Hsueh MF et al. Analysis of “old” proteins unmasks dynamic gradient of cartilage turnover in human limbs. Science Advances, October 2019.

Humans may not be able to regrow amputated limbs, but a recent study showed that damaged cartilage may regrow through a process similar to that of animals such as salamanders and zebrafish. Scientists collected 18 specimens of joint tissue from the hips, knees, or ankles of patients who underwent surgery. They then placed the tissue in a mass spectrometer and measured the age of the cartilage proteins in the sample. These analyses showed that the age of cartilage largely depended on where it resided in the body. Cartilage in ankles is young, middle-aged in the knee, and old in the hips. This correlation between the age of human cartilage and its location in the body suggests that limb repair occurs in humans in a similar fashion to certain animals in which tissue regeneration takes place at the furthest tips such as the ends of legs or tails. This finding also helps to explain why injuries to people’s knees and, especially, hips take a long time to recover and often develop into arthritis, while ankle injuries heal quicker and less often become severely arthritic. The researchers further identified the molecules that are instrumental in the regulation of this region-specific regeneration process. They are called microRNAs and, not surprisingly, are present at very high levels in animals that are known for limb, fin, or tail repair including salamanders, zebrafish, and lizards. Scientists believe that these regulator microRNAs can be utilized in the regeneration of degenerated cartilage of an arthritic joint to reverse arthritis. Regeneration of part or all of an injured human limb may even be possible by finding components salamanders have and we don’t. Finally, it is also possible that this could be a fundamental mechanism of repair that could be applied to many tissues, not just cartilage, which might open up many new avenues in the regenerative medicine.

The universe might have many Earth-like exoplanets

Doyle AE et al. Oxygen fugacities of extrasolar rocks: Evidence for an Earth-like geochemistry of exoplanets. Science, October 2019.

New astrophysical and geochemical evidence suggests that Earth may not be that unique, and Earth-like planets may be common in the universe. All of the planets in our solar system orbit around the Sun. Planets that orbit around other stars are called exoplanets.  The first exoplanets were discovered in the early 1990s. Since then, thousands of exoplanets have been revealed with over 4,000 confirmed and a further 4,495 potential candidates. There have been major efforts to narrow down the exoplanets that may have properties similar to Earth with conditions suitable for life. This includes being a rocky planet that is not too hot or cold so that liquid water can exist. When searching for exoplanets that are similar to Earth, astronomers typically look for worlds in orbit around a type of star called a red dwarf or an M-dwarf. These types of stars are somewhat similar to our sun and make up about 70% of the stars in our galaxy. However, a new study shows that rocky exoplanets in orbit around a different type of star, a white dwarf, can have interiors that are surprisingly similar to our planet. White dwarf stars are dense remains of normal stars that have exhausted their nuclear fuel. These stars are typically composed of light elements such as hydrogen and helium, but in some cases they attract heavier elements such as magnesium, iron, and oxygen in their atmospheres due to their extreme gravity. These heavy elements are thought to be introduced when a rocky exoplanet crashes into a star, which gives astronomers evidence of what the exoplanets were like before they were destroyed. In this recent study, scientists looked at six white dwarfs located 200 to 665 light-years from Earth and rocks from the planets that once orbited it. Their analyses showed that five out of the six white dwarfs had sucked up fragments whose chemical composition is similar to rocks on Earth, Venus, and Mars. While the conditions suitable for life depend upon many additional factors, this study points towards the idea that many rocky planets are likely very familiar in terms of their general composition and, therefore, structure and behavior. This study also made a substantial leap forward in being able to make inferences for bodies outside of our own solar system and indicates that it is very likely that there are truly Earth analogs out there.

Artificial leaf points to a sustainable path to carbon-neutral fuels

Andrei V et al. Bias-free solar syngas production by integrating a molecular cobalt catalyst with perovskite–BiVO4 tandems. Nature Materials, October 2019.

An artificial leaf from which a “clean” fuel alternative to petrol could be produced has been developed. Synthetic gas can be obtained from the lead by using only sunlight, carbon dioxide, and water.

Synthetic gas, also called syngas, is typically a mixture of carbon monoxide and hydrogen. It is largely produced by exposing fossil fuels such as coal or natural gas to high temperature steam and pressure, and the process releases carbon dioxide. Syngas is broadly used in a wide range of commodities including fuels, plastics, and fertilizers. While the utilization of fossil fuels has enabled large-scale industrial development in human history, the burning of fossil fuels is the largest source of emissions of carbon dioxide, which is one of the greenhouse gases that contributes to global warming. For decades scientists have been trying to discover new ways to produce syngas in order to close the global carbon cycle and to establish a sustainable chemical and fuel industry. In a recent study, researchers got inspired by leaves. These perfect little machines use sunlight to convert carbon dioxide and water into fuel for plants through photosynthesis. An artificial leaf has been designed to have two light absorbers, similar to the molecules in plants that harvest sunlight, and a catalyst made from the naturally abundant element cobalt. When the leaf is immersed in water, one light absorber uses the catalyst to produce oxygen and the other one carries out the chemical reaction that reduces carbon dioxide and water into carbon monoxide and hydrogen, thus forming the syngas mixture. The scientists are now searching for ways to use their technology to produce a sustainable liquid syngas that could serve as an alternative to petrol. Although major efforts to generate renewable energy sources are being made, the development of synthetic petrol is critical as electricity can currently fulfill about 25% of our total global energy demand. There is a huge demand for liquid fuels to power heavy transport, shipping, and aviation sustainably.

Artificial photosynthesis transforms CO₂ into liquefiable fuels

Yu and Jain. Plasmonic photosynthesis of C1–C3 hydrocarbons from carbon dioxide assisted by an ionic liquid. Nature Communications, May 2019.

Scientists have recently established a reliable “artificial photosynthesis” paradigm to produce fuels from water, carbon dioxide, and visible light. With the help of sunlight, chemical reactions between water and CO₂ are catalyzed in plants to generate and store solar energy in the form of glucose. This process is called photosynthesis. In the new study, the researchers developed an artificial process that uses the same mechanisms of natural photosynthesis to convert CO₂ and water into liquid fuel by using electron-rich gold nanoparticles as a catalyst. Gold nanoparticles function in the same role as chlorophyll in natural photosynthesis in the absorbing of light and transferring electrons and protons to catalyze the chemical reactions between CO₂ and water. They are known to be efficient at absorbing light and do not break down or degrade like other metals. The energy stored in the bonds of the hydrocarbon fuel can be freed by the conventional method of combustion or by new-generation, environmentally-friendly power fuel cells, thus producing electrical current. By converting CO₂ into more complex molecules like propane, green-energy technology is now one step closer to using excess CO₂ to store solar energy for use when the sun is not shining and in times of peak demand. While the development of this CO₂-to-liquid fuel may be exciting for proponents of green-energy technology, the artificial photosynthesis process is nowhere near as efficient as it is in plants. New methods should be developed to increase the efficiency of the catalysts and downstream chemical reactions at much higher scales.

Brain area that watches for walls identified

Henriksson et al. Rapid Invariant Encoding of Scene Layout in Human OPA. Neuron, May 2019.

Neuroscientists have identified the part of the human brain whose duty is to help us perceive the barriers which define the navigable space around us, such as walls or ceilings, so that so we can avoid bumping into things and navigate safely through our environment. By way of vision we have an almost instant sense of where we are in space. Although this process feels effortless, it requires the coordinated activity of multiple brain regions and neurons working together to give us this sense of our surroundings. This process has remained unknown. But thanks to a new study, we are a step closer to solving the puzzle. Using cutting-edge brain-imaging technologies, researchers examined the mental responses of volunteers as they were shown images of various three-dimensional scenes. The images depicted a typical room with three walls, a ceiling, and a floor, but then were abruptly changed by the removal of a wall or a ceiling. By doing this repeatedly, the team could pinpoint how the participant’s brain encoded every scene. In the brain scans of the volunteers, one brain area called the occipital place area (OPA) clearly stood out. OPA activity represented the geometry of the scenes and activity patterns, reflected the presence or absence of each component, such as a ceiling or a wall, and projected a detailed picture of the overall configuration. Interestingly, OPA seemed to ignore the surface appearance of the various components such as colors or textures in order to focus only on the geometric patterns. The OPA managed to perform all the necessary computations needed to get a sense of a room’s layout extremely fast – in just 100 milliseconds. In the future, the research team plans to incorporate virtual reality technology to create more realistic 3D environments for participants to experience, hopefully achieving much deeper insights into how our brains process and makes sense of the visual information.

Gut segments are organized by function

Esterházy D. et al. Compartmentalized gut lymph node drainage dictates adaptive immune responses. Nature, April 2019.

