Exploring New Energy Alternatives: What Is Most Likely to Satisfy Our Energy Needs in the Future-Wind Farms and Photovoltaic Arrays, or Something Yet to Be Invented? Options for the World's Energy Future May Include Surprises, Thanks to Innovative Research under Way around the World
LePoire, David J., The Futurist
much discussion about going beyond petroleum includes the development of wind farms, solar thermal concentrators, solar cells, and geothermal energy production. But will these satisfy our energy needs in the future? We hope that renewable sources will provide enough energy to supply the world's future needs, but there are still many uncertainties.
How much will low-intensity sources of energy cost over their life spans, and what will their environmental impacts be? The answers depend on research and on the operational experience gained in deploying these technologies and their associated storage, transmission, and conversion systems.
Another area of uncertainty is the growth in world demand for energy. If everyone in the world used energy as the United States does, the rate of energy production would have to increase by a factor of four. In addition, the energy use per person in the developed world might not be stagnant; it might increase. Could renewable sources keep up with this demand?
The following is an overview of a few conventional renewable energy sources that may be expanded in the near future, as well as some more speculative potential "surprises." As the time horizon increases, the uncertainties associated with the technologies, economics, and political scenarios increase.
Fossil fuels currently account for 83% of the U.S. energy supply and slightly less (80%) of the world's energy supply, but energy conservation and efficiency since the oil crises of the 1970s have suppressed growth of energy demand. If energy use had grown as fast as the economy, the United States would be using an estimated 60% more energy than it does now. We've improved energy use in buildings, electrical appliances, cars, and industrial processes. These applications are often motivated by cost savings.
The attainment of energy efficiency through conservation or improved technology allows us to extract more applied energy from a comparable amount of fuel. This has led to growth that has been quicker in the economy than in energy use.
Current nuclear power plants extract the remnant energy from supernova explosions stored in the heavy element of uranium. Since these stellar explosions occurred billions of years ago, before the solar system formed, nuclear power is not renewable. However, there is still much more energy stored in the heavy elements than the amount that is currently utilized. Techniques are being explored to expand the possible fuel materials to include other types of uranium and thorium.
Hydroelectric power is renewable but demonstrates some limitations: Though inexpensive, electricity generated from hydropower (for example, along the Tennessee, Colorado, and Columbia rivers) affects large tracts of land and is generally limited to a few select spots where the topography of the land supports a good reservoir location. Growth globally is limited because prime locations have already been developed.
Direct solar-energy technologies such as solar photovoltaic cells are being rapidly developed and deployed, and other technologies are also advancing our ability to efficiently convert wind, waves, ocean currents, and biofuels into usable energy.
Beyond Conventional Renewable Energy Sources
To hedge our energy bets and reduce future uncertainty, researchers are exploring new options for future energy sources, including ways to improve older ideas, such as fusion energy, space-based solar power satellites, Moon bases, and advanced nuclear fission options.
The strategy of maintaining a variety of energy options could be likened to the strategy of reducing risk in an investment portfolio. For example, our current energy technologies have costs, environmental impacts, and maturity levels that are relatively well known. Researchers are now testing newer renewable technologies, with the aim of cutting production expenses, minimizing negative environmental impacts, and enhancing scalability.
The hypothetical space-based, fusion, and advanced fission energy production systems introduce an extra level of uncertainty, because some technical aspects are not solved and because their relative costs depend on the construction of new infrastructure to support them.
Infrared Solar Technology
Nanotechnology offers a tool that could help create designs that convert energy more efficiently. For example, nano-scale antennas could be built to capture infrared light from the Sun--light that we cannot directly see but we do experience as heat. A solar cell that could extract this infrared energy would be able to provide energy both day and night (although not as much at night).
An antenna is more efficient at capturing energy and absorbs at a wider range of angles than conventional cells, and it does not require exotic materials to make. However, the antenna has to be about the same size as the wavelength of the light. For radios, this is about 1 meter. For cell phones, it is a few inches. For infrared light, the wavelength is about one twenty-fifth of the width of a human hair. One antenna would not only be difficult enough to make, but it would also result in very little energy production.
The challenge to easily produce millions of these small antennas was successfully met at Idaho National Laboratory (a U.S. Department of Energy laboratory), along with other laboratories, in work that received the 2007 Nano50 award. The laboratories were able to "print" 250 million metal antennas on plastic about the size of a standard sheet of paper. However, the problem remains to convert the absorbed energy (10 Ghz frequency) into useful electricity (60 Hz frequency).
Nanotech could also improve energy-conversion efficiency of fission technology by allowing particles of uranium atoms to be converted to electricity before they collide and generate heat. This might be achieved by integrating the fuel and electricity extraction zones at the nano scale. When charged particles hit gas in the small pores, they strip the gas of electrons. The separation of charges then generates a voltage difference. This work is being pursued by a former Los Alamos National Laboratory scientist.
