On the HYway -
Sustainable Assets in Germany's Energy State's Portfolio
Carl-Jochen Winter, Überlingen, Germany
Professor Dr.-Ing. C.-J. Winter, Obere St.-Leonhardstr. 9,
88662 Überlingen, T/F +49 7551 944 5940/1,
cjwinter.energon @ t-online.de
Historically, North Rhine-Westfalia (NRW), Germany's energy state with the heavily industrialized Ruhr area in its middle, provided coal and steel for the industrialization of the country in the late 18th and the 19th century, was key in the recovery process after WWs I and II, and stands today for the ongoing successfully pursued transformation process from carbonaceous energy raw materials to high tech energy technologies. Step by step, prevailing energy policy has become energy technology policy!
The state hosts Germany's partner in the development club for a hydrogen based zero-CO2 coal fired power plant, as well as the biggest PV production capacity in the country; it operates a significant share of Germany's almost 13 GWe wind parks, and runs a remarkable co-operative fuel cell development network of academia and industry. So far, the youngest baby is the rapidly growing hydrogen energy economy structure, consisting of hydrogen technologies for more or less all the links of the hydrogen energy conversion chain, particularly clean hydrogen production from fossil fuels, including CO2 sequestration, or from renewable energy sources. Thus, the transformation process of NRW from coal and steel to solar and hydrogen based high tech energy technologies seems exemplary for many historically similarly structured world regions.
The paper tries to offer an insight into the build-up of hydrogen based decarbonized, hydrogenated, and, thus, dematerialized energy markets. On the energy HYway, energy technologies have taken the lead. They provide more clean energy services at the back end of the energy conversion chain from less environmentally harmful and climate change risking carbonaceous energy raw material at its front end. They grant urgently needed exergetization (exergy = energy - anergy) of the nation's energy system, and, not least, they are pre-conditional for otherwise irrational energy sustainability: H2 is the paving stone of the HYway's sustainable pavement!
Disrespectfully, many speak of "rust belts" as a label for the old degrading coal and steel regions where the industrialization of the world was initiated and carried out through the 19th and most of the 20th centuries. And indeed, the production of hard coal in the German Ruhr area, to use this example, decreased from 135 million tons in the 1950s to today's 25 - 30 million tons, and steel production shrunk from its maximum of 35 million tons to merely 20 million in 2000.
However, long since the wind has changed: Germany's energy state North Rhine -Westphalia (NRW) has in the meantime 15 MWe ≡ 26 % of Germany's total photovoltaic production capacity on-line or under construction; wind conversion in the state stands at 760 MWe (of a total of more than 12,000 MWe (2002) ≡ 9 %); 13 stationary fuel cells of all types from 80°C to 900°C operating temperature are in place, supported by a powerful 3-year (2001/03) fuel cell programme with a tax money contribution of €50 million/a; as of 2002, 34 mine gas fueled heat/power blocs with a total electric capacity of 41 MWe are operational; two 1000 MWe brown coal power plants with a legendary 43 % electric efficiency are in operation or in the planning phase, potentially making use of an efficient raw coal drying process which is still in development. In addition, NRW is committed to its share of the federal greenhouse gas reduction obligation to reduce greenhouse gases by 25% within the 1990 - 2005 time frame, and NRW supports the EU commitment of doubling by 2010 its total renewable electricity production to 10% of its requirements. Finally, NRW's so far last baby, nicknamed "H2NRW – Hydrogen North Rhine-Westphalia", was born in 2000, aiming at hydrogen production, storage, transport and distribution, and utilization technologies along the complete hydrogen energy conversion chain; no chain link is excluded (Wasserstoff, Nachhaltige Energie - stationär, mobil, Landesinitiative Zukunftsenergien NRW, Haroldstr. 4 40213 Düsseldorf, ISBN 3-00-007495-3).
