Economical and political considerations are added when producing and consuming regions are covered . At this point, the topic of a responsible handling of the world by the human being is inevitable: The themes of ecology become most important . When arriving at this point and realizing that the existing large-scale technologies of energy conversion are a cul-de-sac, the relieving step towards alternative technologies is likewise a step towards reinventing the quality of living—which leads back to sociology and life science . When discussing possible implementations of alternative energy concepts, the interrelations between ecology and politics are described in their basics .
In this sketch of what can come to life in such a block, it is easy to see that a strict question and answer schema of cause and effect is not useful . Likewise, thinking and imagining circulation processes alone does not do justice to this problem . Instead of this, students experience an example of intentionally interrelated events (comp . chapter 7) . The uses of certain technologies influence and motivate human creativity . Vice versa, the inventive genius of the human being originates new technologies that in return influence our way of life .
As this is a second block and is taught after main lesson, it is conducted in a
different instructive mode . Instead of a classic main lesson book, a workshop journal is kept, developed mainly during class time . For practicing this work technique, this block adds dealing with statistics and learning how to read challenging journal articles . In class discussions students learn how to present and support their own positions and judgments . Exemplary Flashlights on the
Block Content
About the Concept of Energy
Although the literature speaks almost exclusively of energy production and energy consumption, we will discuss the physical law, according to which there is only energy conversion . Energy therefore has the ability to perform work . If you look at various transformations, you will realize that the efficiency of the transformation into light, heat or driving force never quite reaches 100% . A large proportion transforms into mostly not actively “used” waste heat . From this perception, we introduce the concepts of primary energy, secondary energy, end-point energy and useful energy . The technical literature defines primary energy as the so-called raw material [coal, crude oil, natural gas, uranium, wood, water in an elevated storage, garbage] from which usable energy forms originate after the first transformation . Secondary energy has already gone through a transformation . Examples are electricity from water or nuclear power, or gas from coal . The form of energy that is transformed in a consumer household, in a factory or during a technical locomotion is called end-point energy . Useful energy [usable] is finally the one form of energy, which serves consumers in our civilized way of life after being transformed into light, heat, power or chemical energy bound in batteries .
Astonishing results can be gained from a Swiss energy review, which is provided to the students as a statistical summary . (Schweiz . Bundesamt für Energie and Schweiz . Bundesamt für Energiewirtschaft;
similar results for most other countries, e .g ., European Commission: Directorate-General for Energy and Transport; United States:
Energy Information Administration) Taking 100% primary energy in 1993 as our starting point, end-point energy amounts to 75%;
the energy loss of 25% is caused mostly by the five Swiss nuclear power plants, which reach an efficiency of only 32 to 37% . Useful energy—which is finally usable for the consumer—amounts to only 43%, because 43% of the end-point energy is lost in energy conversion . Altogether this means that 57%
of the energy is lost on the way from primary energy to useful energy, and the efficiency of the energy conversion devices is very low (comp . Fig . 8 .1) . The frontrunners in low efficiency are nuclear power plant at the transition to the end-point consumption, the gasoline combustion engine and the conventional light bulb on the level of energy conversion at the consumer site .
Embodied Energy and Harvest Factor If you want to judge the efficiency of an energy conversion event properly, you have to account for embodied energy . Embodied energy is the conversion of energy which happens during the production of a device or providing a service . A 220-liter refrigerator converts about 450 kilowatt hours [kWh] of energy per year . For its manufacturing, about 1400 kWh of embodied energy is used . The calculation of the yearly consumption of embodied energy for an average Swiss citizen results in the astonishingly high number of 30,000 kWh per year . Compared to this, a family of four with a medium standard of
living [3-bedroom apartment, medium-sized car driving approximately 15,000 km = 9320 miles per year] uses only slightly more energy at 35,000 kWh per year . This number is double if the family travels by plane once a year to the United States [or from the US to Switzerland, according to Strahm 1992]!
Even more impressive is the example of a flashlight battery, with a usable energy conversion of only 0 .012 kWh, while the expenditure in embodied energy amounts to 0 .65 kWh; so calculating the efficiency including the embodied energy, the flashlight battery reaches only 1 .8%!
