NationMaster - Encyclopedia: Hydrogen Economy

A hydrogen economy is a hypothetical economy in which the energy needed for motive power (for automobiles or other vehicle types) or electricity (for stationary applications) is derived from reacting hydrogen (H₂) with oxygen. While the primary purpose is to eliminate the use of carbon-based fossil fuels and thus reduce carbon dioxide emissions, a secondary goal is to provide an energy carrier to replace dwindling supplies of petroleum. Image File history File links Broom_icon. ... Image File history File links Emblem-important. ... Car redirects here. ... The Trikke is a Human Powered Vehicle (HPV) Automobiles are among the most commonly used engine powered vehicles. ... Electricity (from New Latin Ä“lectricus, amberlike) is a general term for a variety of phenomena resulting from the presence and flow of electric charge. ... This article is about the chemistry of hydrogen. ... Fossil fuels or mineral fuels are hydrocarbons found within the top layer of the earthâ€™s crust. ... Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... For other uses, see Peak oil (disambiguation). ...

In the context of a hydrogen economy, hydrogen is an energy storage medium, not a primary energy source (see nuclear fusion for an entirely separate discussion of using hydrogen isotopes as an atomic energy source). Nevertheless, controversy over the usefulness of a hydrogen economy have been confused by issues of energy sourcing, including fossil fuel use, global warming, and sustainable energy generation. These are all separate issues, although the hydrogen economy impacts them all (see below). The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing fusion power. ... Fossil fuels or mineral fuels are hydrocarbons found within the top layer of the earthâ€™s crust. ... Global warming refers to the increase in the average temperature of the Earths near-surface air and oceans in recent decades and its projected continuation. ... This article is about a concept related to renewable energy, of which sustainable energy is a superset. ...

Proponents of a hydrogen economy suggest that hydrogen is an environmentally cleaner source of energy to end-users, particularly in transportation applications, without release of pollutants (such as particulate matter) or greenhouse gases at the point of end use. Analyses have concluded that "most of the hydrogen supply chain pathways would release significantly less carbon dioxide into the atmosphere than would gasoline used in hybrid electric vehicles" and that significant reductions in carbon dioxide emissions would be possible if carbon capture or carbon sequestration methods are utilized at the site of energy or hydrogen production.^[1] Carbon sequestration from a fossil-fuel power station A carbon dioxide (CO2) sink is a carbon reservoir that is increasing in size, and is the opposite of a carbon source. The main natural sinks are (1) the oceans and (2) plants and other organisms that use photosynthesis to remove carbon... Carbon sequestration from a fossil-fuel power station A carbon dioxide sink or CO2 sink is a carbon reservoir that is increasing in size, and is the opposite of a carbon source. The main sinks are the oceans and growing vegetation. ...

Critics of a hydrogen economy argue that for many planned applications of hydrogen, direct distribution and use of energy in the form of electricity, or alternate means of storage such as chemical batteries, fuel plus fuel cells, or production of liquid synthetic fuels from CO₂ (see methanol economy), might accomplish many of the same net goals of a hydrogen economy,^{[citation needed]} while requiring only a small fraction of the investment in new infrastructure. Hydrogen has been called the least efficient and most expensive possible replacement for gasoline (petrol).^[2] A comprehensive study of hydrogen in transportation applications has found that "there are major hurdles on the path to achieving the vision of the hydrogen economy; the path will not be simple or straightforward".^[1] A fuel cell is an electrochemical device similar to a battery, but differing from the latter in that it is designed for continuous replenishment of the reactants consumed; i. ... Synthetic fuel or synfuel is any liquid fuel obtained from coal, natural gas, or biomass. ... The methanol economy is a hypothetical future economy in which methanol has replaced fossil fuels as a means of transportation of energy. ...

Rationale

A hydrogen economy is proposed to solve the ill effects of using hydrocarbon fuels in transportation, and other end-use applications where the carbon is released to the atmosphere. Image File history File links Hydrogen. ... Image File history File links Hydrogen. ... Oil refineries are key to obtaining hydrocarbons; crude oil is processed through several stages to form desirable hydrocarbons, used in fuel and other commercial products. ...

In the current economy, the transportation of people and goods (so-called mobile applications) is fueled primarily by petroleum, refined into gasoline and diesel, and natural gas. However, the burning of these hydrocarbon fuels causes the emission of greenhouse gases and other pollutants. Furthermore, the supply of hydrocarbon resources in the world is limited, and the demand for hydrocarbon fuels is increasing, particularly in China, India and other developing countries. For other uses, see Fuel (disambiguation). ... Pumpjack pumping an oil well near Lubbock, Texas Ignacy Åukasiewicz - inventor of the refining of kerosene from crude oil. ... Petrol redirects here. ... This article is about the fuel. ... This article is about the fossil fuel. ... Oil refineries are key to obtaining hydrocarbons; crude oil is processed through several stages to form desirable hydrocarbons, used in fuel and other commercial products. ... Greenhouse gases are gaseous components of the atmosphere that contribute to the greenhouse effect. ... Pollutants are substances which directly or indirectly damage us or the environment. ...

In a hydrogen economy, hydrogen fuel would be manufactured from some primary energy source and used as a replacement for hydrocarbon-based fuels for transport. The hydrogen would be utilized either by direct combustion in internal combustion engines or as fuel in proton exchange membrane fuel cells. The primary energy source can then become a stationary plant which can use renewable, nuclear or coal-fired energy sources, easing the pressure on finite liquid and gas hydrocarbon resources. There is no carbon dioxide emission at the point of use. With suitable primary energy sources, greenhouse gas emissions can be reduced or eliminated. Excepting minor NOx generation from hydrogen internal combustion engines, the emission footprint of a hydrogen economy remains that of the underlying energy generation technology. An internal combustion engine is an engine that is powered by the expansion of hot combustion products of fuel directly acting within an engine. ... A fuel cell is an electrochemical device similar to a battery, but differing from the latter in that it is designed for continuous replenishment of the reactants consumed; i. ... Renewable energy (sources) or RES capture their energy from existing flows of energy, from on-going natural processes, such as sunshine, wind, flowing water, biological processes, and geothermal heat flows. ... This article is about applications of nuclear fission reactors as power sources. ... Coal Coal (IPA: ) is a fossil fuel formed in swamp ecosystems where plant remains were saved by water and mud from oxidization and biodegradation. ... Top: Increasing atmospheric CO2 levels as measured in the atmosphere and ice cores. ...