As food enters our intestine, it goes through a windy and lengthy journey. A new study provides new insights into how our intestines maximize nutrient uptake while protecting the body from potentially dangerous invading microbes. At first glance, the intestines appear to have a uniform tissue structure. But when scientists looked at them closer, they found that our food-processing canal seems to consist of multiple compartments that pace the immune system’s reactions to the food passing through. Scientists uncovered these functional intestine segments in mice when they examined the intestinal structures called gut draining lymph nodes, which orchestrate immune responses. The researchers found that nodes in different parts of the intestines had different cell composition, and they saw different immune responses between segments when they challenged the mice with a pathogen. They observed less aggressive defenses in the first segments where nutrients are absorbed, and more forceful responses at the end, where pathogens are eliminated. Researchers plan to exploit these immunological differences between the gut segments for treating gastrointestinal disorders. For example, by targeting immune-suppressing drugs to the specific gut segment where they’ll have the most effect, it might be possible to dampen their side-effects. The spectrum of immune responses along the intestines could also be used to make new and better oral vaccines. Thus far, scientists’ efforts to design oral vaccines have been hampered by the difficulty of generating a robust immune response; it is possible that the muted immune response at the beginning of the intestines might be part of the reason why oral vaccines tend to be less effective than injections. Thus, targeting the distant end of the intestine might be much more efficient way of inducing the immune response required.

Fuel cells are very promising chemical energy conversion devices. Though the first fuel cell was made by William Grove in 1839, they’re just now being explored as a real energy alternative (1). Let’s take a look at how they work: in a fuel cell, electricity is generated by the reaction of hydrogen and oxygen, which forms water. They are similar to batteries and internal combustion engines (ICEs): just as in a combustion engine, where fuel is oxidized, the oxidization of hydrogen generates energy. They’ll work as long as fuel is provided.

Despite these similarities there are some differences that make fuel cells more attractive than batteries and ICEs. A fuel cell works more efficiently and quietly than engines do. When hydrogen is used as fuel, power and drinking water are produced as by-products (2). Having safe by-products answers our concerns regarding older power sources. A battery is dead if it is not re-chargeable; however a fuel cell can be continually reused.

Fuel cells are generally defined by the type of electrolyte used in the cell, and they operate at different temperatures. Alkaline fuel cells (AFCs), proton exchange membrane fuel cells (PEMFCs), and direct methanol fuel cells (DMFCs) are called low-temperature fuel cells. Phosphoric acid fuel cells (PAFCs) are an intermediate-temperature fuel cell. Molten carbonate fuel cells (MCFCs) and solid oxide fuel cells (SOFCs) are called high-temperature fuel cells (3, 4).

They have been mainly used for stationary, transportation, and portable applications. Since the need for electricity in daily life has dramatically increased, reliable and efficient power supplies have become necessary. Over 2,000 stationary fuel cell systems have been built in hotels, schools, and hospitals. Stationary power generation is considered more commercialized among the other fuel cell applications. Today, these systems have reached an efficiency of 40% when a hydrocarbon is used as fuel. Fuel cell systems are also used in telecommunication systems, and these cells provide power between 1 and 5 kW (5).

Fuel cells have been identified as the most probable alternative power source for transportation applications in place of internal combustion engines (ICEs). There are two distinct features of fuel cells that make them a better choice than ICEs. First, their carbon dioxide gas emissions are nearly zero. Second, fuel cells are much more efficient than ICEs – about two to three times (6). Ballard Power Systems have been developing zero-emission-vehicles by using PEMFCs, which have low operating temperatures and a higher power density.

NASA decided to use fuel cells on American spacecrafts in the 1960s. The advantage of using them in spacecraft was that while they were generating electric power, they produced drinkable water for the astronauts. A fuel cell was used as an integral part of the power supply PEMFCs (1kW) in the Gemini crafts and AFCs (1kW) in the Apollo crafts, both of which were a part of NASA’s human spaceflight programs (6).

Portable applications of fuel cells offer electrical power when reaching the electrical grid is not possible. When they are used as power sources outdoors, they help to avoid air and noise pollution (4). Because these portable fuel cells are lighter and more durable than batteries, they have been considered as alternative power sources for mobile phones, laptop computers, and some electronic devices (5). They are also used by the military in battle. A 4 kW PEM generator was built for the U.S. military by Intelligent Energy Ltd., out of Europe (7). Since direct methanol fuel cell systems are much lighter than the indirect systems, they are mostly used as portable power systems.

Although fuel cells have benefits when compared to other power sources, they are not widely used because of their high cost. In 2010, the Energy Information Administration released that the cost of fuel cells is $6.83 per installed watt, which is almost 7 times more expensive than a natural-gas turbine generator plant (8). In 2008, the Honda Clarity produced one of the first hydrogen-powered automobiles; these require very expensive catalysts: platinum (9). A catalyst makes the chemical reactions occur faster. Platinum is still the best catalyst, so this explains the prohibitive cost. A cheaper substitute for platinum is needed for use in automobiles. Another problem is that hydrogen is widely used as fuel for transportation applications. Until there is a sufficient hydrogen infrastructure, car manufacturers will find it hard to mass produce cars that use fuel cells.

Cetin is a freelance science writer.

References

1. Grove, W. R. (1839). On voltaic series and the combination of gases by platinum. Philosophical Magazine and Journal of Science, Series 3,14, 127-130.
2. Hoogers, G. (2003). Fuel Cell Technology Handbook. Boca Raton, FL: CRC Press.
3. Mekhilef, S., Saidur, R., Safari, A. (2012). Comparative study of different fuel cell technologies. Renewable and Sustainable Energy Reviews 16, 981-989.
4. Gencoglu, M. T., Ural, Z. (2009). Design of a PEM fuel cell system for residential application. International Journal of Hydrogen Energy 34, 5242-5248.
5. Andujar, J., Segura, F. (2009). Fuel cells: History and updating. A walk along two centuries. Renewable and Sustainable Energy Reviews 13, 2309-2322.
6. Iovine, John. “Fuel Cells.(composition, energy-generating processes and industry developments and innovations).” Poptronics. Poptronix, Inc. 2001. Retrieved May 17, 2012 from High Beam Research: http://www.highbeam.com/doc/1G1-69015426.html
7. Cowey, K., Green, K., Mepsted, G., Reeve, R. (2004). Portable and military fuel cells. Current Opinion in Solid State and Materials Science 8, 367-371.
8. Administration, U. E. (2010, November). Updated Capital Cost Estimates for Electricity Generation Plants. Retrieved from http://205.254.135.24/oiaf/beck_plantcosts.
9. Muller, R. A. (2012). Energy for Future Presidents: The Science Behind The Headlines. New York: W.W. Norton Company, Inc.

Dear Peter, in order for you to understand me better, keep in mind a basic principle about the functioning of living organisms-they all depend on energy use. If no energy enters a living system, then no metabolic activity, no life function can be carried out. Think about a car without fuel. No matter how great the car is, it simply won’t work without any fuel in the tank. The human body is no different. Plants and animal products which people consume as food provide the body with fuel. However, you cannot make use of the energy in nutrients in the form in which you take them in. They need to undergo a process so that they become usable fuel for us, like crude oil being refined into gasoline to make a car work. This is roughly what my duty is. Without my functioning, you would be devoid of the energy to move a finger, and eventually die. Do you understand now how important a set of pipes I am? You just think that I look like a soft and hollow canal and misjudge me as simple. Well, I know that I don’t have such complex parts as the heart, lungs, and kidneys, but I’m created as a perfect work of art in plain design.

Although the hoses you use for watering your garden wear out and break in a relatively short time, my walls made of four layers keep functioning through a lifetime without any holes unless I contract a disease like cancer. My outer layer consists of a durable connective tissue, the next one consists of two sets-one horizontally and one vertically laid-of straight muscles, the next layer under that consists of glands spread in a soft connective tissue, and the innermost layer is the epithelial mucosa where the actual absorption takes place.

Now, let’s come to how I achieve digestion, one of your body’s vital activities. Actually, there is no place for me to take any pride in it; I’m just doing as I am ordered. Anyway, the complex processes occurring within my simple-looking walls are just fascinating! Every one of my cells producing the particular enzymes to break up each nutrient is like a separate factory. Some of these enzymes break proteins into different levels of peptides, some break the peptides into amino acids, some break fats into fat acids and glycerin, whereas some break carbohydrates down into glucose. All of these particular enzymes have their sub-branches within themselves. For example the enzymes breaking down fructose (fruit sugar), lactose (milk sugar), and starch are all different. In order for the enzymes to be effective, my inside needs to have the right pH level; the enzymes work in very sensitive conditions. To give you an idea, the enzymes in the stomach-which happens to be the second station the nutrients are destined for before they come to me-work in an acidic environment (pH: 2.5–3). In my case however, basic fluids are secreted and this strong acidity is neutralized for my enzymes to work.

