BMW Technology - Hydrogen

Hydrogen, designated by its chemical symbol H, is the most common and, at the same time, the lightest element in the Universe. Forming part of water and all organic compounds, it is part of the biological cycle and therefore fully compatible with the environment.

Hydrogen can be stored either in gaseous form or as a cryogenic fluid and is relatively easy to transport. A non-toxic color- and odorless gas, hydrogen is combustible and has approximately one-quarter the calorific value of gasoline in its liquid phase (in terms of volume). In terms of weight, on the other hand, liquid hydrogen has almost three times as much energy as gasoline. Combustion of hydrogen generates water (H2O), but no carbon dioxide (CO2). And given the sum total of its properties, hydrogen, in the opinion of experts, has the potential to become the fuel of the future. In nature hydrogen is virtually non-existent in its pure form outside of compounds. It is to be found most frequently in water, in various forms of hydrocarbon, and in other chemical compounds. Therefore it always requiring a conversion process before it can be used for the generation of energy.

Currently more than 600 billion cubic meters of hydrogen is recovered worldwide each year. This hydrogen comes, for example, from the reformation of natural gas, from the production of coke or electrolysis of chlorine alkali, a process which generates hydrogen as a by-product. Annual production of hydrogen in Germany amounts to approximately 30 billion cubic meters. Half of the hydrogen recovered in this way is required for synthesizing ammonia used for the production of artificial fertilizer and for the synthesis of plastics. A quarter of the ammonia serves for processing petroleum, and the final quarter is used for synthesizing methanol, an alcohol used in the textiles, dye, and plastics industry, and is also applied in a large number of metallurgical production processes.

Hydrogen may be recovered in various ways and through various processes crucial to the overall ecological balance of hydrogen as a fuel.

The processes applied most frequently today use fossil sources of primary energy:

• Reformation of natural gas, liquid gas, and naphta
• Partial oxidation of heavy oil
• Gasification of coal
• Pyrolysis of coal to produce coke
• Reformation of gasoline

None of these processes offers a long-term, sustained alternative: First, they are based on finite raw materials and sources of energy; second, undesired substances such as carbon dioxide are released in the processes involved. Working on behalf of the European Union and the German Federal Government, researchers are examining the options for the so-called sequestration of CO2. This is the process of separating and retaining this gas, for example in recovering hydrogen from natural gas. For the purpose of long-term storage, the carbon dioxide is pumped into former, now empty deposits of crude oil, natural gas, or coal. Another point being critically debated is the option to deposit such carbon dioxide at the bottom of the sea.

Electrolysis: Simple, Effective, Clean

Electrolysis is the most promising method for recovering hydrogen, using electric power to recover hydrogen from water in virtually unlimited quantities. The principle applied in this case is simple and straightforward: Two electrodes dipped into a water bath are subjected to a flow of direct voltage. The positively charged hydrogen ions (cations) gather in this process around the negative cathode, the oxygen ions (anions) move to the positive anode.

The hydrogen gas generated in this process is retained, as is - where required - the gaseous oxygen. Again, this may be done in various ways:

• through alkalic electrolysis
• through membrane electrolysis
• through alkalic high-pressure electrolysis
• through alkalic high-temperature electrolysis

The highly developed process of alkalic electrolysis is currently the most environmentally-friendly and economical production method among these processes. However, electrolysis makes sense in ecological terms only if the electricity used for the fission of water is obtained from regenerating sources of primary energy.

Solar Energy: Free and Unlimited

BMW also active in development of solar-power technology for hydrogen production Before hydrogen drive can be implemented on a sufficiently wide scale, a number of problems remain to be solved, particularly with regard to infrastructure. Hydrogen will only become a viable alternative to fossil fuels when the electricity needed for its extraction can be produced using sustainable sources of energy. Solar cells are one means of accomplishing this, as are solar power stations with troughshaped parabolic mirrors of the type used in the Californian Mojave desert. To test scenarios such as this in practice, BMW decided at an early stage to join the Solar Hydrogen Project in the German town of Neunburg vorm Wald where, in collaboration with other companies, BMW tested the photovoltaic generation of hydrogen and the application of this method for various purposes. The objective is economically viable production of sufficient quantities of hydrogen using solar power. From natural gas to hydrogen As long as hydrogen is unavailable in sufficient volume as a practicable source of energy, non-toxic natural gas represents an ecological and resource-saving alternative to conventional fuels.

