ENERGY - A Unifying Concept
If we view everything from the perspective of energy, a pattern emerges showing not just how everything in science is interrelated, but how natural resources, labor, capital, science and energy are all intertwined.
We could start from a historical point of view, tracing the path from the greatest event in energy for each century to where we are today (e.g., from 1635 to 2000), or we can look at short term trends.
Taking the reverse approach and working from the current into the historical shows another pattern with the diverse strands' interrelationships.
Or we could start with the science of patterns and explain the interrelationships with equations, just as Einstein did in his early 20th Century seminal treatise, "Special Theory of Relativity." These mathematical equations provide the starting point for many aspects of today’s comfort and our progressively longer lives. Patterns sewn by Einstein include the notion that energy is neither created nor destroyed, but can be transformed between its different forms.
Energy BasicsAnother way to build a pattern is to start with energy basics - virtually everything everyone should know about energy and why we need it. Let's try to keep these basics in perspective. Energy is close to the root of theoretical and applied physical and life sciences (e.g., electricity, materials research and bioscience research), engineering (e.g., power for the future), economics (e.g., consumer prices), and local/global politics (e.g., climate change, energy supply, nuclear weapons).
Energy is essential to a broad spectrum of important theoretical scientific concepts: heat flows, kinetic energy, enthalpy, entropy, the Law of Conservation of Energy, and the Laws of Thermodynamics. Electrical energy and magnetic energy can be converted back and forth. Through e=mc2 the ideas of mass and energy are unified - mass and energy can be converted into each other. Energy comes in a variety of forms: heat, light, mechanical, electrical, chemical, and atomic - and some can be transformed into another. Before 1997, the concept of "dark energy" did not exist, but now its influence on the expansion of the universe is being explored. Energy is integral to understanding the physical sciences, life sciences, and engineering. Energy in astrophysics, quantum theory and atomic blasts are expressed with exotic math symbolism (e.g., Riemann vectors/tensors), while the trajectories of spacecraft relies on fuel energy inputs to calculations using Newtonian physics and calculus.
Energy impacts all sectors of all economies, both internationally and domestically. Energy prices have historically been tied directly to oil prices. Energy affects us economically on a daily basis through our food, weather, consumer prices, and transportation. All of these are linked to the oil market. The United States of America is the world's largest energy producer, consumer, and net importer of oil, natural gas, coal, and electricity. It also ranks twelfth worldwide in reserves of oil, sixth in natural gas, and first in coal. Adequate, safe and inexpensive energy resources and production are available in the U.S., but this is not true everywhere. Energy resources will be needed for the future - more so in some ways and places than others.
The Earth's surface has received most of its energy from the sun. Through photosynthesis, solar energy was stored three hundred or so millions of years ago. Geological epochs changed these into fossil fuels that serve as today's energy resources - long before the dinosaurs existed. As these nonrenewable fuels are mined and burned by industrial engineers, the heat is used directly or converted into electricity. Power from water flowing through generators at hydroelectric dams provides the largest source of renewable energy, but these dams primary function continues to be flood control. Solar energy is now used in areas with distant electrical distribution systems. Renewable fuels (i.e., hydroelectric, geothermal, wind, solar thermal, solar photovoltaics, biomass - wood, municipal solid waste and landfill gas) have limitations that make them useful in niche markets, but keep them from having a dominant share of the market for electricity. In Fourth World Nations, wood and biomass still supply most of the energy to residences, while right now natural gas is the most widely burned residential fuel in the U.S.
Finite resources are depleted as fossil fuels are consumed/ burned - and waste products are created. There is a relationship between greenhouse gases, global climate change, and energy. The products of combustion affect our environment (e.g., as precursors to ozone - a health hazard) and change our climate (from increased carbon dioxide and water vapor). Waste products/pollutants may be diluted and dispersed, disposed of, isolated behind engineered barriers, or converted into something useful. Carbon dioxide from fossil fuel combustion might be sequestered. Oil spills waste a finite resource while polluting the environment. But most of the oil that is spilled does not come from major tanker accidents - it comes from "pours", oil that is poured down the drain. Energy conservation is important. For these reasons, converting from a carbon-fuel based economy to a hydrogen-fuel based over the next 20 to 50 years makes sense. Fuel cells will convert hydrogen's energy into electricity, produce clean energy, and conserve natural resources.
Energy conservation has ripple effects. Energy audits of homes and schools identify ways to use energy more wisely - and reduce expenses. Weatherization programs reduce houses energy leakage - and bills. Switching from private vehicles to public transportation or to alternative fueled vehicles reduces foreign oil imports by switching to domestic alternative transportation fuels - and reduces personal flexibility. Recycling energy-intensive items (e.g., copper, aluminum cans, homes, cars) conserves energy, saves on natural resources, and reduces municipal solid waste (garbage) - but requires additional attentiveness and rethinking of old habits. Cogeneration facilities save money by generating both electricity and hot water for nearby commercial and industrial companies. Normally, large-scale electricity generation plants waste about two-thirds of the energy by dissipating it. Pollution reduction often requires more energy than before, but new equipment may be both more efficient and less polluting. Corporate profits may increase as energy-efficient technologies are put into place - but these profits may decrease as emissions controls are implemented and energy consumption grows. Exchanges between two companies, "green twinning", may send one's waste streams to the other company's nearby plant for use as a resource, saving both companies money while reducing waste. Conservation and efficiency affect our environment and the life styles of future generations.
