Hydrogen Economy

A Hydrogen Economy

AgendaA Hydrogen Vision of the FutureHydrogen SystemsProducing HydrogenStoring and Transporting HydrogenHydrogen Fueled TransportProblems with HydrogenThe Promise of HydrogenHydrogen Summary

A Vision of a Hydrogen Future"I believe that water will one day be employed as fuel, that hydrogen and oxygen which constitute it, used singly or together, will furnish an inexhaustible source of heat and light, of an intensity of which coal is not capable. I believe then that when the deposits of coal are exhausted, we shall heat and warm ourselves with water. Water will be the coal of the future."

Jules Vernes(1870) Lle mystrieuse

The Hydrogen H2 Moleculehttp://planetforlife.com/h2/index.html

Hydrogen Economy Schematic

Hydrogen Economy in Hong Konghttp://www.gii.com.hk/eng/clean_energy.htm

Hydrogen Fueling Station

Hydrogen Systems

Hydrogen Energy Cyclehttp://en.wikipedia.org/wiki/Hydrogen_economy

Hydrogen Production CycleCrabtree et al., The Hydrogen Economy, Physics Today, Dec 2004

Operating the Hydrogen EconomyBossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28, 2004http://www.oilcrash.com/articles/h2_eco.htm

Hydrogen Economy Supply Chain

Hydrogen Pathwayshttp://www.ch2bc.org/index2.htm

Advantages of a Hydrogen EconomyWaste product of burning H2 is waterElimination of fossil fuel pollutionElimination of greenhouse gasesElimination of economic dependenceDistributed productionhttp://www.howstuffworks.com/hydrogen-economy.htm

Issues with HydrogenNot widely available on planet earthUsually chemically combined in water or fossil fuels (must be separated)Fossil fuel sources contribute to pollution and greenhouse gasesElectrolysis requires prodigious amounts of energy

Technological QuestionsWhere does hydrogen come from?How is it transported?How is it distributed?How is it stored?http://www.howstuffworks.com/hydrogen-economy.htm

Producing Hydrogen

Current Hydrogen ProductionCurrent hydrogen production 48% natural gas30% oil18% coal 4% electrolysisGlobal Production50 million tonnes / yrGrowing 10% / yrUS Production11 million tonnes / yr

Chart1

0.48

0.3

0.18

0.04

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Natural Gas48%

Oil30%

Coal18%

Electrolysis4%

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Sheet2

Sheet3

How is Hydrogen Produced?Reforming fossil fuelsHeat hydrocarbons with steamProduce H2 and COElectrolysis of waterUse electricity to split water into O2 and H2High Temperature ElectrolysisExperimentalBiological processesVery common in natureExperimental in laboratorieshttp://www.howstuffworks.com/hydrogen-economy.htm

Steam ReformingFrom any hydrocarbonNatural gas typically used Water (steam) and hydrocarbon mixed at high temperature (7001100 C)Steam (H2O) reacts with methane (CH4) CH4 + H2O CO + 3 H2 - 191.7 kJ/mol The thermodynamic efficiency comparable to (or worse than) an internal combustion engineDifficult to motivate investment in technology

Carbon Monoxide ReformingAdditional hydrogen can be recovered using carbon monoxide (CO) low-temp (130C) water gas shift reactionCO + H2O CO2 + H2 + 40.4 kJ/mol Oxygen (O) atom stripped from steamOxidizes the carbon (C)Liberates hydrogen bound to C and O2

Hydrogen Steam Reforming

Hydrogen Steam Reforming Plants

Electrolysis of Water (H2O)http://www.gm.com/company/gmability/edu_k-12/9-12/fc_energy/make_your_own_hydrogen_results.html

Electrolysis of Waterhttp://hyperphysics.phy-astr.gsu.edu/hbase/thermo/electrol.html

Renewable Energy for Electrolysishttp://www.howstuffworks.com/hydrogen-economy4.htm

Biomass Electrolysis Modulehttp://www.nrel.gov/hydrogen/photos.html

High Temperature ElectrolysisElectrolysis at high temperaturesUse less energy to split waterhttp://en.wikipedia.org/wiki/Hydrogen_economy

Biological H2 CreationNature has very simple methods to split water

Scientists are working to mimic these processes in the lab; then commerciallyCrabtree et al., The Hydrogen Economy, Physics Today, Dec 2004

Storing & Transporting Hydrogen

Hydrogen StorageStorage a major difficulty with hydrogenH2 has low energy density per volumeRequires large tanks to storeH2 can be compressed to reduce volumeRequires heavy, strong tanksH2 can be liquefied to reduce volumeBoils at -423 F (cryogenic)Requires heavily insulated, expensive tanksBoth compression and liquefaction require a lot of energy

Ammonia StorageH2 can be stored as ammonia (NH3)Exceptionally high hydrogen densitiesAmmonia very common chemicalLarge infrastructure already existsEasily reformed to produce hydrogenNo harmful wasteBUTAmmonia production is energy intensiveAmmonia is a toxic gas

Metal Hydride StorageMetal hydrides can carry hydrogenBoron, lithium, sodiumGood energy density, but worse than gasVolumes much larger than gasolineThree times more volumeFour times heavierHydrides can react violently with waterLeading contendersSodium BorohydrideLithium Aluminum HydrideAmmonia Borane

Alkali Prod. Energy vs. Instrinsic EnergyEnergy needed to produce alkali metal hydrides relative to the energy content of the liberated hydrogen.Bossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28, 2004http://www.oilcrash.com/articles/h2_eco.htm

Transporting Hydrogen

Storing & Transporting HydrogenStore and Transport as a GasBulky gasCompressing H2 requires energyCompressed H2 has far less energy than the same volume of gasolineStore and Transport as a SolidSodium BorohydrideCalcium HydrideLithium HydrideSodium Hydridehttp://www.howstuffworks.com/hydrogen-economy.htm

Hydrogen Fueled Transport

Hydrogen-Powered Autos

Hydrogen-Powered Autoshttp://planetforlife.com/h2/h2vehicle.html

Hydrogen-Powered Truckshttp://planetforlife.com/h2/h2vehicle.html

Hydrogen-Powered Aircrafthttp://aix.meng.auth.gr/lhtee/projects/cryoplane/Hydrogen powered passenger aircraft with cryogenic tanks along spine of fuselage. Hydrogen fuel requires about 4 times the volume of standard jet fuel (kerosene).http://planetforlife.com/h2/h2vehicle.html

Hydrogen-Powered Rocketshttp://planetforlife.com/h2/h2vehicle.html

Implications of Hydrogen Transporthttp://planetforlife.com/h2/h2swiss.html

Weight of fuelWeight of steel tankWeight of carbon fiber tankVolume of tank contentsVolume of tankTypical 18 wheel truck (diesel)1175 lb(small)NA22.5 feet324.0 feet3Typical sedan (gasoline)108 lb(small)NA2.25 feet32.5 feet3Truck converted to ICE hydrogen313 lb31,300 lb6,960 lb67.5 feet3157 feet3Sedan converted to hydrogen fuel cell17.4 lb1740 lb387 lb4 feet39 feet3