Engines powered by natural gas emit around 20 percent less carbon dioxide (CO2), which contributes to the greenhouse effect, and an 80 percent lower volume of hydrocarbons (HC), which increase the formation of ozone. BMW therefore entered the market with series-produced natural gas cars in 1995, and thus became the first manufacturer in Europe to take the first determined step towards the hydrogen-driven car. In their properties of relevance as motor fuels, natural gas and hydrogen are very similar. Consequently, in the course of development of the natural gas car, a great deal of experience was gained of value for the greater objective hydrogen drive. The next step, not only for this reason, is to make the transition to liquefied natural gas, which needs to be stored at approximately -163 C. Liquefied natural gas has an energy density almost four times that of compressed natural gas. With the same tank volume, a car operating on liquid natural gas can achieve a cruising range of around 70 percent that of a petrol-driven car. Whereas in the case of cars running on compressed natural gas, the alternative of petrol-fuelled operation is to be upheld, once the corresponding infrastructure is established, this will no longer be necessary with liquefied natural gas. From that point it will be only a small technical step away from realization of hydrogen drive.

The highly developed process of alkalic electrolysis is currently the most environmentally-friendly and economical production method among these processes. However, electrolysis makes sense in ecological terms only if the electricity used for the fission of water is obtained from regenerating sources of primary energy.

Here, in the largest solar power complex in the world, 2.3 million square meters of mirrors generate 354 megawatt of electricity - enough energy for approximately 200,000 inhabitants of California. This means that during its overall service life, this solar power plant avoids the emission of 18 million tonnes of CO2 in comparison with facilities running on fossil fuel.

Particularly regions around the 40th latitude are very well suited for solar power plants. But even in Europe solar-thermal plants are seen to have a potential of approximately 1,400 terawatt hours (TWh), equal to almost four million of the solar power plants in California mentioned before. Even photovoltaic technology would be able to generate 600 TWh. The fact nevertheless remains that at least in the mean term wind energy offers the largest energy reserves in Europe not yet tapped, amounting to 1800 TWh offshore and 350 TWh on land. Currently about 60 TWh of electric energy is generated by wind power in Europe, that is roughly 2.4 per cent of the total demand for electricity.

Re-growing raw materials may also be used instead of fossil carbon compounds as input for recovering hydrogen. Using biomass as the source of energy for regenerating hydrogen, the processes applied are unique in two respects: First, they are the only option to recover hydrogen directly from a regenerating source of primary energy. Second, biomass is generally regarded as almost neutral in terms of CO2, since, through photosynthesis, plants take up the same amount of carbon dioxide from the air as they emit themselves when being processed.

Hydrogen can be recovered from biomass either through gasification or fermentation or through other biological processes. For ecological reasons numerous experts claim that hydrogen should only be recovered from waste biomass, and not from energy-bearing plants. Clearly, this alone applies certain strict limits to the availability of biomass really suitable for practical use.

Studies conducted in the context of the TES Transport Energy Strategy state that in Europe hydrogen recovered from biomass has the potential to substitute approximately 30 per cent of the total amount of fuel generated in conventional processes. The assumption made in this case is that all the biomass available, including the cultivation of energy plants, is used exclusively for the production of fuel for road traffic. But since biomass is also used for stationary purposes in the production of electricity and heat, its real potential for substitution is in the region of 15 per cent. In other words, biomass can make a contribution to the reduction of carbon dioxide emissions, but is far from being able to cater to the actual demand.

How Hydrogen is Stored and Distributed

Contrary to electrical energy, hydrogen may also be stored in large amounts, generally either in gaseous or liquid form. This provides the option to use electrical energy generated by solar, hydro or wind power for the fission of hydrogen and, going beyond current practice, to subsequently store the hydrogen recovered in this way.