We put energy into our work and play. When we run out of energy at the end of a wearying day, we sleep. While we will be dependent on fossil fuels for many decades, the Earth is far from running out of energy. Hydrogen fuel cells generate electricity and are being tested in cars, buildings and buses. Reforming domestic fuels into hydrogen for fuel cell powered electric cars means decreasing our dependence on imported transportation fuels. Advanced natural gas turbines and coal combustion technologies are significantly more efficient in electricity production than they were a few years ago. Cogeneration plants are saving money and fuel. Solar energy is good for four or so billion years. Wind power is the fastest growing source of renewable electricity. Biomass energy is derived from three distinct energy sources: wood, waste, and alcohol fuels. Biomass fuels are being researched. Alternative transportation fuels are being developed. Nuclear fusion is getting closer to the goal of being sustainable. While the extent of oil reserves are being debated, enhanced recovery of both oil and natural gas is happening. Gas hydrate resources dwarf all other known fossil fuels - but it may take more energy to get them than they are worth. Geothermal energy is available for heat pumps everywhere. Hot hydrothermal resources for geothermal electricity production are extremely rare, but are still being sought. Renewable energy may get a boost as consumers demand "green electricity" in the deregulated electricity industry. Most fuels should be available for at least the next several decades before becoming dramatically depleted.
Work is important to all States and sectors of our economy (i.e., residential, commercial, transportation, industrial and government sectors). Households consume electricity, natural gas and other fuels to heat, cool, and cook. Commercial markets keep farm products cool, extending their shelf life. Demand for gasoline and diesel fuel has led to a dependence on imported petroleum. Profitable industries have been developed just to find, transform, and market energy resources. Stock market prices fluctuate as oil prices go up and down. Governments have fought wars to acquire and protect energy resources. Politicians have curried votes by promising to keep energy taxes at bay. Federal and State laws have been passed to ensure employee safety (e.g., in coal mines), plan for future energy supplies, and fund energy research (e.g., fusion).
Personal, local and national economies depend on natural resources, labor, capital, and energy (not always in that order). If one of the four is unavailable, unreliable - or becomes too expensive, life gets tougher as productivity slows down and incomes decline. No energy means no jobs. The U.S., with roughly 5% of the world’s population, consumes about one-fourth of the world’s annual energy supply, while the poorest countries (with 64% of all people) consume less than 5%. Average U.S. per capita consumption of energy exceeds that of all others - while U.S. gasoline taxes and prices are the lowest of all industrialized nations.
Everything we buy has had a finite level of energy invested into it. While an estimate of an energy investment may not be known for historical items (e.g., your home, your car), this is not so with the newest projects (e.g., new aircraft). Energy life-cycle roadmaps are being included in plans for:
Implementation of each roadmap calls for planning, then investing in and unifying a broad range of scientific, engineering and economic knowledge, skills and abilities. Maintaining and conserving energy invested into real goods will become increasingly important.
Energy is very personal, supplying fuel to our bodies, hand held games and air conditioners. Energy cleans and pumps our drinking water, makes fertilizer for crops, powers plowing of fields, and then transports our food to supermarkets. Energy makes our lives comfortable.
Work (i.e., whatever moves or changes in our world) does so by the use of a force we call energy. Cheap and readily available energy allows work to be done efficiently, safely and quickly. Research into energy supports growth in this direction, as does education about efficient consumption of energy - and minimization of waste.
1. The "National Science Education Standards", (1996, National Academy Press, ISBN 0-309-05326-9) identifies energy as central to "unifying concepts in science". These standards were prepared by the National Research Council of the National Academies of Science, Engineering and Medicine.2. Concepts:
En-er-gy (en'er-ge) n. pl.
-gies. 1. a. Vigor or power in action. b. Vitality and intensity of expression.
2. The capacity for action or accomplishment: lacked energy to finish the job.
3. Physics. The work that a physical system is capable of doing in changing from
its actual state to a specified reference state, the total includes, in general,
contributions of potential energy, kinetic energy, and rest energy. 4. Usable
heat or electric power [LLat. energia < Gk. energeia <energos, active:
en-. at + ergon, work.].
Atomic Forces: At the atomic
level in science there are only four kinds of forces:
gravity, the electromagnetic force,
and the subnuclear forces called the strong force and the weak force.
3.
Energy Transformation:
Energy is neither created nor
destroyed, but can be transformed between its different forms.Classically, there
have been six forms of energy: heat, mechanical, electrical, chemical, light and
nuclear. Chemical energy can be released (through combustion) into heat from
coal, natural gas and oil. This heat can be transfrerred to steam. Energy from
steam can be transformed from mechanical energy into electricity through a
dynamo. Chemical energy can be stored in batteries before being converted into
electricity. Fuel cells convert chemical energy directly into electricity
without combustion. Light energy can be converted into chemical energy through
photosynthesis and directly into electricity through photovoltaics. Nuclear
energy can be converted into heat for steam and electricity. Electrical energy
can be transformed into mechanical energy in electrical appliances.
4. Roots of Theoretical and Applied Physical Sciences:
Structure of atoms; structures and properties of matter; chemical reactions;
motions and forces; conservation of energy and increase in disorder; and
interactions of energy and matter.
5. Roots of
Theoretical and Applied Life Sciences:
The cell; molecular basis of
heredity; biological evolution; interdependence of organisms; matter, energy and
organization in living systems; and behavior of organisms.
6. Roots of Theoretical and Applied Engineering:
Torques,
stresses, impulses - both physical and electrical.
7. Energy has a variety of units of measure (e.g.,
calories, temperature, Btu) expressed in different systems (i.e., International System of
Units (SI) and British/American), with some terms having different meanings
in different systems (e.g., how big is a
barrel?).
8. Unless, of course, there is some
major oil or economic disruption. The Strategic Petroleum Reserve (SPR) is the
nation's first line of defense against an interruption in petroleum supplies.
As of September 11, 2004.
By Jim Disbrow
U.S. Department of Energy (DOE)