Problems with Hydrogen

Environmental Concerns48% of hydrogen made from natural gasCreates CO2 a greenhouse gas Hydrogen H2 inevitably leaks from containersCreates free radicals (H) in stratosphere due to ultraviolet radiationCould act as catalysts for ozone depletion

H2 Energy DensitiesCrabtree et al., The Hydrogen Economy, Physics Today, Dec 2004

Energy Densities for Various FuelsBossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28, 2004http://www.oilcrash.com/articles/h2_eco.htm Higher Heating Value (HHV) is a measure of energy

H2 and Energy Density for Various FuelsHydrogen density and HHV energy content of ammonia and selected synthetic liquid hydrocarbon fuels Bossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28, 2004http://www.oilcrash.com/articles/h2_eco.htm

Hydrogen vs. MethaneBossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28, 2004http://www.oilcrash.com/articles/h2_eco.htm

Liquifaction Energy vs. Intrinsic EnergyBossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28, 2004http://www.oilcrash.com/articles/h2_eco.htm

Hydrogen Storage DensitiesCrabtree et al., The Hydrogen Economy, Physics Today, Dec 2004

Hydrogen Energy LossesWindmills generate electricity.Electricity converted to H2 70% efficiency.H2 compressed for pumping 20% energy lossH2 pumped long distance 30% loss 65% loss to Europe from the Sahara).Loss at filling stations assume 5%Loss in fuel cell 50% (possibly only 40%)Combining losses only 15-18% useful electricity, or vehicle motor power9.3% in the case of the Sahara Bossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28, 2004http://www.oilcrash.com/articles/h2_eco.htm

Criticism of Hydrogen EconomyHydrogen economy idea does not work for multiple reasons. No practical source of cheap hydrogenNo good way to store hydrogenNo good way to distribute hydrogenProblems with physical & chemical properties of hydrogenTechnology cannot change these facts.Compact / convenient future energy carrier neededMethane, ethane, methanol, ethanol, butane, octane, ammonia, etc. are better energy carriers.Difficult to understand the enthusiasm for hydrogen Hydrogen does not solve the energy problem and it is a bad choice for carrying energy.Bossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28, 2004http://www.oilcrash.com/articles/h2_eco.htm

Elemental Hydrogen EconomyElemental Hydrogen Economy based on the natural cycle of water. Elemental hydrogen is provided to the user Bossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28, 2004http://www.oilcrash.com/articles/h2_eco.htm

Synthetic Liquid Hydrocarbon Economy A Synthetic Liquid Hydrocarbon Economy may be based on the two natural cycles of water and carbon dioxide. Natural and synthetic liquid hydrocarbons are provided to the user.Bossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28, 2004http://www.oilcrash.com/articles/h2_eco.htm

The Promise of Hydrogen

UNIDO-ICHET Projectionhttp://www.unido-ichet.org/ICHET-transition.phpUNITED NATIONS INDUSTRIAL DEVELOPMENT ORGANIZATION INTERNATIONAL CENTRE FOR HYDROGEN ENERGY TECHNOLOGIES

The Iceland ExampleIceland committed to be the first hydrogen economy2050 goalWill use geothermal resources to create hydrogenPower autos, buses, and fishing fleet with hydrogenhttp://en.wikipedia.org/wiki/Hydrogen_economy

Hydrogen Summary

Advantages of a Hydrogen EconomyWaste product of burning H2 is waterElimination of fossil fuel pollutionElimination of greenhouse gasesElimination of economic dependenceDistributed productionThe stuff of starshttp://www.howstuffworks.com/hydrogen-economy.htm

Disadvantages of HydrogenLow energy densitiesDifficulty in handling, storage, transportRequires an entirely new infrastructureCreates CO2 if made from fossil fuelsLow net energy yieldsMuch energy needed to create hydrogenPossible environmental problemsOzone depletion (not proven at this point)

Extra Slides

Energy Density of Hydrogen

Current Uses of Hydrogen

Thermochemical Production

Problems with Hydrogen

Prospects for the Futurehttp://www.howstuffworks.com/hydrogen-economy.htm

The Hydrogen Vision

The term Hydrogen Economy refers to the infrastructure to support the energy requirements of society, based on the use of hydrogen rather than fossil fuels.The concept of using hydrogen as an energy system is not new; it has previously been used both industrially and domestically (town gas - 50% hydrogen was used in the UK until the 1950's). Interest in hydrogen as a vehicle fuel dates back to the 1800's but heightened in the 1970's with the oil crises and with technological advances in the 1980's.

Hydrogen is a good candidate for reducing emissions since when it is reacted with oxygen it produces only water as the reaction product. Hydrogen can be used to provide electricity and heat either through use in a fuel cell or combustion. A fuel cell generates electricity by combining hydrogen with oxygen from air; the only by-product is water. Hydrogen can also be burned in an internal combustion engine in the same way as petrol or natural gas. This produces water as the main by-product, however, small amounts of oxides of nitrogen (air pollutants) are also produced.Unlike oil, gas and coal hydrogen doesn't exist in large quantities in nature in a useful form. Like electricity it is an energy carrier, which must be produced using energy from another source. Hydrogen, however, has the advantage that it can be stored more easily.Today, nearly half the hydrogen produced in the world is derived from natural gas via a steam-reforming process. The natural gas reacts with steam in a catalytic converter. The process strips away the hydrogen atoms, leaving carbon dioxide as the by-product. Therefore, in the future, hydrogen must be produced from renewable energy sources.CKIs Initiative on Hydrogen EconomyGreen Island International (BVI) Limited (Green Island) has plans to test a hydrogen-powered bus with fuel produced by an environmentally friendly hydrogen energy station in Hong Kong. These would be the first of their kind in Hong Kong and we are currently seeking Government approval to demonstrate this facility.As an environmentally friendly alternative to fossil fuel, hydrogen is a cost-effective, zero-emission energy solution for the 21st century.Hydrogen Energy Power Project in Hong Kong Green Island has undertaken a clean energy project to design and install a 200 kW hydrogen power system with vehicle fuelling capability at Tap Shek Kok, Tuen Mun. This Hydrogen Energy Station (HES) will produce and provide an environmentally friendly alternative to fossil fuel for automobiles, emergency back up power and energy applications.When renewable energy sources are used, hydrogen is the cleanest fuel available and is produced from water by a proprietary electrolysis technology. Compared to fossil fuels, hydrogen is carbon free. When hydrogen fuel is used in an internal combustion engine, the exhaust is nothing more than water vapour. This HES includes a hydrogen production unit, or electrolyzer, to produce purified high-pressure hydrogen from electrical power and potable water. As all hydrogen fuel supply is produced on-site, no transportation of bulk hydrogen is necessary. The high-pressure hydrogen will be stored in banks of composite cylinders sufficient to supply a 200 kW backup power for a six-hour period by a hydrogen ICE/GENSET (internal combustion engine / generator set) combination during times of main power failure. The HES is also equipped with a vehicle refueling dispenser capable of refueling hydrogen vehicles at pressures of 250 bar-gauge. Factory Acceptance Tests and Safety Assessments on the equipment have been conducted in Toronto, Canada prior to shipment of the HES modules to Hong Kong. It is Green Islands plan to bring into Hong Kong the first Hydrogen Hybrid Powered Bus. The 49-passenger single deck bus, which is being developed for Green Island in New Zealand, will be powered by a Ford 2.3 litre internal combustion engine. It is a hybrid model incorporating an electrical motor/generator and a special braking system which allows power to be recovered during braking. This clean bus will be deployed to provide a shuttle service for the staff of Green Island Cement and will also serve as a free shuttle for the general public for demonstration and education purposes. The HES at Green Island will demonstrate the capability of hydrogen power applications and will be the first initiative towards development of a market for distributed hydrogen-based power technology in the Asia-Pacific region.Hydrogen fueling station at California Fuel Cell PartnershipFigure 1. The hydrogen economy as a network of primary energy sources linked to multiple end uses through hydrogen as an energy carrier. Hydrogen adds flexibility to energy production and use by linking naturally with fossil, nuclear, renewable, and electrical energy forms: Any of those energy sources can be used to make hydrogen.

