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Materials are the underpinnings of technology - not only figuratively but literally. Some of the most important of all technological "breakthroughs" were associated with materials. The ability to make hard, impervious ceramic pots for the storage of liquids and seeds was one of the first requisites of urban civilization, around 8000 BC. The "Bronze" age and the "Iron" age were major technological milestones. The discoveries of paper and glass (not only for windows but, perhaps more important, for lenses) were only a little less significant in their time. Iron tools and weapons are an enormous improvement over bronze tools, but require much more advanced methods of smelting and working. Steel is as much an improvement over older forms of iron as iron was over bronze. The historian Elton Morrison called steel "almost the greatest invention," with some justice.

However, in some sense the "age of materials" is now past and the "age of information" is upon us. To be sure, most traditional uses of basic materials will continue for many decades, with gradual but cumulative reductions in the sheer mass of materials required for most purposes. Materials of all kinds are becoming more sophisticated and "information intensive," in the sense that they offer more service to the end-user.

But greatly overshadowing this rather broad trend is the enormously rapid increase in the uses of materials specifically for purposes of energy conversion (e.g. magnets, photovoltaics) and processing or storing information. The semiconductors and ferrites constitute the two obvious examples of the latter, but it can be argued that the dominant trend of the future is toward the development of materials that are "information intensive" in this narrower sense. A rough tabulation of the materials of greatest research interest today is given in table 4.7. The degree of sophistication and information content of these materials is continually increasing (fig. 4.14). But they will also be more difficult to produce and to recycle. This will induce increasing interest in re-use and remanufacturing in coming decades.

Table 4.7 Breakthroughs expected in serials


Technological need

Breakthrough technology


Communications Large-volume transmission Milliwaves, laser beams Compound semiconductors (InP, GaAIAs, etc.)
Long-distance transmission Low-loss optical fibre Non-silicic material
Information-processing High-speed operations Compound semiconductors ICs Compound semiconductors (GaAs, InP, etc.)
  Josephson junction device Superconductive materials (alloys, compounds)
High-density recording Perpendicular magnetic recording Perpendicular magnetized film
  Magneto-optic recording Magneto-optic recording materials
  Molecular memory High polymers, biological substances (protein)
Instrumentation and control Improvement in sensing performance Josephson junction device Superconductive materials (alloys, compounds, etc.)
  Biosensor Biological (micro-organisms, enzymes, etc.)
Improved resistance to environmental conditions Devices more resistant to environmental conditions Compound semiconductors (GaAs, InP, etc.)
Energy conversion Solar energy, especially in remote areas Photovoltaics Silicon (crystalline or amorphous) Ga-As, Cd-Te, Cu-In, Se
More efficient generators, transmission lines Superconductivity Cu-Ba-La-O. Other methane oxygen compounds
Transportation Magnetic levitation Ferromagnets Sm-Co, Nd-Fe-B
  Superconductors Cu-Ba-La-O. Other metallic oxygen compounds

Fig. 4.14 Relation between the quantity of materials in a product and its information content


1. Each tonne of fossil fuel burned results in the ultimate release of roughly 3 tonnes of CO2 to the atmosphere, not to mention significant quantities of sulphur oxides (SOx) and oxides of nitrogen (NOx) - the main causes of environmental acidification. Atmospheric carbon dioxide concentration has increased by about 20 per cent since the nineteenth century.

2. Specifically, the first law of thermodynamics, i.e. the law of conservation of mass.

3. The quantities of ore removed from the earth are normally much larger, but physical separation techniques leave much of the excess material at the mine, where it is piled up into small mountains, but not put back into the ground. For instance, copper ores mined in the western United States contain less than 0.4 per cent copper, whereas concentrates delivered to refineries average 20 per cent copper. Thus, for every tonne of concentrate, at least 50 tonnes of crude ore were dug up and processed (by flotation ponds) at the mine. For I tonne of refined copper 250 tonnes of ore are processed. In some cases the quantities of ore processed are much larger. For example, roughly 140,000 tonnes of ore must be processed to yield 1 tonne of platinum group metals.

4. Applications of high-strength low-alloy (HSLA) steels are still continuing to increase how ever, especially in the auto industry. Major process innovations, notably the Basic Oxygen Process (BOF) and continuous casters, also appeared after World War II.