Hydrogen has a high energy density by weight. The fuel cell is also more efficient than an internal combustion engine. The internal combustion engine is said to be 20-30% efficient, while the fuel cell is 35-45% efficient (some even higher) (not accounting for losses in the actual production of hydrogen, which would result in an overall efficiency of about 25%) and together with the electric motor and controller, the drive train overall efficiency approaches 24% with low idling losses.^{[citation needed]} Energy density is the amount of energy stored in a given system or region of space per unit volume, or per unit mass, depending on the context. ... For other uses, see Mass (disambiguation). ...

Perspective: current hydrogen market (current hydrogen economy)

Hydrogen production is a large and growing industry. Globally, some 50 million metric tons of hydrogen, equal to about 170 million tons of oil equivalent, were produced in 2004. The growth rate is around 10% per year. Within the United States, 2004 production was about 11 million metric tons (MMT), an average power flow of 48 gigawatts. (For comparison, the average electric production in 2003 was some 442 gigawatts.) As of 2005, the economic value of all hydrogen produced worldwide is about $135 billion per year. Image File history File links Realizing. ... Image File history File links Realizing. ... A tonne (also called metric ton) is a non-SI unit of mass, accepted for use with SI, defined as: 1 tonne = 103 kg (= 106 g). ... The ton of oil equivalent (TOE) is a unit for measuring energy. ... 2005 is a common year starting on Saturday of the Gregorian calendar. ...

There are two primary uses for hydrogen today. About half is used to produce ammonia (NH₃) via the Haber process, which is then used directly or indirectly as fertilizer. Because both the world population and the intensive agriculture used to support it are growing, ammonia demand is growing. The other half of current hydrogen production is used to convert heavy petroleum sources into lighter fractions suitable for use as fuels. This latter process is known as hydrocracking. Hydrocracking represents an even larger growth area, since rising oil prices encourage oil companies to extract poorer source material, such as tar sands and oil shale. The scale economies inherent in large scale oil refining and fertilizer manufacture make possible on-site production and "captive" use. Smaller quantities of "merchant" hydrogen are manufactured and delivered to end users as well. For other uses, see Ammonia (disambiguation). ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... The Haber Process (also known as Haberâ€“Bosch process) is the reaction of nitrogen and hydrogen to produce ammonia. ... Spreading manure, an organic fertilizer Fertilizers (also spelled fertilisers) are compounds given to plants to promote growth; they are usually applied either via the soil, for uptake by plant roots, or by foliar feeding, for uptake through leaves. ... Map of countries by population â€” China and India, the only two countries to have a population greater than one billion, together possess more than a third of the worlds population. ... Pumpjack pumping an oil well near Lubbock, Texas Ignacy Åukasiewicz - inventor of the refining of kerosene from crude oil. ... In common usage a fraction is any part of a unit. ... In petroleum geology and chemistry, cracking is the process whereby complex organic molecules (e. ... Open pit mining Tar sands, also referred to as oil sand or bituminous sand, is a combination of clay, sand, water, and bitumen. ... Oil shale Oil shale is a general term applied to a fine-grained sedimentary rock containing significant traces of kerogen (a solid mixture of organic chemical compounds) that have not been buried for sufficient time to produce conventional fossil fuels. ...

If energy for hydrogen production were available (from wind, solar or nuclear power), use of the substance for hydrocarbon synfuel production could expand captive use of hydrogen by a factor of 5 to 10. Present U.S. use of hydrogen for hydrocracking is roughly 4 million metric tons per year (MMT/yr). It is estimated that 37.7 MMT/yr of hydrogen would be sufficient to convert enough domestic coal to liquid fuels to end U.S. dependence on foreign oil importation ^[3], and less than half this figure to end dependence on Middle East oil. Coal liquefaction would present significantly worse emissions of carbon dioxide than does the current system of burning fossil petroleum, but it would eliminate the political and economic vulnerabilities inherent in oil importation.

Currently, global hydrogen production is 48% from natural gas, 30% from oil, and 18% from coal; water electrolysis accounts for only 4%.^[4] The distribution of production reflects the effects of thermodynamic constraints on economic choices: of the four methods for obtaining hydrogen, partial combustion of natural gas in a NGCC (natural gas combined cycle) power plant offers the most efficient chemical pathway and the greatest off-take of usable heat energy. This article is about the fossil fuel. ... Pumpjack pumping an oil well near Sarnia, Ontario Petroleum (from Greek petra â€“ rock and elaion â€“ oil or Latin oleum â€“ oil ) or crude oil is a thick, dark brown or greenish liquid. ... Coal Coal (IPA: ) is a fossil fuel formed in swamp ecosystems where plant remains were saved by water and mud from oxidization and biodegradation. ... This article is about the chemical process. ... Combined cycle describes when a power producing engine or plant employs more than one thermodynamic cycle. ...

The large market and sharply rising prices have also stimulated great interest in alternate, cheaper means of hydrogen production. ^[5]

Production, storage, distribution

Today hydrogen is produced for merchant use and captive industrial applications using mature, thermodynamically efficient technologies. Linking its centralized production to a fleet of light-duty fuel cell vehicles will require the siting and construction of a distribution infrastructure with large investment of capital. Further, the technological challenge of providing safe, energy-dense storage of hydrogen on-board the vehicle must be overcome to provide sufficient range between fillups. This article or section is incomplete and may require expansion and/or cleanup. ...