My overall length is around 8.5 meters from the first entrance at the stomach to the last exit. The small intestine is nearly 7 meters long and the remaining 1.5-meter section is the large intestine. Although the small intestine is the longest section of the digestive tract, it is still called small since it is smaller in diameter than the large intestine.

The small intestine is also divided into three sections. The very short (25–30cm) and relatively thicker part right after the stomach is the duodenum. Bile-which works like detergent and facilitates breaking up fats-produced by the liver and digestive enzymes from the pancreas enter the duodenum. Thus, the nutrients are digested one step further and pass on to the second section (jejunum) and then to the third (ileum). You cannot easily tell apart these final two sections. As blood circulation is more intense in the second section, this section is more reddish and the contractions here are faster and stronger. The third section is narrower and has thinner walls. The blood circulation here is relatively lower and the movements are more limited. The thin membrane of connective tissue (mesentery) around me which attaches me to the abdomen wall and prevents me from knotting up is relatively fatty in this third section.

My most vital parts are the villi-tiny nipples covering the curly surface of my inner wall like a carpet. Shaped like the fingers of a glove, villi yield an enormously large inner surface. They contain a net of capillaries and lymph canals. In addition to the glands secreting the enzymes to break down nutrients, the secretion of certain glands protects me against the destructive effect of the stomach acid. Some cells secrete mucus for lubrication and protection of the passing nutrients. As some cells of the villi secrete digestive enzymes, some of my cells absorb the nutrients broken down until the final phase and pass them to the bloodstream.

Peter, how can some guys mistake such a splendid mechanism as a work of unconscious nature? What I’m telling you about is a manifestation of such great knowledge and might that it leaves you spellbound. I know the characteristics of foods, I know about the other organs’ needs, I adjust various enzymes and an absorption system, I fit them in a limited space… In addition, I do all these in the most ideal way, without any waste or flaw! C’mon Peter, can all these happen by themselves? Now, if I were to start telling everyone about the absorption mechanism in detail, they would probably see those cells as divine beings! The One who assigned special carrier molecules and a system for every nutrient molecule, has placed two transfer systems as blood and lymph pathways in every single one of those millions of villi! The blood pathway passes amino acids, water and salts into the blood directly, whereas the lymphatic pathway absorbs fats to pass them to the blood indirectly. After absorption, the nutrients become a property of the body and they are carried in the bloodstream to all the cells waiting for them in need.

Well, what about the waste then? Since everything you eat is not beneficial and usable, and some things are even toxic, they should be disposed of as soon as possible. The unabsorbed remnants are still too watery to be disposed of; sending them away as they are will be a waste of water and minerals. But don’t worry, everything is perfectly planned! Now the large intestine comes on duty. In this 1.5-meter section, the water of the waste and certain minerals are absorbed, and the waste solidifies. The large intestine is also divided into three sub-sections. The pouch connected to the junction of the small and large intestines is named the cecum and there’s the appendix at its end. This end sometimes festers and you have to have it removed in an appendectomy. Now, there’s this made-up story that the appendix was once longer since your ancestors only ate plants, that it has evolved into a shorter form for I now eat more meat, so on and so forth… Bah! Nothing is created in vain, Peter. If it didn’t have a duty, it simply wouldn’t be created. Only after some time did it dawn on them, after researchers proved that it is so necessary, that as a lymphoid organ, rich in blood vessels, it produces antibodies to fight the germs which somehow make their way into me.

The rest of the large intestine is the colon and the rectum. The mucosa covering my inner surface is rather smooth. It secretes mucus to facilitate the removal of waste. In addition, useful bacteria are made to work in abundance in the large intestine for your needs. These bacteria synthesize the group B vitamins like B12, thiamin, and riboflavin, along with vitamin K. You see how all the processes are carried out so splendidly? If it weren’t for vitamin K, your blood would fail to coagulate, and the slightest injury to your blood vessels would kill you. Could you ever have imagined that what looks to you like a sewage canal could produce vitamins of vital significance? Your Creator has infinite wisdom.

Peter, now you may wonder how the acts of this organ which resembles a long hose are regulated, how the nutrients inside are propelled, and then thrown out. To put it briefly, the “willful” part of your brain does not even know about it. Indeed, if it knew, it would be constantly busy with me and unable to do anything else.

Under the control of the autonomous nervous system, the straight muscles of my walls gradually contract in waves-this is squeezing act is called peristalsis. The nerve fibers connected to me fall into two basic categories-sympathetic and parasympathetic. As the sympathetic fibers pressure me to slow down, parasympathetic fibers stimulate me to act. Thus, I try to keep a balanced functioning between these two opposite effects. When the waste material I propel this way assumes a state to be disposed of, it reaches the rectum, and when the walls here strain, I make a natural call to you that I need to get rid of garbage. This is the step where your will has a partial interference.

Colon cancer, which troubles many people today, appears in this final section. The major reason is consuming too much meat and fatty foods, lack of movement, and leading a stressful life. When these are combined, I fail to function properly. If you want to help me at that, you should consume fiber-rich foods such as fruit and vegetables, and also lead a peaceful life. My web of nerves is amazingly rich and complex. Therefore, I am sensitive to nervous changes. If you feel down or sad, and if you suffer too much stress, I begin to go into spasms. Then I fail to dispose of waste, the toxic material inside me begins to damage my inner walls and eventually increases your cancer risk. Therefore, you’d better take up the habit of a glass of warm water when you get up in the morning, and try to have regular meals at the same times of the day. Most importantly, always have fresh green vegetables on your table, reduce meat intake… and it would be great if you could afford to consume olive oil rather than any other.

Hey, wait! I was about to forget the most important point. If you don’t have any peace of mind, all of these will be useless. This doesn’t mean that you will never worry; after all, this world is a testing ground and you are a human being like anyone else. However, if you give in to troubles and get overcome by feelings like panic, fatigue, and hopelessness, then my functioning will be upset. So, troubles faced with active patience and effort without giving up hope do not harm me much.

Peter, I do not wish you to wait until you see colon cancer patients disposing of waste through a hole in their belly into a plastic bag before you feel grateful for the blessings you enjoy. Actually, maybe I have told you at most a tenth of what I know about myself. Anyway, I think even this much will give you an idea of what a work of art I am. Thanks for listening to me, Peter!

Irfan Yilmaz is a professor of biology at Dokuz Eylül University, Izmir, Turkey.

One of the most important reasons for the last two world wars was the sharing of energy sources. 60 years on from the last world war, the world is now very close to confronting the same problem. There has been an enormous rise in energy demand since the middle of the last century. This increase has resulted from both rapid industrial development and population growth. As shown in Figure 1 and 2, the world population is 4.8 times greater, and the total energy requirement has increased more than 30 fold from between 1850 and 2000. Many studies have demonstrated that while global demand increases by at least 2-3% per year, the current oil fields are depleting at an average of 3-5% per year. If this demand continues at this rate, we will reach a point of crisis in oil sometime after 2010, and the same will be true for natural gas somewhat later, between 2020 and 2030 [1, 3]. The basic energy source of the world, hydrogen, is a new hope for solving the energy problem. It is likely that this century will be the century of the fuel cell. This technology uses hydrogen as fuel, and offers the prospect of supplying the world with clean, sustainable electrical power.

Hydrogen, which is the simplest element in space, was discovered in the 16th century and its inflammable property was understood in the 18th century. Ninety percent of the known universe consists of this simple element. Hydrogen is colorless, odorless, nonpoisonous, and 14.4 times lighter than air. In its liquid phase it has a temperature of -252.77 °C. It is the fuel of the sun and other stars, hence the main energy source of the universe. Hydrogen is not found as a free element in nature, but rather it is found as a compound, particularly as water. Hydrogen has the largest energy amount per unit mass among known fuels. The energy of 1 kg of hydrogen equals 2.1 kg of natural gas and 2.8 kg gasoline. However, its volume per unit energy is higher. It is 1.33 times more efficient compared with fossil fuels as an energy source. When hydrogen is used to produce heat or propulsion, only liquid water or water vapor emerge, making it an extremely clean energy source.

Hydrogen can be used with fuel cells to produce electricity. At the present time, the cost of this method is 3 times more expensive when compared to other fuels. Fuel cells use hydrogen, or hydrogen containing compounds to produce electrical energy and heat. A fuel cell has no moving parts and makes no noise when operating. A single fuel cell contains three layers, as shown in Figure 3. These are the anode-electrode layer, the membrane layer, and the cathode-electrode layer.