Very large amounts of hydrogen are stored in so called gasometers, medium quantities are kept in gaseous form in pressure tanks at approximately 30 bar. Small amounts, in turn, may be filled into pressure cylinders made of steel or carbon-fiber-reinforced composite materials up to a pressure of 400 bar. New tank systems able to withstand pressure of up to 700 bar are currently being examined.

Hydrogen can be stored in liquid form at a temperature of -253 °C. Since this kind of storage, as opposed to the storage of hydrogen in gaseous form at 700 bar, provides 1.78 more energy density per unit of volume, BMW advocates the use of liquid hydrogen for storage in the vehicle: The more energy one can take along within an existing tank of given capacity, the longer the range of the vehicle. To achieve the same energy density as liquid hydrogen, gaseous hydrogen would have to be compressed and stored at a pressure of 1250 bar.

Another option is to store hydrogen in a so-called hybrid reservoir, where the hydrogen is kept under pressure in metallic powder and then released again as required through the infusion of heat. Hydrid reservoirs are able to take up approximately 2 per cent of their weight in hydrogen, which is not enough for use in a motor vehicle.

One more option being examined is the storage of hydrogen in nano-fiber structures or alanates (= chemical hydrogen compounds). Should these technologies prove viable, they would indeed open up new perspectives for the storage of hydrogen energy.

Transport by pipeline, ships and trucks - already standard practice today

There are already pipeline networks in regions with a high concentration of chemical plants and companies for the long-distance transport of gaseous hydrogen. In principle natural gas pipelines are also quite suitable for this purpose, provided they meet the necessary technical requirements such as ensuring proper sealing without leaks. This is the case throughout most of the European gas pipeline network.

Hydrogen is also well-known in communal use: The city or light gas used in the past was a synthesized gas made up of 50 per cent hydrogen. In many cities this gas was used for purposes such as street lighting until well into the second half of the former century.

Intercontinental transportation of hydrogen is also a routine procedure these days, with the technical solutions required being largely in place. And since liquid hydrogen takes up only about one-tenth of the volume of gas compressed to 30 bar, ships and trucks are designed to carry cryogenic hydrogen. As in the case of nitrogen, oxygen or argon, the tank systems used in this case are high-vacuum-insulated double-jacket tanks.

These facilities allow efficient transportation of hydrogen from its place of production all the way to the car: Immediately after recovery, the gas is cooled to a temperature of -253 °C. From here, ships and tank trucks transport the - now liquid - hydrogen to the filling station, where it is again stored in cryogenic form. Then, at the fuel pump itself, the hydrogen flows into the tank of the car either in liquid form or, after being allowed to warm up, is pumped into a pressurized tank under the pressure required. Both of these processes can be applied at one and the same filling station, meaning that the filling station of the future will be able to offer the motorist not only gasoline and diesel, but also gaseous and liquid hydrogen.

How Hydrogen Goes into Your Car

One of the basic prerequisites for the broad-scale introduction of hydrogen as fuel is the availability of a tank-filling system just as easy to use as the system we have today. This applies both to cryogenic, liquid hydrogen and to gaseous hydrogen under high pressure.

The BMW Group advocates the use of liquid hydrogen. The main reason for this decision is that the energy density of liquid hydrogen relative to the tank system is almost twice that of gas compressed to 700 bar, reaching a level of almost 2.5 kilowatt hours per liter.

Cooperating with Magna Steyr in a joint venture, BMW is developing a tank system allowing vehicles to be filled up with liquid hydrogen virtually just as fast, with no loss and no danger of any kind, that is with the same convenience and efficiency as in the case of gasoline or diesel. To offer the customer optimum comfort and convenience, this tank-filling system is already in use at the world's first public "robotized" filling station for liquid hydrogen at Munich Airport. In April 2004 the project partners responsible for installing and operating this filling station were able to look back at five years of experience, so far filling more than 30,000 liters of liquid hydrogen into various vehicles in more than 600 operations.