A key tradeoff: centralized vs. distributed production

In a future (full) hydrogen economy, primary energy sources and feedstock would be used to produce hydrogen gas as stored energy for use in various sectors of the economy. Producing hydrogen from primary energy sources other than coal, oil, and natural gas, would result in lower production of the greenhouse gases characteristic of the combustion of these fossil energy resources.

One key feature of a hydrogen economy is that in mobile applications (primarily vehicular transport) energy generation and use is decoupled. The primary energy source need no longer travel with the vehicle, as it currently does with hydrocarbon fuels. Instead of tailpipes creating dispersed emissions, the energy (and pollution) can be generated from point sources such as large-scale, centralized facilities with improved efficiency. This allows the possibility of technologies such as carbon sequestration, which are otherwise impossible for mobile applications. Alternatively, distributed energy generation schemes (such as small scale renewable energy sources) can be used, possibly associated with hydrogen stations. Carbon sequestration from a fossil-fuel power station A carbon dioxide sink or CO2 sink is a carbon reservoir that is increasing in size, and is the opposite of a carbon source. The main sinks are the oceans and growing vegetation. ... Distributed generation generates electricity from many small energy sources. ... A hydrogen station is a storage or filling station for hydrogen, usually located along a road or highway, or at home as part of the distributed generation resources concept. ...

Aside from the energy generation, hydrogen production could be centralized, distributed or a mixture of both. While generating hydrogen at centralized primary energy plants promises higher hydrogen production efficiency, difficulties in high-volume, long range hydrogen transportation (due to factors such as hydrogen damage and the ease of hydrogen diffusion through solid materials) makes electrical energy distribution attractive within a hydrogen economy. In such a scenario, small regional plants or even local filling stations could generate hydrogen using energy provided through the electrical distribution grid. While hydrogen generation efficiency is likely to be lower than for centralized hydrogen generation, losses in hydrogen transport can make such a scheme more efficient in terms of the primary energy used per kilogram of hydrogen delivered to the end user. Hydrogen damage is the generic name given to a large number of metal degradation processes due to interaction with hydrogen. ...

The proper balance between hydrogen distribution and long-distance electrical distribution is one of the primary questions that arises in the hydrogen economy.

Methods of production

Molecular hydrogen is not available on Earth in convenient natural reservoirs, though it is an atmospheric trace gas having a mixing ratio of 500 parts per billion by volume (Novelli, 1999) in addition to being produced by microbes and consumed by methanogens in a rapid biological hydrogen cycle. Most hydrogen on Earth is bonded to oxygen in water. Hydrogen is presently most economically produced using fossil fuels. In practice this is usually methane, though hydrogen can also be produced via steam reforming or partial oxidation of coal. More expensively it can also be produced via electrolysis using electricity and water, consuming approximately 50 kilowatt hours of electricity per kilogram of hydrogen produced. Nuclear power can provide the energy for hydrogen production by a variety of means ^[6], but its widescale deployment is opposed in some Western economies while it is embraced in others. Renewable energy is being used to produce hydrogen in Denmark^[7] and Iceland.^[8] Hydrogen production is done in bulk today from hydrocarbon fossil fuels via a chemical path. ... The parts-per notations are used to denote extremely low concentrations of chemical elements. ... A microorganism or microbe is an organism that is so small that it is microscopic (invisible to the naked eye). ... Methanogens are archaea that produce methane as a metabolic byproduct. ... This article is about the chemical process. ... Renewable energy effectively utilizes natural resources such as sunlight, wind, tides and geothermal heat, which are naturally replenished. ...

The environmental effects of hydrogen production can be compared with alternatives, taking into account not only the emissions and efficiency of the hydrogen production process but also the efficiency of the hydrogen conversion to electricity in a fuel cell.

While hydrogen (the element) is abundant on Earth, and indeed is the most abundant element in the universe, manufacturing hydrogen does require the consumption of a hydrogen carrier such as a fossil fuel or water. The former consumes the fossil resource and produces carbon dioxide, but often requires no further energy input beyond the fossil fuel. Decomposing water requires electrical or heat input, generated from some primary energy source (fossil fuel, nuclear power or a renewable energy). The economics and environmental impact of any implementation of any future hydrogen economy will largely be determined by future energy development. Fossil fuels or mineral fuels are hydrocarbons found within the top layer of the earthâ€™s crust. ... Chemical decomposition or analysis is the fragmentation of a chemical compound into elements or smaller compounds. ... Fossil fuels or mineral fuels are hydrocarbons found within the top layer of the earthâ€™s crust. ... This article is about applications of nuclear fission reactors as power sources. ... Renewable energy effectively utilizes natural resources such as sunlight, wind, tides and geothermal heat, which are naturally replenished. ... Face-to-face trading interactions on the New York Stock Exchange trading floor. ... This article is about the natural environment. ... Future energy development, providing for the worlds future energy needs, currently faces great challenges. ...

Electrolysis

The predominant methods of hydrogen production rely on exothermic chemical reactions of fossil fuels to provide the energy needed to chemically convert feedstock into hydrogen. But when the energy supply is mechanical (hydropower or wind turbines), hydrogen can be made via electrolysis of water. In current market conditions, the 50 kWh of electricity consumed to manufacture one kilogram of hydrogen is roughly as valuable as the hydrogen produced, assuming 8 cents/kWh. The price equivalence, despite the inefficiencies of electrical production and electrolysis, are due to the fact that most hydrogen is made from fossil fuels which couple more efficiently to producing the chemical directly, than they do to producing electricity. However, this is of no help to a hydrogen economy, which must derive hydrogen from any source other than fossil fuels if it is to achieve the goals which primarily drive it. This article is about the chemical process. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ...