5. A 16 megabyte chip was announced in early 1987 by NTI (Nippon Telephone and Telegraph Co.). As of 1997 we are in the gigabyte range.

6. These are materials that lose all electrical resistivity at a temperature below some "critical", level so long as the magnetic field strength (including the field induced by the superconductive current itself) is below a critical level.

7. Data recording requires "soft" magnetic materials, i.e. materials that can easily be magnetized and demagnetized at high frequency without large "eddy current" losses. The latter requirement cannot be met by metals, but oxides fill the bill because of very high electrical resistivity.

8. Magnetic energy is measured in mega-gauss oersteds (MGOe).


Barnett, Harold and Chandler Morse (1962) Scarcity and Growth: The Economics of Resource Scarcity. Baltimore, MD: Johns Hopkins University Press.

Barney, Gerald (1980) The Global 2000 Report to the President. Technical Report, vol. 2. Washington D.C.: Council on Environmental Quality, US Department of State.

Claasen, R. S. and L. A. Girifalco (1986) Materials for energy utilization. Scientific American 255(4): 85-92.

Clark, J. P. and M. C. Flemings (1986) Advanced materials and the economy. Scientific American 255(4): 43-49.

Gordon, James E. (1973) The New Science of Strong Materials. Harmondsworth, UK: Penguin Books.

Gordon, T. J. and T. R. Munson (1982) Research into Technology Output Measures. Danbury, CN: The Futures Group.

Hitachi Research Institute (n.d.) In Search of Future Technology in Electronics.

Larson, Eric D., H. Marc Ross, and Robert H. Williams (1986) Beyond the era of materials. Scientific American 254(6): 24-31.

Lynch, Charles T. (1975) Handbook of Materials Science. Cleveland, OH: CRC Press.

Maycock, P. D. (1982) Overview-Cost Goals in the LSA Project. Unpublished.

Moravec, Hans (1991) Mind Children. Cambridge, MA: Harvard University Press.

NAS/NRC (1989) Materials Science and Engineering for the 1990s. Washington D.C.: National Academy Press.

NIRA (National Institute for Research Advancement) (1985) Comprehensive Study of Microelectronics. Technical Report. Tokyo: National Institute for Research Advancement.

NMABNRC (National Materials Advisory Board) (1975) Structural Ceramics. Washington D.C.: National Research Council.

Robinson, Arthur L. (1986) A chemical route to advanced ceramics. Science 233(4579), 4 July: 25-27.

Smith, V. Kerry (1979) Scarcity and Growth Revisited. Baltimore, MD: Johns Hopkins University Press.

Steinberg, M. A. (1986) Materials for aerospace. Scientific American 255(4): 59-64.

Sullivan, Walter (1987) New York Times, 17 February.

White, R. M. (1985) Opportunities in magnetic materials. Science 229(4708), 5 July: 11-16.

Zweibel, Kenneth (1987) Interview, New York Times, 13 February.

5. Global energy futures: The long-term perspective for eco-restructuring

What is the energy system?
Energy system inefficiencies
The deep future energy system
Transition and the rate of change of the energy system
North-South disparity and sustainable energy systems
Concluding remarks

Hans-Holger Rogner


Since the mid-nineteenth century, world energy use has been growing, on average, by 2.1 per cent per year. This growth in energy use has fuelled an annual expansion of the world economy of 3.2 per cent. Most importantly, energy and economic growth have combined to raise world population from 1.2 to 5.3 billion, corresponding to an average growth rate of 1.1 per cent per year.

This account of past rates of growth is incomplete as long as it neglects the environmental degradation associated with industrial development, economic growth, and energy use, ranging from local air and water pollution, soil contamination, and reduced biodiversity, to stratospheric ozone depletion and the damage potentially caused by global climate change. Whereas initially the burdens placed by humans on the environment and their resulting consequences were primarily local, it is now apparent that the adverse impacts of human activity are rapidly approaching global dimensions. Foremost among these impacts is the potential for global climate change caused by a growing concentration of greenhouse gases (GHG) in the atmosphere. Climate change is likely to emerge as one of the greatest threats to the development of mankind during the twenty-first century. Scientific evidence linking unrestricted fossil fuel use to potential climatic change is increasingly gaining credibility (see IPCC 1990, 1992). The Second Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) states that "the balance of evidence suggests a discernible human influence on global climate" (IPCC 1996a). However, fundamental disagreement in the scientific community exists as to the eventual impacts of global climatic change, especially at the regional level.