The procedure applied is very simple and straightforward: Like at every other filling station, cars running on hydrogen drive up to the fuel pump located in the public area of Munich Airport. Then the driver initiates the fully automatic tank-filling process. While the tank is being filled up - this takes roughly as long as a conventional tank-filling process with gasoline or diesel - the driver in theory need not even get out of his car, since he is identified by his tank card or by electronic remote control. Liquid hydrogen at a temperature of -253 °C is subsequently able to "rain" into the tank of his BMW, hydrogen gas in the tank condensing on the droplets via the liquid phase and thus reducing the partial pressure of the hydrogen gas. As a result, absolutely no hydrogen is lost in the process of filling the tank.

In terms of the operations involved, the process of filling the tank manually is again virtually exactly the same as at a conventional filling station. By and large, the system differs only in terms of the pressure- and low temperature-proof connector taking the place of the usual pump nozzle: To fill up the tank, the driver places the connector on the tank filler pipe and locks it in position, enabling the hydrogen to "flow" in.

This process of filling the tank manually is to be studied in a large-scale demonstration project in Berlin, where the first hydrogen tank in Germany integrated in a public filling station will be opened in autumn 2004. And to develop a standardized liquid hydrogen connector suitable for worldwide use on the automobile as soon as possible, the BMW Group and General Motors/Opel established an open consortium in April 2003 together with Linde and Walter.

Crash tests with tanks for liquid hydrogen

In close cooperation with the TÜV South Germany Technical Inspection Authority, the BMW Group has conducted a comprehensive range of tests examining various accident scenarios and determining how the liquid hydrogen tank behaves in the process. One of the test procedures was to destroy full tanks under high pressure after deliberately blocking their safety valves. The predetermined rupture point inside the tank provided for such an extreme case allows controlled discharge of the hydrogen without any major risks or hazards.

In a further series of tests vehicle tanks filled with liquid hydrogen were subjected to various fire conditions in a special test area: In the process the tanks were surrounded by flames at a temperature of almost 1000 °C or approximately 1850 °F for up to 70 minutes. Again, the tanks did not present any problems, the evaporated hydrogen slowly escaping through the safety valves in a smooth, almost imperceptible flow of gas. In the last series of tests, finally, car tanks containing liquid hydrogen were deformed and seriously damaged by hard, solid objects. None of the tanks exploded.

Thorough and very demanding crash tests were also conducted successfully on the overall vehicle as a complete "system" and are described in greater detail in the Chapter on "How Cars Run on Hydrogen". After these comprehensive examinations, the TÜV Technical Inspection Authority arrived at the conclusion that hydrogen can be used just as safely as gasoline.

The procedure applied is very simple and straightforward: Like at every other filling station, cars running on hydrogen drive up to the fuel pump located in the public area of Munich Airport. Then the driver initiates the fully automatic tank-filling process. While the tank is being filled up - this takes roughly as long as a conventional tank-filling process with gasoline or diesel - the driver in theory need not even get out of his car, since he is identified by his tank card or by electronic remote control. Liquid hydrogen at a temperature of -253 °C is subsequently able to "rain" into the tank of his BMW, hydrogen gas in the tank condensing on the droplets via the liquid phase and thus reducing the partial pressure of the hydrogen gas. As a result, absolutely no hydrogen is lost in the process of filling the tank.

In terms of the operations involved, the process of filling the tank manually is again virtually exactly the same as at a conventional filling station. By and large, the system differs only in terms of the pressure- and low temperature-proof connector taking the place of the usual pump nozzle: To fill up the tank, the driver places the connector on the tank filler pipe and locks it in position, enabling the hydrogen to "flow" in.

This process of filling the tank manually is to be studied in a large-scale demonstration project in Berlin, where the first hydrogen tank in Germany integrated in a public filling station will be opened in autumn 2004. And to develop a standardized liquid hydrogen connector suitable for worldwide use on the automobile as soon as possible, the BMW Group and General Motors/Opel established an open consortium in April 2003 together with Linde and Walter.

Crash tests with tanks for liquid hydrogen

In close cooperation with the TÜV South Germany Technical Inspection Authority, the BMW Group has conducted a comprehensive range of tests examining various accident scenarios and determining how the liquid hydrogen tank behaves in the process. One of the test procedures was to destroy full tanks under high pressure after deliberately blocking their safety valves. The predetermined rupture point inside the tank provided for such an extreme case allows controlled discharge of the hydrogen without any major risks or hazards.