High-temperature electrolysis (HTE)

Hydrogen can be generated from energy supplied in the form of heat (e.g., that of concentrating solar thermal or nuclear) and electricity through high-temperature electrolysis (HTE). In contrast with low-temperature electrolysis, HTE of water converts more of the initial heat energy into chemical energy (hydrogen), potentially doubling efficiency, to about 50%. Because some of the energy in HTE is supplied in the form of heat, less of the energy must be converted twice (from heat to electricity, and then to chemical form), and so potentially far less energy is required per kilogram of hydrogen produced. HTE has been demonstrated in a laboratory, but not at a commercial scale. High-temperature electrolysis schema. ... For other uses, see Heat (disambiguation) In physics, heat, symbolized by Q, is energy transferred from one body or system to another due to a difference in temperature. ... Fuel efficiency, in its basic sense, is the same as thermal efficiency, meaning the efficiency of a process that converts energy contained in a carrier fuel into energy or work. ...

HTE processes are generally only considered in combination with a nuclear heat source, because the only other non-chemical form of high-temperature heat (concentrating solar thermal) is not consistent enough to bring down the capital costs of the HTE equipment. It is possible that research into HTE and high-temperature nuclear reactors may eventually lead to a hydrogen supply that is cost-competitive with natural gas steam reforming. For example, some prototype Generation IV reactors have coolant exit temperatures of 850 to 1000 degrees Celsius, considerably hotter than existing commercial nuclear power plants. High temperature (950-1000 °C) gas cooled nuclear reactors have the potential to split hydrogen from water by thermochemical means using nuclear heat. General Atomics predicts that hydrogen produced in a High Temperature Gas Cooled Reactor (HTGR) would cost $1.53/kg. In 2003, steam reforming of natural gas yielded hydrogen at $1.40/kg. At 2005 natural gas prices, hydrogen costs $2.70/kg. Hence, just within the United States, a savings of tens of billions of dollars per year is possible with a nuclear-powered hydrogen supply of this type. Much of this saving would translate into reduced oil and natural gas imports. Generation IV reactors (Gen IV) are a set of theoretical nuclear reactor designs currently being researched. ... The degree Celsius (°C) is a unit of temperature named after the Swedish astronomer Anders Celsius (1701–1744), who first proposed it in 1742. ... This article is about applications of nuclear fission reactors as power sources. ... General Atomics is a nuclear physics and defense contractor headquartered in San Diego, California. ... â€œKgâ€ redirects here. ... 2005 is a common year starting on Saturday of the Gregorian calendar. ...

One side benefit of a nuclear reactor that produces both electricity and hydrogen is that it can shift production between the two. For instance, the plant might produce electricity during the day and hydrogen at night, matching its electrical generation profile to the daily variation in demand, and offloading the extra output at night into a storable medium for energy. If hydrogen can be produced economically, this scheme would compete favorably with existing grid energy storage schemes for electrical power. There is sufficient hydrogen demand in the United States that all daily peak generation could potentially be handled by such plants, with their excess generation converted to hydrogen at other times. Electricity (from New Latin Ä“lectricus, amberlike) is a general term for a variety of phenomena resulting from the presence and flow of electric charge. ... Ffestiniog pumped storage power station upper reservoir Grid energy storage lets energy producers send excess electricity over the electricity transmission grid to temporary electricity storage sites that become energy producers when electricity demand is greater. ...

Thermochemical production

Some thermochemical processes, such as the sulfur-iodine cycle, can produce hydrogen and oxygen from water and heat without using electricity. These processes can be more efficient than high-temperature electrolysis. Thermochemical production of hydrogen using chemical energy from coal or natural gas is generally not considered, because the direct chemical path is more efficient. The sulfur-iodine cycle is a series of thermochemical processes used to produce hydrogen. ...

None of the thermochemical hydrogen production processes have been demonstrated at production levels, although several have been demonstrated in laboratories.

Reactive Production

Hydrogen is the product of a number of chemical reactions with metals. Sodium is a classic example, with water and sodium metal reacting to form sodium hydroxide and hydrogen. Another example which has gained some recent interest is aluminium (as an aluminium/gallium alloy) reacting with water to produce aluminium oxide and hydrogen.^[9] In all cases the pure metal is consumed. For sodium in the diet, see Edible salt. ... Flash point Non-flammable. ... Aluminum redirects here. ... General Name, Symbol, Number gallium, Ga, 31 Chemical series poor metals Group, Period, Block 13, 4, p Appearance silvery white Standard atomic weight 69. ... An alloy is a homogeneous hybrid of two or more elements, at least one of which is a metal, and where the resulting material has metallic properties. ... Alumina redirects here. ...

Storage

Although molecular hydrogen has very high energy density on a mass basis, due in part to its low molecular weight, as a gas at ambient conditions it has very low energy density by volume. If it is to be used as fuel stored on board the vehicle, pure hydrogen gas must be pressurized or liquefied to provide sufficient driving range. Increasing gas pressure improves the energy density by volume, making for smaller, but not lighter container tanks (see pressure vessel). Achieving higher pressures necessitates greater use of external energy to power the compression. Alternatively, higher volumetric energy density liquid hydrogen may be used. However liquid hydrogen is cryogenic and boils at 20.268 K (–252.882 °C or –423.188 °F). Cryogenic storage cuts weight but requires large liquification energies. The liquefaction process, involving pressurizing and cooling steps, is energy intensive. The liquefied hydrogen has lower energy density by volume than gasoline by approximately a factor of four, in part due to the low density of liquid hydrogen—there is actually more hydrogen in a liter of gasoline (116 grams) than there is in a liter of pure liquid hydrogen (71 grams). Storage tanks must also be well insulated to minimize boil off. Ice may form around the tank and help corrode it further if the insulation fails. Insulation for liquid hydrogen tanks is usually expensive and delicate. Hydrogen storage is the main technological problem of a viable hydrogen economy. ... The molecular mass of a substance (less accurately called molecular weight and abbreviated as MW) is the mass of one molecule of that substance, relative to the unified atomic mass unit u (equal to 1/12 the mass of one atom of carbon-12). ... Steel Pressure Vessel A pressure vessel is a closed, rigid container designed to hold gases or liquids at a pressure different from the ambient pressure. ... Cryogenics is the study of very low temperatures or the production of the same, and is often confused with cryobiology, the study of the effect of low temperatures on organisms, or the study of cryopreservation. ... In physics, to liquefy or liquify means to turn something into the liquid state. ...