In large part the threat of climatic change is the result of greenhouse gas emissions from the energy system. The energy system is not the sole source of greenhouse gases, but it is the most important one, currently accounting for roughly half of all such emissions. More importantly, the global energy system is the fastest-growing emitter.

Stabilization of atmospheric GHG concentrations is a policy objective in several industrialized countries. GHG emission reduction targets are a key issue on the agenda of the United Nations Framework Convention on Climate Change (UNFCCC) where the socalled ANNEX 1 countries (OECD and Reforming Economies) have committed themselves to stabilization. Present energy research and environmental policy aim at the identification of energy technology options and strategies that mitigate greenhouse gas emissions. Technology responses analysed by numerous researchers range from efficiency improvements, fuel and technology switching, to GHG emission abatement or removal, and environmentally benign GHG disposal or sequestration. Presently, the discussion centres around issues such as the costs and benefits of different measures, least-cost and hedging strategies, etc. Yet these all focus on incremental and add-on technology fixes within the current energy sector, rather than on a systematic restructuring of the energy system.

What is missing in the current energy-environment debate is a zero-order understanding of the structure of a fully sustainable energy system. Long-term energy and environmental policy requires a reference or target energy system a target beyond the issues of local air pollution and greenhouse gas emission levels. Once established, the long-term reference energy system then plays the role of a beacon for energy policy, for public investment in infrastructure changes beyond the capability of free market forces, for publicly funded research and development activities, as well as for private sector investments. This paper attempts to present a "reference" structure of a sustainable energy system that could serve not only as a long term target for energy and economic policy but also as a guideline for public and private investment.

In a world of continuous technical change, the "reference" energy system is a moving target. Over a period of 50 years and more, technology forecasting based on current knowledge will certainly fail to anticipate future inventions and rates of innovation. The target energy system, therefore, should incorporate least-regret cost features, i.e. it is structured so that future innovation enhances the system's performance rather than making previous infrastructure investments obsolete. Despite the large uncertainties involved, it can be shown that the overall system architecture and some fundamental technological characteristics are quite robust even in a rapidly changing world of technology (Rogner and Britton 1991).

The environmental gains from restructuring the energy system will be compounded if it takes place as an integral part of a fundamental eco-restructuring of the entire economic production and consumption process. Energy is not an end in itself; the prime purpose of energy is to provide energy services such as heating, cooking, mobility, communication, consumption goods, and numerous industrial processes. Eco-restructuring of the energy system, then, goes hand in hand with changes in settlement patterns and transportation infrastructures, workplace arrangements that include telecommuting, de-materializing of the production process, and recycling.

The fundamental features of a sustainable energy system can be defined in terms of the following four compatibility constraints:

1. environmental compatibility,
2. economic compatibility,
3. social compatibility, and
4. geopolitical compatibility.

Regarding environmental compatibility, the fluxes to and from the target energy system should be coherent with nature's energy and material fluxes and should not perturb nature's equilibria. Only then will it be possible to provide for economic growth without environmental costs undermining the gains. On the other hand, economic reasoning demands that the costs of protecting the environment should not exceed the benefits.

An effective and, in the long run, sustainable target energy system should also consider the implications of the historically observed linkage between per capita energy service requirements and demographics. In a world whose population has doubled in a single generation and which continues to grow at alarming rates, even drastic changes that one might be able to engineer in terms of specific energy efficiency improvements or environmental impacts over the next decades could well be swamped by the underlying demographic explosion.

Future energy systems and associated technologies need to be socio-politically acceptable in terms of convenience, level of risk, and economic affordability. Supply security and other potential geopolitical concerns including proliferation issues need also to be effectively resolved.

Once a target energy system is defined, the question of managing the transition must be addressed in terms of both energy system evolution and policy. Given the inherently long lifetime of existing energy infrastructures and lead-times from blueprint to operation of a dozen and more years for new production capacity, the energy system does not lend itself to quick adaptation or modification. The transition phase towards a sustainable energy system is likely to last well into the twenty-first century.