According to the May and June issues of Energietechnik (1996), the harvest factor is introduced in order to describe the ratio between usable energy and embodied energy (comp . TA 3 .5 .1996) . In an energy conversion device, the harvest factor represents the usable energy [room temperature, power] produced during its lifetime divided by the expenditure in non-renewable energy resources for the manufacturing and disposal of the device as well as for the processing of the energy carrier [oil, gas, coal, uranium, wood] . Positive energy balances with harvest factors above one are reached by modern wood heaters
[7 .1], solar warm water heaters [4 .0] and solar electric generators [1 .6] . Newer solar collector systems with a life expectancy of 20 years reach a harvest factor of 11 .2, solar cell systems with a life expectancy of 30 years reach 6 .2 . (Infoenergie 1994) All other devices show a negative energy balance: heat pumps [0 .8 using Swiss electricity, 0 .6 using EU electricity], heating systems using gas or oil [0 .7], coal heating [0 .5], electricity conversion originating from Swiss power plants [0 .3; with 40% nuclear power plants, 25% hydroelectric power plants and 35%
storage power plants], electricity conversion originating from EU power plants [0 .2] . These harvest factors are published in the study Graue Energie und Umweltbelastungen von Heizungssystemen [Embodied Energy and Environmental Impact of Heating Systems], May 1996, which is a condensed version of the study Ökoinventare für Energiesysteme [Eco Inventories for Energy Systems] by the ETH Zürich and the Paul Scherrer-Institute, Dones 2003; Frischknecht et al . 1995 . Non-Renewable Energy
The Formation of Raw Materials
To begin, we will discuss the geological origin of the non-renewable energy sources of crude oil and coal (refer to Fig . 8 .2) . Corresponding details would also be valid for natural gas . All of these energies originate from a massive formation of biomass, caused by photosynthetic processes, which split carbon dioxide into carbon compounds and oxygen . These processes lead to a reduction of the carbon dioxide content in water and atmosphere and consequently a reduction of the greenhouse effect, which means a cooling of the earth . (Graedel and Crutzen 1989, 1993, 1995; Keeling 2006; comp . chapter 9)
It is something special that the carbon compounds in crude oil and hard coal were deposited in depths of several kilometers in such a way that they could not bond to atmospheric oxygen (refer to Fig . 8 .2) . The events described above—the enormous presence of life and successive die-offs leading to carbon deposits—were the preconditions for the development of modern life on earth with ideal global temperatures and, more importantly, the temperature conditions for a rhythmic sequence of ice and warm ages .
This process peaked first during the Carboniferous (350 to 290 mya, or million years ago; refer to Fig . 8 .3) [In the US the Carboniferous is usually divided into two periods, an earlier period named Mississippian and a later period referred to as Pennsylvanian—tr .] . The associated cooling led to a mild ice age and important developments of life on land [solid ground] . During the major extinction of life at the end of the Permian, the mean annual temperature on earth had risen to approximately 22°C . temperature developed which provided the basis for the rhythmically appearing ice- and warmth-ages .
If man opens these carbon deposits and uses them for fuel, it is a logical consequence that the CO2 content in the atmosphere will increase and global temperature will rise to values corresponding to the Mesozoic . The dangerous difference of this reversed process induced by human activity is its 100,000 times faster speed . Life cannot adapt to this process or actively shape it . Nature
Fig. 8.2: Climate and carbon dioxide content between the Cambrian and today . A shows estimated carbon dioxide concentrations from seafloor spreading and land covering data . B shows the field of possible carbon dioxide concentrations gained from carbon isotope ratios . R (CO2) indicates the ratio between historic and current (= 1) concentrations . C, from paleoecological data, shows the fluctuations in global temperatures over the course of time, shown in contrast to today’s climate . D shows the fluctuations of the sea level, starting at today’s reference 0 m .a .s .l . Asterisks (*) indicate major extinctions of marine life forms . (A, B, D drawn according to Graedel and Crutzen 1995; C drawn according to Allègre and Schneider 1994, supplemented)
Fig. 8.3: Position of continents at the Upper Carboniferous [Pennsylvanian, 320 mya] . Regions with coal formation marked with a K . The equatorial tropical belt, the coastal subtropical coal regions and the coal area of the northern temperate forest zone of today’s Siberia are clearly visible . (According to Closs, Giese, and Jacobshagen 1987;
Smith, Hurley, and Briden 1981, supplemented)
experiences this reverse process as a shock, although we humans may think this process as slow, as it has progressed over several generations . A logical consequence of these reflections is: Non-renewable energies such as coal, oil and gas may be taken from earth only at such a rate and speed as the rate and speed needed to form corresponding amounts of these carbon compounds . This would mean that the extraction of non-renewable energy would have to be reduced by several 100,000 times, which would be at a rate sufficient to produce synthetic substances from these resources but not to burn them .
