ABSTRACT
    The purpose of this Energy FAQ is to provide a few answers to common questions about energy. Concepts in this FAQ are based on the principles in the web-book Energy Science Made Simple which is available on this website. Minimum Year 10.

WHAT IS ENERGY SCIENCE?
    Presently science is divided into the fields of physics, chemistry and biology. Many modern scientific and engineering developments involve energy concepts from many scientific disciplines. Modern scientists and engineers therefore should be more familiar with energy concepts outside of their specific areas. It is beneficial then to group the basic concepts of energy from the different areas of science together. Such a common study of energy is called energy science which does not cover specific details of all of science but rather only the ones specifically relating to the concepts of energy.

    Sodium lights produce photons of the same wavicle frequency and so their light is monochromatic. This does not mean however that the wavicles will be synchronized with each other. Such light is incoherent because it does not have a regular spacing between photons as shown in the diagram. Radio and especially laser wavicles on the other hand can be coherent as well as monochromatic. This is why laser light is so powerful. The vibrations of the photon wavicles are completely in step. This is why radio wavicles can induce a current in an electric wire, whereas infrared light wavicles cannot.

DO OUR EYES DETECT SINGLE PHOTONS?
    Our eyes are pretty sensitive instruments. It only takes about five or six photons striking a nerve cell in rapid succession to send a message to the brain.

WHY DO FORCES OCCUR?
    Presently forces are not very well understood in science. Most scientists think that forces are produced by the exchange of interactive wavicles such as photons. In this view it is imagined that the magnetic field is actually a huge cloud of photons constantly traveling from one end of the magnet and being returned to the other. However it is also a well known fact that different types of blackbodies absorb any type of photon that is emitted. Surely then some type of blackbody placed in the path of a stationary magnetic field would absorb the photons that were emitted and quickly heat up. Tests show that a stationary magnetic field can not be absorbed. It appears that forces are transferred through the substratum by some presently unknown mechanism. Presently we do not know whether all force fields are the result of one basic type of field or if there are four or even more individual fields that exist. Force fields it seems are not composed of energy or contain energy. They can be thought of as extensions of the energy wavicles that drive them. For example a magnetic field can be produced by a flow of electrons in a wire. This magnetic field can in turn produce a flow of electrons in another wire some distance away. Imagine the fields to be similar to a rigid member that transfers the energy from one wire directly to the other.

HOW ARE RADIO "WAVES" PRODUCED?
    When the lines of force in a magnetic field move, there are often real photons that are formed. For example when the electromagnetic field around a radio transmission aerial expands and contracts, real photons of low energy called radio wavicles are formed. The moving fields in effect scoop out small wavicles of energy as if out of nothing. In reality though the new wavicle of energy was created by direct transfer of the energy in the transmission aerial through the fields and to the new energy wavicles. If the forces in the field collapse slowly, wavicles with slow vibration equal to the vibrations of the magnetic field will be created. If the magnetic force field collapse quickly, wavicles with a fast vibration will be created.

IS PERPETUAL MOTION POSSIBLE?

    In the microscopic world, the motion of atoms and electrons is a world of constant "perpetual motion". In modern science though perpetual motion does not refer to the goings on in the microscopic world, it is the ability to achieve endless macroscopic motion such as the swinging of a pendulum. The question that has been asked so often over the centuries is whether perpetual motion is possible. For example it has been suggested that the substratum of space may not be totally uniform. If there were compressions and expansions of the substratum itself, then energy may be squeezed out in the process. If the universe is expanding or contracting there would be the same effect.
    Thousands of men have searched for ways to convert the seemingly endless thermal energy contained in the environment around us into useful work. It appears James Joule who introduced to science the concept of conservation of energy, believed that this would be possible. James Maxwell, the famous 1880s scientist, joked about a very tiny demon which might be pressed into service to separate quickly moving molecules from slower molecules by operating a trap door between two chambers as shown in the illustration. A fact taught in high school chemistry is that the temperature of a substance is only a measure of the average energy of the molecules. The illustration shows a bell curve of the range of energies that a typical gas would have. At any instant of time some molecules contain more and some less energy. These two reservoirs of energy produced by the demon could then be used to operate an engine to produce external energy. So far it appears that perpetual motion may well be impossible.