There are three types of fuel cells; Polymer Electrolyte Membrane (PEM), Direct Methanol Fuel Cell (DMFC), and Solid Oxide Fuel Cell (SOFC), each named after the material used as fuel. The PEM fuel cell is fueled by pure hydrogen. In the anode, hydrogen is split into its basic elements, a proton and an electron. While the proton migrates through the membrane of the fuel cell, the electron travels around the membrane and goes to the cathode, creating an electrical current. In the cathode-hydrogen proton the electron reacts with oxygen to form water, which is rejected as waste. The basic system is the same for the DMFC and the SOFC fuel cells. The DMFC is fueled by a mixture of methanol and water. Before reaching the anode electrode, the methanol is split into CO²and hydrogen. The SOFC fuel cell can use different kinds of fuels that contain methane and hydrogen. All the reactions are shown in Table 1. One fuel cell can produce 0.6 of a volt. To get enough power, several fuel cells are piled in a stack. The space between fuel cells is filled with gas that helps to distribute the hydrogen and oxygen gas to the membranes.

Although hydrogen energy is a new source, the production of hydrogen is not a new concept. Every year, 500 billion m³ of hydrogen is produced, stored, transported, and utilized in the world. Initially, hydrogen was used for the production of ammonia, but today hydrogen utilization has expanded tremendously to incorporate applications in chemical and petroleum refining, metallurgy, the hydrogenation of edible fats and oils, space and weather programs, fuel cells, and the manufacture of high quality electronic components. The most important consumer is in the petroleum- chemistry industry.

Hydrogen can be obtained by using different methods. Hydrogen can be produced from electricity, using electrolysis to split water into hydrogen and oxygen. Reforming is another method that produces hydrogen. In this method, hydrogen is extracted from a gas with a high concentration of methane, such as natural gas. This process uses hot steam to obtain hydrogen from the methane. When methane gas is mixed with hot water vapor, the gas is split into carbon monoxide and hydrogen.

Although hydrogen can be stored as a gas or liquid, storing and handling hydrogen is difficult as compared to gasoline. While gasoline is a liquid, hydrogen is a gas. At atmospheric pressure at sea level (pressure at sea level is 1.0 atm = 1.01325 bars), hydrogen has a volume 3,100 times greater than gasoline. To decrease the volume of the hydrogen, pressure is used. Hydrogen can be stored under pressure up to 700 bars. At this pressure, hydrogen has a volume 6.4 times greater than that of gasoline.

Another method for storing hydrogen is in the liquid phase. In this phase, hydrogen has a volume 3.6 times greater than gasoline. Liquid hydrogen can be stored under high pressure in steel tubes. Hydrogen should be cooled to -252.77 °C to become liquid. The cooling process requires energy. 25% of hydrogen energy is used for the cooling process. The largest liquid hydrogen tank is at the Kennedy Space Center in Florida. It contains up to 3,400 m³ liquid hydrogen.

Hydrogen can also be stored in metal hydrides. When cooling is applied, the hydrogen atoms diffuse inside the metal hydrides. To release the hydrogen, the reverse process, heating, is needed. Due to the large storage necessary, aluminum and boron hydrides have been used extensively over the last 10 years. In particular, boron hydrides are important as they can be used in liquid conditions. Metal hydride storage is very safe because of the low pressure and the fact that there is little free hydrogen inside the storage tank. Another advantage of this way of storing is that metal hydrides hold hydrogen at very low volumes.

It seems that hydrogen may be the major energy source in the future. Eventually, it will be used to supply the energy needed in the economy, being used for transportation, central and distributed electric power, and combined heat and power for buildings, and industrial processes. However, hydrogen technology is currently in the pre-production stage of development. Hydrogen energy is not cheap when compared to other energy sources at this time. There are some challenges that need to be overcome, such as producing, storing, and using hydrogen efficiently before we use hydrogen instead of fossil fuels. However, hydrogen is the key to solving the energy problems of the world. Hydrogen is available in every country, everywhere. Using hydrogen as an energy source will prevent many conflicts between countries. This energy source will help address concerns about energy security, global climate change, and air quality. It seems that the views of Jules Verne, quoted at the beginning of this article, will be realized one day in the future. And people will thank God not only for water, but also for the hydrogen in it.

References

1. “Energy Wars” by David Chapman – a director of Bullion Management Services the manager of the Millennium BullionFund (www.bmsinc.ca).

2. Cook B., ‘An Introduction to Fuel Cells and Hydrogen Technology’, Heliocentris, 2001.

3. www.un.org

4. www.census.gov

5. www.worldenergy.org

6. www.fuelstore.com

7. www.minihydrogen.dk

After the sixth phase, the typical characteristic in the universe was a temperature that reached as high as 4,000 C. At that temperature space was not as dark as it is today, rather it gleamed brightly. As matter condensed into gases and cooled down as time passed, the density values increased and the planets that we know today started to form out of the increasingly solidifying matter. The universe, presumably, was still a homogeneous gas cloud of helium and hydrogen when it reached an age of 700,000 years. Yet, the universe did not become a single galaxy by collapsing on a single point; rather billions of galactic centers were created. So, what made the universe wait as a gas cloud in just that state? Why did it not collapse in on a single point?

While cosmology has been asking this question for years, Roger Penrose, a theoretical physicist and black hole expert, tried to compute the first creation power in one of his studies in 1973. Some tiny particles, smaller than a proton, were discovered. Those particles had been formed not by the collapse of the stars, but during the first creation after The Big Bang. Although those tiny black particles were far smaller than atoms, they behaved like black holes and swallowed everything they encountered. Yet it seems that they left their footprints as they passed. It seems as if hydrogen and helium clouds had gathered around those enormous attraction centers and the cores of billions of galaxies had thus formed. The universe was being shaped and was expanding from particles made up of a cosmic soup, a gas cloud. The Qur’an also relates the great transformation that took place in shaping the universe:

Have the unbelievers not beheld that the heavens and the earth were a solid mass, then We separated them; and of water We produced every living thing, will they not believe, then? (21:30)

From Dust and Gas Clouds to Cosmic Systems

Stars, like living beings, grow older and demise. They go through an infancy, then youth and adulthood. Some gas and dust clouds, known as Nebulas lie among galaxies. Nebulas are considered to be the raw material of stars. In our galaxy, the Milky Way, gas and dust clouds are mostly located on the spiral arms that extend outward. An impact, called a shock wave, causes interstellar matter to come together and condense into huge clouds and spheres in space. The clouds that condense during the first formation of stars are so thin that they do not even have gravitational effect. Due to this lack of gravity, it has not yet been fully understood how these gas and dust clouds came together and condensed.

A condensed cloud heats up due to the collisions within it; these collisions increase as the cloud is compressed in a process that lasts millions of years. These collisions cause the cloud to sparkle and gleam. Initially, some rays, such as infrared or radio waves, are emitted.

While the star forms, the outer crust collapses very slowly, whereas the central parts collapse at a much greater rate. As the cloud condenses farther, it emits more light and starts to shine inside the dark, dusty covering that surrounds it. This nuclear cooking-pot, which has a temperature of 10 million C at its core, sparkles. With the flaring of the star, a disk forms around the newly created center. Strong winds, triggered by the powerful hot gases that are emitted from the upper and lower surfaces of the disk, blow in opposite directions; they sweep away most of the original gas cloud that formerly impeded the visibility of the new star. Thus, the star begins to be visible through an ordinary telescope. The energy produced in the center of the star after it has been formed and reaches a certain age, impedes greater collapse. This energy provides the necessary pressure to block the collapse of matter and seeks a way to escape. Hence, the star reaches an equilibrium.

We cannot observe stars being born in interstellar gas clouds with normal telescopes. This is because the gases in space and within the dust clouds act like the particles in cigarette smoke and absorb the light. Thus, we see the clouds as dark silhouettes on the surface of the star. Formations of stars can only be observed through infrared telescopes. An infrared telescope was first placed on a satellite sent into orbit in 1983. That telescope discovered thousands of young stars hiding in the depths of interstellar clouds.

A condensed gas cloud needs to be of a certain size in order to become a star. If the gathering gas clouds are not large enough, a different situation occurs: a planet is born! The stars and planet systems that orbit the stars are formed in this way. While stars are being formed, the planets are made out of smaller gas clouds.

The Sun is a typical small star that is relatively very young. We can see stars in space that are up to a hundred times as large as the Sun, or ones that are one-tenth its size. When stars are compared to the Sun, the dimmer ones that have a surface temperature of only 3,000 C are at the bottom of the range, while ones similar to the Sun, with a surface temperature of 6,000 C, occupy the middle range. Stars that are much larger than the Sun have a surface temperature surpassing 30,000 C. Contrary to general thought, larger stars live shorter lives, because the denser and the hotter the core is, the more intense are the nuclear reactions that take place.