As regards policy measures, initiating the shift away from the potentially unacceptable burdens that the present system places on the environment will probably require more than the present measures ranging from energy price manipulations (green taxes), standards, regulated emission levels, and tradable permits to prescribed technology fixes. Present policy focuses primarily on short-term reductions in local air pollution, not on providing the market with guidelines and incentives for a transition toward an environmentally sustainable energy system. From the perspective of eco-restructuring, one of the most important policy steps would be to get the prices right by internalizing external costs. Still, the enormous changes in infrastructure associated with the transition towards a sustainable energy system are most likely beyond the domain of market forces. Therefore, effective energy policy must be based on a clear understanding of both the eventual shape and structure of the deep future energy system and the implications for the transition phase (Rogner and Britton 1992). This includes our understanding of the energy sources and principal technologies that will be key during this transition phase.

What is the energy system?

Energy analysts often use the term "energy system" when they are actually referring to the "energy sector." The energy sector is only the upstream part of the energy system. Figure 5.1 puts this difference into perspective by representing the architecture of the energy system as a series of vertically linked source-to-service pathways. The examples next to each system component are randomly chosen and do not represent any special correlation across the various columns.

Fig. 5.1 The architecture of the energy system

The energy sector in figure 5.1 primarily focuses on the production and sale of energy currencies. Electric utilities generate and sell kWhs, while the oil sector explores for and produces oil, refines the oil into marketable products, and sells these in the market-place. The success of any particular agent within the energy sector is usually measured in terms of kWh or litres of gasoline sold. However, the reason people purchase kWhs of electricity or litres of gasoline is only indirectly related to these products. What people really want are energy services, i.e. information via electronic mail, the exchange of information through a telephone conversation, or the service of getting back safely from work to a comfortably temperature-conditioned home. It is important to note that the demand for energy services changes (in quantity and quality) as a function of demographics, income, technology, and location. But their fundamental nature does not change.

The supply of energy services depends on two or more interdependent inputs: one or more energy service technologies plus one or more energy currencies. It is the combination of the technology "automobile" and the currency "gasoline" that provides the energy service "transportation" - not the energy product gasoline alone.1 The downstream market conditions - in essence oil products' ability to provide the energy services demanded by residential, commercial, and industrial consumers - drive the upstream activities of the oil industry. Oil product demand, end-use competition, and interfuel substitution depend, in all but the shortest term, as much on the techno-economic performance of the energy service technologies providing the services as they do on the actual oil product market prices. As technologies change, so do the competitive edges of the associated fuels.

More precisely, energy services are the product of energy service technologies plus infrastructures (capital), labour (know-how), materials, and energy currencies. Clearly, all these input factors carry a price tag and are substitutes for each other. From the perspective of an energy service consumer, the important issue is the quality and cost of energy services. It matters very little what the energy currency is, and, even less, what the source of that currency was. It is fair to say that most energy services are blind to the upstream activities of the energy system.

But, for the development of civilization, it is the end-service technologies, such as automobiles, aircraft, furnaces, electric motors, and computers, that are most important - or at least the most visible. It is these technologies (including associated infrastructures) and their mix that determine the quality and quantities of energy services people can buy.

The energy system is service driven, i.e. from the bottom up. Energy, however, flows top-down. It appears that the energy industry's priorities resemble the flow of energy - top-down - and approach zero once energy leaves the domain of the energy sector indicated in figure 5.1. Only recently have some energy sector industries begun to adopt a full source-to-service perspective, prompted in most cases by regulatory intervention. "Integrated resource planning" (IRP) and "demand-side management" (DSM) have been promoted to assist the industry in getting out of the energy sector "ghetto." In essence, IRP and DSM explicitly call for the inclusion of the end-use devices into the utilities' investment planning activity. Extending this to an example outside the utility domain, oil company subsidiaries might sell transportation services by leasing out highly efficient vehicles and charging for their use on a mileage basis only (the gasoline, car maintenance, etc., would be on the company).