WHAT IS ENTROPY?

    Entropy often is confusing to people learning energy. This is because entropy is often implied as being a type of energy. It is not. Entropy...is a number that can be multiplied by the ambient temperature of the surroundings to obtain the bound energy. The bound energy...is the part of the energy that could never be converted into external energy or useful work based on the particular ambient environment.

WHAT IS CARNOT'S LAW?

    Carnot's Law is usually written down as an equation but a definition of it could be...it is impossible to construct a heat engine which will convert a given quantity of thermal energy into an equivalent amount of mechanical power. It is often said that because fuel cells do not create electricity by converting thermal energy into work, they are not limited to Carnot's Law. This is not entirely a valid statement. Carnot's Law, because it was written a long time ago, only related to processes that converted thermal energy into mechanical power. The principles behind Carnot's Law however do relate to chemical processes as well. The carnot ratio is a more modern interpretation that relates to all forms of internal energy.

WHAT IS THE SECOND LAW OF THERMODYNAMICS?
    In engineering, the Second Law of Thermodynamics states that...thermal energy can never be entirely converted into useful work. Thermal energy is a form of internal energy which is the motion energy of the molecules. There are however other forms of internal energy such as chemical energy that also cannot be completely converted into useful work or external energy. Even a fuel cell theoretically can not entirely convert chemical energy into electricity. Therefore all types of conversion of internal energy into external energy are limited by the Second Law of Energy...different forms of energy can not necessarily be entirely converted into other forms of energy. Obviously this law is not very explicit because it will take several pages of words to describe what the limitations on energy conversion are. It is simply a warning of what to expect.

WHY CAN'T A HEAT ENGINE BE 100% EFFICIENT?

    Useful work or external energy can only be extracted from a source of thermal energy if it can flow into another reservoir of lower temperature. The maximum amount of external energy that can be extracted from two reservoirs of internal energy is predictable. The model shown above can be used to analyze such interactions. When two atoms collide they do not merely bounce off each other, the impact of the collision is absorbed temporarily by the atom's electron which gains energy. At times a real photon is emitted which is radiated away from the atom in the form of radiant energy. In collisions, it appears that the atoms come to a complete stop relative to each other and become at least temporarily glued together by the van der Waal forces. Because the atom collisions results in all the atoms' motion being removed, each photon produced represents an energy amount that corresponds to the absolute temperature, not just the difference in temperature between the two reservoirs. The photon absorption is however different than the photon emission. The photon is not absorbed into only atoms with zero thermal energy, it merely finds any atom to be absorbed into. It is these differences in emission vs absorption of the system that result in the limited amount of external energy that can be taken from internal energy. In Reservoir T, as shown in the above illustration, there are two atoms of 300°K colliding, depicting the average wavicle energy in the reservoir. The photon of 300°K could travel over into Reservoir T0 where atoms are emitting photons of 288°K. In between the two reservoirs there is a 100% efficient solid state material called the U-X converter that absorbs the photon, extracts some external energy and re-emits a smaller photon into the T0 reservoir. It would be possible to only extract the difference in photon energy or 12°K of external energy because of the laws of equilibrium. If more external energy than this is extracted, the photons from the T0 reservoir would be hotter and the net photon flow would be in the reverse direction. Imagine following a single photon traveling from Reservoir T to Reservoir T0. The amount of external energy that was extracted was 12 units, the amount of internal energy U2 removed from T was 300 units and the amount of internal energy transferred to Reservoir T0 was 288 units.

DO ALL FUEL CELLS RUN ON HYDROGEN?
    Some fuel cells use only hydrogen in the electrochemical reaction of the fuel cell. All fuel cells however can chemically convert carbon based fuels such as natural gas into hydrogen in a reformer attached to the fuel cell. There are several fuel cells that use both hydrogen and carbon monoxide in the electrochemical reaction. The Direct Methanol Fuel Cell uses methanol alcohol directly in the fuel cell.