Hydrogen Joins Electricity as Energy Carriers in a Growing Secondary Energy Market
Peculiarly, the establishment of the modern hydrogen energy economy began by putting the cart before the horse! Of the typically three sections of a hydrogen energy conversion chain, production, storage and transport, and finally utilization, the third section, utilization, seems to be in the foreground of interest: In the space business, hydrogen handling and utilization is day-to-day practice, and so is the usage of captive hydrogen in refineries, in glass or electronics manufacturing, in methanol or ammonia production, in the margarine industry, and as a coolant of electric generators. Storing of hydrogen, though still a challenge for very high pressures of up to 700 bars for gaseous hydrogen, or very low boil-off rates of less than 0.1 %/d for liquefied hydrogen, seems well understood and is routinely handled in the technical gases industry. Similar things apply for piping or delivering hydrogen in both gaseous and liquid forms. The industrial countries are well experienced thanks to many decades, up to almost a century, of running hydrogen pipelines up to hundreds of kilometers long and inside pressures of a few tens of bars (Carl-Jochen Winter, Joachim Nitsch, Hydrogen as an Energy Carrier, Technologies - Systems - Economy, Springer Verlag Berlin, 1988, ISBN 3-540-18896-7, ISBN 0-387-18896-7).
Further, no energy lab in the world which makes much of itself is not engaged in fuel cell research; there is no auto maker not experimenting with mobile fuel cells and electric drive trains; no manufacturer of home heating devices or portable electronics not interested in replacing traditional energy conversion equipment by efficient, quiet, compact fuel cells. Truly, forging the hydrogen energy conversion chain has begun from behind: Utilization of hydrogen seems the number one chain link, number two is storage, transport and distribution. And the number three link, hydrogen production? Who takes care of that? From where does the hydrogen come? In which process? Who is potentially capable of constructing a world hydrogen energy trade system, similar to the one in operation for hydrocarbons?
Two major hydrogen production processes are widely known and in operation: (1) Using electricity for splitting water into both its constituencies, hydrogen and oxygen; and (2), stripping hydrogen off hydrocarbons in a steam-methane-reforming, or partial oxidation, or plasma reforming, or coal gasification process. The one supplies only a few percent of the world's hydrogen demand, since inexpensive electricity is pre-conditional, which is only the case at big hydro dams; the other, delivering the bulk of hydrogen, uses natural gas, or heavy oil products, or even coal as the primary energy raw material and contributes to the operational world hydrogen trade of some 600 to 700 billion Nm³/a; in addition, there are significant amounts of captive hydrogen in use in chemical plants or oil refineries.
In Germany, electricity is not, and, most probably, will never be, inexpensive. Consequently, the chance is minimal to obtain economically viable electrolytic hydrogen within the country; that applies all the more for solar hydrogen or hydrogen from wind energy; hydrogen from biomass might serve as an addendum. - Hydrogen from natural gas or oil derivatives was, is today, and will presumably be, the way to go. Decades of experiences are behind us, although the unaltered perpetuation of the hydrocarbon approach is to be called into question. Germany is a heavy oil and gas importer; it pumps only less than 20% of its gas demand and only a few percent of its oil demand out of its own soil. And the situation must be expected to become worse with time: Since major European gas fields in the North Sea are near to being emptied, the country is left with its other major supplier, Siberia. The situation for oil is not at all easier: More or less all oil importing countries must face the expectation that future big oil exporters will be concentrated in the so-called "energy strategic ellipse" spread out from the Gulf via Iran, Iraq, Azerbaijan, Central Asian states to as far as Siberia - altogether world regions which are still striving for permanent political stability, to put it that way.
As a consequence, in a situation where a decision is due on "where is the hydrogen to come from?" the nation is left on the long run with two options: (1) import of hydrogen, and (2) generation of hydrogen from coal. As an energy importer for more than two thirds of its needs, it seems not too complicated to switch from hydrocarbon to hydrogen import, i.e., oil from Saudi Arabia today, reformed hydrogen or solar hydrogen tomorrow; or natural gas from Siberia today, steam-methane-reformed hydrogen tomorrow; or even clean hydrogen import from world regions which, for the time being, are not contributing to the world energy trade at all, for example, Patagonia, where the wind potential is big enough to theoretically supply the overall energy demand of the world, some 13 billion tce. – And the other option, hydrogen from coal?