http://www.physicstoday.org/vol-57/iss-12/p39.htmlBut have the physics and chemistry been properly considered? Most attention has been given to the apparent benefits of hydrogen in use, while the upstream aspects of a hydrogen economy are rarely addressed, Figure 1.Like any other product, hydrogen must be packaged, transported, stored and transferred, to bring it from production to final use. These standard product processes require energy. In todays fossil energy economy, the energy lost between the well and the consumer is about 12% for oil and about 5% for gas. The present paper gives estimates of the upstream energy required to operate a Hydrogen Economy. Our analysis should be of particular interest for the assessment of fuel options for transport applications.Without question, technology for a hydrogen economy exists or can be developed. In fact, considerable amounts of hydrogen are generated, handled, transported and used in the chemical industry today. However, this hydrogen is a chemical substance, not an energy commodity. Hydrogen production and transportation costs are absorbed in the price of the synthesized chemicals. The cost of hydrogen is irrelevant as long as the final products find markets. Today, the use of hydrogen is governed by economic arguments and not by energetic considerations.However, if hydrogen is to be used as an energy carrier, energetic issues must also be considered. How much high-grade energy is required to make, to package, to handle, to store and to transport hydrogen? It would be difficult to establish a sustainable energy future if much of the energy harvested from nature is wasted before it reaches the energy consumer. We have examined the key stages by physical and chemical reasoning and conclude that the future energy economy is unlikely to be based on elemental hydrogen. Hydrogen may be the main link between renewable physical and chemical energy, but most likely it will reach the consumer chemically packaged in the form of one or more consumerfriendly natural or synthetic liquid hydrocarbons.

Bossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28, 2004http://www.oilcrash.com/articles/h2_eco.htm

Ahypothetical supply chain for a 'hydrogen-based economy'. (Image courtesy of theCenter for Energy, Environmental, and Economic Systems Analysisat Argonne National Laboratory.) Advantages of the hydrogen economy In the previous section we saw the significant, worldwide problems created by fossil fuels. The hydrogen economy promises to eliminate all of the problems that the fossil fuel economy creates. Therefore, the advantages of the hydrogen economy include: The elimination of pollution caused by fossil fuels - When hydrogen is used in a fuel cell to create power, it is a completely clean technology. The only byproduct is water. There are also no environmental dangers like oil spills to worry about with hydrogen. The elimination of greenhouse gases - If the hydrogen comes from the electrolysis of water, then hydrogen adds no greenhouse gases to the environment. There is a perfect cycle -- electrolysis produces hydrogen from water, and the hydrogen recombines with oxygen to create water and power in a fuel cell. The elimination of economic dependence - The elimination of oil means no dependence on the Middle East and its oil reserves. Distributed production - Hydrogen can be produced anywhere that you have electricity and water. People can even produce it in their homes with relatively simple technology. The problems with the fossil fuel economy are so great, and the environmental advantages of the hydrogen economy so significant, that the push toward the hydrogen economy is very strong.

http://www.howstuffworks.com/hydrogen-economy.htm

Unfortunately, pure hydrogen is not widely available on our planet. Most of it is locked in water or hydrocarbon fuels. It can be produced using other high-energy fuels, i.e. fossil fuels, but such methods require fossil fuels and generate CO2 to a greater extent than conventional engines and thus contribute to global warming more than if those fossil fuels were to be used directly to power automobiles for example. It can also be produced using huge amounts of energy and water. Nuclear power can provide the energy, but has well known disadvantages. Some 'Green' energy sources are capable of generating energy in a cost effective way if the externalities of conventional energy sources are factored in, but the policies of the world's major governments do not factor them in. However, most 'green' sources tend to produce rather low-intensity energy, not the prodigious amounts of energy required for extracting significant amounts of hydrogen using thermochemical electrolysis for example. This is called the production problem.

http://en.wikipedia.org/wiki/Hydrogen_economyTechnological Hurdles The big question with the hydrogen economy is, "Where does the hydrogen come from?" After that comes the question of transporting, distributing and storing hydrogen. Hydrogen tends to be bulky and tricky in its natural gaseous form. Once both of these questions are answered in an economical way, the hydrogen economy will be in place. We'll look at each of these questions separately in the following sections.


Hydrogen production is a large and growing industry. Globally, about 50 million metric tons of hydrogen were produced in 2004; the growth rate is about 10% per year. The energy in the current flow corresponds to about 200 gigawatts. Within the U.S., production was about 11 million metric tons, or 48 GW (10.8% of the average U.S. total electric production of 442 GW in 2003). Because hydrogen storage and transport are so expensive, most hydrogen is currently produced locally, and used immediately, generally by the same company producing it. As of 2005, the economic value of all hydrogen produced is about $135 billion per year.48% of current hydrogen production is from natural gas, 30% is from oil, 18% is from coal, and electrolysis accounts for about 4%.