The mass of the tanks needed for compressed hydrogen reduces the fuel economy of the vehicle. Because it is a small, energetic molecule, hydrogen tends to diffuse through any liner material intended to contain it, leading to the embrittlement, or weakening, of its container. Hydrogen embrittlement is the process by which various metals, most importantly high-strength steel, become brittle and crack following exposure to hydrogen. ...

Distinct from storing molecular hydrogen, hydrogen can be stored as a chemical hydride or in some other hydrogen-containing compound. Hydrogen gas is reacted with some other materials to produce the hydrogen storage material, which can be transported relatively easily. At the point of use the hydrogen storage material can be made to decompose, yielding hydrogen gas. As well as the mass and volume density problems associated with molecular hydrogen storage, current barriers to practical storage schemes stem from the high pressure and temperature conditions needed for hydride formation and hydrogen release. For many potential systems hydriding and dehydriding kinetics and heat management are also issues that need to be overcome. Hydride is the name given to the negative ion of hydrogen, Hâˆ’. Although this ion does not exist except in extraordinary conditions, the term hydride is widely applied to describe compounds of hydrogen with other elements, particularly those of groups 1â€“16. ... In physical chemistry, chemical kinetics or reaction kinetics is the study of reaction rates in a chemical reaction. ...

A third approach is to absorb molecular hydrogen into a solid storage material. Unlike in the hydrides mentioned above, the hydrogen does not dissociate/recombine upon charging/discharging the storage system, and hence does not suffer from the kinetic limitations of many hydride storage systems. Hydrogen densities similar to liquefied hydrogen can be achieved with appropriate absorption media. Some suggested absorbers include MOFs, nanostructured carbons (including CNTs) and clathrate hydrate. Absorption, in chemistry, is a physical or chemical phenomenon or a process in which atoms, molecules, or ions enter some bulk phase - gas, liquid or solid material. ... Metal-Organic Frameworks (MOFs) are porous crystalline compounds consisting of metal ions coordinated to an often rigid organic molecule, creating holes in the structure. ... A nanostructure is an intermediate size between molecular and microscopic (micrometer-sized) structures. ... 3D model of three types of single-walled carbon nanotubes. ... Clathrate hydrates (or alternatively gas clathrates, gas hydrates, clathrates, hydrates etc) are a class of solids in which gas molecules occupy cages made up of hydrogen-bonded water molecules. ...

The most common method of on board hydrogen storage in today's demonstration vehicles is as a compressed gas at pressures of roughly 700 bar (70 MPa). Many people believe that the energy needed to compress hydrogen to these pressures presents a major barrier to a hydrogen economy. For example, if one considers the entire world using hydrogen just in their cars, then a large amount of energy would be needed simply to compress the hydrogen for storage, of the order of 30% of the total energy used for transport. If this energy was not recovered in any way, the net energy used to compress it would be wasted. Currently, vehicle fuel cells are very expensive, typically 100 times more expensive per kW output than conventional internal combustion engines. It further has been suggested that cars utilizing Li-ion or Li-polymer batteries for onboard energy storage are capable of being more efficient than hydrogen-fueled cars would ever be, and that they just need to be mass produced to become cost effective. There are also prototype designs for zinc-air fuel cells, which can function as large, rechargeable batteries, and are as efficient as any battery based system, but with ranges around 400 to 500 miles ^{[citation needed]}. For long trips, the electrolyte can even be completely replaced/exchanged at filling stations, which then recharge and recycle the spent electrolyte. For other uses, see Pascal. ... Lithium ion batteries (sometimes abbreviated Li-Ion or Li-On) are a type of rechargeable battery commonly used in consumer electronics. ... Lithium ion polymer batteries, or more commonly lithium polymer batteries (Abbreviated Li-Poly or LiPo) are rechargeable batteries which have technologically evolved from lithium ion batteries. ... Zinc-air batteries, also called â€œzinc-air fuel cells,â€œ are non-rechargeable electro-chemical batteries powered by the oxidation of zinc with oxygen from the air. ...

Distribution

Efficiency as an automotive fuel

An accounting of the energy utilized during a thermodynamic process, known as an energy balance, can be applied to automotive fuels. With today's technology, the manufacture of hydrogen via steam reforming can be accomplished with a thermal efficiency of 75 to 80 percent. Additional energy will be required to liquefy or compress the hydrogen, and to transport it to the filling station via truck or pipeline. The energy that must be utilized per kilogram to produce, transport and deliver hydrogen (i.e., its well-to-tank energy use) is approximately 50 megajoules. Subtracting this energy from the enthalpy of one kilogram of hydrogen, which is 141 megajoules, and dividing by the enthalpy, yields a thermal energy efficiency of roughly sixty percent (Kreith, 2004). Gasoline, by comparison, requires less energy input, per gallon, at the refinery, and comparatively little energy is required to transport it and store it owing to its high energy density per gallon at ambient temperatures. Well-to-tank, the supply chain for gasoline is roughly 80 percent efficient (Wang, 2002). The most efficient distribution however is electrical, which is typically 95% efficient. Electric vehicles are typically 3 to 4 times as efficient as hydrogen powered vehicles.^[10] Steam reforming, hydrogen reforming or catalytic oxidation, is a method of producing hydrogen from hydrocarbons. ... Transmission lines in Lund, Sweden Electric company redirects here. ... For electric vehicles other than battery powered passenger automobiles, see electric vehicle. ... Image File history File links Size of this preview: 800 Ã— 392 pixelsFull resolution (1506 Ã— 738 pixel, file size: 251 KB, MIME type: image/png)This chart was created with data found here. ...

Distributed electrolysis

Another pathway proposed for hydrogen production is distributed electrolysis. This method would bypass the problems of distributing hydrogen somewhat by distributing electricity instead. It would take advantage of existing infrastructure to transport electricity to small, on-site electrolysers located at filling stations. Hydrogen can be produced through electrolysis of water, which is roughly 70 percent efficient (using the lower heating value for hydrogen). However, accounting for the energy used to produce the electricity (i.e., enlarging the system boundary) and accounting as well for transmission losses will reduce this efficiency.