Coal-Hydrogen Argumentation: A Sketchbook of Pros and Cons
- Availability: Coal was already available long before oil and natural gas exploration; coal is available during the present time period of oil and gas exploration and utilization; and coal will still be available when oil and gas will be long exhausted. For the time being, the world proven reserves of oil to gas to coal are estimated to 40 : 60 : 200 years.
- Ubiquity: Coal is ubiquitous. Not one of the five continents does not mine coal. A fictitious "Coal-OPEC" seems highly improbable.
- Global coal market: Since the very beginning of industrial coal mining in England and, thus, the start of the world industrialization some 250 years ago, utilization of coal has never ended. An economically viable, reliable world coal trade system has been operable since long. Competition works well, price volatility is moderate. Supply security is not in question.
- Coal technologies: Mining technologies have a very high standard and are continuously further developed. Handling and treating coal, as well as its storage and transport on land and sea, are day-to-day practice.
- Safety: The safety standard in modern coal mines has reached levels which almost exclude hazards. Coal shipwrecks are very seldom. If one occurs, the consequences are by far less severe than those related to oil tanker wrecks.
- Coal and power: Coal in earlier times provided heat centrally and de-centrally and helped industrialize production. Coal fueled steam engines on locomotives and aboard ocean going ships started intra- and intercontinental transport. – Today, coal is almost completely left with only central power and steel production, though, in both cases, absolutely efficiently. Modern coal – fired power plants have electric efficiencies in the mid-40 %, approaching 50 %. After World War II 600 grams of coal were needed in order to generate one kilowatt-hour of electricity; now less than 300 grams will do.
- The greenhouse: Still, much too much CO2 from coal power plants is being released into the atmosphere, contributing to the anthropogenic greenhouse effect. Finally, never CO2-emissions will be zero, because efficiencies of 100% are thermodynamically inexistent.
- Zero-CO2 power: Attempts at zero-CO2 emitting coal plants point into the right direction of capturing carbon and sequestering CO2, and generating hydrogen. One promising process is the anaerobic conversion of coal-lime-slurry, providing hydrogen and calcium carbonate, which is recycled to lime and CO2. The lime returns into the anaerobic coal conversion process, and the CO2 is mineralized and stored away without risking release to the atmosphere. – Another possibility to get rid of the CO2 is injecting it into un-minable coal seams, or into emptied oil or gas fields, in each case under gas-tight layers. The benefits here are threefold: (1) CO2 is prevented from being emitted into the atmosphere; (2) the pressurized injection into gas fields helps to bring out more gas; and (3) the procedure avoids potential CO2 taxes.
- De-carbonization, hydrogenation, dematerialization: Historically, the switch from coal to oil and further to natural gas in the last 120 years has already de-carbonized energy-specific carbon-containing energy by some 35 %. It is to be expected that the further switch to energy efficiency, to operationally carbon free renewable energies, and finally to hydrogen, will perpetuate the trend to less carbon, more hydrogen and, consequently, to dematerialized, lighter energy. The gradient of that process is still reasonably steep. Clearly, the tendency points to less carbon and more hydrogen (Fig.1)
- Hydrogen from coal: Hydrogen generates electricity extremely efficiently (~70 %) in a high temperature fuel cell/gas turbine/steam turbine combi-bloc, or hydrogen is piped to millions of de-central fuel cells in residential heating devices, or it fills up millions of de-centrally operated automobiles with ICEs or fuel cells under the hood.
- Coal and de-central heat and power, and mobility: Thus, the pros of zero-CO2 coal plants mark a watershed and are twofold: (1) Coal gets rid of its "dirty image" and factually ceases to contribute to the anthropogenic greenhouse effect. And (2), hydrogen enables coal to leaving the confinement of centralized electricity generation and to contribute to the rapidly growing markets for decentralized electricity and heat, as well as clean transport. With CO2 sequestration and via hydrogen, a veritable renaissance of coal in industry, households, and transport realms is not too far fetched.