Thus, these stars have brighter surfaces. A massive star that uses more nuclear power is more likely to run out of fuel sooner. On the other hand, a smaller star that uses its fuel sparsely has a longer life, even though it has less fuel. We know that there is a simple relation between the temperature and the pressure of a gas. If we heat up a gas in an enclosed container, the pressure will increase; if we cool it down, the pressure will decrease. When you think of a star with a temperature reaching millions of degrees Celsius at its center, you can understand how great the pressure is there. We know that heat is being produced through nuclear reactions. Every star is under the influence of an attraction force that approximates and compresses the elements of the atoms it contains. As the mass of the star increases so does the attraction force. This inward force is balanced by the force of outward nuclear explosions. The most significant reaction that ensures the vitality and continuity of the star is the transformation of hydrogen into helium through fusion. Yet, while this happens, the fuel lessens and the reactor will fail to function properly. At this point, the force of the pressure keeping the star in a balance is endangered and the star begins to lose its long struggle against the attraction within its mass.

As stars lose their fuel, they are exposed to different “deaths,” in proportion to their mass. The number 1.44 is the coefficient related to the mass of the Sun. Stars with a mass of less than 1.44 times the mass of the Sun become black or white dwarves, whereas those with a mass of more than 1.44 times the mass of the Sun become supernovas, neutron stars, and eventually black holes. If the mass of a star is more than 1.44 times the mass of the Sun, it will not remain as a dwarf. Its inner temperature and density will increase and the fuel, in the form of iron, nickel, chrome and cobalt, will not be able to burn anymore. Temperature and pressure turn the electrons and protons into neutrons by adhering them to one another. The iron core becomes a huge ball with a diameter measuring 100 kilometers. At a critical temperature the star explodes, emitting a billion times its normal light intensity. This is a supernova explosion. With the explosion, a terrific shock wave and the flow of neutrino (an elementary particle with zero charge and zero mass) spreads. The materials produced in the explosion flow into space as gas clouds.

The Event of the Supernova and the World

As a matter of fact, at one time we were physically part of a star. That star was probably larger than the Sun and was formed right after the creation of the universe, namely in the first few hundred thousand years.

At those times, the universe was almost completely made up of hydrogen. The solar system and the earth had been formed of this element. Hydrogen was the beginning of everything, and whatever material was available in the universe had been derived from the hydrogen atom. Only after being processed in the nuclear furnace for billions of years did hydrogen turn into helium.

Consequently, the star’s life was over. As the fuel in the depots was running out, demise emerged on the horizon. It began in fits and starts, and then when the furnace was about to go out, the mass of the huge star collapsed in on itself. Having increased in size after the collapse, the pressure triggered new nuclear reactions. Thus, a series of elements, ranging from carbon to iron, came to be part of the body. Finally, the star gave its all with an enormous explosion that we call a supernova. A billion-year life ended in just a few seconds. Atom particles at the core of the star melted and turned into neutrons in just a few seconds, and the parts closer to surface were thrown into space at a speed of ten million kilometers per second. It was a magnificent moment in which billions of degrees of heat was produced and in which a great light, as bright as one billion suns, shone. Some of the elements that are heavier than iron were also created during that time.

Supernova means death to a star. The enormous energy once unleashed heats up the outer layers of the star so much that the way is paved for new fusion and energy-absorbing reactions to occur instead of energy-freeing ones. Not only iron, but also other heavy elements, such as gold, lead, and uranium are manufactured in this furnace. These elements are thrown into space together with pre-synthesized and lighter ones, like carbon and oxygen, and combine with the wreckages of other supernovas. During the succeeding millenniums, new star and planet generations are created.

For our planet, fantastic and extraordinary cosmic events, such as supernovas, have been the starting point for the existence of some elements, like oxygen, gold and silver, and ultimately for the creation of life. The sources of carbon and oxygen that are essential to life, the silver and gold rings that we wear on our fingers, the lead plates on our roofs, and the uranium that fuels our nuclear reactors are all results of the death throes of stars that died prior to the birth of the Sun.

As we have seen, a supernova explosion causes matter to move from one point to another. As a result of such explosions, many of the remnants of stars are spread over space and new stars or star systems are created by the accumulation of such remnants. The Sun and the planets in our solar system and surely those in our universe exist as the result of a very early supernova. In this immense universe which houses humanity, the transformation that matter undergoes, and the gradual advance toward a certain destination, all indicate that the Divine Knowledge, Power and Will are intermingled with His Compassion and Grace.

Enviromnental damage ramains a growing concern. Despite rigorous energy efficiency programs and research and development (R&D) efforts on cleaner energy technologies in most developed countries, no developing country views these as priorities. And they have a case: Developed countries, which enjoyed high economic growth for decades by ignoring the environmental consequences, are hindering developing countries’ economic growth. On the other hand, representatives from developed countries say that we are all in the same boat and will sink together if developing countries do not pay attention to environmental consequences.

In December 1997, world leaders gathered in Kyoto to address the problem of global warming and to decide which countries should cut emissions and to what extent. Not surprisingly, developing countries objected to any restriction that might limit their economic growth. Such discussions will become more intense in the aftermath of the Kyoto Protocol.

This article will not address the issue of environmental reparations. Rather, it will discuss the energy markets’ current situation and short-term future trends.

Basic Properties of the Energy Systems

Present-day energy systems have several basic characteristics. All policy makers dealing with energy systems should know these basics by heart.

First, energy systems develop slowly because they require significant capital and infrastructure that can be replaced only gradually. There are two important consequences resulting from this fact:

•Intense capital requirements are a strong barrier to average-sized firms. Thus, energy systems are seldom run by private enterprises. In most countries they are constructed and run by the state, and a separate government body deals with energy issues. Energy systems have been dominated by heavy regulations even in most market-oriented economies. The recent trend of deregulation is an exception rather than the norm.

•Even if a state realizes that current energy systems can be improved significantly (e.g., switching to other fuel types or deregulating the market), making changes to a huge, functioning infrastructure is a slow and painful process. It is relatively easy to make changes during the initial stages of an energy system. But as time passes, this becomes more difficult.

As in most cases, good planning is essential. A state must be very careful when building its energy systems, and should pay attention to underlying energy market trends. Important lessons can be learned from the long history of mistakes committed by developing countries. And if a developing country fails to keep up with recent trends, it may find itself trapped by its own hands in an inherently inefficient system for decades.

Second, energy systems are heavily reliant on fossil fuels. Historically, coal has been a prominent energy resource in most countries. Despite its widely acknowledged negative impact on human health and the environment, it still dominates energy systems in such developing countries as India and China. In most countries, oil is the primary energy source.

Oil was one of the most influential key factors of the twentieth century. Just by looking at the traffic on our teeming highways or the modern political landscape, we can understand how profoundly oil has changed the way we live and handle international politics. In the light of the oil crises of 1973 and 1980, the reverse-shock of 1986, and another crisis during the Gulf War of 1990, the need to diversify away from oil becomes abundantly clear.

Environmental concerns also support the case against oil. This is how natural gas, a slightly cleaner fossil fuel, gradually entered the picture. Given the current energy systems’ dependence on these fossil fuels and the fact that energy systems change slowly, oil, coal and natural gas will continue to be dominant for years.

Third, the driving force behind the dynamic of switching from one fuel type to another is economics. Fuel types with smaller unit costs survive in the long run. Oil, for example, now has the lowest unit cost (cost per unit of energy) in most regions of the world.1

Given this, cleaner fuel (e.g., solar energy) still have a long way to go before becoming economically viable. Why would you pay $5 for what you can get for $3? Countries that use non-oil energy resources do this for a number of reasons, such as they do not have natural resources and so transporting oil ends up costing more, or they have abundant natural energy resources of other types. But, in general, economics is the most important issue here.

Introducing New Fuels

What trajectory does the unit cost follow when a new fuel is introduced? Consider photovoltaic (PV) cells. The term photovoltaic refers to a family of technologies that convert light directly into electricity. PV technology is an appealing alternative-it is a renewable, environmentally benign, and domestically secure energy source. It is modular and can be scaled up to meet demand.2 However, unit cost is currently high compared to fossil fuels.

A new technology’s unit cost is believed to follow a learning (or experience) curve as a function of installed capacity. As shown in Figure 1, technologies may experience declining costs due to their increasing adoption by society. This decline may be attributed to several factors:

• Technology innovation and manufacturing improvements: Costs may decline due to a better understanding of the underlying science, progress in related fields, or via learning by doing as well as learning by using.

• Economies of scale: Unit cost is a function of total production. Products produced in large quantities have lower unit costs. Most new fuel types have high unit costs, and demand is too low to encourage large-scale production. It almost seems paradoxical. But there are ways to break this cycle. Regulations encouraging usage of new fuel types may be enforced, consumers who have priorities other than cost may be targeted to expand the current market, or the cost may drop low enough for the technology to become attractive even for low production levels.

In achieving economies of scale, consumer demand should he considered. A major concern for the end-use consumer is convenience. The value of oil would be much lower if gas stations were not located all over the country. The same issue applies to fuel cells and electric cars. They will not be as convenient as conventional cars until the proper infrastructure exists.

