chapter  14
4 Pages

The twelve-terawatt challenge

We have recently welcomed the seven-billionth person to our planet. Collectively, we use enough energy in the course of a year such that, converted to an annual rate of using power, the global consumption by all of us is twelve terawatts (TW), or 12,000,000,000 kilowatts. In comparison, a human metabolism operates at around eighty watts. A superbly trained athlete at peak condition performing at his or her optimum, might be able to produce about 500 watts. The energy used for all the interior processes inside the Earth, including the motion of portions of continents, is about 40 TW. Right now, our annual consumption of power is between a quarter to a third of all the processes inside our planet. A volcanic eruption can release about 50 TW, and an enormous earthquake even more. The 2004 earthquake in the Indian Ocean, which produced a devastating tsunami, may have released 2000 TW. However, earthquakes and volcanoes are very short-term events on our human time scale, and are a mere moment on a geological time scale. Our consumption of 12 TW goes on all the time, all day every day. In today’s world a very large fraction of humanity lacks access to

some, or all, of the crucial necessities of life-clean water, adequate nutrition, shelter, enough education for literacy, basic health care. Roughly, between a third and half of the world’s population lacks

access to at least one of these services, and often access to more than one. Suppose we were to try to lift all of the world’s population to a level at which any person, any place, could reasonably expect to have safe and warm shelter, drinking water, enough food, and access to a school and a clinic. This does not mean providing everyone with the resources to use energy at the prolifigate scale, such as the energy consumption in the United States, but to a level of a rather modest standard of living that would at least assure health, nutrition, and safety. Doing only this job will require about twelve more terawatts. One way of formulating the twelve-terawatt challenge is this: Where are we going to get the ‘extra’ twelve terawatts? During my career, I have been fortunate to meet executives and

senior managers from many energy industries and government agencies. When the topic comes up of addressing future energy needs, all of them, regardless of personal professional interests, have said almost exactly the same thing: We’re going to need everything. In other words, every energy resource we have available will have to be mobilized to meet the future energy needs, and expectations, of the ever-growing world population. In mobilizing all the world’s energy resources, we need to keep

three things in mind. First, every energy source has some technical advantages, and some technical disadvantages. Second, every energy source has an impact on the environment, and may have some advantages or benefits for the environment as well. And third, every energy source has some economic advantages, and some economic disincentives. These facts mean that all of us, not just professional workers in

energy science and engineering, have to understand how to navigate between the technical advantages and disadvantages, the environmental impacts and benefits, and the economic incentives and disincentives, to arrive at a mixture of energy sources for wherever we happen to live that provide a reasonable balance among reliability, affordability, and impact on the environment. There is no ‘one size fits all’ solution to energy needs. Further, addressing the many aspects of the twelve-terawatt challenge is going to require the efforts not only of scientists and engineers, but also sociologists, political scientists, economists, historians, anthropologists, and people from many other disciplines or areas of

expertise. In other words, not only are we going to need everything, we’re going to need everybody. Improving standard of living, at least in terms of GDP, requires

improving per capita energy consumption (recall Figure 1). As developing countries continue to improve their standards of living, their energy use will inevitably increase. If everyone on the planet enjoyed a standard of living comparable to that in many European countries, the collective power used would be somewhere around 40 TW. This scenario is highly unlikely, because raising everyone’s standard of living to that of Europe would require an international humanitarian effort on a scale unprecedented in history. But, as population expands, more people will necessarily consume more energy. Continued population growth coupled with improved standards of living means that it’s not unlikely that a time will come when we humans generate as much power as does the planet itself (i.e., 40 TW). The energy source that is certain to last beyond the lifetime of

the human species is solar energy. The solar energy flow to our planet is so large that, if it could all be captured and transformed to useful work, we could satisfy our current annual energy needs with forty-five minutes’ worth of incoming solar energy. Perhaps continued improvements in photovoltaic energy conversion, continued with development of improved rechargeable batteries (including reduction in the cost of both), would allow deployment of decentralized, small-scale photovoltaic + battery systems almost anywhere in the world. These systems would allow any impoverished society to bypass steam turbines, large central electricity-generating stations, the electricity grid, and all their assorted paraphernalia. Small, simple, decentralized, inexpensive electricity generation

offers advantages that could provide immediate improvements in quality of life: electric lights and electric motors. Lighting provides safety for working or being outdoors after dark. It provides a way to read after dark, which means that even people who must work full time could study during the evening, toward improving themselves or possibly moving into a better job. Electric motors can operate water pumps, for improved watering of livestock and irrigation of crops. Electric motors can operate refrigerators and freezers. Another vital application of a refrigerator is that many medicines and vaccines need to be refrigerated. Being able to do

this in remote rural villages can have an immediate impact on public health. John Hofmeister, former president of Shell Oil Company and

current head of the US-based organization Citizens for Affordable Energy, has described the solutions to future energy needs in terms of the ‘four mores.’1 These are more energy from all sources; more efficiency in producing and using energy; more environmental protection; and more infrastructure-the technologies to transport or transmit energy from wherever it is produced to the places where it is needed to be used. Without doubt we will need more energy. We can start getting

more simply by doing a better job of what we’re doing already, just increasing the efficiency of how we do it. We will need to increase the contribution from energy sources that today are relatively small contributors in many places-wind, water, and biofuels, as examples. We need new ideas in energy science and new breakthroughs in energy technology. And perhaps the ultimate challenge is that we need to find these additional twelve terawatts without destroying our environment. Finally, we can all profit from the advice of one of the great

figures of our time, Nelson Mandela: ‘The world remains beset by so much human suffering, poverty, and deprivation, it is in your hands to make of our world a better one for all.’