http://en.wikipedia.org/wiki/Hydrogen_economyWhere does the hydrogen come from? One of the more interesting problems with the hydrogen economy is the hydrogen itself. Where will it come from? With the fossil fuel economy, you simply pump the fossil fuel out of the ground (see How Oil Drilling Works) and refine it (see How Oil Refining Works). Then you burn it as an energy source. Most of us take oil, gasoline, coal and natural gas for granted, but they are actually quite miraculous. These fossil fuels represent stored solar energy from millions of years ago. Millions of years ago, plants grew using solar energy to power their growth. They died, and eventually turned into oil, coal and natural gas. When we pump oil from the ground, we tap into that huge solar energy storehouse "for free." Whenever we burn a gallon of gasoline, we release that stored solar energy. In the hydrogen economy, there is no storehouse to tap into. We have to actually create the energy in real-time. There are two possible sources for the hydrogen: Electrolysis of water - Using electricity, it is easy to split water molecules to create pure hydrogen and oxygen. One big advantage of this process is that you can do it anywhere. For example, you could have a box in your garage producing hydrogen from tap water, and you could fuel your car with that hydrogen. Reforming fossil fuels - Oil and natural gas contain hydrocarbons -- molecules consisting of hydrogen and carbon. Using a device called a fuel processor or a reformer, you can split the hydrogen off the carbon in a hydrocarbon relatively easily and then use the hydrogen. You discard the leftover carbon to the atmosphere as carbon dioxide. The second option is, of course, slightly perverse. You are using fossil fuel as the source of hydrogen for the hydrogen economy. This approach reduces air pollution, but it doesn't solve either the greenhouse gas problem (because there is still carbon going into the atmosphere) or the dependence problem (you still need oil). However, it may be a good temporary step to take during the transition to the hydrogen economy. When you hear about "fuel-cell-powered vehicles" being developed by the car companies right now, almost all of them plan to get the hydrogen for the fuel cells from gasoline using a reformer. The reason is because gasoline is an easily available source of hydrogen. Until there are "hydrogen stations" on every corner like we have gas stations now, this is the easiest way to obtain hydrogen to power a vehicle's fuel cell.

http://www.howstuffworks.com/hydrogen-economy.htm_______________________________________________________When the energy supply is chemical, it will always be more efficient to produce hydrogen through a direct chemical path. But when the energy supply is mechanical (hydropower or wind turbines), hydrogen can be made via electrolysis of water. Usually, the electricity consumed is more valuable than the hydrogen produced, which is why only a tiny fraction of hydrogen is currently produced this way.When the energy supply is in the form of heat (solar thermal or nuclear), the only existing path to hydrogen is currently through low-temperature electrolysis. Research into high-temperature electrolysis (HTE) and high-temperature nuclear reactors may eventually lead to a hydrogen supply that is cost-competitive with natural gas steam reforming. 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 less energy is lost.HTE processes are generally only considered in combination with a nuclear heat source, because the other nonchemical form of high-temperature heat (concentrating solar thermal) is not consistent enough to bring down the capital costs of the HTE equipment.

http://en.wikipedia.org/wiki/Hydrogen_economy

http://en.wikipedia.org/wiki/Hydrogen_economyhttp://en.wikipedia.org/wiki/Hydrogen_economyBy providing energy from a battery, water (H2O) can be dissociated into the diatomic molecules of hydrogen (H2) and oxygen (O2). This process is a good example of the the application of the four thermodynamic potentials.Right now there are several different ways to create electricity that do not use fossil fuels: Nuclear power Hydroelectric dams Solar cells Wind turbines Geothermal power Wave and tidal power Co-generation (For example, a sawmill might burn bark to create power, or a landfill might burn methane that the rotting trash produces.) In the United States, about 20 percent of the power currently comes from nuclear and 7 percent comes from hydroelectric. Solar, wind, geothermal and other sources generate only 5 percent of the power -- hardly enough to matter. In the future, barring some technological breakthrough, it seems likely that one of two things will happen to create the hydrogen economy: Either nuclear-power or solar-power generating capacity will increase dramatically. Remember that, in a pure hydrogen economy, the electrical generating capacity will have to approximately double because all of the energy for transportation that currently comes from oil will have to be replaced with electrically generated hydrogen. So the number of power plants will double, and all of the fossil fuel plants will be replaced. The electrical-generation problem is probably the biggest barrier to the hydrogen economy. Once the technology is refined and becomes inexpensive, fuel-cell vehicles powered by hydrogen could replace gasoline internal combustion engines over the course of a decade or two. But changing the power plants over to nuclear and solar may not be so easy. Nuclear power has political and environmental problems, and solar power currently has cost and location problems. When the energy supply is in the form of heat (solar thermal or nuclear), the only existing path to hydrogen is currently through low-temperature electrolysis. Research into high-temperature electrolysis (HTE) and high-temperature nuclear reactors may eventually lead to a hydrogen supply that is cost-competitive with natural gas steam reforming. 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 less energy is lost.HTE processes are generally only considered in combination with a nuclear heat source, because the other nonchemical form of high-temperature heat (concentrating solar thermal) is not consistent enough to bring down the capital costs of the HTE equipment.

http://en.wikipedia.org/wiki/Hydrogen_economy____________________________________________High-temperature electrolysis (HTE), or steam electrolysis as it is sometimes called, is a variation of the conventional electrolysis process. Some of the energy needed to split the water is added as heat instead of electricity, thus reducing the overall energy required and improving process efficiency. Because the conversion efficiency of heat to electricity is low compared to using the heat directly, and energy efficiency can be achieved by providing the energy to the system in the form of heat rather than electricity. The figure on the right demonstrates the effect of increased temperature of feedsteam on system energy requirements. About 350 megajoules (thermal) are needed to produce 1 kilogram of hydrogen at 100C, whereas it takes onlyabout 225 megajoules at 850C. The HTE process, while conceptually the same as conventional electrolysis, differs in its hydrogen production mechanism.

Figure 2. Nature has developed remarkably simple and efficient methods to split water and transform H2 into its component protons and electrons. The basic constituent of the catalyst that splits water during photosynthesis is cubane (top)clusters of manganese and oxygen. Researchers are only beginning to understand cubane's oxidation states using crystallography and spectroscopy (see J.Z. Wu et al., ref. 6). Bacteria use the ironbased cluster (bottom, circled) to catalyze the transformation of two protons and two electrons into H2. The roles of this enzyme's complicated structural and electronic forms in the catalytic process can be imitated in the laboratory. The hope is to create synthetic versions of these natural catalysts (see F. Gloaguen et al. and J. Alper, ref. 6).

Crabtree et al., The Hydrogen Economy, Physics Today, Dec 2004Storage is the main technological problem of a viable hydrogen economy. Some attention has been given to the role of hydrogen to provide grid energy storage for unpredictable energy sources, like wind power. The primary difficulty with using hydrogen for grid energy storage is that converting power to hydrogen and back is not cheap.Hydrocarbons are stored extensively at the point of use, be it in the gasoline tanks of automobiles or propane tanks hung on the side of barbecue grills. Hydrogen, in comparison, is quite expensive to store or transport with current technology. Hydrogen gas has good energy density per weight, but poor energy density per volume versus hydrocarbons, hence it requires a larger tank to store. A large hydrogen tank will be heavier than the small hydrocarbon tank used to store the same amount of energy, all other factors remaining equal. Increasing gas pressure would improve the energy density per volume, making for smaller, but not lighter container tanks (see pressure vessel). Compressing a gas will require energy to power the compressor. Higher compression will mean more energy lost to the compression step. Alternatively, higher volumetric energy density liquid hydrogen may be used (like the Space Shuttle). However liquid hydrogen is cryogenic and boils around 20.268 K (252.882 C or -423.188 F). Hence its liquefaction imposes a large energy loss, used to cool it down to that temperature. The tanks must also be well insulated to prevent 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. Assuming all of that is solvable, the density problem remains. Even liquid hydrogen has worse energy density per volume than hydrocarbon fuels such as gasoline by approximately a factor of four.