Natural gas combined cycle power plants, which account for almost all builds of new electricity plants in the United States, generate electricity at efficiencies of 60 percent or greater. Increased demand for electricity, whether due to hydrogen cars or other demand, would have the marginal impact of adding new combined cycle power plants. On this basis, distributed production of hydrogen would be roughly 40 percent efficient. However, if the marginal impact is referred to today's power grid, with an efficiency of roughly 40 percent owing to its mix of fuels and conversion methods, the efficiency of distributed hydrogen production would be roughly 25 percent. (Note that, analogous to hydrogen production from a fossil fuel, gasoline must be refined from crude oil, the "primary energy resource" (Nakicenovic, 1998).)

The distributed production of hydrogen in this fashion will be expected to generate air emissions of pollutants and carbon dioxide at various points in the supply chain, e.g., electrolysis, transportation and storage. Such externalities as pollution must be weighed against the potential advantages of a hydrogen economy. Other fuel cell technologies based on the exchange of metal ions (i.e. zinc-air fuel cells) are typically more efficient at energy conversion than hydrogen fuel cells, but the widespread use of any electrical energy->chemical energy->electrical energy systems would necessitate the production of electricity. Zinc-air batteries, also called â€œzinc-air fuel cells,â€œ are non-rechargeable electro-chemical batteries powered by the oxidation of zinc with oxygen from the air. ...

In summary, the so-called production problem is seen to be a combination of two different problems: one of producing hydrogen efficiently from energy sources, and the other of locating suitable (renewable or at least less polluting) energy sources to do it.

End use: fuel cells as alternative to internal combustion

One of the main offerings of a hydrogen economy is that fuel cells can replace internal combustion engines and turbines as the primary way to convert chemical energy into kinetic or electrical energy. The reason to expect this changeover is that fuel cells, being electrochemical, are usually (and theoretically) more efficient than heat engines. Currently, fuel cells are more expensive to produce than common internal combustion engines, but are becoming cheaper as new technologies and production systems develop. A fuel cell is an electrochemical device similar to a battery, but differing from the latter in that it is designed for continuous replenishment of the reactants consumed; i. ... The internal combustion engine is an engine in which the combustion of fuel and an oxidizer (typically air) occurs in a confined space called a combustion chamber. ... A Siemens steam turbine with the case opened. ... Electrochemistry is the study of the electronic and electrical aspects of chemical reactions. ...

Some types of fuel cells work with hydrocarbon fuels while all can be operated on pure hydrogen. In the event that fuel cells become price-competitive with internal combustion engines and turbines, large gas-fired power plants could adopt this technology. Such commercialisation would be an important step in driving down the cost of fuel cell technology.

Much of the interest in the hydrogen economy concept is focused on the use of fuel cells in cars. The cells can have a superior power-to-weight ratio, are much more efficient than internal combustion engines, and produce no harmful emissions. If a practical and engineerable method to store and carry hydrogen is introduced and fuel cells become cheaper, they can be economically viable to power hybrid fuel cell/battery vehicles, or purely fuel cell-driven ones. The economic viability of fuel cell powered vehicles will improve as the hydrocarbon fuels used in internal combustion engines become more expensive, due to the depletion of easily accessible reserves or economic accounting of environmental impact through such measures as carbon taxes. This article or section does not cite its references or sources. ... Hydrogen storage is the main technological problem of a viable hydrogen economy. ... For other types of Hybrid Transportation, see Hybrid (disambiguation)#Transportation. ... Four double-A batteries In science and technology, a battery is a device that stores energy and makes it available in an electrical form. ... A carbon tax is a tax on energy sources which emit carbon dioxide into the atmosphere. ...

Infrastructure

Since hydrogen causes hydrogen embrittlement of steel, it is not clear if hydrogen can simply be put into today's natural gas transmission systems. Proponents of the hydrogen economy envision local hydrogen sources. The challenges that large, rural high-efficiency hydrogen generators face are far more acute in an urban environment. Thus, some kind of transmission system will probably be required for cities. Image File history File linksMetadata Photo_praxair_plant. ... Image File history File linksMetadata Photo_praxair_plant. ... Hydrogen embrittlement is the process by which various metals, most importantly high-strength steel, become brittle and crack following exposure to hydrogen. ...

Hydrogen use would require the alteration of industry and transport on a scale never seen before in history. For example, the distribution of hydrogen fuel for vehicles in the U.S. would require an entirely new infrastructure costing hundreds of billions of dollars, or more.

Costs

Hydrogen seems unlikely to be the cheapest carrier of energy over long distances. Advances in electrolysis and fuel cell technology have not addressed the underlying cost problem.

Hydrogen pipelines are more expensive ^[11] than even long-distance electric lines. Hydrogen is about three times bulkier in volume than natural gas for the same enthalpy, and hydrogen accelerates the cracking of steel (hydrogen embrittlement), which increases maintenance costs, leakage rates, and material costs. The difference in cost is likely to expand with newer technology: wires suspended in air can utilize higher voltage with only marginally increased material costs, but higher pressure pipes require proportionally more material. t In thermodynamics and molecular chemistry, the enthalpy or heat content (denoted as H or Î”H, or rarely as Ï‡) is a quotient or description of thermodynamic potential of a system, which can be used to calculate the useful work obtainable from a closed thermodynamic system under constant pressure. ... Hydrogen embrittlement is the process by which various metals, most importantly high-strength steel, become brittle and crack following exposure to hydrogen. ...

Setting up a hydrogen economy would require huge investments in the infrastructure to store and distribute hydrogen to vehicles. In contrast, battery electric vehicles, which are already publicly available, would not necessitate immediate expansion of the existing infrastructure for electricity transmission and distribution, since much of the electricity currently being generated by power plants goes unused at night when the majority of electric vehicles would be recharged. A study conducted by the Pacific Northwest National Laboratory for the US Department of Energy in December 2006 found that the idle off-peak grid capacity in the US would be sufficient to power 84% of all vehicles in the US if they all were immediately replaced with electric vehicles^[12]. For electric vehicles other than battery powered passenger automobiles, see electric vehicle. ...

