Powering the Singularity
We produce about 14 trillion (about 1013) watts of power today in the world. Of this energy about 33 percent comes from oil, 25 percent from coal, 20 percent from gas, 7 percent from nuclear fission reactors, 15 percent from biomass and hydroelectric sources, and only 0.5 percent from renewable solar, wind, and geothermal technologies.115 Most air pollution and significant contributions to water and other forms of pollution result from the extraction, transportation, processing, and uses of the 78 percent of our energy that comes from fossil fuels. The energy obtained from oil also contributes to geopolitical tensions, and there’s the small matter of its $2 trillion per year price tag for all of this energy. Although the industrial-era energy sources that dominate energy production today will become more efficient with new nanotechnology-based methods of extraction, conversion, and transmission, it’s the renewable category that will need to support the bulk of future energy growth.
By 2030 the price-performance of computation and communication will increase by a factor of ten to one hundred million compared to today. Other technologies will also undergo enormous increases in capacity and efficiency. Energy requirements will grow far more slowly than the capacity of technologies, however, because of greatly increased efficiencies in the use of energy, which I discuss below. A primary implication of the nanotechnology revolution is that physical technologies, such as manufacturing and energy, will become governed by the law of accelerating returns. All technologies will essentially become information technologies, including energy.
Worldwide energy requirements have been estimated to double by 2030, far less than anticipated economic growth, let alone the expected growth in the capability of technology.116 The bulk of the additional energy needed is likely to come from new nanoscale solar, wind, and geothermal technologies. It’s important to recognize that most energy sources today represent solar power in one form or another.
Fossil fuels represent stored energy from the conversion of solar energy by animals and plants and related processes over millions of years (although the theory that fossil fuels originated from living organisms has recently been challenged). But the extraction of oil from high-grade oil wells is at a peak, and some experts believe we may have already passed that peak. It’s clear, in any case, that we are rapidly depleting easily accessible fossil fuels. We do have far larger fossil-fuel resources that will require more sophisticated technologies to extract cleanly and efficiently (such as coal and shale oil), and they will be part of the future of energy. A billion-dollar demonstration plant called FutureGen, now being constructed, is expected to be the world’s first zero-emissions energy plant based on fossil fuels.117 Rather than simply burn coal, as is done today, the 275-million-watt plant will convert the coal to a synthetic gas comprising hydrogen and carbon monoxide, which will then react with steam to produce discrete streams of hydrogen and carbon dioxide, which will be sequestered. The hydrogen can then be used in fuel cells or else converted into electricity and water. Key to the plant’s design are new materials for membranes that separate hydrogen and carbon dioxide.
Our primary focus, however, will be on the development of clean, renewable, distributed, and safe energy technologies made possible by nanotechnology. For the past several decades energy technologies have been on the slow slope of the industrial era S-curve (the late stage of a specific technology paradigm, when the capability slowly approaches an asymptote or limit). Although the nanotechnology revolution will require new energy resources, it will also introduce major new S-curves in every aspect of energy—production, storage, transmission, and utilization—by the 2020s.
Let’s deal with these energy requirements in reverse, starting with utilization. Because of nanotechnology’s ability to manipulate matter and energy at the extremely fine scale of atoms and molecular fragments, the efficiency of using energy will be far greater, which will translate into lower energy requirements. Over the next several decades computing will make the transition to reversible computing. (See “The Limits of Computation” in chapter 3.) As I discussed, the primary energy need for computing with reversible logic gates is to correct occasional errors from quantum and thermal effects. As a result reversible computing has the potential to cut energy needs by as much as a factor of a billion, compared to nonreversible computing. Moreover, the logic gates and memory bits will be smaller, by at least a factor of ten in each dimension, reducing energy requirements by another thousand. Fully developed nanotechnology, therefore, will enable the energy requirements for each bit switch to be reduced by about a trillion. Of course, we’ll be increasing the amount of computation by even more than this, but this substantially augmented energy efficiency will largely offset those increases.