About Hard Coal Mining
For example, coal mining has required the development of highly qualified workers and a highly developed professional ethic . Mining requires intensive safety measures and a permanent monitoring of all ducts and tunnels . The miner experiences every day how the mountain changes dynamically in
its depth . Human engineering tries to meet this deformation activity consequently and without remorse . In this line of work in the depth, it is completely natural that nobody works alone; hour for hour the workers are watching each other to avoid possible accidents .
If it were not for government financial support, these extreme efforts in qualified labor would cause coal prices to be four times higher than oil prices, and, in contrast to oil production, at these prices there would not even be profit . It is special for mining jobs that the workers develop important faculties: considerate cooperation, reverence for the overwhelming forces of nature, forward-looking craft skills and interpersonal solidarity . When looking at this economic sector in Europe, it is obvious that coal mining is economically sentenced to death, and that state aid only delays the eventual closing down of mines .
Fig. 8.4: Position of the continents at the beginning of the Cretaceous . Continental areas covered by the shallow waters [continental shelf] of the global Tethys Sea are indicated with beveled shading . This is where most of the crude oil and natural gas deposits have formed . (According to Smith, Hurley, and Briden 1981; Stanley 2008;
Stanley and Schweizer 1994, supplemented)
About Crude Oil Extraction
In contrast to coal mining, crude oil extraction is much less labor-intensive . True, there are huge high-tech expenses and the payroll of utilizing competent scientists to discover natural oil traps and determine the location of drill derricks, which is in principle similar to coal mining . The oil production itself is simple . Once an oil well is opened, the outflow of the oil under pressure only needs to be controlled to allow its smooth transportation via pipelines . No worker has to reach the oil well itself . This explains why oil prices are still low despite tremendous profits of land owners and the oil-processing industrial complexes . It is justified to say that oil production is the cleverest and most efficient exploitation of any natural resource!
How Limited are Non-renewable Energy Resources?
An assessment of the supplies is not a simple task . From the previous representation it should be clear that especially crude oil and natural gas resources will run out soon . It is relatively clear in which earth regions to find oil and gas deposits, but weighing costs and benefits to exploit known deposits is much landscape changes . It is difficult to estimate the accompanying technical problems and political and ecological conflicts . In 1993, oil reserves globally [without oil shale]
amounted to 136,000 million tons . (Fischer Weltalmanach 1995) During the last several years, exploitation increased 1 .4% per year—
and, if it stays like this, oil deposits will be completely exhausted at the latest in 43 years (comp . Fig . 8 .5b) . The political dimension of this situation is even more dramatic when we consider that only 6% of the reserves are located within the industrial regions of North America and Europe . Another 8%
of oil is stored in Russia and China . The remaining 86% is in Latin America, North Africa and the Middle East . In other words, if production stays at the current level in all regions of the world, deposits in Europe and North America will be exhausted around the turn of the millenium, leaving the entire industrialized world dependent on the oil resources in Latin America, Africa and most of all the crisis-ridden Middle East . Saudi-Arabia, Iraq, Kuwait, the United Arab Emirates and Iran alone have a reserve potential of 87,000 million tons of crude oil which converts to an exploitation potential
Fig. 8.5a: CO2 concentrations and global temperatures within the last 160,000 years . Measurements are based on ice cores from the Vostok station in Antarctica . The increase in CO2 over the last 250 years is completely outside of the cyclic norm . (from Houghton and Woodwell 1989) [The Riss glacial is roughly contemporaneous to the Illinoian glacial in the US, the Würm glacial to the Wisconsin stage—tr .]
at their disposal of more than 100 years (numbers from Fischer Weltalmanach 1992, and BP Statistical Review of World Energy 1993) .