Different production methods each have differing associated investment and marginal costs. The energy and feedstock could originate from a multitude of sources i.e. natural gas, nuclear, solar, wind, biomass, coal, other fossil fuels, and geothermal. Some facts and figures have recently been suggested by the magazine Popular Mechanics (November, 2006):^{[citation needed]}

A gasoline gallon equivalent (GGE) is amount of alternative fuel it takes to equal the energy content of one liquid gallon of gasoline. ...

Alternatives to the hydrogen economy

Hydrogen is simply a method to store and transmit energy. Various alternative energy transmission and storage scenarios may be more economic, in both near and far term. These include: Image File history File links Emblem-important. ...

Hydrogen storage has been proposed by some^{[citation needed]} to be optimal in a narrow range of energy storage time, probably somewhere between a few days and a few weeks. This range is subject to further narrowing with any improvements in battery technology. It is always possible that some kind of breakthrough in hydrogen storage or generation could occur, but this is unlikely given the physical and chemical limitations of the technical choices are fairly well understood. Methane is a chemical compound with the molecular formula CH4. ... This article is about the fossil fuel. ... The number of US survey respondents willing to pay $4,000 more for a plug-in hybrid car increased from 17% in 2005 to 26% in 2006. ...

The definition of alternative fuel varies according to the context of its usage. ...

Environmental concerns

Hydrogen gas can be created through the natural gas steam reforming/water gas shift reaction method, outlined above. This creates carbon dioxide (CO₂), a greenhouse gas, as a byproduct. This is usually released into the atmosphere, although there has also been some research into interring it underground or undersea. The steam reformers in methane-based fuel cells convert hydrocarbons into either carbon dioxide or carbon monoxide (CO). ^[17] Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Top: Increasing atmospheric CO2 levels as measured in the atmosphere and ice cores. ... A carbon dioxide (CO2) sink is a carbon reservoir that is increasing in size, and is the opposite of a carbon dioxide source. The main natural sinks are (1) the oceans and (2) plants and other organisms that use photosynthesis to remove carbon from the atmosphere by incorporating it into... Methane is a chemical compound with the molecular formula CH4. ... A fuel cell is an electrochemical device similar to a battery, but differing from the latter in that it is designed for continuous replenishment of the reactants consumed; i. ... In chemistry, a hydrocarbon is a cleaning solution consisting only of carbon (C) and hydrogen (H). ... Carbon monoxide, with the chemical formula CO, is a colorless, odorless, and tasteless gas. ...

Recently, there have also been some concerns over possible problems related to hydrogen gas leakage, (this has been pointed out in a paper published in Science magazine by a group of Caltech scientists). Molecular hydrogen leaks slowly from most containment vessels. It has been hypothesized that if significant amounts of hydrogen gas (H₂) escape, hydrogen gas may, due to ultraviolet radiation, form free radicals (H) in the stratosphere. These free radicals would then be able to act as catalysts for ozone depletion. A large enough increase in stratospheric hydrogen from leaked H₂ could exacerbate the depletion process. However, the effect of these leakage problems may not be significant. The amount of hydrogen that leaks today is much lower (by a factor of 10-100) than the estimated 10%-20% figure conjectured by some researchers; for example, in Germany, the leakage rate is only 0.1% (less than the natural gas leak rate of 0.7%).^{[citation needed]} At most, such leakage would likely be no more than 1-2% even with widespread hydrogen use, using present technology.^{[citation needed]} In chemistry free radicals are uncharged atomic or molecular species with unpaired electrons or an otherwise open shell configuration. ... Global monthly average total ozone amount Ozone depletion describes 14 distinct, but related observations: a slow, steady decline of about 4 percent per decade in the total amount of ozone in Earths stratosphere since around 1980; and a much larger, but seasonal, decrease in stratospheric ozone over Earths...

Direct dangers in use

Hydrogen has been feared in the popular press as a relatively more dangerous fuel, and hydrogen in fact has the widest explosive/ignition mix range with air of all the gases. Hydrogen also usually rapidly escapes after containment breach. Additionally, hydrogen flames are difficult to see, so may be difficult to fight. Most of these problems are offset in reality by the fact that hydrogen rapidly disperses by lifting off the scene due to buoyancy, and this is true to some extent of hydrogen fires.

In the LZ 129 Hindenburg disaster, 2/3 of passengers and crew survived (most deaths were from jumping). In a more recent event, an explosion of compressed hydrogen during delivery at the AEP Muskingum River Coal Plant caused significant damage and killed one person.^[18] LZ 129 Hindenburg was a German zeppelin. ... AEP headquarters in Columbus, Ohio. ...

One of the measures on the roadmap is to implement higher safety standards like early leak detection with hydrogen microsensors. A hydrogen microsensor is a small-scale device that detects the presence of hydrogen. ...