Since 1960s, cooperative investments by manufacturers and governments have resulted in the accumulation of experience within the solar industry and the subsequent cost reduction of PV systems. Significant cost reductions have occurred in both the PV modules that house the solar cells, and the ancillary components (known as balance-of-system). Between 1968 and 1998, the global cumulative installed capacity of PV modules doubled more than thirteen times, from 95 kW to 950 MW, while costs ($/Wp) were reduced by an average of 20.2% for each doubling.4

Trends for Different Fuel Types

After this overview of energy systems, lets look at the trends for specific fuel types. Figure 2 is taken from International Energy Outlook 2000 (IEO2000), an annual report published by the U.S. Energy Information Administration (EIA).5 It displays projections of energy usage by fuel type up to 2020. The highlights following the figure are summarized from the reports contents.

Coal: Carbon dioxide is a very effective greenhouse gas and contributes significantly to global warming. Since coal is the most carbon-intensive fuel, global climate change debates focus on reducing its use. Coal use also has significant public health consequences, due to particulate matter emissions. Historically, coal has been a major source of energy. Although it has lost market share to petroleum products, natural gas, and nuclear power in the last decades, it remains a key source of energy, especially for generating electricity. In the IEO2000 reference case, coals share of total energy consumption falls only slightly, from 24 percent in 1997 to 22 percent in 2020 (Figure 3). Its historical share is nearly maintained, because large increases in energy use are projected for developing Asian countries, where coal continues to dominate many national fuel markets. China and India are projected to account for 97 percent of the worlds total increase in coal use.

Oil: Oil use will grow in absolute terms, but even optimistic oil supply scenarios predict that its share in the fuel mix will decline gradually. Despite efforts to reduce reliance on Middle Eastern oil, as well as advances in technical capability, new oil reserves are not compensating for depleted ones. The experts estimates of vast oil reserves in the Caspian and Tarim basins proved to be somewhat high, and the latest probes have been partially disappointing. According to EIA estimates, the share of the Persian Culf supplies is likely to increase in the coming years. Economic theory says that prices rise as supply declines. Oil prices have been quite volatile and can be expected to remain so in the future, principally as the result of unforeseen political and social circumstances. Without attempting to predict any crisis, the IEO2000 forecast shows a gradual rise in world oil prices. Oil currently provides a larger share of world energy consumption than any other energy source and is expected to remain in that position throughout the forecast period. Its share of total energy consumption declines slightly, however, from 39 percent in 1997 to 38 percent in 2020, as countries in many parts of the world switch to natural gas and other fuels, particularly for electricity generation. World oil consumption is projected to increase by 1.9 percent annually over projection period. Most of the growth in oil use is projected for the transportation sector, where few alternatives are currently economical.

Natural Gas: Natural gas remains the fastest growing component of global energy consumption. Over the IEO2000 forecast period, its use is projected to more than double in the reference case, reaching 167 trillion cubic feet. The natural gas share of total energy consumption increases from 22 percent in 1997 to 29 percent in 2020. It also accounts for the largest increment in electricity generation. Combined-cycle gas turbine power plants offer some of the highest commercially available plant efficiencies, and natural gas is environmentally attractive because it emits less sulfur dioxide, carbon dioxide, and particulate matter than either oil or coal.

World Energy Consumption Shares Type: 1970-2000

In the industrialized world, natural gas consumption has the largest projected increase among the major fuels, increasingly becoming the choice for new power generation because of its environmental and economic advantages. Its incremental use in developing countries is expected to supply both power generation and other uses, such as town gas and fuel for industry. Despite concerns about the extent of natural gas reserves worldwide, current proven reserves suffice for this markets steady development without a substantial price increase.

Nuclear Power: The prospects for nuclear power are uncertain, despite a projected growth rate of 2.5 percent per year in total electricty demand through 2020. In the IEO2000 reference case, global nuclear capacity is projected to increase to 368 gigawatts in 2010 and then gradually fall to 303 gigawatts in 2020. Aggressive plans to expand nuclear capacity, mainly in Asia, lead to a near-term increase. However, plant retirements in America and other countries exceed total new additions worldwide, and produce a decline later in the forecast. The International Institute for Applied Systems Analysis [IIASA] is one of the authorities on energy issues.

IIASA projections [which extend until 2100] hold a slightly pessimistic view of nuclear energy. Nuclear energy production has stagnated for several decades, and IIASA suggests that this will continue. Currently, nuclear energy is prominent in only a handful of countries. Not many nuclear plants are being built, and existing ones are being dismantled. With large up-front capital costs, plant safety, and recycling nuclear material after dismantling issues, this option is becoming less and less attractive. Public opposition, already strong in the US and Europe, is growing in Asia. Nuclear safety issues moved to the forefront in Asia in 1999 after several leaks at nuclear power plants in South Korea and China, and the serious accident in a reprocessing facility in Tokaimura, Japan. Such events are likely to raise concerns about Asias aggressive plans for nuclear capacity expansion. IIASA predicts that if a safer and cheaper new generatinn of nuclear plants is introduced, nuclear powers ultimate share in fuel mix will grow. Otherwise, it eventually will come to an end.

Renewables: The development of renewable resources is constrained in the IEO2000 reference case projections by expectations that fossil fuel prices will remain relatively low, and that, as a result, renewables will have a difficult time competing. Failing a strong global commitment to environmental programs, such as the limitation and reduction of greenhouse gases outlined in the Kyotu Protocol, it is difficult to foresee significant and widespread increases in renewable energy use. Modest growth in renewabte energy is projected to continue, maintaining an 8 percent share of total energy consumption. Nevertheless, in the long run, as other fossil fuel types become more expensive due to depletion and R&D efforts push the unit cost further down, new opportunities will emerge. Even conservative estimates predict that the worlds energy will rely considerably on renewables before 2100.7

Conclusion

In this article,we highlighted several basic characteristics of energy systems, and drew attention to some underlying trends for particular fuel types. Based on this information, we can say that:Energy systems are capital-intensive and hard to change once they have been built. Therefore, developing countries should track energy system trends closely and build their energy systems according to their future needs. The most important factor influencing the decision of which energy source to use is economics. Until a resources unit cost is competitive with others, it will not enjoy widespread acceptance and usage. Fossil fuels will dominate energy markets in the short run. The shares of coal and oil in the fuel mix will remain relatively constant until 2020, while the market for natural gas will expand rapidly. Nuclear power will survive only if a new generation of safer and cheaper reactors is introduced. Renewables will be the ultimate choice of the future. Currently, however, they cannot compete successfully on cost with conventional fuels.

Footnotes

1. Although the cost of extraction rises as the amount of oil remaining underground decreases, extraction technology also advances and pushes the cost down. Transporting oil from the field to the marketplace is added to the extraction (or purchasing) cost.
2. Christopher Harmon, Experience Curves of Photovoltaic Technology (March 2000). The entire report is available on IIASA web site: http: www.iiasa.ac.at/Publications/Documents lR-00-014.pdf
3. Netherlands Energy Research Foundation (ECN at Petten), “Endogenous Technological Change in Energy System Models.” Paper presented at the 1999 IIASA conference.
4. IIASA-WEC. 1998.
5. International Energy Outlook 2000 is available on the EIAs Web site: http: www.eia.doe.gov/oiaf/ieo/index.html.
6. N. Nakicenovic, A. Gruebler, and A. McDonald, Global Energy Perspectives (Cambridge. UK: 1998).
7. Experts differ over what exactly is included in this category. For practical purposes, renewables cover all energy sources except coal, oil, natural gas, and nuclear. Therefore this group includes, but is not limited to, hydroelectricity, wave, wind, biomass, and solar energy.

You would indeed have a lot to calculate before taking off: What is the most economical flight speed of your aircraft, and how does it vary with winds, flight altitude, and the extra weight of fuel reserves? Perhaps the gliding performance of your aircraft is good enough to permit you to travel some distances by soaring in up- draughts, with the engine off. It may even be economical to make detours in order to stay over regions with strong up-draughts. Would it be favourable to bring along large fuel reserves and fly non-stop for long distances without refuelling, or to travel by numerous short flights, saving transport costs for extra fuel? To solve that problem, you have to know about possible refuelling stations along your route, about petrol prices, landing fees, and the time delay you will face by landing at a particular site.

Which is the optimal route to your destination? Perhaps it pays to follow the Great Circle, or should you make a detour where you can benefit from favourable winds? Of course, you will fly only on days when the weather is as favourable as possible, but which is the best weather? And how can you know which weather condition is most favourable for you? What flight altitude will you prefer under different weather conditions? You must also consider whether and how you will compensate for wind drift, when to fly low along coast-lines and other leading-lines to gain protection from the wind and avoid drift, and how to exploit the winds at high altitudes. And you must also take into account many unpredictable situations that you will face. There are lots of questions and you would spend a long time looking up facts and making calculations before you could arrive at a reasonable strategy for your flight.

