Energy
Consumption
Fraction
Effective Cost
(1998 U.S. $/GJ)
Thermal Energy
Coal
SNG
0.30
0.10
17.75
36.64
Electric Power
Coal 0.30 17.25
Surface Transportation
SNG
Syn-gasoline
0.10
0.10
36.64
51.65
Air Transportation
Syn-jet 0.10 45.45
TOTAL OF FRACTIONS
1.00
OVERALL EFFECTIVE COST
27.55
Table XII. Effective Cost of solar-Hydrogen Energy System
Application
Fuel3 Energy
Consumption
Fraction
Effective Cost
(1998 U.S. $/GJ)
Thermal Energy
Flame Combustion
Steam Generation
Catalytic Combustion
GH2
GH2
GH2
0.20
0.10
0.10
26.04
20.83
20.83
Electric Power
Fuel Cells
GH2 0.30 14.06
Surface Transportation
IC Engines
Fuel Cells
GH2
GH2
0.10
0.10
21.36
10.41
Air Transportation
Subsonic
Supersonic
LH2
LH2
0.05
0.05
26.26
22.51
TOTAL OF FRACTIONS
1.00
OVERALL EFFECTIVE COST
19.23
3It has been assumed that 1/3 of hydrogen will be produced from hydropower and/or windpower, and 2/3 from solar.
Question 6: What are the advantages of hydrogen and the solar-hydrogen energy system?
Answer 6:
As a result of the investigations presented above, it can be seen that hydrogen as a fuel and the solar hydrogen energy system have unmatched advantages as compared with fossil fuels and the fossil fuel system respectively.
Hydrogen
The advantages of hydrogen versus fossil fuels can be listed as follows:
Liquid hydrogen is the best transportation fuel when compared with liquid fuels such as gasoline, jet fuel and alcohols; and gaseous hydrogen is the best gaseous transportation fuel.
While hydrogen can be converted to useful energy forms (thermal, mechanical and electrical) at the user end through five different processes, fossil fuels can only be converted through one process, i.e., flame combustion. In other words, hydrogen is the most versatile fuel.
Hydrogen has the highest utilization efficiency when it comes to conversion to useful energy forms (thermal, mechanical and electrical) at the user end. Overall, hydrogen is 39% more efficient than fossil fuels. In other words, hydrogen will save primary energy resources. It could also be termed as the most energy conserving fuel.
When fire hazards and toxicity are taken into account, hydrogen becomes the safest fuel.
Solar Hydrogen Energy System
The advantages of solar hydrogen energy system versus the present fossil fuel system and synthetic fossil fuel system can be listed as follows:
When the environmental impact is taken into consideration, the solar hydrogen energy system becomes the most environmentally compatible energy system. It will not produce greenhouse gases, ozone layer damaging chemicals, oil spills, climate change and little or no acid rain ingredients and pollution. It will actually reverse the global warming and bring the earth back to its normal temperatures by decreasing the co2 in the atmosphere to its pre-industrial revolution level.
The solar hydrogen energy system has the lowest effective cost when environmental damage and higher utilization efficiency of hydrogen are taken into account. In
other words, the solar hydrogen energy system will cost society the least, when compared with the present fossil fuel system and the synthetic fossil fuel system.
Question 7: What can one do to help convert to the solar-hydrogen energy system?
Answer 7:
We must stand up and be counted, spread the news, write to the elected officials and help end the unfairness.
Spreading the News
The author of this paper cannot do much alone to spread the knowledge. Papers are read by a few thousand people, of whom a mere few hundred retain the knowledge for more than a few months.
To make any headway in a democratic system, there has to be political pressure. Our elected representatives and their aides have to know the views of the electorate. The most important thing a reader of this paper can do, therefore, is to spread the news that there is a cure for atmospheric pollution, acid rain and global warming. It is a new and revolutionary technology in which the sun’s energy are collected and used to produce hydrogen, a clean and storable fuel [25].
And how is this information to be spread? Well, it will depend on your circumstances, on your enthusiasm and on your degree of contact with other people. For example, where do you work? In a factory, an office, a communications center, a school? Wherever you work there is the possibility of talking to other people. They will not want their atmosphere polluted, poisoned and destroyed, but they are unlikely to do anything about it unless there are viable alternatives to the present energy system that delivers today’s standard of living. You can explain what these alternatives are. More than that, you can explain that the initiative for change will not come from the government; it has to come from you, the members of the public.
The next step then is to phone or pay a personal visit to your government representatives, who have to be re-elected every few years. They must be made aware that the people are willing to make their voices heard at the polls.
Further more, if the public knows that a viable alternative exists, a market for the solar-hydrogen energy system can then be established. And once industries realize a market is there, they will invest their money and effort toward creating what the public desires.
Writing to Your Elected Officials
Writing to your elected representatives is part of democracy; indeed, in many ways, apart from the ballot box, it is the main way that democracy works. Elected representatives have aides and assistants, and one of their purposes is to help the elected officials know what the public is saying. Eventually, politicians have to respond to their electorate’s wishes.
So, writing to the people you elect to office is good and helpful; you cannot do it too often. But keep the letter short and neat. One page is enough. Express a single idea per letter, and leave it at that. For example, you could suggest a carbon tax, or demand that polluters should pay.
Ending the Unfairness
We pride ourselves on being concerned with civil rights. But the truth is that air pollution violates everyone’s civil rights. It robs us of liberty; for there is nowhere on this planet we can go to be free of air pollution. Air pollution robs us of life; it is a murderer. But the ones who suffer most are those least able to defend themselves – the children, elderly and the poor.
Young children’s immune systems are still developing, and are not able to ward off respiratory ailments caused by unclean air. The elderly suffer the same symptoms, but for the opposite reason; their immune systems are aging and unable to cope as well as they once did to ward off diseases.
Perhaps the most disturbing of all is the polluted air that people in the inner cities and large suburban areas are forced to endure. Buses and trucks belching diesel fumes, exhaust gases being emitted from taxis, delivery vans and other vehicles as they wait at traffic lights, the waste fumes of small industries like dry cleaners and bakeries, large industries such as utility plants and steel or paper mills producing soot and ash; all these are examples of the pollution to which these people are subjected daily. They are the least able to afford to be sick, but are often afflicted with chronic respiratory ailments., For this is where the poor and homeless must live, since they are the least able to afford housing outside of the city. This then becomes their entombment.
It is time to end this dilemma. One way is by advocating the implementation of an ‘atmosphere users fee’ that would consider fully the social, or real cost of a product. These fees would then be collected and spent to develop clean, renewable energy for use in transportation, manufacturing and in our own homes, thereby giving everyone the quality of life to which they are entitled – air that is healthy to breathe, and an environment that is conducive to sustaining, not robbing individuals of life.
The solar-hydrogen energy system is an idea whose time has arrived. There can be no return. There is no doubt that it will prevail, and eventually, the good earth will have the energy system it deserves – a system that is supportive of its ecosystem and its inhabitants. But the ‘ball is in your court’. Let’s have it soar way beyond the horizon.
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) but the tables are fucked. Kinda makes me miss the comparisons. 