When keeping these potential dependencies in mind, it is all of a sudden easy to understand why the Russians in Chechnya, the Americans and Europeans in Iraq and in the living area of the Kurds,
and Palestinians are involved in military actions, which on a first view seem politically unwise and ethically irresponsible . They are, however, logical and consistent if it is all about gaining or securing political influence on these crude oil-producing regions as well as the areas through which the critical pipelines are drawn .
Fig. 8.5b: Connection between global temperatures, carbon dioxide content and energy conversions between 1750 and 1995 and forecasted values until 2050 . A shows the trend towards temperature changes based on astronomical facts but without any human influence . B shows the temperature graph; Bl was gained from historical data, B2 is based on measurements, B3 shows an average forecast . C shows the population increase in billions of people . D represents the expenses of energy conversions [primary energy], measured in Mio . Barrels of oil per day . Graph E, which is almost parallel, shows the annual release of carbon originating from the combustion of fossil fuels [oil, gas, coal, wood] and changed land use such as forest fires . F documents the atmospheric CO2 content; compared to graph E, this graph shows a delayed increase . At the right border are graphs showing estimates for the remaining reserves of oil, gas and coal (D and estimated until 2050 according to the Statistical Review of World Energy, British Petroleum Company (1992–2009) and the Fischer Weltalmanach, Redaktion Weltalmanach 2009;
comparable to The World Factbook (United States, Central Intelligence Agency); B2, B3, F according to Graedel and Crutzen 1995; B between 1880 and 1990 according to Hansen and Lebedeff 1988; E according to Houghton and Woodwell 1989; B2, B3 according to Jones and Wigley 1990 .
The Non-cycle of the Uranium Technology The dispute about the development and use of civil and military nuclear technology is stuck; even eleventh graders have quite solid opinions . Despite of this, it is still possible to discuss one specific aspect: Compared to the geological cycles of carbon in the use of coal, oil or gas, or in the closed loop of a hundred-year cycle of wood use and forestry, no cycle is possible in the case of nuclear power . Uranium ore, the necessary raw material for the operation, was formed very early in the earth’s history . Uranium oxide was formed during the late Precambrian as a marine precipitation in connection with the process of photosynthesis performed by early protists (comp . chapter 9) . The release of oxygen into
the water led to the formation of uranium oxide, which was subsequently deposited . Again it is the reduction of the atmospheric CO2 content and the reduction in the earth’s surface temperature that brought about the formation of uranium oxide .
Since its formation, uranium ore has gone through several metamorphoses and is predominantly mined in surface mining causing massive waste dumps that quickly emit most of their radioactivity into the environment . Before mining was begun, uranium ore deposits were geologically screened off from the environment and only very little radioactivity was released . Nowadays spoil dumps are usually not treated in any way . A diagram of the mass
Fig. 8.6: Global oil production, oil conversion and oil reserves for 1989 . Crude oil contributes 40% to the total global energy conversion . Kuwait alone has as many oil reserves as the US, Russia, western Europe and Canada
balance for a single year of operation of a 1000-megawatts [MW] nuclear power plant helps to illustrate the dimensions of this problem (Fig . 8 .7) .
The extraction of 440,000 metric tons of uranium ore is needed to convert process heat into electrical power in such a nuclear power plant (of the Gösgen or Leibstadt type, both in Switzerland) . [The two blocks of Three Mile Island near Harrisburg, PA had/
have a comparable performance at 875 and 906 MW—tr .] . From these are gained 33 metric tons of uranium fuel . The remaining approximately 400,000 t of rock material, containing decay products of uranium such as thorium, radium and lead, is dumped onto the soil dump . During the production of uranium gas from the ore, which is suitable for the enrichment of the fuel rods, additional waste is generated . From the original radioactivity of 10 Peta-Becquerel in the rocks, only 0 .43 Peta-Becquerel can be used for enrichment, which means that 95%
of radioactivity stays in the environment . The process of radioactive decay takes a very long time; the quantitatively important nuclide thorium 230 has a half-life of 75,000 years .
The consequences of radioactive decay are therefore not apparent immediately but are spread over several hundred thousand years . The highest radiation hazard occurs during uranium mining . In most cases, the mining sites are far away from the sites of nuclear power plants and therefore from the
The consequences of radioactive decay are therefore not apparent immediately but are spread over several hundred thousand years . The highest radiation hazard occurs during uranium mining . In most cases, the mining sites are far away from the sites of nuclear power plants and therefore from the