Manufacturing using molecular nanotechnology fabrication will also be far more energy efficient than contemporary manufacturing, which moves bulk materials from place to place in a relatively wasteful manner. Manufacturing today also devotes enormous energy resources to producing basic materials, such as steel. A typical nanofactory will be a tabletop device that can produce products ranging from computers to clothing. Larger products (such as vehicles, homes, and even additional nanofactories) will be produced as modular subsystems that larger robots can then assemble. Waste heat, which accounts for the primary energy requirement for nanomanufacturing, will be captured and recycled.
The energy requirements for nanofactories are negligible. Drexler estimates that molecular manufacturing will be an energy generator rather than an energy consumer. According to Drexler, “A molecular manufacturing process can be driven by the chemical energy content of the feedstock materials, producing electrical energy as a by-product (if only to reduce the heat dissipation burden). . . . Using typical organic feedstock, and assuming oxidation of surplus hydrogen, reasonably efficient molecular manufacturing processes are net energy producers.”118
Products can be made from new nanotube-based and nanocomposite materials, avoiding the enormous energy used today to manufacture steel, titanium, and aluminum. Nanotechnology-based lighting will use small, cool, light-emitting diodes, quantum dots, or other innovative light sources to replace hot, inefficient incandescent and fluorescent bulbs.
Although the functionality and value of manufactured products will rise, product size will generally not increase (and in some cases, such as most electronics, products will get smaller). The higher value of manufactured goods will largely be the result of the expanding value of their information content. Although the roughly 50 percent deflation rate for information-based products and services will continue throughout this period, the amount of valuable information will increase at an even greater, more than offsetting pace.
I discussed the law of accelerating returns as applied to the communication of information in chapter 2. The amount of information being communicated will continue to grow exponentially, but the efficiency of communication will grow almost as fast, so the energy requirements for communication will expand slowly.
Transmission of energy will also be made far more efficient. A great deal of energy today is lost in transmission due to the heat created in power lines and inefficiencies in the transportation of fuel, which also represent a primary environmental assault. Smalley, despite his critique of molecular nanomanufacturing, has nevertheless been a strong advocate of new nanotechnology-based paradigms for creating and transmitting energy. He describes new power-transmission lines based on carbon nanotubes woven into long wires that will be far stronger, lighter, and, most important, much more energy efficient than conventional copper ones.119 He also envisions using superconducting wires to replace aluminum and copper wires in electric motors to provide greater efficiency. Smalley’s vision of a nanoenabled energy future includes a panoply of new nanotechnology-enabled capabilities:120
Photovoltaics: dropping the cost of solar panels by a factor of ten to one hundred.
Production of hydrogen: new technologies for efficiently producing hydrogen from water and sunl
ight.
Hydrogen storage: light, strong materials for storing hydrogen for fuel cells.
Fuel cells: dropping the cost of fuel cells by a factor of ten to one hundred.
Batteries and supercapacitors to store energy: improving energy storage densities by a factor of ten to one hundred.
Improving the efficiency of vehicles such as cars and planes through strong and light nanomaterials.
Strong, light nanomaterials for creating large-scale energy-harvesting systems in space, including on the moon.
Robots using nanoscale electronics with artificial intelligence to automatically produce energy-generating structures in space and on the moon.
New nanomaterial coatings to greatly reduce the cost of deep drilling.
Nanocatalysts to obtain greater energy yields from coal, at very high temperatures.
Nanofilters to capture the soot created from high-energy coal extraction. The soot is mostly carbon, which is a basic building block for most nanotechnology designs.
New materials to enable hot, dry rock geothermal-energy sources (converting the heat of the Earth’s hot core into energy).