ARE FUEL CELLS MORE EFFICIENT THAN ENGINES?

    Heat engines such as gas turbines are considered to be inferior to fuel cells because they must convert the high temperament chemical energy into low temperature thermal energy first. In spite of this, gas turbines (with addition of heat exchanging or steam turbines) can be highly efficient in the large sizes and produce little pollution. The latest are 57% efficient in converting fuel to electricity. In the future, ceramic gas turbines could reach 70% efficiency. This would result in a higher efficiency than what the fuel cell can achieve by itself. There is even some possibility of using energy transformers in the combustion process to increase the efficiency to 80%. Unfortunately very small gas turbines are not nearly as efficient. Present microturbines in the 30 kw range are only about 25% efficient even when heat exchanging is employed, though future ceramic microturbines in this size may achieve 35% efficiency. Small fuel cells on the other hand can be up to 50% efficient.

FUEL CELLS ARE NOT LIMITED BY CARNOT'S LAW ARE THEY?

    Carnot's Law, because it was written a long time ago, only relates to processes that convert thermal energy into external energy or useful work. The principles of Carnot's Law however also relate to chemical processes occuring in the fuel cell. The carnot ratio is a more modern interpretation that relates to all forms of internal energy being converted into external energy. A fuel cell therefore is also bound by the carnot ratio. The theoretical efficiency of a fuel cell can generally be higher that a heat engine because the carnot ratio of the electrochemical process is over 90% while many heat engines have a carnot ratio of around 72%.

IS THE HUMAN BODY MUCH MORE EFFICIENT THAN AN ENGINE?

    Human muscles don't convert the chemical energy in foods into thermal energy first as is done in an engine such as a gas turbine. It is often thought that this must mean that the human body is very efficient in converting chemical energy into useful work or external energy. Tests have been done with cyclists, and it appears that the body only has a 25% net efficiency in converting food into muscle power. A modern gas turbine combined cycle powerplant is up to 57% efficient in converting chemical energy into external energy.

WHAT IS THE MAXIMUM TEMPERATURE THAT SUNLIGHT CAN PRODUCE?

    The average energy of each photon arriving on earth from the sun could produce a temperature of up to 6000°C. This however is only the average. As shown on the bell curve, some light photons have considerably more energy. If these were separated out, temperatures of over 10,000°C could be produced. The dilemma with solar energy is that a window is required to let the sunlight into any process. This same window also allows radiant energy to escape back out. One-way coatings generally only work to keep the low temperature heat rays from escaping. So it is hard to create the maximum temperatures possible.

WHAT IS A HEAT PUMP?
    A heat pump is the reverse of an air conditioner. With a small amount of mechanical or electrical energy, it can move a greater amount of thermal energy into an indoor environment at an elevated temperature. Laws of energy are still being obeyed. The extra thermal energy is transferred from the ambient environment.

WHAT IS AN ENDOTHERMIC CHEMICAL REACTION?
    In many types of chemical reactions a great deal of thermal energy is liberated and the reaction become hotter. This is called an exothermic reaction. There are other types of chemical reactions that actually absorb thermal energy from the surroundings. This is called an endothermic reaction. Usually the added thermal energy must be of a high temperature. For example in a chemical recuperated gas turbine, water gas can be created from natural gas and water. Water gas is a mixture of hydrogen and carbon monoxide. The water gas produced has more chemical energy than the natural gas that was used to make it. High temperature thermal energy from the gas turbine's exhaust is drawn into the water gas reaction because it is endothermic.
    If natural gas could be made into some other sort of intermediate fuel gas with a low helmholtz ratio, a fuel gas of perhaps ten times the original amount of chemical energy in the natural gas could be created if it could draw the additional thermal energy from the ambient environment. Such a low helmholtz ratio fuel gas could burn at around 27°C which would be a barely high enough temperature to heat a house using a very efficient sort of heat exchanger. Only one-tenth as much natural gas would be required to heat the house. Would such a furnace defy the laws of energy. No, the chemical reaction is just acting like a type of heat pump.