In a further series of tests vehicle tanks filled with liquid hydrogen were subjected to various fire conditions in a special test area: In the process the tanks were surrounded by flames at a temperature of almost 1000 °C or approximately 1850 °F for up to 70 minutes. Again, the tanks did not present any problems, the evaporated hydrogen slowly escaping through the safety valves in a smooth, almost imperceptible flow of gas. In the last series of tests, finally, car tanks containing liquid hydrogen were deformed and seriously damaged by hard, solid objects. None of the tanks exploded.

Thorough and very demanding crash tests were also conducted successfully on the overall vehicle as a complete "system" and are described in greater detail in the Chapter on "How Cars Run on Hydrogen". After these comprehensive examinations, the TÜV Technical Inspection Authority arrived at the conclusion that hydrogen can be used just as safely as gasoline.

Liquid hydrogen is always cryogenic

Liquid hydrogen inside the tank of a car warms up in a "natural" process. The pressure inside the tank thus increases in the course of time until a limit currently set at 5.5 bar, the maximum pressure allowed in a tank for liquid hydrogen. Under higher pressure, gas is able to escape in a controlled process through a spillover valve in a process comparable to the evaporation of gasoline from a conventional car tank when parked in bright sunshine.

Currently it takes about one day for the fuel in a hydrogen tank to reach a pressure of 5 bar with the engine not running. And whenever the car is driven in the meantime, pressure decreases and the loss of hydrogen during extended standstill periods may be avoided altogether.

Joint Ventures

CleanEnergy Partnership (CEP): Thorough test operation and hydrogen trials in Berlin

To promote hydrogen technology in Germany along straightforward, practical lines, the BMW Group joined forces with Aral, BVG, DaimlerChrysler, Ford, GHW, Linde, Opel, and MAN in June 2002 to form the CleanEnergy Partnership or CEP for short. Established for a project term scheduled up to the year 2007 and with a budget of Euro 33 million, the CEP forms part of the German National Sustainability Strategy and is supported by the German Federal Government. It demonstrates technologies pointing into the future and presents the technical and economic prerequisites for the use of alternative fuel in road traffic.

An elementary point of fundamental significance in this context is to prove the positive effects of a new technology on the environment. This is why hydrogen is to be recovered to the greatest possible extent through regenerating energy, that is mainly with electricity derived from solar energy, hydro or wind power. This means that in practice no undesired emissions are generated from the initial recovery of hydrogen all the way to its final use in the car. BMW is participating in the project through the operation of hydrogen vehicles.

Filling station for fluid and gaseous hydrogen under construction.

One of the key activities of the CEP is to build and operate a hydrogen filling station under regular conditions. Integrated in the everyday operations of a conventional filling station, this hydrogen filling station will be opened in autumn 2004. Apart from gasoline and diesel fuel, customers are able to fill their tank here with two types of hydrogen: compressed gaseous hydrogen (CGH2) and liquid hydrogen (LH2). The BMW Group favors the latter for reasons of handling and the range the car is able to cover.

Gaseous hydrogen produced locally

Gaseous hydrogen is produced locally at the filling station by means of pressure electrolysis virtually free of emissions. This technology has indeed been developed for local production of a hydrogen energy supply with a high degree of purity. The principle applied is simple, water being split under pressure by direct current into its two elements hydrogen and oxygen.

The compact facility used for this purpose is designed for fully automatic, ongoing and safe operation. A particular factor is the direct link established between the production of hydrogen and actual demand at the filling pump, with only as much hydrogen being produced as is actually required. A compressor unit compresses the gaseous hydrogen from approximately 15 to 350 bar, that is the pressure at which hydrogen is filled into the cars. And filling pumps are indeed already prepared for a filling process under a pressure of 700 bar.

Tank trucks delivering liquid hydrogen

Liquid hydrogen is produced at a central location and delivered by tanker trucks. At the filling station the cryogenic hydrogen is stored in a highly insulated double-jacket 10,000-liter reservoir. Since evaporation pressure is reduced every time hydrogen is pumped into a car, the loss of hydrogen and the cooling operations required are kept to a minimum.