http://en.wikipedia.org/wiki/Hydrogen_economyAmmonia (NH3) can be used to store hydrogen chemically and then release it in a catalytic reformer. Ammonia provides exceptionally high hydrogen storage densities as a liquid with mild pressurization and cryogenic constraints. It can also be stored as a liquid at room temperature and pressure when mixed with water. Ammonia is the second most commonly produced chemical in the world and a large infrastructure for making, transporting and distributing ammonia already exists. Ammonia can be reformed to produce hydrogen with no harmful waste, or can mix with existing fuels and burned efficiently, however, pure ammonia burns poorly and is not a suitable fuel for most combustion engines. Ammonia is very energy expensive to make and the existing infrastructure would have to be greatly enlarged to handle replacing transportation energy needs. Ammonia is a toxic gas at normal temperature and pressure and has a potent odor.

http://en.wikipedia.org/wiki/Hydrogen_economyThere are proposals to use metal hydrides as the carrier for hydrogen instead of pure hydrogen. Hydrides can be coerced, in varying degrees of ease, into releasing and absorbing hydrogen. Some are easy-to-fuel liquids at ambient temperature and pressure, others are solids which could be turned into pellets. Proposed hydrides for use in a hydrogen economy include boron and lithium hydrides. These have good energy density per volume, although their energy density per weight is often worse than the leading hydrocarbon fuels.Solid hydride storage is a leading contender for automotive storage. A hydride tank is about three times larger and four times heavier than a gasoline tank holding the same energy. For a standard car, that's about 45 US gallons (0.17 m) of space and 600 pounds (270 kg) versus 15 US gallons (0.057 m) and 150 pounds (70 kg). A standard gasoline tank weighs a few dozen pounds (tens of kilograms) and is made of steel costing less than a dollar a pound ($2.20/kg). Lithium, the primary constituent by weight of a hydride storage vessel, currently costs over $40 a pound ($90/kg). Any hydride will need to be recycled or recharged with hydrogen, either on board the automobile or at a recycling plant.Often hydrides react by combusting rather violently upon exposure to moist air, and are quite toxic to humans in contact with the skin or eyes, hence cumbersome to handle (see borane, lithium aluminium hydride). This is why such fuels, despite being proposed and vigorously researched by the space launch industry, have never been used in any actual launch vehicle.Few hydrides provide low reactivity (high safety) and high hydrogen storage densities (above 10% per weight). Leading candidates are sodium borohydride, lithium aluminium hydride and ammonia borane. Sodium borohydride and ammonia borane can be stored as a liquid when mixed with water, but must be stored at very high concentrations to produce desirable hydrogen densities, thus requiring complicated water recycling systems in a fuel cell. As a liquid, sodium borohydride provides the advantage of being able to react directly in a fuel cell, allowing the production of cheaper, more efficient and more powerful fuels cells that do not need platinum catalysts. Recycling sodium borohydride is energy expensive and would require recycling plants. More energy efficient means of recycling sodium borohydride are still experimental. Recycling ammonia borane by any means is still experimental.

http://en.wikipedia.org/wiki/Hydrogen_economyTo produce the hydrides, at least 1.6 time more high grade energy has to be invested to produce 1 HHV energy unit of hydrogen, giving a stage efficiency of less than 1/1.6 = 60 %. When the electrolytic production of the alkali metals (calcium, sodium, or lithium) and the efficiency of electric power generation are also considered, the source-to-service energy losses are much higher. They may exceed 500% for electricity from coal-fired power plants. Therefore chemical packaging of hydrogen in alkali metal hydrides would suit very few applications.The weight of alkali hydride materials appears to pose no problem. One kg of CaH2 reacting with about 0.86 liter of water yields 96 g of hydrogen, with an HHV energy of 13.6 MJ, while 1 kg LiH yields 36.1 MJ. Alkali metal hydrides are high density energy carriers with energy content comparable to firewood or lignite. However, the energy losses in producing the alkali metals and then the hydrides would discourage their use on any substantial scale.


How do you store and transport the hydrogen? At this moment, the problem with putting pure-hydrogen vehicles on the road is the storage/transportation problem. Hydrogen is a bulky gas, and it is not nearly as easy to work with as gasoline. Compressing the gas requires energy, and compressed hydrogen contains far less energy than the same volume of gasoline. However, solutions to the hydrogen storage problem are surfacing. For example, hydrogen can be stored in a solid form in a chemical called sodium borohydride, and this technology has appeared in the news recently because Chrysler is testing it. This chemical is created from borax (a common ingredient in some detergents). As sodium borohydride releases its hydrogen, it turns back into borax so it can be recycled. Once the storage problem is solved and standardized, then a network of hydrogen stations and the transportation infrastructure will have to develop around it. The main barrier to this might be the technological sorting-out process. Stations will not develop quickly until there is a storage technology that clearly dominates the marketplace. For instance, if all hydrogen-powered cars from all manufacturers used sodium borohydride, then a station network could develop quickly; that sort of standardization is unlikely to happen rapidly, if history is any guide. There might also be a technological breakthrough that could rapidly change the playing field. For example, if someone could develop an inexpensive rechargeable battery with high capacity and a quick recharge time, electric cars would not need fuel cells and there would be no need for hydrogen on the road. Cars would recharge using electricity directly.


