As a source of energy, nothing matches the sun. It out-powers anything that human technology could ever produce. Only a small fraction of the sun’s power output strikes the Earth, but even that provides 10,000 times as much as all the commercial energy that humans use on the planet.
Overcoming the barriers to widespread solar power generation will require engineering innovations in several arenas — for capturing the sun’s energy, converting it to useful forms, and storing it for use when the sun itself is obscured.
To make solar economically competitive, engineers must find ways to improve the efficiency of the [solar] cells and to lower their manufacturing costs.
Another idea for enhancing efficiency involves developments in nanotechnology, the engineering of structures on sizes comparable to those of atoms and molecules, measured in nanometers (one nanometer is a billionth of a meter).
Already, the sun’s contribution to human energy needs is substantial — worldwide, solar electricity generation is a growing, multibillion dollar industry. But solar’s share of the total energy market remains rather small, well below 1 percent of total energy consumption, compared with roughly 85 percent from oil, natural gas, and coal.
Those fossil fuels cannot remain the dominant sources of energy forever. Whatever the precise timetable for their depletion, oil and gas supplies will not keep up with growing energy demands.
For a long-term, sustainable energy source, solar power offers an attractive alternative. Its availability far exceeds any conceivable future energy demands.
If you have a laptop computer, its battery probably contains the metallic element lithium. In theory, the lithium in that battery could supply your household electricity needs for 15 years. Not in the form of a battery, of course. Rather, lithium could someday be the critical element for producing power from nuclear fusion, the energy source for the sun and hydrogen bombs. Power plants based on lithium and using forms of hydrogen as fuel could in principle provide a major sustainable source of clean energy in the future.
Human-engineered fusion has already been demonstrated on a small scale. The challenges facing the engineering community are to find ways to scale up the fusion process to commercial proportions, in an efficient, economical, and environmentally benign way.
Building full-scale fusion-generating facilities will require engineering advances to meet all of these challenges, including better superconducting magnets and advanced vacuum systems. The European Union and Japan are designing the International Fusion Materials Irradiation Facility, where possible materials for fusion plant purposes will be developed and tested. Robotic methods for maintenance and repair will also have to be developed. While these engineering challenges are considerable, fusion provides many advantages beyond the prospect of its almost limitless supply of fuel.
From a safety standpoint, it poses no risk of a runaway nuclear reaction — it is so difficult to get the fusion reaction going in the first place that it can be quickly stopped by eliminating the injection of fuel.
The growth in emissions of carbon dioxide, implicated as a prime contributor to global warming, is a problem that can no longer be swept under the rug. But perhaps it can be buried deep underground or beneath the ocean.
Evidence is mounting that carbon dioxide’s heat-trapping power has already started to boost average global temperatures. If carbon dioxide levels continue upward, further warming could have dire consequences, resulting from rising sea levels, agriculture disruptions, and stronger storms (e.g. hurricanes) striking more often.
One of the grand challenges for the 21st century’s engineers will be developing systems for capturing the carbon dioxide produced by burning fossil fuels and sequestering it safely away from the atmosphere.
Carbon sequestration is capturing the carbon dioxide produced by burning fossil fuels and storing it safely away from the atmosphere.
It doesn’t offer as catchy a label as “global warming,” but human-induced changes in the global nitrogen cycle pose engineering challenges just as critical as coping with the environmental consequences of burning fossil fuels for energy.
The nitrogen cycle reflects a more intimate side of energy needs, via its central role in the production of food. It is one of the places where the chemistry of the Earth and life come together, as plants extract nitrogen from their environment, including the air, to make food. Controlling the impact of agriculture on the global cycle of nitrogen is a growing challenge for sustainable development.
Unfortunately, that nitrogen is not readily available for use by living organisms, as the molecules do not easily enter into chemical reactions. In nature, breaking up nitrogen requires energy on the scale of lightning strikes, or the specialized chemical abilities of certain types of microbes.
Until recent times, nitrogen fixation by microorganisms (with an additional small amount from lightning strikes) was the only way in which nitrogen made its way from the environment into living organisms. Human production of additional nitrogen nutrients, however, has now disrupted the natural nitrogen cycle, with fertilizer accounting for more than half of the annual amount of nitrogen fixation attributed to human activity.
Such human activity has doubled the amount of fixed nitrogen over the levels present during pre-industrial times. Among the consequences are worsening of the greenhouse effect, reducing the protective ozone layer, adding to smog, contributing to acid rain, and contaminating drinking water.
Maintaining a sustainable food supply in the future without excessive environmental degradation will require clever methods for remediating the human disruption of the nitrogen cycle.