Your situation is analogous to that of migrating birds. The migratory strategy of birds, a harmonious mixture of rigid and flexible behaviour to achieve a safe and economical journey which can be affected by a bewildering number of factors, is an astonishing feat – where do they get the skills and capabilities to accomplish it?

There are many animals, not only birds, which migrate on a regular basis. Some examples: Bull elephant seals travel 21,000 km (over 12,000 miles) each year, from California to the Gulf of Alaska, the longest migration of any mammal. Millions of monarch butterflies fly 2,000-3,000 km from Canada to the Gulf of Mexico. Grey whales swim 10,000 km from the Arctic Ocean to California and Mexico. In Bracken Cave in Texas 20 million free-tailed bats assemble every summer. All are female. They leave their mates 1500 km to the south in Mexico to come here to give birth to their young. Herring migrate annually and cover over 3,000 km. The bison, the wildebeest, the sockeye salmon, the eel are also known to migrate long distances. But here we will consider the migration of birds – one of the most impressive feats in animal behaviour- across thousands of kilometres of ecological barriers, like oceans, mountains and deserts.

Birds store fat for use as fuel during their migratory flights. They start to do so well before migration starts. Stored fat is the most economical type of fuel in terms of high oxidizing energy per unit mass. Once the animal is in the right condition to migrate, it may need some further environmental cues to initiate the actual migratory movement. A bird may wait for the right weather conditions or at least the disappearance of the wrong ones, such as fog or very strong winds.

In order to locate its goal at a different position on the earth’s surface, an animal must possess certain sensory systems and have certain decision-making programmes in its behaviour. The ability to take up a particular direction with respect to some feature or property of the environment is called orientation’. The orienting animal is rather like a man who possesses a compass and an instruction to proceed in some particular direction. Animals may orient with respect to objects on the earth’s surface, to the sun, to the stars, to the earth’s magnetic field, to the directions of current flow and so on. Further, they may use more than one of these environmental sources of information at any one time, and may use different ones at different times.

Birds may use continuous flapping flight or soaring flight. Migration of soaring birds attracts much attention among bird-watchers because of spectacular concentrations of these migrants at passages with favourable soaring conditions. The migrants make long detours to avoid having to use flapping flight over the sea, and the sites most famous for soaring bird migration in Europe, Falsterbo, Gibraltar and the Bosphorus, are situated at minimal sea crossings. Migrants’ coasting behaviour probably is part of their ‘strategy’ to exploit winds and conserve energy at the same time. Coastal migration occurs mainly under opposed and cross-winds, while migrants usually fly across the coast and depart over the open sea with following winds. Due to differences in friction, winds generally are stronger over the sea than over land. Migrants minimize the headwind force by following the coast, where they can use local topography and vegetation to gain additional protection from the wind. Furthermore, over the sea they will be exposed to wind drift, and under certain cross-winds it is beneficial to follow a coastline, some distance in the direction of their goal, rather than to take a direct route over the sea.

Some birds travel by numerous short flights, each of about three to ten hours duration. Many species depart either by day or by night, whenever weather becomes favourable. Flying with a small load of fat is advantageous, since the labour costs for carrying the extra fat can be high. However, there are also drawbacks involved in migrating by numerous short flights: the birds have to refuel often and find suitable resting sites on their route.

Some species undertake enormous non-stop flights. A regular migration route from North to South America directly over the Western Atlantic Ocean, a distance between 3,000-4,000 km, is used by many species. Just to mention some examples of long, nonstop flights over oceans other than the Atlantic: there are some geese that fly almost 4,000 km across the Pacific Ocean from the Alaska Peninsula to the South Californian coast; two species of New Zealand cuckoos fly about 3,500 km to the Solomon and Samoa islands; passerines, bee-eaters and Amur falcons travel almost 3,000 km of the Indian Ocean between India and East Africa.

Many migrants fly between Europe and Africa across the Mediterranean Sea and the Sahara desert in one single non-stop flight, lasting at least 40 hours in the autumn, when winds are generally favourable, and 60 hours in spring when they are less favourable.

Honey buzzards migrate by cross-country soaring over a distance of 7000 km from Europe to tropical Africa without refuelling. Common buzzards cover a distance of 10000 km between East Europe/West Siberia and South Africa by soaring migration. Many young Manx shear waders, in their autumn flight from Britain to Brazil, cover almost 0,000 km without refuelling. Various water species wintering in South Africa cover the total distance to their high Arctic Eurasian breeding grounds, about 13,000 km, in four or so long flights.

Arctic terns are transglobal travellers on a scale unequalled by any other migrant. Some annually commute between the Northern and Southern pack ice, crossing the equator twice. The round trip must be at least 40,000 km (25,000 miles).

Low temperatures seem not to prevent birds from migrating at high altitudes, The highest migrants over Puerto Rico experience temperatures of about –12 C, and over Switzerland migration is perfectly regular at altitudes with temperatures around -IC to -15 C. In fact, the birds’ capacity to fly under conditions of low temperature and low oxygen pressure is so great as to be hardly credible: On 9 December 1967, a radar controller in Northern Ireland reported an echo at high altitude moving south over the Hebrides. The radar height finder indicated an altitude between 8,000 and 8,500 m. The pilot of an aircraft in the vicinity was asked by radio to make a course deviation to pass near the position of the echo. In doing so, the pilot reported a flock of about 30 swans at just over 8,200 m. The observation probably refers to whopper swans, which are known to migrate, sometimes in the middle of the winter; from Iceland to Britain. At 8,200 m, the temperature was -48 C and very strong northerly tailwinds blew at this altitude.

Although, according to some radar studies, probably 90% of birds travel below 2,000 m, two small flocks close behind each other of curlew-like birds were observed at I 0,000 m above sea level.

These observations, indeed, are extraordinary. One wonders, are such enormous flight altitudes merely exceptional or do some birds regularly migrate that high?

We tend to think of events which happen regularly, as ‘normal’ or ‘ordinary’. But are they really? Very often, we do not realize the dimensions of the events. Hundreds of millions of birds migrate from one place to another. Tens of thousands of birds start to fly together. They fly very long distances together and land and feed together. Many of them have never flown that long, nor been to those places. But still they are able to fight against all the odds and finish their journey How do they know when to start? How do they recognize the landscape? How do they decide which route to take? How do they find their way to their destination? How do they know where they can find food? How come so many birds can act together? How and when did they learn to use the sun and other stars, or the earth’s magnetic field, for navigation? How did they acquire the necessary means in the first place?

There are numerous such questions to ask and very often, it is not easy to find the right answers. When the other migrating animals are taken into account, the questions get more complicated and more challenging Hundreds of millions of animals migrate twice a year covering thousands of kilometres. We must ask questions which start with how and why and not take ‘ordinary’ events for granted.

In May 1994, the world received a shock when 6 grams of highly purified (99.7 %) weapons-grade plutonium-239 was found in the house of a German businessman. It originated from one of Russia’s plutonium plants. This was the first of several such cases. In one raid, 310 grams of weapons grade ptutonium-239 was uncovered, a third of what is needed to make a massive kiloton nuclear bomb. It is believed that these ‘incidents’ are just the tip of the iceberg. The world is justifiably alarmed at the prospect of uncontrolled plutonium proliferation.

Plutonium is one of the most dangerous materials on earth. Five kilograms is enough to make a crude nuclear weapon. Some experts even believe that only one kg will suffice. Of course this is not the only reason that makes it one of the most dangerous of materials. Less than one thousandth of a gram is enough to cause cancer if inhaled. Plutonium is the second of the transuranium elements with an atomic number 94. It is a silvery looking and highly reactive material. It is so reactive that it is processed in special chambers filled with inert gases to prevent it from reacting with atmospheric gases and the moisture in the air, but it is not the reactivity of plutonium that attracts attention: it is its radioactivity. All transuranium elements are highly radioactive, but only plutonium and neptunium occur naturally, both in very minute amounts. The others are manufactured. The fact that plutonium occurs naturally means that it is stable enough to last if it can be produced by some means. Actually, it is very stable; its most prevalent form has a half-life of 24,131 years. Therefore; if manufactured, it is not easy to get rid of. Nearly all the plutonium that exists on earth today is produced this way.

The road to plutonium production

Of all radioactive materials, three are extremely important for nuclear energy generation by fission: plutonium-239, uranium- 233 and uranium-235. These are the only 3 radioactive materials which can provide a self-sustaining nuclear fission reaction. This means that by bringing together a critical amount of any of these three, a chain reaction can be initiated. This is the principle behind nuclear energy and nuclear weaponry.