Ford Motor Company recently introduced the P2000, a new car with a hydrogen internal combustion engine (ICE) that "could help bridge the gap between gasoline vehicles and the fuel cell vehicles of the future." [1] The engine is not much different from an ordinary gasoline engine. The use of hydrogen greatly reduces emissions although nitrous oxides are still a problem. Engine efficiency about equals a diesel, about 35%. The hydrogen is stored in a tank that is rated at 240 atmospheres (240 bars). The range is only 62 miles. Ford does not give the price of the P2000, but it should be inexpensive given that all of the components are rather ordinary. Honda has introduced the FCX, a car utilizing a fuel cell instead of an ICE. [3] This gives an overall efficiency of 45%. A fuel cell turns hydrogen into electricity which drives the wheels through electric motors. The hydrogen is stored in carbon fiber tanks at 333 bars. This gives the FCX a range of 150 miles. The fuel cells provide only the average power. Super capacitors provide extra power during acceleration and hill climbing. The tanks, the fuel cell, the super capacitors, etc. take up 4 times more space compared to a conventional design. There is not much room left for passengers and cargo. The FCX costs 3 million dollars, but Honda leases them for $500 per month to the state of California.The engineers at Honda have also provided a solar powered hydrogen source. On sunny days in California it produces 16 liters per day. The tanks of the FCX holds 156 liters. The solar powered hydrogen source can move one FCX 16 miles each day.Modern18 wheel semi-trucks are a formidable piece of engineering. The durable diesel engines can develop 500 horsepower continuously, and they achieve 35% efficiency. They can haul 80,000 pound loads at high speeds over mountains. Carbon fiber and aluminum are used to reduce weight. Designing a hydrogen powered replacement would be a very difficult project. Trucks need a lot of power all the time while cars need a lot of power only during short bursts of acceleration. Most of the time, cars need only a low power engine. The Honda FCX exploits that fact.The diesel engine could be replaced by a hydrogen internal combustion engine. At 35% efficiency, there would no gain in fuel economy. The Bossel and Eliasson (B&E) section of this website discusses the problem of hydrogen storage in detail.A fuel cell capable of developing the equivalent 500 horsepower of electrical power would cost millions of dollars. Improving overall efficiency from 35% to 45% hardly seems worth it.The objective of the project is to examine the use of hydrogen as a fuel for aircrafts. Airplanes moving with hydrogen will practically emit only vapor. Due to the high emittance of greenhouse gases from the use of kerosene, it becomes obvious that hydrogen technology could lead to sustainable development of the air traffic.However, the extent to which kerosene's substitution from hydrogen is environmentally willful, does not depend only on the pollution caused by the airplanes. The hydrogen production is an energy consuming process that fatefully leads to pollution. The use of a new fuel calls for the development of a new substructure for the transport and storage of it as well. The development of this substructure involves the environmental impact analysis.For the examination of the utility of hydrogen usage as a fuel, an analysis of the whole "life cycle" of the fuel (production, transport, storage and consumption) has to be done.The implementation of the "Life Cycle Assessment" methodology will result in the environmental comparison of hydrogen use to that of kerosene. The Laboratory of Heat Transfer and Environmental Engineering has been assigned this task in the CRYOPLANE research program. The conclusions of this significant research effort will define to a great extent the evolution of aircraft construction and, as a consequence, of the air traffic in the new century, at the dawn of which we now are.______________________________This is an artist's rendering of a hydrogen powered version of the A310 Airbus. It is also called the "Cryoplane" because of the very visible cryogenic hydrogen tank located above the passengers. Cryogenic hydrogen is the only possibility for aircraft as high pressure tanks would be too heavy. The physical properties of liquid hydrogen determine the appearance of the Cryoplane. Liquid hydrogen occupies 4.2 times the volume of jet fuel for the same energy which means that the tanks have to be huge. Jet fuel weighs 2.9 times more than liquid hydrogen for the same energy. The reduced weight partly compensates for the increased aerodynamic drag of the tanks. The Cryoplane would have less range and speed than the A310 Airbus. Whatever energy source is used, 30% will be lost in hydrogen liquefaction.Boeing has also studied the feasibility of a hydrogen powered passenger plane. [4] The Boeing study explorers different tank configurations. They also mention the engineering challenge of designing a vacuum insulated tank of the required size and lightness.

http://planetforlife.com/h2/h2vehicle.htmlThe second stage of the Saturn 5 rocket that took 3 men to the moon used liquid hydrogen. A vehicle that can go directly to orbit has always been the dream of space travel. The X-33, now canceled, was designed to do that. Liquid hydrogen is the only fuel light enough and energetic enough to do the job. The X-33 had liquid hydrogen tanks with very little insulation resulting in rapid hydrogen loss. This is only a small problem because the tanks can be topped off just before launch. Travel time from earth to orbit is only a few minutes and so high hydrogen losses are tolerable. http://planetforlife.com/h2/h2vehicle.htmlHydrogen is difficult to store because has very low volumetric energy density. It is the simplest and lightest element--it's lighter than helium. Hydrogen is 3.2 times less energy dense than natural gas and 2700 times less energy dense than gasoline. Hydrogen contains 3.4 times more energy than gasoline on a weight basis. Hydrogen must be made more energy dense to be useful for transportation. There are three ways to do this. Hydrogen can be compressed, liquefied, or chemically combined.Compressed hydrogen Hydrogen compressed to 800 atmospheres (also called bars) occupies 3 times more volume than gasoline for the same energy. It is necessary to reach this density if a vehicle is to carry enough hydrogen to be practical. A pressure of 800 bars works out to 6 tons, or 12,000 lbs, per square inch. It is very difficult to contain such pressures safely in a lightweight tank. Catastrophic tank failure releases as much energy as an equal weight of dynamite. A tank made of high strength steel weighs 100 times more than the hydrogen it contains. A truck or an automobile using a steel tank would be impractical as the tank would weigh nearly as much as the vehicle.High pressure hydrogen tanks made from carbon fiber may be a solution. Carbon fiber is a material used in aircraft and sporting goods. At the present time, carbon fiber tanks are very expensive. The DOE has proposed a performance goal as part of the FreedomCar initiative. The goal for 2005 is 4.5% as the ratio of hydrogen to tank weight at 800 atmospheres. [5] (page 6)A typical 18 wheeled semi-truck carries two 90 gallon tanks, providing a range of 750 miles. A typical 4 cylinder sedan has an 18 gallon tank, providing a range of 575 miles. (The practical range would be somewhat less.) The diesel engine achieves an efficiency of 35% at cruising speeds. The gasoline engine achieves an efficiency of 25% at cruising speed. Both vehicles could be converted to hydrogen operation. Internal combustion engines (ICE) could be used resulting in an efficiency of 35%. Or, fuel cells could be used resulting in an efficiency of 45%.The space, weight and expense of steel tanks make them impractical. Any gains in energy efficiency would be offset by losses incurred in hauling the very heavy tanks. Carbon fiber tanks of this size and performance do not exist--they are only goals. Gasoline, by contrast, requires only a small, low-tech tank.48% of hydrogen gas is 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 interning it underground or undersea.Recently, there have also been some concerns over possible problems related to hydrogen gas leakage. 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; in Germany, for example, the leakage rate is only 0.1% (less than the natural gas leak rate of 0.7%). At most, such leakage would likely be no more than 1-2% even with widespread hydrogen use, using present technology. Additionally, present estimates indicate that it would take at least 50 years for a mature hydrogen economy to develop, and new technology developed in this period could further reduce the leakage rate.

http://en.wikipedia.org/wiki/Hydrogen_economyFigure 3. The energy densities of hydrogen fuels stored in various phases and materials are plotted, with the mass of the container and apparatus needed for filling and dispensing the fuel factored in. Gasoline significantly outperforms lithiumion batteries and hydrogen in gaseous, liquid, or compound forms. The proposed DOE goal refers to the energy density that the US Department of Energy envisions as needed for viable hydrogenpowered transportation in 2015.