This supply of liquid hydrogen also serves as back-up for the supply of gaseous hydrogen: Should the supply of compressed hydrogen run low, liquid hydrogen can be converted into gaseous hydrogen to set off any bottlenecks in the supply process. The filling pumps for liquid hydrogen are equipped with a transfer pump and a cold-draw coupling for rapid tanking. The advantage of such a filling station with liquid hydrogen is that it is able to achieve a potentially greater throughput of energy.

Long-term cooperation: the TES Transport Energy Strategy

No single company will be able to produce hydrogen as the fuel of the future all by itself. Precisely this is why the BMW Group, acting as a pioneer, has initiated various joint ventures: The TES Transport Energy Strategy Project started in May 1998 with the support of the German Federal Government and now comprising Aral/BP, the BMW Group, DaimlerChrysler, MAN, Opel, RWE, Shell, TOTAL and VW.

The objective of this initiative is to develop a common strategy for the introduction of alternative energy and drive systems. Further fundamental goals are to make transport less dependent on petroleum, to preserve finite resources, to further reduce emissions such as CO2, and to expand the initiative to the whole of Europe. These objectives are based on the vision of a crisis-resistant, sustained, environmentally-friendly and resource-preserving supply of energy which, in combination with a new generation of highly efficient vehicles, is intended to pave the way into a more ecologically-minded and economical world of mobility in future.

TES: hydrogen is the most sensible alternative in the long term

The TES initiative has carefully studied and assessed all alternative fuels for their possible potentials. Focusing in the process on more than 80 alternatives, the researchers established beyond doubt that hydrogen is the best solution for the future offering the most powerful potential. The main advantage of hydrogen in political and strategic terms is that the process of regenerating production is very flexible and offers substantial opportunities for the future. In practice this means that both CO2 emissions and supply risks may be considerably reduced in the long term both in mobile and stationary applications. And at the same time hydrogen technology offers a substantial potential for innovative mobile applications, thus opening up new growth opportunities for Germany as a centre of industry.

The Transport Energy Strategy has been successfully presented at numerous international events, international corporations in the energy and car industries joining the TES initiative.

A lot has happened recently also in Europe in developing a fully-fledged hydrogen economy: The new European Hydrogen and Fuel Cell Technology Platform (EHP) held its first General Assembly in Brussels in early 2004, expressing its commitment to the development and application of low-cost, competitive European energy systems based on hydrogen and fuel cell technologies for mobile, portable and stationary applications. In the next 10 years the EU will provide up to Euro 2.8 billion in funds in its quest to initiate a hydrogen economy compatible with the environment. Specialists of the BMW Group have been appointed to bodies such as the Advisory Council and the Deployment Strategy Panel of the EHP as well as the California Hydrogen Highway Implementation Advisory Panel in order to offer their advice and know-how. This ensures an effective transfer of know-how also on an international level, the BMW Group being able to contribute experience from 25 years of hydrogen research.

BMW CleanEnergy - further partnerships and joint ventures

In the series development of the hydrogen car, the BMW Group is working with a network of partners in industry. Magna Steyr, for example, has already become a highly competent BMW partner in the development and supply of the hydrogen tank.

Within an open Development Consortium, the BMW Group has joined forces with General Motors in the development of a liquid hydrogen tank coupling to be established as a global standard.

This projected liquid hydrogen coupling is based on the Draft Directive of the European Integrated Hydrogen Project (EIHP) serving in turn as the basis for compiling the future ECE Directives for Hydrogen-Drive Vehicles (ECE = Economic Commission of Europe of the United Nations). The actual process of developing the coupling is being conducted with the support of Linde and Walter, two specialist companies in this area.

BMW CleanEnergy Partnership in the U.S.: Controlled Hydrogen Fleet and Infrastructure Demonstration Project

The U. S. Department of Energy has awarded a grant to a partnership, which includes BMW and is led by Air Products and Chemicals, Inc., for a combined research project titled "Controlled Hydrogen Fleet and Infrastructure Demonstration Project". The goal of the project is to study hydrogen as a fuel in real-world driving conditions. This 5-year program will use Federal funds, as well as donations from partnership members, to finance construction and testing of 24 hydrogen filling stations in California. Due to the nature of the project, the stations will vary from using renewable resources such as wind power to using a hydrogen pipeline. Some stations will be fixed; others will be relocatable.