Examples and pilot programs

Several domestic U.S. automobile manufactures have committed to develop vehicles using hydrogen. (They had previously committed to producing electric vehicles in California, a program now defunct at their behest.^{[citation needed]}) Critics argue this "commitment" is merely a ploy to sidestep calls for increased efficiency in gasoline and diesel fuel powered vehicles and diverts us from needed steps to address global warming, such as greater focus on conservation, green fuel production and other green technologies. The distribution of hydrogen for the purpose of transportation is currently being tested in very limited markets around the world, particularly in Portugal, Iceland, Germany, California, Japan^[19] and Canada, but the cost is very high. Image File history File linksMetadata Download high-resolution version (1536x1024, 135 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Hydrogen economy Metadata This file contains additional information, probably added from the digital camera or scanner used to... Image File history File linksMetadata Download high-resolution version (1536x1024, 135 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Hydrogen economy Metadata This file contains additional information, probably added from the digital camera or scanner used to... Citaro in Essen, Germany Articulated Citaro G in London The Mercedes-Benz Citaro (or O530) is the current Mercedes-Benz/EvoBus mainstream bus intended for public transport, introduced in 1997. ... Coordinates: Country Czech Republic Region South Moravia Founded 1146 Area - city 230. ... Motto: (Out Of Many, One) (traditional) In God We Trust (1956 to date) Anthem: The Star-Spangled Banner Capital Washington D.C. Largest city New York City None at federal level (English de facto) Government Federal constitutional republic - President George Walker Bush (R) - Vice President Dick Cheney (R) Independence from... â€œCarâ€ and â€œCarsâ€ redirect here. ... For battery powered passenger automobiles, see battery electric vehicle. ... Petrol redirects here. ... This article is about the fuel. ... Official language(s) English Capital Sacramento Largest city Los Angeles Largest metro area Greater Los Angeles Area Ranked 3rd - Total 158,302 sq mi (410,000 kmÂ²) - Width 250 miles (400 km) - Length 770 miles (1,240 km) - % water 4. ...

Some hospitals have installed combined electrolyzer-storage-fuel cell units for local emergency power. These are advantageous for emergency use due to their low maintenance requirement and ease of location compared to internal combustion driven generators.

The North Atlantic island country of Iceland has committed to becoming the world's first hydrogen economy by the year 2050. Iceland is in a unique position. Presently, it imports all the petroleum products necessary to power its automobiles and fishing fleet. Iceland has large geothermal and hydroelectric resources, so much that the local price of electricity actually is lower than the price of the hydrocarbons that could be used to produce that electricity. The Atlantic Ocean, not including Arctic and Antarctic regions. ... A fishing fleet is an aggregate of commercial fishing vessels. ...

Iceland already converts its surplus electricity into exportable goods and hydrocarbon replacements. In 2002, it produced 2,000 tons of hydrogen gas by electrolysis-- primarily for the production of ammonia (NH₃) for fertilizer. Ammonia is produced, transported, and used throughout the world, and 90% of the cost of ammonia is the cost of the energy to produce it. Iceland is also developing an aluminium -smelting industry. Aluminium costs are primarily driven by the cost of the electricity to run the smelters. Either of these industries could effectively export all of Iceland's potential geothermal electricity. Ammonia is a chemical compound with the formula NH3. ...

Neither industry directly replaces hydrocarbons. Reykjavík, Iceland, has a small pilot fleet of city buses running on compressed hydrogen ^[20], and research on powering the nation's fishing fleet with hydrogen is under way. For more practical purposes, Iceland might process imported oil with hydrogen to extend it, rather than to replace it altogether. Location in Iceland Coordinates: , Constituency Government - Mayor (BorgarstjÃ³ri) Dagur B. Eggertsson Area - Total 274. ...

The Reykjavík buses are part of a larger program, HyFLEET:CUTE ^[21], operating hydrogen fueled buses in eight European cities. HyFLEET:CUTE buses also operate in Beijing and Perth (see below).

A pilot project demonstrating a hydrogen economy is operational on the Norwegian island of Utsira. The installation combines wind power and hydrogen power. In periods when there is surplus wind energy, the excess power is used for generating hydrogen by electrolysis. The hydrogen is stored, and is available for power generation in periods when there is little wind. County Rogaland Landscape Municipality NO-1151 Administrative centre Utsira Mayor (2005) Geir Helge Rasmussen (Bygdalista for Utsira) Official language form Neutral Area - Total - Land - Percentage Ranked 433 6 kmÂ² 6 kmÂ² 0. ... An example of a wind turbine. ... This article is about the chemical process. ...

A joint venture between NREL and Xcel Energy is combining wind power and hydrogen power in the same way in Colorado. ^[22] The National Renewable Energy Laboratory (NREL), located in Golden, Colorado, as part of the U.S. Department of Energy, is the United Statess primary laboratory for renewable energy and energy efficiency research and development. ... Xcel Energy, Inc. ... An example of a wind turbine. ...

Hydro in Newfoundland and Labrador are converting the current wind-diesel Power System on the remote island of Ramea into a Wind-Hydrogen Hybrid Power Systems facility. ^[23] To meet Wikipedias quality standards, this article or section may require cleanup. ... This article is about the Canadian province of Newfoundland and Labrador. ... For remote communities that are not directly connected to an electricity grid generally diesel engines linked generating sets have often been the sole source of power as they offer a high degree of reliability. ... One of the key issues with wind energy is its intermittent nature. ...

A similar pilot project on Stuart Island (Washington) uses solar power, instead of wind power, to generate electricity. When excess electricity is available after the batteries are full, hydrogen is generated by electrolysis and stored for later production of electricity by fuel cell. ^[24] Stuart Island is a located in the San Juan Islands of Washington state, USA. The small island is home to two distinct communities of full and part-time residents, a one-room schoolhouse, and two airstrips. ... Solar power describes a number of methods of harnessing energy from the light of the sun. ... An example of a wind turbine. ...

The UK started a fuel cell pilot program in January 2004, the program ran two Fuel cell buses on route 25 in London until December 2005, and switched to route RV1 until January 2007. ^[25] This article is about the capital of England and the United Kingdom. ...

The Hydrogen Expedition is currently working to create a hydrogen fuel cell-powered ship and using it to circumnavigate the globe, as a way to demonstrate the capability of hydrogen fuel cells.^[26]

Western Australia's Department of Planning and Infrastructure currently operates three Daimler Chrysler Citaro fuel cell buses as part of its Sustainable Transport Energy for Perth Fuel Cells Bus Trial in Perth.^[27] The buses are operated by Path Transit on regular Transperth public bus routes. The trial began in September 2004 and will conclude in September 2006. The buses' fuel cells use a proton exchange membrane system and are supplied with raw hydrogen from a BP refinery in Kwinana, south of Perth. The hydrogen is a byproduct of the refinery's industrial process. The buses are refueled at a station in the northern Perth suburb of Malaga.

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