WILL WE ALL BE DRIVING FUEL CELL POWERED CARS SHORTLY?
    There are still many problems to be sorted out before fuel cells will be powering the majority of vehicles. Presently the Proton Exchange fuel cell is the leading contender for an automobile power plant. Such a fuel cell uses hydrogen gas. There have been problems in making a reliable reformer for converting other hydrocarbon fuels to hydrogen gas on board the vehicle. This means that the vehicle would need to fuel up on pure hydrogen. It would be expensive to set up a worldwide hydrogen fueling system. The Solid Oxide fuel cell can run on all kinds of hydrocarbon fuels. It needs a few minutes warm up time before any electric power is developed. The Direct Methanol fuel cell is the most attractive contender. It can produce power already at ambient temperatures and runs directly on liquid methanol fuel without any reforming. This fuel can be easily handled by slightly modified service stations. There are still some unresolved problems with this type of fuel cell.

IS IT POSSIBLE THAT FUSION POWER WILL BE DEVELOPED SOON?
    In a nuclear fission power plant, there is a lot of radiation produced during the nuclear reaction. Waste products from the reaction are highly radioactive for 100s of years in the future. A nuclear fusion power plant does produce harmful radiation during the reaction, but there are no radioactive waste products produced. In a typical fusion reaction, two hydrogen molecules are fused together to form a helium atom. There is a small amount of mass left over that can not be utilized in the formation of the helium atom. This small amount of mass results in a great deal of energy being liberated. Fusion reactions are inhibited by the repulsive force that acts between two positively charged nuclei. In a hot fusion process, very hot temperatures are needed. The atoms at these high temperatures are traveling very fast. The momentum of the atoms is so large that they can bump together and fuse in spite of the repulsive forces involved. There have also been many proposals for cold fusion processes. In chemical processes, atoms can often be recombined at normal room temperatures by using catalysts. If a nuclear catalyst could be found, it may be possible to combine hydrogen atoms into helium at normal room temperatures. In the ideal cold fusion process, electricity would be generated directly from the excess energy of the fusion just like in a fuel cell.
    Fusion occurs in the sun, so we know that hot fusion is possible. So far scientists have had some success at duplicating the process on earth. Very short reactions have been achieved. So far there have been no working models of cold fusion. It is hard to tell whether either of these two methods will ever be successful in producing power. If any form of fusion reaction could be developed, it would completely change our way of producing energy in the world. Our environment would be cleaner because less hydrocarbon fuel would be burned.

WHY IS SOLAR POWER NOT MORE WIDELY USED?
    Solar energy from the sun shines on the entire earth every single day. It is free to anyone that wants to use it, and moreover it would be hard for any country to tax its use. Why then is solar energy not more widely utilized? The problem with the sun is that it does not shine during the night. During the day clouds can severely reduce the amount of energy received. Some sort of backup power is required. This increases the cost of the equipment. Till now the overall cost of producing electricity or generating heat with solar energy was slightly more expensive than by burning fossil fuel. This may change in the near future.

CAN ALTERNATE ENERGY SUPPLY THE WORLD WHEN OIL RUNS OUT?
    This is a big question that looms over the world. The people on earth use more and more energy every year. Where will all the energy come from? Will the supply of fossil fuels such as oil, coal, and natural gas run out soon? It appears there are tar sands that could supply the world with oil for some time to come. But if oil is in short supply, will the price of energy climb so high that our standard of living will be compromised? Are there alternative sources of energy that could totally replace the oil at a reasonable price? Nuclear fission power is not the answer it was once thought to be. It is not known presently whether nuclear fusion power will be viable in the next 100 years. The greatest dilemma is that the people on the earth can't seem to control the population growth. This is the single biggest threat to a high standard of living. If the world's population could be held at present levels, scientists believe that there are enough sources of alternate energy around for people to maintain a reasonable standard of living. Solar energy alone could provide all the power needs of the world. Quick calculations show that the present population of the entire world could have a reasonable standard of living by collecting solar energy from an area of about 270 km by 270 km square, if high efficiency solar panels were available.