Another option for energy transmission is wireless transmission by microwaves. This method would be especially well suited to efficiently beam energy created in space by giant solar panels (see below).121 The Millennium Project of the American Council for the United Nations University envisions microwave energy transmission as a key aspect of “a clean, abundant energy future.”122
Energy storage today is highly centralized, which represents a key vulnerability in that liquid-natural-gas tanks and other storage facilities are subject to terrorist attacks, with potentially catastrophic effects. Oil trucks and ships are equally exposed. The emerging paradigm for energy storage will be fuel cells, which will ultimately be widely distributed throughout our infrastructure, another example of the trend from inefficient and vulnerable centralized facilities to an efficient and stable distributed system.
Hydrogen-oxygen fuel cells, with hydrogen provided by methanol and other safe forms of hydrogen-rich fuel, have made substantial progress in recent years. A small company in Massachusetts, Integrated Fuel Cell Technologies, has demonstrated a MEMS (Micro Electronic Mechanical System)-based fuel cell.123 Each postage-stamp-size device contains thousands of microscopic fuel cells and includes the fuel lines and electronic controls. NEC plans to introduce fuel cells based on nanotubes in the near future for notebook computers and other portable electronics.124 It claims its small power sources will run devices for up to forty hours at a time. Toshiba is also preparing fuel cells for portable electronic devices.125
Larger fuel cells for powering appliances, vehicles, and even homes are also making impressive advances. A 2004 report by the U.S. Department of Energy concluded that nanobased technologies could facilitate every aspect of a hydrogen fuel cell–powered car.126 For example, hydrogen must be stored in strong but light tanks that can withstand very high pressure. Nanomaterials such as nanotubes and nanocomposites could provide the requisite material for such containers. The report envisions fuel cells that produce power twice as efficiently as gasoline-based engines, producing only water as waste.
Many contemporary fuel-cell designs use methanol to provide hydrogen, which then combines with the oxygen in the air to produce water and energy. Methanol (wood alcohol), however, is difficult to handle, and introduces safety concerns because of its toxicity and flammability. Researchers from St. Louis University have demonstrated a stable fuel cell that uses ordinary ethanol (drinkable grain alcohol).127 This device employs an enzyme called dehydrogenase that removes hydrogen ions from alcohol, which subsequently react with the oxygen in the air to produce power. The cell apparently works with almost any form of drinkable alcohol. “We have run it on various types,” reported Nick Akers, a graduate student who has worked on the project. “It didn’t like carbonated beer and doesn’t seem fond of wine, but any other works fine.”
Scientists at the University of Texas have developed a nanobot-size fuel cell that produces electricity directly from the glucose-oxygen reaction in human blood.128 Called a “vampire bot” by commentators, the cell produces electricity sufficient to power conventional electronics and could be used for future blood-borne nanobots. Japanese scientists pursuing a similar project estimated that their system had the theoretical potential to produce a peak of one hundred watts from the blood of one person, although implantable devices would use far less. (A newspaper in Sydney observed that the project provided a basis for the premise in the Matrix movies of using humans as batteries.)129
Another approach to converting the abundant sugar found in the natural world into electricity has been demonstrated by Swades K. Chaudhuri and Derek R. Lovley at the University of Massachusetts. Their fuel cell, which incorporates actual microbes (the Rhodoferax ferrireducens bacterium), boasts a remarkable 81 percent efficiency and uses almost no energy in its idling mode. The bacteria produce electricity directly from glucose with no unstable intermediary by-products. The bacteria also use the sugar fuel to reproduce, thereby replenishing themselves, resulting in stable and continuous production of electrical energy. Experiments with other types of sugars such as fructose, sucrose, and xylose were equally successful. Fuel cells based on this research could utilize the actual bacteria or, alternatively, directly apply the chemical reactions that the bacteria facilitate. In addition to powering nanobots in sugar-rich blood, these devices have the potential to produce energy from industrial and agricultural waste products.