- Combination of central production and de-central utilization: The combination of central hydrogen generation and CO2 sequestration at the mine mouth at the front end of the coal conversion chain, and the de-central usage of hydrogen at its back end where humans live and work is only beneficial. Sequestering CO2 is easier where its density is high (at the front end), and utilizing hydrogen where the market density is "dilute" (at the back end) corresponds with hydrogen's rather low specific energy density. In between, the small number of central production plants and millions of de-central user stations are means of hydrogen storage, transport and distribution which, more or less, are state of the art, subject to further development, though.
- Severe cons: time and cost: Two predominant cons are cost and time. Empirically, experience says that the time needed for the development, demonstration and market introduction of a zero-CO2 coal/hydrogen plant will be many decades rather than years. If each and everything goes right, the first operational units may be seen in the 2030s. - After all we know, the build-up of hydrogen-fueled user technologies at the conversion chain's back end (the fuel cells, hydrogen vehicles, hydrogen filling stations. ...) will not be much faster. So, the first and the last dissimilar technology links of the chain have comparative time characters and can be expected to be ready for the market at almost the same time.
- Cost: Cost is coal's Achilles' heel. Although the international coal market's price volatility shows only marginal variations over time, we said it already, the capital cost for the research, development, demonstration and market introduction (R, D, D&M) phase of a first of its kind zero-CO2 coal/hydrogen plant will be significant; the low return on investment within a reasonable time period can only be compensated for by avoiding climate change risk abatement costs.
- The thermodynamicist's most convincing pro: The national energy efficiency of an industrial nation (Germany) is some 30 % - bitter to say, after an industrialization period of, say, 250 years! Three kilowatt-hours of primary energy raw materials must be introduced into the national economy at the front end of the energy conversion chain in order to provide one kilowatt-hour of energy services at its back end. (The energy efficiency of the world is even more out of balance, namely some 10 %.) - However, energy efficiencies are only the one side of the coin, the other, and the much more important, is the exergy efficiency, which tells how much of the introduced energy raw material is converted into something enabling us to perform technical work: Energy = Exergy + Anergy. And this exergy efficiency of the national economy of Germany is only a little more than 15%, that of the world only a few percent. The exergetically most inefficient chain links of the national energy conversion chain are at its back end, from end energy to useful energy and further to energy services: The central heating system of a residential household is energetically superb, exergetically, however, miserable. The same applies to automobile transport, where only some 20 %, at most 25 %, of the energy content in the tank is converted to the longitudinal motion of the vehicle, "tank-to-wheel."
Here, hydrogen from coal helps decisively to exergize the system, in both cases. Hydrogen from coal to fuel household fuel cells first provides at some 35 to 40% efficiency electricity which is pure exergy, since it can be converted to any other form of energy. The exhaust heat (anergy) still contains sufficient exergy to heat the radiators of the dwelling. Or, similarly, hydrogen in the tank of an automobile fuels a fuel cell which generates exergetically efficient electricity to run the electric drive train of the vehicle. - Since the energy sector's households and transport consume about two thirds of the nation's end energy demand, one gets a feeling for the importance of the coal-hydrogen supported exergetization process of just that two thirds!
