Energy why do we need it

Course Introduction Taught By. Michael J. Orlando Lecturer. Try the Course for Free. Explore our Catalog Join for free and get personalized recommendations, updates and offers. Get Started. Learn Anywhere.

Over the past century, dependence on vehicles burning petroleum-based fuels has become a defining component of American life, bringing countless benefits. Indeed, whenever any fossil fuels are burned, carbon dioxide is released into the atmosphere, where it functions as a heat-trapping greenhouse gas.

Efforts are already well under way to find suitable alternatives to oil. The federal government has an aggressive program to encourage its production.

As a result, in about 4 billion gallons of fuel ethanol mixed with gasoline hit the domestic market. But in the same year, the United States consumed about billion gallons of gasoline and 40 billion gallons of diesel fuel, so ethanol accounted for only a small percentage of the total gasoline pool. Ethanol raises other concerns. One drawback of corn ethanol production is that it requires a large amount of land and fresh water, along with inputs of fertilizers and energy.

This results in potential competition with food sources for land use and fresh water for other industrial and commercial uses. In addition, with current technology, two-thirds of the energy value of corn ethanol is used just to produce the fuel—and most of that energy comes from fossil-fuel-based electricity or heating, offsetting much of the benefit.

Unlike oil, our natural gas comes primarily from North America. The annual volume of consumption is projected to rise from New activity in Alaska will supply some of that, but most will likely come from the lower 48 states and the Gulf of Mexico. These imports will largely take the form of liquefied natural gas, which is natural gas cooled to its liquid phase, making it easier to transport. Global consumption of natural gas in was TCF. Known world reserves of conventional natural gas total about 6, TCF, with perhaps another one-tenth of that amount still undiscovered.

At that rate, known reserves will be adequate for about 60 years. Like all fossil fuels, its combustion emits carbon dioxide, but at about half the rate of coal.

America has plenty of coal. Its mines produced 1. That was a record year, but it barely scratched the surface of U. More than one-fourth of the total known world coal reserves are in the United States, and supplies are sufficient for hundreds of years at current consumption rates. Of all the fossil-fuel sources, coal is the least expensive for its energy content. However, burning coal in electric power plants is a major source of CO2 emissions, and its use has repercussions beyond combustion.

Mining coal disturbs the land and modifies the chemistry of rainwater runoff, which in turn affects stream and river water quality. Coal-fired power plant emissions include oxides of nitrogen, sulfur dioxide, particulate matter, and heavy metals such as mercury that affect air quality and human health, often even hundreds of miles from the power plant. Use of renewable energy sources will increase, in some cases dramatically, over the next two decades.

While they may make significant contributions to the energy supply in certain geographic areas, absent major changes in economic, political, or technological factors, they will still provide a small fraction of our overall energy. Energy from wind, solar, and other renewable sources is expected to nearly triple.

Hydroelectric production currently accounts for about 2. The idea of drawing our energy from sources that are renewable, are independent of foreign nations, and do not emit greenhouse gases has powerful appeal. But capturing these resources is expensive, and many are intermittent, or sporadic, which complicates using them on a large scale.

Further development promises reduced costs and improved storage and controls to overcome the intermittency problem. America is unlikely to face problems in obtaining enough uranium ore to meet anticipated demand for several decades. However, a U. In the United States, the issue prompts considerable debate, including concern over security and arguments about where and how to dispose of nuclear waste.

Even with renewed U. According to the Council on Foreign Relations, known worldwide reserves are adequate for about 70 years at current consumption rates and under current policies. This figure depicts the flow of energy, measured in quadrillion 1 million billion BTUs, across the energy system of the United States for , based on data from the Energy Information Administration of the U. Department of Energy. The chart illustrates the connections between primary energy resources fossil, nuclear, and renewables , shown at the far left, and end-use sectors categorized into residential, commercial, industrial, and the three principal components of transportation: cars, freight, and aviation.

Electricity, a carrier derived from primary resources, powers the sectors to varying degrees and is positioned closer to the middle of the chart to display its inputs and outputs. This enables hydro, wind, and solar to be counted on a similar basis as coal, natural gas, and oil.