A major need for engineering innovation will be in improving the efficiency of various human activities related to nitrogen, from making fertilizer to recycling food wastes.
Today, the availability of water for drinking and other uses is a critical problem in many areas of the world.
Lack of clean water is responsible for more deaths in the world than war. About 1 out of every 6 people living today do not have adequate access to water, and more than double that number lack basic sanitation, for which water is needed. In some countries, half the population does not have access to safe drinking water, and hence is afflicted with poor health. By some estimates, each day nearly 5,000 children worldwide die from diarrhea-related diseases, a toll that would drop dramatically if sufficient water for sanitation was available.
It’s not that the world does not possess enough water. Globally, water is available in abundance. It is just not always located where it is needed.
In many instances, political and economic barriers prevent access to water even in areas where it is otherwise available. And in some developing countries, water supplies are contaminated not only by the people discharging toxic contaminants, but also by arsenic and other naturally occurring poisonous pollutants found in groundwater aquifers.
In addition to sanitation, most of the water we use is for agriculture and industry.
Infrastructure is the combination of fundamental systems that support a community, region, or country. It includes everything from water and sewer systems to road and rail networks to the national power and natural gas grids.
It is no secret that America’s infrastructure, along with those of many other countries, is aging and failing, and that funding has been insufficient to repair and replace it. Engineers of the 21st century face the formidable challenge of modernizing the fundamental structures that support civilization.
The problem is particularly acute in urban areas, where growing populations stress society’s support systems, and natural disasters, accidents, and terrorist attacks threaten infrastructure safety and security.
Furthermore, solutions to these problems must be designed for sustainability, giving proper attention to environmental and energy-use considerations (though cities take up just a small percentage of the Earth’s surface, they disproportionately exhaust resources and generate pollution), along with concern for the aesthetic elements that contribute to the quality of life.
Advances in computer science and robotics should make more automation possible in construction, for instance, greatly speeding up construction times and lowering costs. Electricity networks linking large central-station and decentralized power sources will also benefit from greater embedded computation.
And so, a major grand challenge for infrastructure engineering will be not only to devise new approaches and methods, but also to communicate their value and worthiness to society at large.
No aspect of human life has escaped the impact of the Information Age, and perhaps in no area of life is information more critical than in health and medicine. As computers have become available for all aspects of human endeavors, there is now a consensus that a systematic approach to health informatics — the acquisition, management, and use of information in health — can greatly enhance the quality and efficiency of medical care and the response to widespread public health emergencies.
Apart from collecting and maintaining information, health informatics should also be put to use in improving the quality of care through new technologies. Some of those technologies will involve gathering medical data without a visit to the doctor, such as wearable devices to monitor such things as pulse and temperature. Monitoring devices might even come in the form of tiny electronic sensors embedded in clothing and within the body.
The value of information systems to help protect public safety and advance the health care of individuals is unquestioned. But, with all these new databases and technologies comes an additional challenge: protecting against the danger of compromise or misuse of the information. In developing these technologies, steps also must be taken to make sure that the information itself is not at risk of sabotage, and that personal information is not inappropriately revealed.
Doctors have long known that people differ in susceptibility to disease and response to medicines. But, with little guidance for understanding and adjusting to individual differences, treatments developed have generally been standardized for the many, rather than the few.
Beyond physical appearance, genes give rise to distinct chemistries in various realms of the body and brain. Such differences sometimes predispose people to particular diseases, and some dramatically affect the way a person will respond to medical treatments.
One engineering challenge is developing better systems to rapidly assess a patient’s genetic profile; another is collecting and managing massive amounts of data on individual patients; and yet another is the need to create inexpensive and rapid diagnostic devices such as gene chips and sensors able to detect minute amounts of chemicals in the blood.
In addition, improved systems are necessary to find effective and safe drugs that can exploit the new knowledge of differences in individuals.
New methods are also needed for delivering personalized drugs quickly and efficiently to the site in the body where the disease is localized.
Figuring out how the brain works will offer rewards beyond building smarter computers. Advances gained from studying the brain may in return pay dividends for the brain itself. Understanding its methods will enable engineers to simulate its activities, leading to deeper insights about how and why the brain works and fails. Such simulations will offer more precise methods for testing potential biotechnology solutions to brain disorders, such as drugs or neural implants. Neurological disorders may someday be circumvented by technological innovations that allow wiring of new materials into our bodies to do the jobs of lost or damaged nerve cells.
Implanted electronic devices could help victims of dementia to remember, blind people to see, and crippled people to walk.
But to fully realize the brain’s potential to teach us how to make machines learn and think, further advances are needed in the technology for understanding the brain in the first place.