In a traveling wave reactor, only a small slice of a cylinder core is undergoing intense nuclear reactions with fast neutrons. The reactor needs an initial ignition with enriched uranium, but then it burns much like a candle. Its advantages include the ability to use unenriched fuel such as natural uranium, waste (depleted) uranium, thorium (much more plentiful than uranium), and spent nuclear fuel (considered a waste product of current nuclear power electricity generation).
This design was originally proposed in the 1950s, but no actual reactor has been built. Currently, TerraPower has developed designs for such a reactor, which were publicized in a 2010 Technology Entertainment and Design (TED) presentation by Bill Gates. These reactors would use the fuel more efficiently by using more of the available uranium and thorium, and would operate at higher temperatures and thereby allow higher thermal efficiency. They would also be contained, such that the fuel would last for 60 years, and generate much less waste as more material was burned.
Fusion is the process of merging two small atomic nuclei into a larger one. If the resulting nucleus is lighter than iron, the reaction also releases energy. The difficulty lies in getting two electrically charged nuclei close enough for the merger, or fusion, to occur. For energy production, the nuclei need to be pushed together in a controllable, energy-efficient, and economical way.
In nature, there is one system--stars--that controllably and efficiently generates energy. However, it is impossible to replicate the confinement mechanisms that stars use, since it requires the gravitational attraction of the mass of the Sun. The process of confining plasma is necessary for generating controllable, energy-efficient, and economical fusion energy. Although the concept of nuclear fusion for energy generation was identified early after World War II, its implementation has been frustrated because of the various ways the plasma finds to escape confinement. It seems that fusion has been "about 30 years away" for the past 50 years!
One way to confine the plasma is through the inertial forces from an implosion. This is the technique used by the large facility at Lawrence Livermore National Laboratory--the National Ignition Facility--whose construction just ended in 2010 and is scheduled for experiments.
Another technique to magnetically compress hydrogen long enough for fusion to take place is to run a large current through wires. The large current vaporizes the wire into a plasma, while simultaneously creating a large magnetic field to compress the plasma and hydrogen. The Z machine at Sandia National Laboratories has been experimenting with this concept for many years.
A 25-year quest for scalable solar energy solutions has drawn from biomimicry for inspiration. In its search for creating artificial photosynthesis, an MIT team led by Dan Nocera recently identified two natural biological techniques that had previously remained hidden. Nocera noticed that some life-forms use cobalt in photosynthesis. He then developed a long-lived cobalt-based catalyst that uses sunlight to convert water into oxygen and hydrogen gas.
This work supports Nocera's goal of finding a chemical process that could be distributed (e.g., on houses) and robust (e.g., not decay) in converting sunlight into liquid chemicals (e.g., alcohols) that store the energy for later use in transportation as a gasoline substitute or as electricity with a fuel cell.
The MIT team's recent discoveries have led to a startup company, Sun Catalytix, that is partially funded by the U.S. government's Advanced Research Projects Agency-Energy (ARPA-E) program, which funds selected promising energy-related innovations. In the lab, it seems like the catalyst also works in impure water, which could lead to it being used not only to generate and store solar energy but also to purify water.
Nate Lewis at Caltech is also searching for artificial photosynthesis in a different way, by using nano-tubes along with a membrane to generate hydrogen from light.
Space-Based Solar Technology
The idea of space-based solar energy extraction has been around for decades. Obstacles include the high price of sending reliable equipment into space and of maintaining it there and the uncertainties associated with transmitting the energy back to Earth.
Two locations are currently being explored: geosynchronous orbit and on the Moon. The latter offers the advantages of using existing materials and providing a more conventional work environment.
A Japanese company, Shimizu, is exploring the use of semi-autonomous robots to do the primary conversion of materials and build the solar energy collection system. The idea is to create a continuous strip of land, perhaps going all around the Moon's equator, of solar cell collectors built with lunar materials.
The resulting LUNA RING, a complete equatorial ring, would allow continuous energy collection. The Sun shines only half the time on the far side of the Moon, yet the same side of the Moon is always facing the Earth, so just a limited number of transmitters would be needed. [Editor's note: For more on the LUNA RING concept, see "Solar Power from the Moon" by Patrick Tucker, THE FUTURIST, May-June 2011.]
To make this plan more feasible, space travel and the movement of materials need to be more economical. There have been several attempts to improve the space elevator concept, which was first proposed by Russian scientist Konstantin Tsiolkovsky in 1895. A major obstacle is the strength of the material needed for the spine of the elevator, which must reach more than 24,000 miles from the geosynchronous orbit down to near the Earth level. Recently, NASA and physicist Brad Edwards have been updating the design on the basis of the idea that carbon nanotubes, which have the necessary strength, can be scaled up to provide enough material and consistency for the long cable.