ARE HYDROCARBON FUELS BAD FOR THE ENVIRONMENT?
    Hydrocarbon fuels contain both carbon and hydrogen atoms. When they react with the oxygen in the air, water and carbon dioxide are produced. The carbon dioxide is considered a greenhouse gas. It appears that higher percentages of carbon dioxide in the atmosphere result in increased average temperatures. It is really only fossil fuels such as oil, coal, and natural gas that result in increased levels of carbon dioxide. If biomass is used instead, the carbon dioxide is simply recycled in the atmosphere. When fuels are burned, nitrogen oxides, carbon monoxide, unburned hydrocarbons, as well as other harmful chemicals are often released into the air. This can also occur with hydrogen combustion but to a more limited extent. In fuel cells hydrocarbon fuels can be reacted with little resulting pollution except for carbon dioxide.

COULD A SUPER BATTERY BE DEVELOPED?
    There is some remote possibility that a battery could be developed that could be based on the nuclear energy instead of chemical energy that is available in a substance. This would be a cold fusion battery where the nuclear energy is converted directly to electricity instead of being converted into thermal energy first. The energy available would be very large. About one gram of fusion fuel would be the equivalent of 9,000 liters of oil. It may be possible to slip a new set of throw away style batteries into your electric car every year or so. Presently cold fusion in any form is science fiction, but there do not appear to be any laws of nature that would be broken in such a device.

COULD BATTERY OPERATED VEHICLES BE PRACTICAL?
    The major problem with battery operated vehicles is that the batteries need to be recharged for several hours when they become discharged. Many families don't have room in their driveways or parking garages to have both an electric vehicle as well as one that uses fuel. If the families want to go on a vacation or just to see the relatives on Thanksgiving, the electric car may not be able to go the whole distance on one charge. How many people would put up with sitting around a charging station for a few hours in the middle of a trip while the batteries are charging. Would the relatives have charging facilities at the other end. Many people don't have a spot to park cars on their property. It is not likely that plugs would be provided at the side of all streets.

WHICH TYPE OF FUEL CELL IS THE MOST EFFICIENT?
    When considering practical fuel cells, it appears that the Solid Oxide fuel cell will be the most efficient. Small SOFC will be about 50% efficient from about 15%-100% power. To achieve even greater efficiency, medium sized and larger SOFC are generally combined with gas turbines. The fuel cells are pressurized and the gas turbine produces electricity from the extra waste thermal energy produced by the fuel cell. The resulting efficiency of the medium SOFC could be 60% and large one's over 70%.

WHAT IS MOST OF THE ENERGY IN THE WORLD USED FOR?
    A 1975 study showed that in Canada, of the total energy used, about 33% was used to heat buildings, 12% to heat water, 25% for transportation, 14% for electrical equipment, 6% for products like plastics and fertilizer, and 10% for generation production losses. Statistics like this show that a large part of our energy is consumed in heating buildings and hot water. This is low temperature thermal energy that is required that could often be obtained as a byproduct of generating electricity.