Partnership members Toyota, Honda and Nissan will contribute a total of 65 fuel-cell powered vehicles to the project. BMW, as the leader in hydrogen internal combustion engines will provide up to 15 7 Series cars, the only test vehicles using proven internal-combustion engines.

Q: Is hydrogen available today?

A: There is a large infrastructure of hydrogen today to meet the needs of industrial applications including metals processing, refining, chemical production, fats and oils production, and electronics processing. About 45 billion kilograms (50 million tons) is produced every year -- enough hydrogen to fuel 250 million fuel cell cars. Some of this hydrogen is being used to fuel vehicles.

Q: How do we produce hydrogen today?

A: The majority of merchant hydrogen is produced by a process called steam methane reforming. Hydrogen is generated from a hydrocarbon (such as natural gas) and water at high temperatures in catalytic reactors. The hydrogen is typically purified using pressure swing adsorption. Some of the merchant hydrogen sold is recovered from industrial processes. While this is still fossil fuel based, it is allowing us to recover the hydrogen for direct application instead of being combusted by its industrial producer for its heating value.

About 95% of the total global hydrogen production is captive meaning it is used at the site where it is produced. (Merchant hydrogen represents the balance.) Much of the hydrogen produced from coal is in China for ammonia production.

Click here for more info on hydrogen production.

Q: What does hydrogen cost?

A: The cost of hydrogen is dependent on the production technology, the cost of the feedstock, and power. Delivery, storage and fuel delivery equipment are also part of the cost. Our industrial customers see a wide range in price difference depending on their geography, delivery method and use quantity. It is our belief that hydrogen has the potential to compete with gasoline when the improved efficiency of the fuel cell is taken into consideration.

The cost of hydrogen produced at a large SMR is approximately equal on an energy equivalent basis to gasoline at a refinery.

Click here for more info on Fuel Cell.

Q: In what units of measure is hydrogen sold?

A: Most industrial hydrogen is sold as a normal cubic meter (Nm3) or by hundred standard cubic foot (cscf) or thousand standard cubic foot (mscf) increments. This is even true when it is sold as a cryogenic liquid. For vehicle fueling, fills are reported in kilograms (kg) or gasoline gallon equivalents (GGE). In the United States, the sale of hydrogen cannot take place at the fueling dispenser until the Bureau of Weights and Standards has approved hydrogen as a motor fuel.

Q: Can hydrogen be put into natural gas pipelines?

A: Some, but not all natural gas pipelines have the potential for conversion to hydrogen. Hydrogen is used in pipelines today. Air Products has seven pipeline systems in the US, the UK, The Netherlands and Thailand. Some of these pipelines were originally in natural gas service.

There are many issues that must be taken into account when considering converting a pipeline, the most important being materials of construction and weld procedures. Hydrogen pipelines use a low to moderate strength steel to limit concerns of hydrogen embrittlement. Some natural gas pipelines use pipes with higher strength steels or other materials as this allows reduced wall thickness.

Q: How much will it cost to develop a hydrogen infrastructure?

A: There are many companies and governments working to understand what the various possibilities are for the development of a hydrogen infrastructure. Just as the current gasoline infrastructure wasn't built at once, the hydrogen infrastructure won't be built at once either. Many questions have to be answered first, such as:

• Will we produce hydrogen from natural gas as an interim solution and phase towards renewable production?
• Will we fuel our vehicles differently than at the corner gas station? Maybe at home or work?
• Will our car power our home?
• Will new storage technology allow more efficient delivery?
• Will we need to develop a much larger pipeline infrastructure to make enough fuel available?

Q: Can I buy hydrogen generated from renewable resources?

A: Just as most power produced today comes from fossil fuels like coal and natural gas, so does most hydrogen. There are a few solar, wind and hydroelectric projects producing hydrogen, but this hydrogen is generally committed and volumes are limited. Several biomass projects are planned. More renewable hydrogen will become available as customers demand renewable fuel and the cost of renewable power becomes more competitive.