Since the 1950’s, scientists have believed that plutonium and not uranium may be the ultimate solution to the world’s energy problem. Although uranium can be found naturally in several minerals, the fissile isotope U-235 is extremely low. With plutonium and uranium are both rare, one may ask ‘why has plutonium become so important?’. The answer is simple: in fast breeder reactors, more plutonium is produced than burnt. This process uses an isotope of uranium U-238, which is not fissile itself but more common than the fissile isotope U- 235. If you irradiate U-238-which we have plenty of-with highly energetic neutrons, it will capture them and eventually decompose into the most dangerous form of plutonium, Pu- 239 , by two successive 13-decays. After that step, plutonium is chemically separated from other material by means of remote controlled facilities. So if you have unusable U-238 you can turn it into highly desirable Pu-239 by using some U-235 or Pu-239. Once you have bred enough plutonium, you can start feeding in the new plutonium without the need for more U- 235 as fuel. The only drawback is that reprocessing and purifying it to use as nuclear fuel is not easy.

Today, things have changed. Countries determined to stay with commercial nuclear energy production need not use plutonium, fuels made of low-enriched uranium will suffice and unlike the past, reserves are enough to sustain nuclear energy production commercially. These fuels are not weapons-usable and are much cheaper and easier to handle. Reprocessing plutonium for reintroduction as nuclear-fuel is a very complex, dangerous and expensive process.

Given these facts, we may wonder why nations want to possess plutonium for nuclear energy generation. Another phenomenon differentiates plutonium from uranium: unlike uranium, all forms of plutonium can be made into weapons (although some mixtures of isotopes are less desirable to a weapons designer). If a nation insists on using costly plutonium rather than cheaper low-enriched uranium for energy generation, one may suspect that the country has other intentions.

Politics of plutonium

Plutonium has proliferated since 1942. Twenty-two countries possess or control separated plutonium in various forms and amounts, either for military or commercial use. As the nuclear warheads are decommissioned according to the Nuclear Nonproliferation Treaty, stockpiles are growing sharply in the world. Although long-standing governmental and commercial secrecy make estimates highly uncertain, roughly 1,100 metric tons of the material exist today. Approximately 260 tons of that stockpile are deployed in the form of surplus nuclear weapons. Of the roughly 650 tons of plutonium in commercial programs, approximately 530 tons are contained in untreated spent reactor fuel, while roughly 120 tons are stored in weapons-usable form or recycled as fuel awaiting potential future use. Every year, the world’s reactors collectively generate 60 or 70 extra tonnes of plutonium and at the moment there is no law against reprocessing it. By the turn of the century, this is estimated to reach around 1700 tonnes. It is calculated that by the year 2003, Russia will have accumulated enough plutonium to make 21,700 crude weapons, whereas US will have accumulated enough for 18,100 weapons.

Nuclear policies are among the most sensitive and closely guarded secrets of any nation. States are unwilling to disclose data related to plutonium stockpiles. International non-proliferation movements are pressurizing governments. Japan has a special attachment to plutonium since their nuclear energy generation policy was originally based on plutonium. It is now the only country to rely on plutonium for nuclear energy and is said to be reviewing its policy. A few months ago, US had declared that it would stop the transfer of plutonium handling technology to Japan because there was the risk that Japan may be using this technology to make nuclear weapons. After months of pressure from the international community and internal non-proliferation groups, last month Japan declared that at the end of 1993 it had 4684 kgs of plutonium inside the country and 6197 kgs in France and Britain waiting to be shipped to Japan, and became the first nation to give the exact figures about its stockpiles. Previously, US had started to declassify some documents about its plutonium stockpiles and reported that it has produced 89 tonnes of weapons-grade plutonium since 1945 and it has 33.5 tonnes of it now stored in Texas. Russians can’t even decide how much plutonium they have. There are discrepancies between the accounting systems of their military and the ministry of atomic energy.

Before the end of the cold war there was the perceived threat of a nuclear war. The threat has now changed. The loose security measures in the underfunded Russian and other former eastern-block nuclear industries are a much greater threat than a nuclear war or the hazards of nuclear waste. A nuclear war is a remote possibility because everybody seems to be aware that it would be a zero-sum game with no winners. Also nuclear waste disposal technology is so powerful that once the waste is disposed, it is nearly impossible for the nuclear waste to return to circulation or effect the human environment again. On the other hand, growing stockpiles of nuclear material that can be made into nuclear weapons is certainty a greater threat, especially when it is in unsafe hands prepared to sell at very low rates. Russia has reported 900 illegal attempts to gain entry to its nuclear facilities and another 700 cases where nuclear workers tried to smuggle out nuclear material. We don’t have any reason to believe that all attempts were stopped. Some material may well have been smuggled secretly. Some experts say that it is possible to make a nuclear bomb equivalent to the one dropped on Nagasaki, out of 7 kilograms of spent nuclear fuel instead of 5 kilograms of weapons grade plutonium and the know how for it is at large now. That technology is now available to everybody who wants to learn it, from the US documents of 1950’s that are no longer classified. Add the international loose measures for the monitoring and reprocessing of nuclear waste to this and the threat we are face to face today is clearly evident.

An institution called the International Atomic Energy Agency is responsible for monitoring the nuclear reactors in countries with no nuclear arms and that have signed the Nuclear Non-proliferation Treaty. It keeps an eye on those countries and makes sure no plutonium is secretly diverted to military use. There are countries like India and Israel that are not signatories and evidence that IAEA can be fooled. Both North Korea and Iraq recently declared that they had secretly produced 3 grams of weapons-grade plutonium. Even if the countries are unable to divert plutonium to the military, this does not prevent them from developing nuclear weapons. A nation can develop other parts of the bomb such as the case and electronics, and when the nation’s leader decides it is time to have a nuclear bomb, plutonium can be directed to the military. The nation would have a nuclear bomb in a few days.

With plutonium, the odds are weighed against the well being of humankind. If nation states persist in the costly production and use of plutonium, they risk weapons proliferation, environmental devastation and damage to human health. In addition to its dangers as a deadly nuclear weapon constituent, the release of plutonium into the environment also poses health and environmental risks. Even if plutonium does not reach and damage the environment and human health via the routes mentioned above, there is always the danger posed by the nuclear powered warships and submarines as a rather easy way to a nuclearly polluted environment. Four sunken nuclear submarines lie in the depths of the Atlantic and there are reports that the reactors and the war-heads they were carrying are leaking plutonium and other nuclear materials into the ocean. This may turn out to be the biggest environmental and health hazard ever encountered, if these nuclear materials enter the food chain. Although there is no risk that at that depth, fish will eat these materials, it is always possible that they can be carried to suitable places by strong ocean currents where fish may feed. A stronger possibility is that it may be eaten by plankton which is in turn eaten by fish. Indeed, the risks are enough to require that plutonium production is judged too dangerous to allow its dangerous continuous production. Building on the international non-proliferation regime and current practices in the nuclear industry, a more comprehensive and specific regime must be constructed to manage plutonium and hasten its elimination. But such an international step is not that easy to take. 161 countries are signatories to the non-proliferation treaty and any change such as the banning of plutonium reprocessing, requires that they all agree on the subject and sign again.

These risks might be more tolerable if plutonium held unquestionable economic value in the foreseeable future. But no proven technology exists to generate electricity from plutonium or highly enriched uranium at economically competitive costs. As noted above, fuels made of low enriched uranium are both cheaper and less dangerous. Also, they do not pose comparable health, environmental or security hazards. The reserves of low-cost, low-enriched uranium accessible world-wide may run out, but not before the late 21st century, and then only if nuclear energy use increases markedly without eliciting increased supplies from either more efficient uranium handling or discovery of new reserves. Such an outcome is unlikely. Plutonium for long-term research and development programs will always be available in the form of spent fuel, even after the large surpluses of separated plutonium are reduced.

Today, the nuclear arms race is not accelerating as it was in the late 1940s and again in the late l970s; rather, it is being reversed, and unlike the 1970s, plutonium is not seen as the millennial solution to the energy needs of the world or as the salvation for the international nuclear power industry. Today, plutonium is increasingly perceived as a global problem that must be solved. Even the research grants for the reprocessing technology of plutonium are coming to a halt. Central to the establishment of an international plutonium regime is giving priority to gaining control of surplus stockpiles of separated plutonium that could be most readily reintroduced into weapons. The difficulties lie not in the mechanics but in the politics of international storage and ultimate disposal. Because it will take time to determine how and where to dispose of plutonium, the issue of safe, secure storage must be addressed at once.

By internationalizing the disposal and safety problem, the plutonium regime could provide a forum for scientists, engineers, environmentalists and others to examine the world’s technical capabilities and geography in order to identify the best possible options for disposing of plutonium and other radioactive materials.