- The Transition Concept from Solids via Liquids to Gases: Wood, hay, peat, coal, and uranium are solids; whale oil, mineral oil, and hydro are liquids; and city gas, natural gas, and hydrogen are gases. Beginning in the mid 19th century at 100 %, the relative total world market percentage of solids has been, and still is, continuously declining(C. Marchetti, N. Nakicenovic, The Dynamic of Energy Systems and the Logistic Substitution Model, IIASA - International Institute for Applied Systems Analysis, Laxenburg, Austria, RR - 79 -13, 1979). Wood, hay and peat are essentially nil in the meantime; coal and uranium are at 20 to 30 %. Liquids are in a transitional state between solids and gases. Their climbing phase began in the second half of the 19th century, they have now reached a plateau at about 40 % of the world market and face their decline. Gases began their rise at the turn of the 19th to the 20th centuries with coal derived city gas, which now is almost completely replaced by methane containing natural gas, with hydrogen ante portas. The concept of entering the age of energy gases is based on mainly two considerations: (1) History telling us the truth about the transition from solids via liquids to gases; and (2), the perpetuation of the related ongoing de-carbonization (less energy specific carbon), hydrogenation (more hydrogen), and dematerialization ("energies-of-light") making the concept highly plausible. The atomic ratio of hydrogen and carbon is for coal : oil : gas : hydrogen = <1 : 2 : 4 : ∞. Dematerialization makes energy lighter. Coal's influence on this concept is only by means of clean coal - hydrogen! And hydrogen is constituent of the present innovation cycle which, as is generally the case, precedes the upcoming economic cycle of "markets-of-light"! (Fig.2). Ceramics are lighter than steel, and so are fiber reinforced plastics, lasers as machine tools use weightless concentrated light, biotechnological products are lighter than bulk chemicals, fast electrons are lighter than bulky letters, - and, relative to the unit of energy, energy efficiency and particularly exergy efficiency make more energy services out of less heavyweight primary energy raw materials, coal weighs (per mole) relatively more than oil, oil more than natural gas, and gas more than hydrogen which is #1 in the Periodic Table of Elements.
- Coal - hydrogen and the expertise of traditional energy engineers: Modern hydrogen research and development was started by, and is more or less still in the hands of, energy "youngsters": "Naïveté and freedom from bias are mothers of progress!" - On the other hand, new energies and novel energy approaches absolutely need the expertise of the "old" experienced energy engineers of the engineering corps, whose expertise can never be underestimated. Perhaps coal-hydrogen is on the right track if it takes advantage of a combination of the two as the favorable mix.
- Coal and Energy Sustainability (Carl-Jochen Winter, Energy Sustainability - The Road is the Destination, Invited Paper given at the Energy and Sustainability Forum of the Federal Institute of Technology (EPFL), Lausanne, Switzerland, on 28 March 2000): Sustainability has to meet economic, ecological, and social criteria, as well as criteria of reversibility; the same criteria apply for energy sustainability, and thus for coal as an energy-carrying energy raw material. Both the economic and social criteria in the coal business are met or can be met with an appropriate management policy. Step by step, with de-sulfurization, de-NOXing, low-to-zero dust, and striving for ever higher electric efficiencies, the environmental criteria of coal conversion to power are near to being fully met. What is left is climate change risk because of release of CO2 into the atmosphere, and the irreversibility of coal consumption, since the coal mines are emptied without compensational restitution (which, of course, applies to all sorts of energy systems operationally dependent on primary energy raw material, i.e., coal, mineral oil, natural gas, nuclear fission). - One of the aforementioned sustainability drawbacks, climate change risk, can be overcome with the zero-CO2 coal-hydrogen plant, for two reasons: (1) because the CO2 is mineralized and stored away without risking release into the atmosphere over its entire lifetime, and (2), because de-central hydrogen utilization in heat-power blocs like fuel cells enables coal conversion with a total efficiency of up to 70 to 80 %. The other drawback, however, still remains unresolved, although the mineralization of carbon and its storage on earth or in the earth's crust leaves the vague possibility open to get back to it, should that ever be desired.
To close, hydrogen is key for energy sustainability; energy sustainability without hydrogen is irrational: Hydrogen allows for paving stones of the HYway's sustainable pavement. Hydrogen enables coal to become one of these paving stones with heavy tonnage carrying capacity! - Of course, fairness and sincerity ask for the confession of the experts involved that the development pathways to their very end hold a good many disappointments in stock, as is generally the case in comparatively far reaching projects. Consequently, hydrogen in general, and in particular hydrogen from coal, needs vigour, not faintheartedness; working capital, not small change; perseverance, not haste; and, finally above all, conviction, not ambivalence.