Volume 22, Number 4 October 1993


Conference Report: Using Energy in an Intelligent Way

A Europhysics Study Conference, Using Energy in an Intelligent Way, was held at Trassenheide, Germany, during 6-10 May 1993. The conference was organized in collaboration with the WE-Heraeus Foundation.

The conference identified the gap between scientists on the one hand and economists and politicians on the other as the main problem in defining energy research goals. This has led to energy being considered as a resource and not a production factor, so only 4% of a developed country's GNP is accounted for by energy, while a massive 75% covers labor. An overall energy policy within which research objectives can be structured will not emerge from short-term political expediency based on advice from specialists who only talk to colleagues.

Physicists must therefore teach, and learn from, others. The task may not be so difficult. Economists, for instance, understand mathematical optimization, and behavioral scientists and psychologists can show us how to convince people of the need for rational energy policies. B. Gonsior (Ruhr University, Bochum, and Chairman of the meeting) argued in his introduction that one will have to tackle energy issues by "pulling together the pieces within their social context." So the European Physical Society's (EPS) Action Committee for Physics and Society (ACPS), which helped organize the event, is an appropriate forum. K. Rebane (Institute of Physics, Tartu), in his summary, felt that developing strategies will not be easy as evolution and man's history indicate that the "winners have been those species and societies who act quickly, consume high-quality energy and materials, and pay little or no attention to long-term consequences."

Knowing what to say will not be enough as reasoning must also be communicated to the public at large. One conclusion of a discussion session convened by the 40 participants was that one should exploit the fact that decision makers who define boundaries and rules for intelligent action are sensitive to the media. The fundamental message -- that we must address the unavoidable production of entropy and not energy conservation (which is automatically guaranteed by the laws of physics) and that economic calculations should be based more on entropy than on energy -- have not yet taken root. One strategy may be to formulate positions that can be defended by the physics community. However, there were no specific decisions on priorities for future action; these should emerge following an analysis by the ACPS and a discussion of the report (1) of the meeting during the symposium Physics in a Changing World at the EPS-9 General Conference in Florence, 14-17 September 1993.

Clear objectives

One of the meeting's aims was to review progress following the American Physical Society's (APS) landmark study in 1975 to identify areas of research which held promise of improved technology by bringing a physics approach to bear on energy issues. The conclusion was that fundamental understanding had not advanced greatly. Physicists, however, have made useful contributions to the formulation of an intelligent research agenda. It was unfortunate that owing to last-minute difficulties, R.H. Socolow, who led the 1975 APS study and is planning a new one, could not attend. R. Dekeyser, the ACPS Secretary, reviewed instead three recent papers by Socolow, who is optimistic that growth and full development in the third world are compatible with environmental objectives (see below). Energy issues will become deeply embedded in human attitudes, implying an abundance of new technology, especially for developing countries where there must be "technological leap-frogging" and not simply transplantation.

The argument that well-designed government policies will be good for the economy was taken up by several participants. G. De Lepeleire, an engineer from the University of Leuven who advises the Belgian government on energy issues, proposed transferring taxes from employment to energy to give a dramatic decrease in the ratio of labor to energy costs. This would stimulate both energy saving and employment -- an appropriate strategy in Europe where social charges are high. R. Kmmel from the University of Wrzburg and an advisor to GermanyUs energy minister, felt that measures must be taken to decrease energy consumption for "unreasonable" purposes by taxing fossil fuels to make non-fossil energy sources economically competitive, the extra revenue being used to inform the public and to boost the development of non-fossil options. The justification is the high real cost of fossil fuels owing to entropy production involving both thermal and chemical emissions.

The emission situation was reviewed by B. Gonsior. "Business as usual" models estimate worldwide energy consumption in 2020 of 11.2 to 17.2 TWy/y, with industrial countries consuming 3.2-8.5 kW per capita (kW/c) and the third world only 1.1-1.4 kW/c. Consumption in 1990 was 10 TWy/y or 2 kW/c, so the production of greenhouses gases would double. For 4 kW/c (the lower limit) and a doubling of population in 50 years, we have a fourfold increase in energy demand that will be difficult to meet. He advocated 2 kW/c as a target, close to the 1.5 kW/c "greatest acceptable amount" proposed in 1981. It is compatible with projections that consumption in industrialised countries can be halved by 2020, and that a western standard of living could be achieved in the third world with a 30% increase in their consumption. Conscious that some countries consumed close to 10 kW/c in 1983, he invited participants to envisage "what a sustainable world would look like" by drawing up their own menus of energy consumption, remembering that a trip of 20 km by car needs 24 kWh. Research, meanwhile, should focus second-law thermodynamics on specific energy-using tasks to define minimum energy paths and standards of efficiency for energy conversion.