Speculative Physics: Dark Energy, Muons, and Mini Black Holes
Still further in the future, and associated with far greater uncertainty, are speculations about using new potential physics discoveries. Although a surprise might arise from this area, the probability of any one technique being successful is small, and it would take a large amount of effort to develop it into an integrated energy production system.
History has shown that surprises can revolutionize energy generation. In the mid-twentieth century, nuclear fission power was able to go from the lab to the power station in about 40 years. There are still many natural mysteries that might point the way to new energy technologies.
Among these mysteries are dark matter and dark energy, which account for about 95% of the energy in the universe. Accelerators such as the CERN Large Hadron Collider might discover new particles, as predicted by a variety of competing theories. Or they might produce mini black holes, whose physics would be interesting to explore. Physicists have begun speculating about potential theories and about how new forms of matter and energy might be exploited to generate useful energy.
For example, heavy, negatively charged particles can catalyze fusion. This is seen when muons enter water. Muons are a heavy relative of the electrons that are produced by natural cosmic rays or accelerators, which have been known since the 1950s. Hydrogen nuclei are attracted to the heavy negatively charged muons and form atoms with the nuclei that are orbiting the muon. This is a form of containment of the hydrogen nuclei. Eventually, the nuclei fuse, releasing energy. Therefore, no large temperature or containment facility is necessary. The muons are then released to catalyze more reactions.
However, the muons are unstable and eventually decay. Currently, the energy necessary to produce the muons is more than the energy generated by the limited number of fusions they catalyze. If a new, more stable, negatively charged particle is found, the economical catalysis of fusion might be developed.
Another possibility is that mini black holes might one day be produced and controlled to extract energy from the material fed into them. As the material entered, some of the energy would radiate out. Very small theoretical black holes would be too unstable and radiate before control was established, but there might be a "sweet spot" of black-hole size that would radiate at a beneficial rate. Mini black holes have been proposed as an energy source for a spaceship in the far future.
Finally, there are aspects of quantum physics that are still very puzzling. Researchers are exploring the connection between quantum physics and gravity, as well as the fundamental aspects of quantum physics behavior, such as the way in which spin influences collective behavior. Another possibility is finding a way to extract energy from vacuum energy (zero point energy).
Diversity for the Energy Portfolio
These examples of potential new energy sources highlight an essential ingredient in the future of energy: the diversity of the organizations involved in developing it.
Some projects are government-based, such as those sponsored by DOE, Others are collaborations between a government and an industry, such as the Japanese Artemis group. Some projects are sponsored by individual philanthropists and investors, such as Bill Gates and Vinod Khosla. And some, such as the ITER fusion reactor, require international collaboration. The space elevator, for example, would probably require similar international agreements and cooperation.
Besides direct research funding, other ways to foster innovation include contests in which many different types of organization can participate. Successful contests include the X Prize for space travel and the Defense Advanced Research Projects Agency (DARPA) Grand Challenge for autonomous vehicle navigation.
Energy is a major determinant in economic development, not only with regard to heating, transportation, and entertainment, but also with regard to staples such as food, shelter, and health. The energy fuel types have periodically changed over the last 200 years, and our current dependence on fossil fuels may soon be at an end.
We have been applying energy-efficiency methods to curb energy demand, and we have been developing renewable energy sources, such as solar and wind power, to increase supply. However, these energy sources might not be able to meet all future energy needs because of their economics or environmental impacts.
Searching for more potential future sources of energy to prepare for the challenges ahead requires research. New tools that employ nanotechnology, supercomputers, and space technology enable such exploration. A balanced portfolio of energy options and organizational support can reduce uncertainty and minimize the potential for surprises.
About the Author
David J. LePoire is an environmental analyst at Ar-gonne National Laboratory. E-mail firstname.lastname@example.org. This work was supported by the U.S. Department of Energy under Contract No. DE-AC02-06CH171357.
This article draws from his essay, "Beyond (Conventional) Renewable Energy?" in the World Future Society's 2011 conference volume, Moving from Vision to Action, which may be ordered from www.wfs.org/wfsbooks.…
Questia, a part of Gale, Cengage Learning. www.questia.com
Publication information: Article title: Exploring New Energy Alternatives: What Is Most Likely to Satisfy Our Energy Needs in the Future-Wind Farms and Photovoltaic Arrays, or Something Yet to Be Invented? Options for the World's Energy Future May Include Surprises, Thanks to Innovative Research under Way around the World. Contributors: LePoire, David J. - Author. Magazine title: The Futurist. Volume: 45. Issue: 5 Publication date: September-October 2011. Page number: 34+. © 1999 World Future Society. COPYRIGHT 2011 Gale Group.
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