Nanotubes have also demonstrated the promise of storing energy as nanoscale batteries, which may compete with nanoengineered fuel cells.130 This extends further the remarkable versatility of nanotubes, which have already revealed their prowess in providing extremely efficient computation, communication of information, and transmission of electrical power, as well as in creating extremely strong structural materials.
The most promising approach to nanomaterials-enabled energy is from solar power, which has the potential to provide the bulk of our future energy needs in a completely renewable, emission-free, and distributed manner. The sunlight input to a solar panel is free. At about 1017 watts, or about ten thousand times more energy than the 1013 watts currently consumed by human civilization, the total energy from sunlight falling on the Earth is more than sufficient to provide for our needs.131 As mentioned above, despite the enormous increases in computation and communication over the next quarter century and the resulting economic growth, the far greater energy efficiencies of nanotechnology imply that energy requirements will increase only modestly to around thirty trillion watts (3 × 1013) by 2030. We could meet this entire energy need with solar power alone if we captured only 0.0003 (three ten-thousandths) of the sun’s energy as it hits the Earth.
It’s interesting to compare these figures to the total metabolic energy output of all humans, estimated by Robert Freitas at 1012 watts, and that of all vegetation on Earth, at 1014 watts. Freitas also estimates that the amount of energy we could produce and use without disrupting the global energy balance required to maintain current biological ecology (referred to by climatologists as the “hypsithermal limit”) is around 1015 watts. This would allow a very substantial number of nanobots per person for intelligence enhancement and medical purposes, as well as other applications, such as providing energy and cleaning up the environment. Estimating a global population of around ten billion (1010) humans, Freitas estimates around 1016 (ten thousand trillion) nanobots for each human would be acceptable within this limit.132 We would need only 1011 nanobots (ten millionths of this limit) per person to place one in every neuron.
By the time we have technology of this scale, we will also be able to apply nanotechnology to recycle energy by capturing at least a significant portion of the heat generated by nanobots and other nanomachinery and converting that heat back into energy. The most effective way to do this would probably be to build the energy recycling into the nanobot itself.133 This is sim
ilar to the idea of reversible logic gates in computation, in which each logic gate essentially immediately recycles the energy it used for its last computation.
We could also pull carbon dioxide out of the atmosphere to provide the carbon for nanomachinery, which would reverse the increase in carbon dioxide resulting from our current industrial-era technologies. We might, however, want to be particularly cautious about doing more than reversing the increase over the past several decades, lest we replace global warming with global cooling.
Solar panels have to date been relatively inefficient and expensive, but the technology is rapidly improving. The efficiency of converting solar energy to electricity has steadily advanced for silicon photovoltaic cells from around 4 percent in 1952 to 24 percent in 1992.134 Current multilayer cells now provide around 34 percent efficiency. A recent analysis of applying nanocrystals to solar-energy conversion indicates that efficiencies above 60 percent appear to be feasible.135
Today solar power costs an estimated $2.75 per watt.136 Several companies are developing nanoscale solar cells and hope to bring the cost of solar power below that of other energy sources. Industry sources indicate that once solar power falls below $1.00 per watt, it will be competitive for directly supplying electricity to the nation’s power grid. Nanosolar has a design based on titanium oxide nanoparticles that can be mass-produced on very thin flexible films. CEO Martin Roscheisen estimates that his technology has the potential to bring down solar-power costs to around fifty cents per watt by 2006, lower than that of natural gas.137 Competitors Nanosys and Konarka have similar projections. Whether or not these business plans pan out, once we have MNT (molecular nanotechnology)-based manufacturing, we will be able to produce solar panels (and almost everything else) extremely inexpensively, essentially at the cost of raw materials, of which inexpensive carbon is the primary one. At an estimated thickness of several microns, solar panels could ultimately be as inexpensive as a penny per square meter. We could place efficient solar panels on the majority of human-made surfaces, such as buildings and vehicles, and even incorporate them into clothing for powering mobile devices. A 0.0003 conversion rate for solar energy should be quite feasible, therefore, and relatively inexpensive.