Fundamentals examined

Before addressing systems and technology designed in the physics perspective of second-law efficiencies, A.S. Silbergleit (A.F. Ioffe Physical-Technical Institute, St. Petersburg) gave a detailed analysis of the laws of thermodynamics. The second law assumes an integrating factor (the temperature) which is the same for all thermodynamic systems. This universality can be checked by seeking a single-parameter system whose integrating divisor (temperature) is not the absolute gas temperature. He claimed a rotating wheel with spokes made from a shape-memory metal may be such a system. More significantly, ideal processes in energy conversion systems based on cyclic changes of the thermodynamic properties of a working body have zero power, while actual devices involve irreversible energy losses due to heat flow. One may be able to escape these constraints on energy conversion by exploiting a strongly non-equilibrium open system that has a device using a working fluid with a high degree of self-organization (giving negative entropy production). One possibility is a so-called vortex turbine based on the condensation of a vapour vortex on the inside of a rotating cone. While the concept remains to be verified experimentally (and this will be difficult), it at least highlights the importance of analysing the efficiencies of irreversible processes.

Designing specific energy conversion systems and processes will, in general, require numerical simulation in addition to exact analysis owing to their complexity. S. Wirz (Ruhr University, Bochum) described, for example, a sophisticated, computer-based modeling tool for combustors. Industrial interest in this type of approach has waned considerably in the present era of cheap energy so it is perhaps not surprising that his was the only presentation in this important area. This may also account for comments by other German groups that development and engineering skills have been "wasted" owing to the absence of a long-term commitment to energy conservation.

Sophisticated systems analysis

J. Gretz (JRC, Ispra) who manages the European Community's (EC) hydrogen-in-transport program on behalf of the EC Parliament (hydrolytically-produced H2 is shipped from Canada for a fleet of buses which are already operating and for a H2-powered passenger aircraft due to fly next year) analysed the limiting performance of specific systems. Solar energy conversion is limited to about 70% efficiency, while the global efficiency of photosynthesis, in spite of a 33% quantum efficiency, is below 1%; the influence on the climate of a solar power plant is proportional to the difference between its conversion efficiency and that of the terrain it replaces (currently about the same, but likely to increase); electrolysis is more efficient overall than thermochemical cycles for producing H2 (belief in the opposite misdirected research for many years--a potent reminder of the importance of careful analysis). Atmospheric CO2 can be managed using forestry (foresting 6% of Earth's surface will absorb all of the CO2 produced today) so it was fitting that J.T. McMullan, who heads the the University of Ulster's Centre for Energy Research, described a detailed analysis of power generation from wood combustion. A 1000 tonne/day plant is optimum, and the UK has enough productive woodland to support 60 plants generating 3000 MW in a neutral way with respect to greenhouse gas emissions.

According to W. Eichhammer and E. Jochem (Fraunhofer Institute, Karlsruhe) the potential for energy (and entropy) savings in large-scale, regional energy supply systems will be more important in the domestic sector than in industry. Experience with gas-driven heat pumps for air-conditioning in Japan and with co-generation units in Denmark has shown the value of consistent, long-term planning in the domestic sector. Potential savings in transport are also large, and R.D. Kuhne (Steierwald Schonharting GmbH, Stuttgart) described how government policies are being used to reverse the trend toward modes involving high energy consumption.

C.D. Andriesse (University of Utrecht) took the case of co-generation to demonstrate the utility of fairly simple analyses for "braking entropy production." A device producing slightly more kinetic energy than heat is optimum and given the relative cost of transporting electricity and heat, it should be rated at about 10 MW. A more sophisticated stochastic optimization model described by R. Kummel predicted roughly 20% reductions in CO2 production and energy consumption for a German city using local co-generation. But the 40-50% increase in costs are only economic in the entrepreneurial sense if energy prices at least double. Extending models requires much more detailed information on energy demand along the lines being addressed by a new 50 million DM German project called IKARUS, probably the largest study of its type in Europe.

Technology will be a necessary but not a sufficient condition for energy conservation. Contributions concerning energy conversion and technology/materials conservation will not be summarised because it is too difficult to do justice to the many physics concepts involved in the topics presented (convective thermal rectification, thermionics, photovoltaics, combustion diagnosis, light concentration, spectrally selective materials). Readers are referred instead to the meeting report (1). Little was said about monitoring and datataking, two aspects of entropy braking in the widest sense to which physics will increasingly contribute.

1. Using Energy in an Intelligent Way, Proc.111th WE-Heraeus Semnar, 6-10 May 1993, Trassenheide, Germany; Ed.: E.W.A. Lingemean (to published; price: SFR 70.-).

P.G. Boswell
Editor, Europhysics News
European Physical Society
P.O. Box 69
Ch-1213 Petit-Lancy 2
Geneva, Switzerland

A Tale of Six Cities

Few technologies have as powerful an effect on US culture as the automobile. Direct effects include unnatural deaths, injuries, pollution, global warming, petroleum consumption, land consumption, and materials consumption. Indirect effects such as suburbanization and downtown decay may be even more important.