Nuclear security […] represents one of the most urgent policy issues of the 21st century. In addition to its political and institutional aspects, it poses acute technical issues as well.
Engineering shares the formidable challenges of finding all the dangerous nuclear material in the world, keeping track of it, securing it, and detecting its diversion or transport for terrorist use.
Challenges [to preventing nuclear terror attacks] include: (1) how to secure the materials; (2) how to detect, especially at a distance; (3) how to render a potential device harmless; (4) emergency response, cleanup, and public communication after a nuclear explosion; and (5) determining who did it. All of these have engineering components; some are purely technical and others are systems challenges.
A possible engineering solution would be the development of a passive device, situated near a reactor, which could transmit real-time data on the reactor’s contents, betraying any removal of plutonium. (This sort of device would be especially useful if it could also detect signs that the reactor was being operated in a way to maximize plutonium production rather than power.) Such devices are already being designed and tested.
No doubt other nuclear challenges will surface and additional engineering methods will be needed to protect against the variety of possible nuclear assaults. But the ingenuity of systems and nuclear engineers, and the deep understanding of nature’s nuclear secrets provided by basic physics research, offer encouragement that those challenges can be met in the 21st century.
Personal privacy and national security in the 21st century both depend on protecting a set of systems that didn’t even exist until late in the 20th — the electronic web of information sharing known as cyberspace.
Electronic computing and communication pose some of the most complex challenges engineering has ever faced.
[Networks] of electronic information flow are now embedded in nearly every aspect of modern life. From controlling traffic lights to routing airplanes, computer systems govern virtually every form of transportation. Radio and TV signals, cell phones, and (obviously) e-mail all provide vivid examples of how communication depends on computers — not only in daily life, but also for military, financial, and emergency services. Utility systems providing electricity, gas, and water can be crippled by cyberspace disruptions. Attacks on any of these networks would potentially have disastrous consequences for individuals and for society.
The problems are currently more obvious than the potential solutions. It is clear that engineering needs to develop innovations for addressing a long list of cyber security priorities. For one, better approaches are needed to authenticate hardware, software, and data in computer systems and to verify user identities.
All engineering approaches to achieving security must be accompanied by methods of monitoring and quickly detecting any security compromises. And then once problems are detected, technologies for taking countermeasures and for repair and recovery must be in place as well. Part of that process should be new forensics for finding and catching criminals who commit cybercrime or cyberterrorism.
Finally, engineers must recognize that a cybersecurity system’s success depends on understanding the safety of the whole system, not merely protecting its individual parts. Consequently cybercrime and cyberterrorism must be fought on the personal, social, and political fronts as well as the electronic front.
[Virtual] reality is becoming a powerful new tool for training practitioners and treating patients, in addition to its growing use in various forms of entertainment.
For virtual reality systems to fully simulate reality effectively, several engineering hurdles must be overcome. The resolution of the video display must be high enough, with fast enough refresh and update rates, for scenes to look like and change like they do in real life. The field of view must be wide enough and the lighting and shadows must be realistic enough to maintain the illusion of a real scene. And for serious simulations, reproducing sensations of sound, touch, and motion are especially critical.
Young brains (and older brains, for that matter) are not all alike. Learning is personal.
In recent years, a growing appreciation of individual preferences and aptitudes has led toward more “personalized learning,” in which instruction is tailored to a student’s individual needs.
Recommender systems are widely encountered on the Web — search engines that fail to find a particular term often recommend alternatives, for instance, and pages that sell books or music will suggest additional purchases based on what someone has already bought. But such systems have not yet been developed extensively for education.
Ongoing research in neuroscience is providing new insights into the intricacies of neural processes underlying learning, offering clues to further refine individualized instruction.
In the popular mind, scientists and engineers have distinct job descriptions. Scientists explore, experiment, and discover; engineers create, design, and build.
But in truth, the distinction is blurry, and engineers participate in the scientific process of discovery in many ways. Grand experiments and missions of exploration always need engineering expertise to design the tools, instruments, and systems that make it possible to acquire new knowledge about the physical and biological worlds. In the century ahead, engineers will continue to be partners with scientists in the great quest for understanding many unanswered questions of nature.
In its profundity, only one question compares with that of consciousness — whether the universe is host to forms of life anywhere else than on Earth. Systems capable of probing the cosmos for evidence surely represent one of engineering’s grandest challenges.
All things considered, the frontiers of nature represent the grandest of challenges, for engineers, scientists, and society itself. Engineering’s success in finding answers to nature’s mysteries will not only advance the understanding of life and the cosmos, but also provide engineers with fantastic new prospects to apply in enterprises that enhance the joy of living and the vitality of human civilization.