Crabtree et al., The Hydrogen Economy, Physics Today, Dec 2004

At any given pressure, hydrogen gas contains less energy per unit volume than methane (representing natural gas), methanol, ethanol, propane or octane (representing gasoline). At a pressure of 80 MPA (800 bar), gaseous hydrogen reaches the volumetric energy density of liquid hydrogen. Even then, its volumetric energy content is lower than that of 80 MPA methane gas by a factor of 3.2. The common liquid energy carriers like methanol, ethanol, propane and octane surpass liquid hydrogen by factors of 1.8, 2.3, 2.5 and 3.4, respectively. However, hydrogen at 80 MPa or in the liquid state must be contained in hi-tech pressure vessels or in cryogenic containers, while the liquid hydrocarbon fuels can be kept under in simple tanks at atmospheric (propane slightly above) pressure


Compared with liquid or high-pressure (80 MPa) gaseous hydrogen, each of the ten compounds (A to J) contains from two to almost four times as much energy per unit volume. Of these, ammonia, methanol, ethanol, DME, and toluene have relatively simple molecular structures, while the gasoline-like octane is the best hydrogen carrier and also second with respect to energy content per unit volume.Although ammonia contains 136 kg of hydrogen per cubic meter, it is extremely poisonous. Whether one wants to distribute energy or hydrogen, the best way is to combine it with carbon to make a liquid fuel. Compared with methanol and ethanol, octane is harder to synthesize, e.g. by the Fischer-Tropsch process, and harder to reform to produce hydrogen for use in fuel cells. Dimethylether (DME) has good characteristics, but is less versatile than the alcohols.Methanol can be directly converted to electricity either via heat engines or by Direct Methanol Fuel Cells (DMFC), Molten Carbonate Fuel Cells (MCFC) and Solid Oxide Fuel Cells (SOFC). It can also be reformed easily to hydrogen for use in Polymer Electrolyte Fuel Cells (PEFC or PEM) and Alkaline Fuel Cells (AFC). Methanol could become a universal fuel for fuel cells and many other applications.Ethanol is non-poisonous (in moderation), and may be derived directly from biomass, e.g. by fermentation, as well as synthesized from bio-carbon and water. Having a relatively high volumetric energy density, it is particularly suitable for use in vehicles. It may be used in spark ignition (SI) engines as an 85% blend with gasoline (E85) in dedicated or Flexible Fuel Vehicles, or in compression ignition (CI) engines as a 95% blend with diesel fuel (E95) [24]. In principle, it could also be used in fuel cell vehicles. Hence ethanol could be an excellent solution for an energy economy based on renewable energy sources and the recycling of carbon dioxide.


Since the production of hydrogen is governed by the heat of formation or the higher heating value, its use should also be related to the HHV energy content. Our analysis is based on physical and chemical reasoning and therefore uses the higher heating value (HHV) throughout. The reference density and heating values of hydrogen and methane used in this study are shown in Table 1.


The required energy input for liquefaction relative to the HHV of hydrogen is shown in Figure 8. For very small liquefaction plants (>5 kgLH2/h), the energy needed to liquefy hydrogen may exceed the HHV energy. Even 10,000 kgLH2/h plants (perhaps four times larger than any existing liquefaction facility) would consume about 25% of the HHV energy of the liquefied hydrogen. For the available technology, 40% would be a reasonable number. On other words, 1.4 units of energy would have to be supplied to the liquefier as hydrogen and electricity to obtain 1 HHV unit of liquid hydrogen. However, no liquefaction plants of comparable performance have yet been built.Moreover, liquid hydrogen storage systems lose some hydrogen gas by boil-off. This is due to unavoidable heat leakage, and must be permitted for safety reasons. The loss rate is dependent on the size of the store, but would be significant for those used in vehicles, and may amount to 3 to 4 per cent a day [16]. While this gas may be used when the vehicle is operated, it would have to be vented if the vehicle was parked. For example, if parked at an airport for 14 days, the loss of hydrogen could be 50 to 60 per cent.


Figure 4. The storage density of hydrogen in compressed gas, liquid, adsorbed monolayer, and selected chemical compounds is plotted as a function of the hydrogen mass fraction. All compounds here except the graphite monolayer store hydrogen at greater than its liquid density at atmospheric pressure; green data points on the righthand side indicate liquid and gaseous H2 densities. The straight lines indicate the total density of the storage medium, including hydrogen and host atoms. Of the inorganic materials (plotted as triangles), the compounds shown in boxes all form the alanate structure, composed of a tetrahedral, methanelike AlH4 or BH4 anion and a metal cation. Those compounds are among the most promising hydrogenstorage fuelcell materials. (Adapted from L. Schlapbach and A. Zuttel, ref. 7.)

Crabtree et al., The Hydrogen Economy, Physics Today, Dec 2004

Even for the best pathways, A and C, the elemental Hydrogen-Economy depicted in Figure 15 is not convincing. All the losses with the elemental Hydrogen Economy are directly related to the nature of hydrogen. Hence they cannot be significantly reduced by any amount of research and development. We have to accept that hydrogen is the lightest element and its physical properties do not suit the requirements of the energy market. The production, packaging, storage, transfer and delivery of the gas are so energy consuming that other solutions must be considered. Mankind cannot afford to waste energy for uncertain benefits; the market economy will always seek practical solutions and, as energy becomes more expensive, select the most energy-efficient. Judged by this criterion, the elemental Hydrogen-Economy can never become a reality.This study provides some clues for the strengths and weaknesses of hydrogen as an energy carrier. Certainly the proportion of energy lost depends on the application. The analysis shows that transporting hydrogen gas by pipeline over thousands of kilometers would suffer large energy losses. Moreover, in practice, the demands on materials and maintenance would probably result in prohibitive levels of leakage and system costs. Furthermore, the analysis shows that compression or liquefaction of the hydrogen, and transport by trucks would incur large energy losses. However, hydrogen solutions may be viable for certain niche applications. For example, excess rooftop solar electricity could be used to generate hydrogen, stored at low pressure in stationary tanks, for heat and power co-generation with engines or fuel cells may be a viable solution for private buildings.As stated at the beginning, hydrogen generated by electrolysis may be the best link between mostly physical energy from renewable sources and chemical energy. It is also the ideal fuel for modern clean energy conversion devices like portable fuel cells, and can even be used in modified IC engines. But hydrogen is far from ideal for carrying energy from primary sources to distant or mobile end users. For the commercial bridge between the electrolyzer and the fuel cell or IC engine, other solutions must be considered.


The hydrogen-only perspective is obscuring a superior clean energy solution an energy economy based on synthetic liquid hydrocarbons. The ideal energy carrier would be a liquid with a boiling point above 80C and a freezing point below -40C. Such energy carriers would remain liquid under normal climate conditions and at high altitudes. Gasoline, diesel fuel (= heating oil) are excellent examples. They are in common use not only because they can be derived from crude oil and natural gas, but mainly because their physical properties make them ideal for transportation applications. They emerged as the best solutions with respect to handling, storage, transport and energetic use. Even if oil had never been discovered, the world would not use synthetic hydrogen, but one or more synthetic hydrocarbons for portable fuels, and particularly for road transport.A Synthetic Liquid Hydrocarbon Economy could be based on the two natural cycles of water and carbon dioxide, and provide consumer-friendly energy carriers produced entirely from renewable sources. Water is the source of hydrogen while carbon is taken from the biosphere (bio-carbon) e.g. from biomass, organic waste and CO2 captured from flue gases. Typically, biomass has a hydrogen-tocarbon ratio of two. In methanol synthesis, two additional hydrogen atoms are attached to every bio-carbon. Instead of converting biomass into hydrogen, hydrogen from renewable sources or even from water could be added to biomass by a chemical process to form methanol or ethanol. In a Synthetic Liquid Hydrocarbon Economy, carbon atoms stay bound in the energy carrier until its final use. They are then returned to the atmosphere (or in stationary plant may be directly recycled by recovery from flue gases). Due to the lesser upstream energy required especially for packaging, delivery, storage, and transfer such Synthetic Liquid Hydrocarbons are environmentally superior to elemental hydrogen itself.