During an unforgettable vacation last summer, I noted several features of European transportation that might hold useful lessons for America.


Vienna is an unpolluted city with a high quality of life, partly thanks to intelligent transportation policies. It is compact, like most European cities. Suburbanization has helped kill America's cities. The lack of extended suburbs makes public transit more viable, and brings middle-class people downtown to live.

Cars are prohibited or restricted in central Vienna. Most travel is by foot and public transit. The entire center of this big city is accessible by foot. There are none of the parking lots that create sprawl and desolation in US downtowns. Around the perimeter of the center is a broad boulevard with twelve separate lanes: two sidewalks and one bicycle lane on each side of the street, two lanes exclusively for trolleys, and the remaining four lanes for cars, taxis, and buses. So one-third of the boulevard is for cars, and two-thirds is exclusively for alternative transportation. In America, a typical ratio is two to six car lanes, zero to two sidewalks, and nothing for bikes or transit.

Europe's healthy $4 per gallon gasoline tax discourages driving. Many Europeans recognize that it is smarter to save the thousands of dollars that Americans throw away annually on their cars and invest a portion of it instead in good public transit. Meanwhile, America argues over whether the gasoline tax should be 14 or 18 cents per gallon.

Vienna was the nicest city I visited, thanks largely to its wise transportation policy.


Cars overrun Budapest, but it remains beautiful. Buda and Pest are two cities, separated by the Danube. Automobiles are restricted in the older city, Buda, but not in Pest. Visitors cannot enter Buda with an automobile, but Pest is wide open to cars that park all over the sidewalks and fill every street to the point that one can hardly walk or breathe. A bus tour guide told me that the lifespan is seven years longer in Buda than in Pest, and that mothers in Pest are advised to move their young children out of the city, because of automobile pollution. So citizens value their cars more than their lives or their children.


Florence, a once-picturesque city, is lost to the car. Hordes of automobiles and mopeds buzz like pollution-spewing hornets around the cathedrals, bridges, and art galleries. There is no respect for pedestrians, or for painted pedestrian crosswalks. The internal combustion engine is everywhere. One crosses every street with fear and trembling, breathes air filled with exhaust fumes, and views buildings made dingy with soot. Only a one-block region in the center is off-limits to the great god of car. I had planned to stay for four nights, but left this scene from Dante's Inferno after one.


I traveled everywhere by train, one of Europe's great pleasures. They are 30 times safer per passenger-mile than cars, with room to sleep, read, work on a large table-top, eat or drink elegantly, and stroll the aisles, instead of gripping a steering wheel for hours or being confined to a small expensive airplane seat. Trains link every city and town. These beautiful machines cut a thin line through undisturbed cow pastures at up to 200 miles per hour. The French TGV got me across all of France from Marsielle to Paris in five hours. America could have trains like this, but instead with every highway and airport decision we opt for slow, expensive, dangerous, polluting, sprawling, boring, cramped modes of travel. Will we ever learn?


Aix-en-Provence is a small town that keeps cars mostly out of its large central area. The center is livable, breathable, and still beautiful. Its population is over 100,000, but its area is smaller than most US towns (such as mine) of less than half that population, because of our preference for suburbs and parking lots. Because of its high density, there are many more sights and activities within a short walking distance in Aix than in US towns, and the central area is alive with shops, cafes, and people.


The tension between cars and civilization pervades Paris. Horns cannot be used here or in most cities, which helps. But cars and exhaust make it impossible to sit comfortably in sidewalk cafes along the Champs Elysees, so that many cafes are now replaced by boring mall-like air conditioned stores. However, newspapers report that Paris will soon restrict driving and parking along this boulevard, so there might be hope for the formerly most beautiful street in the world.


There seem to be no pollution controls in London. Outside my hotel, three lanes were always filled with vehicles. Taxis and especially buses spewed great volumes of nauseating exhaust right into the lobby. I often had to cover my mouth and nose, and brush soot from my eyes. A few daring bicycle riders dart through the dense traffic, wearing masks against the fumes. London needs pollution controls and removal of cars from dense regions such as the West End theater district.

On the other hand, London drivers stop for pedestrians at cross-walks, drive at reasonable speeds, and obey traffic laws. Mass transit is the strong backbone of transportation in London, Paris, and Vienna. Buses and taxis are prevalent in London, with private cars in the minority. On most streets, one lane is reserved for buses only.

Unlike US cities, European cities don't have parking lots. This is one reason that US cities are typically 60% paved for cars, while European cities devote far more area to people. It is this stretching-out of US cities that, in turn, makes our downtowns inhospitable to pedestrians, a major factor in urban blight.

Because of crowding, the automobile is an even more difficult problem for European cities than for US cities. Except for Florence and Budapest, the European cities I visited are striving to cope with this challenge.

Art Hobson