With regard to the evolution of the architecture of the energy system depicted in figure 5.1, the following observations are in order:

1. the bottom-up, service-to-source architecture is time invariant;
2. the basic services of shelter (keeping warm), security, nutrition, communication, and health care are time invariant; and
3. the components of all chains from service technologies to sources are time "variant."

In the context of time variance or energy system evolution, there are several questions that must be addressed:

- Which components of which chains are most subject to change?
- What causes the change, i.e. is the change policy driven or innovation driven (market pull or technology push)?
- What is the rate of change (the dynamics of technology diffusion or evolution)?

Energy system inefficiencies

Most energy services have surprisingly low minimum energy input requirements. Figure 5.2 shows the average exergy2 efficiency of electricity and total weighted average of selected energy services as a percentage of primary energy. The services considered are space heating, transportation, and lighting. There are many difficulties and definitional ambiguities involved in estimating the exergy efficiencies for comprehensive energy source-to-service chains or entire energy systems, and only few exergy efficiency estimates have been attempted to date. All estimates conclude that source-to-service exergy efficiencies are as low as a few percent. For example, Ayres (1988) calculates an overall source-to-service exergy efficiency of 2.5 per cent for the United States. Wall (1990) estimates a source-to-useful exergy3 efficiency in Japan of 21 per cent, and Wall et al. (1994) calculate a source-to-useful exergy efficiency of less than 15 per cent in Italy. Schaeffer and Wirtshafter (1992) estimate a primary-to-useful energy efficiency of 32 per cent and an exergy efficiency of 23 per cent for Brazil. Other estimates include Rosen (1992) for Canada and Özdocan and Arikol (1995) for Turkey. Estimates of global and regional primary-to-service exergy efficiencies vary from 10 per cent to as low as a few percent (Gill) et al. 1990, 1995; Nakicenovic et al. 1993).

Fig. 5.2 Source-to-service energy efficiencies for a weighted basket of energy services (solid line) and exergy efficiency of electricity (dashed line) for the industrialized countries, 1990 (Source: adapted from Nakicenovic et al. 1993)

Figure 5.2 reveals that the present practice of energy service provision in the industrialized countries is quite inefficient when compared with the ideal exergy efficiencies. The large inefficiency of the system indicates that most services could be provided with considerably lower energy inputs than those represented by current practice. With the exception of the electricity source-to-service chain, the present energy systems exhibit lowest efficiencies at the interface between the traditional energy sector and the domain of energy services (the service technology component of fig. 5.1). In the case of electricity, the generating process provides the largest potential for efficiency improvement along the electricity source-to-service supply pathway. One should note, however, that electricity also has significant room for improvement at the useful-to-service interface.

Obviously, the opportunities for efficiency improvements suggested by figure 5.2, i.e. closing the gap to 100 per cent, are theoretical potentials that in real-life systems can never be fully exploited. Still, an overall exergy efficiency in the developed world of less than 10 per cent reflects a significant efficiency gap, a gap that represents opportunities for future innovation, policy incentives, and business development. Energy and environmental policy should encourage public and private sector investment towards the narrowing of this gap wherever this is techno-economically feasible, because more efficient provision of energy services not only reduces the amount of primary energy required but, in general, also reduces material requirements and emission releases to the environment. Although efficiency is an important performance parameter influencing investment or purchase decisions, it is not the only one. Other, and often more important, issues include investments, operating costs, lifetime, peak power, ease of installation and operation, plus many other technical, economic, and convenience factors. For entire energy systems, further consideration must be given to regional resource endowments, conversion technologies, geography, information, time, prices, investment finance, operating costs, age of infrastructures, and know-how.

In essence, figure 5.2 contains one answer to the question of which system links are likely to change. It identifies energy service technologies as the critical component for overall energy system performance improvements. Not only is the energy system driven by service requirements, but the end-use technologies (e.g. the furnace linking final energy and useful energy) and infrastructures (e.g. building codes and insulation standards, which determine the share of useful space heating energy that becomes available for providing these energy services) constitute the system component with the largest potential for narrowing of the efficiency gap. As already mentioned, service technologies are intimately tied to settlement patterns, as well as to housing, transportation, and industrial production infrastructures. These infrastructures are as much responsible for the current inefficiency of the energy system as are the numerous energy conversion technologies associated with these infrastructures.

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