Fuels from Heaven, Fuels from Hell
By Ulf Bossel
The term "Fuels from Heaven, Fuels from Hell" was coined by Rochelle Lefkowitz, the president of Pro-Media Communications and the wife of CalCar's founder Felix Kramer, to describe the differences between depletable fuels and renewable forms of energy
The words "sustainable" and "sustainability" have become fashionable. Investments are called "sustainable" if profit is guaranteed for a number of years. Paper mills receive "sustainability" awards for recycling waste water and natural gas is claimed to become "sustainable" when it is converted to hydrogen by steam reforming. These examples show that the true meaning of the word is not properly understood. "Sustainability" needs to be defined. Things as such cannot be sustainable. Only processes can be organized in a sustainable way.
In simple terms, sustainability is living forever from nature without hurting it. Long-term, our chosen energy options must be sustainable, because energy is essential for services such as warmth (in buildings), mobility (for transport) and mechanical power, lighting and electronics (from electricity). It is also essential for obtaining materials, by mining and refining, synthesis, and recycling.
Sustainability has two requirements. The first concerns the harvesting of energy and materials from nature. The concept of sustainability (German: "Nachhaltigkeit") was first postulated in 1713 by Hans Carl von Carlowitz, the Supervisor of Mining for Saxony [PDF at http://www.efcf.com/reports/E23.pdf includes cover page of the original "Anweisungen zur Wilden Baum-Zucht" (Instructions for the Natural Tree Growth)]. He stated that avoiding future shortages of timber and firewood requires harvesting only the natural growth of wood, not the tree stock itself. His rule has since been adopted by prudent forest managers in Europe and elsewhere. It amounts simply to living on the interest from an investment, not on the capital itself.
The second concerns the return to nature of products and wastes arising from the use of energy and materials. These can arise anywhere in the chain between the source and the sink. For example, power plants lie between coal mines and electricity users. However, the carbon dioxide they emit is harmful for nature. Hence the second sustainability criterion is violated in this case.
The reserves of coal, oil, natural gas and uranium are limited. In our time scale, they do not regenerate. Hence we can use them only as long as they last. In addition, their emissions -- carbon dioxide and radioactive waste -- cannot be absorbed by nature. Consequently, none of these energy sources can satisfy both sustainability criteria. In fact, sustainable energy solutions cannot be based on any of the "below-ground" energy deposits.
Another characteristic of "below-ground" energy is often overlooked. More and more energy is needed for recovering energy from sources of deteriorating quality, for transporting the crude materials over longer distances and for refining lower-grade crude to obtain high-grade fuels for market needs. Even for a constant net energy demand, the gross primary energy requirement must increase exponentially. The price of energy from such sources, and their carbon dioxide emissions, follow this exponential trend. Eventually, the "energy cost of energy" exceeds the "energy return" -- and what was an energy source becomes an energy sink. At some point, neither increased prices nor increased energy conversion efficiency can overcome this.
Therefore, sustainable energy can never be achieved with "below-ground" fossil or uranium sources. The character of the original coal fuel does not change if it is converted to hydrogen. Even "clean coal" can never be a sustainable energy option because of the dwindling coal supplies. In the event CCS (carbon capture and sequestration) becomes commercially feasible, it is likely to suffer from similar exponential increases in the energy fraction used and in cost as the easier locations to store CO2 become filled.
In contrast, renewable energy sources exhibit no such exponential increase, because no energy is required to make the sun shine or the wind blow. After the initial energy investment in a renewable energy plant, the "energy return" is always positive and, averaged over time, remains the same. The fuels generate no harmful emissions; the only emissions come from constructing the generating, storage and distribution facilities. For energy supply, only renewable sources can satisfy the sustainability criteria. However, even some renewables are not always harvested sustainably. Ethanol from corn is not sustainable -- the total fossil energy input from plowing the fields to distilling the mash may exceed that of the end-product, and large quantities of water are required. Silt deposits in water reservoirs may gradually reduce the hydroelectric power production. Arable land may be spoiled by intensive farming. Geothermal wells may be exhausted as they are cooled by heat extraction.
The sustainability criteria are best satisfied by solar, wind, wave and most hydropower options. This renewable energy is available "above ground" in our biosphere -- installations for harvesting renewables from sun, wind, and waves are all visible. Land for energy production is occupied by installations, but not consumed. Although there may be some visual impacts, all "above-ground" renewable energy installations satisfy the sustainability criteria.
Other options that can help to meet the sustainability goals are energy savings and increased energy efficiency. The first reduces the energy consumption by responsible use of energy -- e.g., turn off lights when leaving a room. The second reduces energy losses of energy conversion processes -- e.g. use more efficient lamps for the conversion of electricity to light. Together, energy saving and energy efficiency can reduce the demand for fuels and any resulting emissions.
Today, significant losses result when "below-ground" energy resources are converted to motion and electricity. This also applies to hydrogen produced inefficiently by electrolysis, or with CO2 emissions from natural gas. In a sustainable future, energy services will be supplied at the highest efficiency by electricity from renewable sources. Except for biofuels and solar heat, most energy from renewable sources is harvested as electricity. This may be obtained from wind turbines, photo-voltaic arrays, and thermal power plants "fueled" by concentrated solar, municipal waste, biomass and geothermal heat. Clean electricity will become the "lead currency" of a sustainably organized energy "electron economy." It can produce warmth via heat pumps and motion in electric cars with high efficiency. For long distance land, sea and air transport, requiring high-density portable fuels, the remaining oil or biofuels will be preferred.
The difference between "below-ground" and "above-ground" sources is not just a matter of definition, or a reflection of ideology or wishful thinking. Only the "below-ground" sources are subject to the exponential growth of primary energy requirements, carbon dioxide emissions and energy prices. Mankind must escape from these exponentially increasing constraints, the sooner the better. Achieving a sustainable energy future can become a common political goal, with all regions, countries and continents effecting the necessary transition. Some countries have already accepted this requirement while others hesitate even to recognize the problem. A swift and determined switch to energy savings, increased energy efficiency and renewable energy supplies would increase the level of sustainable energy service. Why are we so reluctant to start the transition?
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