Following the proposal by the Hydrogen Romantics of the Hydrogen Energy System, one of their first actions was to establish the International Association for Hydrogen Energy,IAHE . IAHE was established with the aim of promoting conversion to the Hydrogen Economy by informing the public in general, along with energy and environment scientists and decision makers in particular about the advantages and benefits of the Hydrogen Energy System. In January 1975, IAHE started the publication of its scientific journal, the International Journal of Hydrogen Energy, IJHE, and now publishes some 15 issues a year. Starting in 1976, IAHE began organizing the biennial World Hydrogen Energy Conferences (WHECs). In parallel with the International Association for Hydrogen Energy, a growing number of national hydrogen energy organizations have been established around the world which organize their own publications together with national and regional conferences. During the first quarter century, from 1974 through 2000, utilising the research and development activities in universities and energy related industries, and through information dissemination activities, such as conferences and publications, the foundations of the Hydrogen Energy System were established. By the year 2000, the transition to the Hydrogen Economy had started. In Japan and in the U.S.A., hydrogen fueled cars are available for leasing. In Europe, the Americas and Australia, Rapid Transport Authorities have started operation of fleets of hydrogen fueled buses. Several types of hydrogen fuel cells as well as hydrogen hydride electric batteries are available commercially for electricity generation. Many countries have initiated programmes for roadmaps for conversion to the Hydrogen Economy. However, present modeling studies indicate that if no incentives are provided for clean energy, full transition to the Hydrogen Economy will take three quarters of century. 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: at present, it imports all the petroleum products necessary to power its automobiles and fishing fleet. But Iceland has large geothermal and hydroelectric resources, so much so that the local price of electricity actually is lower than the price of the hydrocarbons that could be used to produce that electricity.Iceland already converts its surplus electricity into exportable goods and hydrocarbon replacements. In 2002, it produced 2000 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 aluminum-smelting industry - aluminum 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.But neither directly replaces hydrocarbons. Reykjavik has a small pilot fleet of city busses runing on compressed hydrogen [1], and research on powering the nation's fishing fleet with hydrogen is underway. For practicality, Iceland may end up processing imported oil with hydrogen to extend it, rather than to replace it altogether.

http://en.wikipedia.org/wiki/Hydrogen_economyAdvantages of the hydrogen economy In the previous section we saw the significant, worldwide problems created by fossil fuels. The hydrogen economy promises to eliminate all of the problems that the fossil fuel economy creates. Therefore, the advantages of the hydrogen economy include: The elimination of pollution caused by fossil fuels - When hydrogen is used in a fuel cell to create power, it is a completely clean technology. The only byproduct is water. There are also no environmental dangers like oil spills to worry about with hydrogen. The elimination of greenhouse gases - If the hydrogen comes from the electrolysis of water, then hydrogen adds no greenhouse gases to the environment. There is a perfect cycle -- electrolysis produces hydrogen from water, and the hydrogen recombines with oxygen to create water and power in a fuel cell. The elimination of economic dependence - The elimination of oil means no dependence on the Middle East and its oil reserves. Distributed production - Hydrogen can be produced anywhere that you have electricity and water. People can even produce it in their homes with relatively simple technology. The problems with the fossil fuel economy are so great, and the environmental advantages of the hydrogen economy so significant, that the push toward the hydrogen economy is very strong.


Hydrogen also has a poor energy density per volume. This means you need a large tank to store it, even when additional energy is used to compress it, and the high pressure compounds safety issues. The large tank reduces the fuel efficiency 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. This is called the storage problem.

http://en.wikipedia.org/wiki/Hydrogen_economyThere are two primary uses for hydrogen today. About half is used to produce ammonia (NH3) via the Haber process, which is then primarily used directly or indirectly as fertilizer. 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.Because the world population and the intensive agriculture used to support it are both growing, ammonia demand is growing. Hydrocracking represents an even larger growth area, as rising oil prices encourage oil companies to extract poorer source material, such as tar sands and oil shale. http://en.wikipedia.org/wiki/Hydrogen_economySome thermochemical processes, such as the sulfur-iodine cycle, can produce hydrogen and oxygen from water and heat without using electricity. Since all the input energy for such processes is heat, they 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.None of the thermochemical hydrogen production processes have been demonstrated at production levels, although several have been demonstrated in laboratories.

http://en.wikipedia.org/wiki/Hydrogen_economyThe most common way to store hydrogen, and really the only way to do it efficiently is to compress it to around 700 bar (~10,000 PSI). Many people believe that the energy needed to compress the gas is one of the major faults in the idea of a hydrogen based economy. For example, if one considers the entire world using hydrogen just in their cars, then a massive amount of energy would be needed to be compressed and stored. Thus, if it were not used in any way, the net energy used to compress it would be wasted. These types of fuel cells are very expensive, typically 100 times more expensive per kW output than conventional internal combustion engines. It has further been suggested that cars powered by Li-on or Li-polymer batteries are capable of being more efficient than hydrogen-based cars would ever be, and that they just need to be mass produced to become cost effective.

http://en.wikipedia.org/wiki/Hydrogen_economyProspects for the future You will hear more and more about the hydrogen economy in the news in the coming months, because the drumbeat is growing louder. The environmental problems of the fossil fuel economy are combining with breakthroughs in fuel-cell technology, and the pairing will allow us to take the first steps. The most obvious step we will see is the marketing of fuel-cell-powered vehicles. Although they will be powered initially by gasoline and reformers, fuel cells embody two major improvements over the internal combustion engine: They are about twice as efficient. They can significantly reduce air pollution in cities. Gasoline-powered fuel-cell vehicles are an excellent transitional step because of those advantages. Moving to a pure hydrogen economy will be harder. The power-generating plants will have to switch over to renewable sources of energy, and the marketplace will have to agree on ways to store and transport hydrogen. These hurdles will likely cause the transition to the hydrogen economy to be a rather long process.


Large rural high efficiency generators combined with a distribution system (like the natural gas distribution system but able to meet hydrogen's additional transport challenges) and fuel cells that run on hydrogen might be able to replace today's electrical distribution and generation systems, and fuel vehicles. Similar systems are currently used with natural gas to produce electricity, such as large urban developents with cogeneration facilities. The energy source could be nuclear, or fossil fuel. Large generators that produced hydrogen from fossil fuel energy sources would generate huge amounts of pollution, but centralize emissions, so emission control systems would be easier to inspect and hence perhaps better maintained than systems on automobiles owned by individuals. However there are several technological "showstoppers" that stand in the way.

http://en.wikipedia.org/wiki/Hydrogen_economy

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