WILL COGENERATION BE WIDELY USED IN THE FUTURE?
    Presently most of the electricity in the world is generated by large power stations. Most of these powerplants generate power by using heat engines such as gas turbines and steam turbines. With a heat engine, there will always be large amounts of low temperature thermal energy that are thrown away. Because the powerplants are generally far away from potential users, this low temperature heat is not generally used. If the powerplants were smaller, they could be located near the potential users. Why has there not been more of a move in this direction in the past? It is largely because electricity generation was often regulated by regional authorities that were granted a monopoly. This is changing. Now that the regulatory roadblock is removed, will there be a big shift to cogeneration or Combined Heat and Power as it is often called?
    To achieve extensive cogeneration, almost every building would need to have its own powerplant. Many experts feel that this level of cogeneration will only be achieved once fuel cells become commonly available. Not only do they produce reasonable efficiencies in small sizes, they will likely be able to run quietly, need infrequent maintenance, emit little pollution and have high efficiency even at part load conditions.
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HOW CAN HOUSES BE MADE THE MOST ENERGY EFFICIENT?
    A study in 1980 of an average Canadian house showed that 64% of the total energy was used for space heating, 9% for hot water, and 27% for appliances and lights. A prototype high efficiency house used only 7% as much energy for space heating as the average house.

IS THE "STEAM" ENGINE A THING OF THE PAST?
    Most new large electric powerplants use the gas turbine combined cycle. On these, a steam turbine is used to convert the large amounts of thermal energy available in the exhaust of the gas turbine. A very large amount of electricity in the world is still generated from coal fired steam powerplants. Nuclear powerplants and large military ships and submarines also use steam turbines. There are several large solar energy powerplants that use steam-turbines to extract power from steam produced in solar concentrators. The Microvel hybrid electric vehicle slated for production in Canada uses a small steam-turbine to recharge the batteries of the vehicle. Modern high temperature alloy metals may give the steam turbine a new life as efficiencies of over 50% can be achieved in large powerplants.

IS THE CARNOT CYCLE THE MOST EFFICIENT ENGINE POSSIBLE?
    Yes and no! It is not possible to have a theoretical heat engine cycle that is more efficient than the Carnot cycle. The Carnot cycle though is not the only heat engine cycle that can develop this maximum efficiency in theory. Many theoretical cycles can approach this efficiency under low power conditions. The Stirling and Ericsson cycle are the only practical cycles that can develop this efficiency at maximum power conditions. The Stirling and Ericsson cycles achieve this efficiency by employing heat exchanging, while the Carnot cycle does not.

WHY ARE SOLAR CELLS SO INNEFFICIENT?
    Present day low cost commercialsolar cells only convert about 11% of the radiant energy into electricity at most. This means that 89% of the remaining sunlight is converted into thermal energy. Solar cells are actually sheets of semiconductor material. When the sunlight strikes the semiconductor an electrical potential is created by dislodging electrons from the impact of the photons. Sunlight however is made of photons that contain different amounts of photon energy. The semiconductor cannot easily be tuned to receive all types efficiently. This means that some photons will not be converted at all because they have too little photon energy and some photons will only have a part of their energy converted to electricity because they have too much photon energy. Scientists in laboratories are working on solar cells that have multiple layers of different semiconductors. Each layer is tuned to photons with a specific photon energy. Another type of solar cell first separates the light into different colors and then each color is converted in a different type of semiconductor.

WHY DOES A "SILVERED" SURFACE REDUCE HEAT LOSS?
    Day hikers often carry a safety blanket or survival suit with them in case they become stranded in the mountains. The blankets or suits are generally made from a polyethylene plastic sheet that has an aluminum coating applied to one side. The plastic by itself is a windbreaker. It prevents the wind from carrying away your body heat. Your body is also constantly radiating away thermal energy in the form of infrared radiant energy. This radiant energy, which is really composed of low energy photons, would easily pass straight through clear plastic. To prevent this radiant energy from passing through, an aluminum coating is applied to the plastic film. Most of the radiant energy is bounced back to your body. It is better to apply an aluminum coating to the plastic than to color it. The coloring of course would prevent the radiant energy from passing straight through the plastic. The plastic would absorb more of the radiant energy and become slightly warm. This thermal energy would then be carried away by wind blowing by your body.

REVISION HISTORY
1999Jul12 Started Energy FAQ webpage.
1999Dec31 Completely changed webpage.
2002May03 Changed hyphenated names such as helmholtz-energy to helmholtz energy.

COPYRIGHT © 1999-2008 by Ben Wiens Energy Science Inc. All rights reserved.