For this reason, the sum of the inputs for electricity differs slightly from the displayed total electricity output. Given the anticipated growth in every U. And other countries are poised to experience increases in energy use as they become more industrialized and improve their standard of living.

Can the United States actually meet its growing needs? It remains to be seen. The demand for energy has not been growing as rapidly as the economy, resulting in a significant drop in what is called energy intensity. At present, Americans use about half as much energy per dollar of Gross Domestic Product GDP —the total market value of all the goods and services produced in a country during one year—as they did in Were it not for this development, the U.

Energy-efficiency investments and structural shifts in the economy away from energy-intensive industry and toward service and information-based jobs have both contributed to the phenomenon. So have engineering improvements in scores of systems, from automobile engines to building insulation to electric power-generating facilities.

This trend is expected to continue. The EIA projects that by Americans will be using only slightly more energy per capita than they did in —but less than half as much per dollar of GDP. Continuing this downward trend in energy intensity depends in part on the nation taking advantage of numerous opportunities for efficiency advances in current technology.

Fortunately, recent history provides ample evidence that efficiency research and education can pay enormous dividends. Reducing demand through the improved efficiency of devices and procedures achieves the same effect. The use of electricity is a dramatic example. During the s, total U. In the s, it grew only 2. Current projections are 1. That trend is partly a result of ongoing improvements in efficiency.

Similar progress is visible in nearly every sector of the economy as a result of independent technological breakthroughs, directed research, government mandates and incentives, consumer education, or a combination of these elements. One of the most impressive efficiency successes in modern memory is the result of the federal Corporate Average Fuel Economy CAFE standards established in CAFE standards stipulated that the average fuel economy for new passenger cars would be The U.

Department of Transportation later stipulated that the average for light trucks would be This legislation will further push technology, leading to greater fuel economy and reducing fuel consumption in the fleet. Automotive technology also demonstrates how developments and breakthroughs in fields unrelated to energy can have a profound effect on the energy sector. The electronics and computer revolutions of the s and s, which continue to this day, led to the development of very small sensors and computers.

In addition, the ability to develop new materials such as catalysts—substances that prompt chemical reactions—led to ways to cut down on the pollutants in automobile exhaust and in power plants.

Putting these technologies together into systems on automobiles has led to more efficient automotive drivetrains, more power, better control, and lower emissions. The continuing development of electronics, small electric motors, sensors, and computers is also contributing to the advancement of hybrid electric vehicles. Improved understanding of the combustion of fuels in the engine has led to more efficient engine technologies. At present, there are advanced technologies that have the potential to improve vehicle fuel economy substantially, but at a higher cost.

Refrigeration provides another case in which targeted research produced remarkable results: a reduction of more than two-thirds in the energy consumed by the household refrigerator during the past 30 years.

In , the average consumption per unit was 1, kilowatt-hours per year, and average sizes were increasing as well. The effort began to pay off almost immediately. By the early s, electricity consumption per refrigerator had dropped by one-third and new developments kept coming. Even the changeover from ozone-threatening chlorofluorocarbons CFCs did not impede progress. Today there are still enormous opportunities for efficiency gains across a wide range of products and processes.

Major research efforts are in progress to reduce those costs by using the same technology that now creates the glowing lights on appliances: the light-emitting diode LED. They produce illumination by allowing electrons to flow across an electrical junction the diode and drop into a lower energy state, releasing the difference as light. Additionally, they do not require bulky sockets or fixtures and could be embedded directly into ceilings or walls. At present, such systems are too expensive for broad commercial use.

But if they can be made affordable, the effect will be dramatic. Other researchers are exploring ways to make industrial and manufacturing processes much more efficient. In particular, processes used to separate chemicals and to enable chemical reactions are being evaluated for possible savings. A similar effort is under way in analyzing the energy intensive forest products industry. Researchers have identified enhanced raw materials, next-generation mill processes, improved fiber recycling, and wood processing as candidates for improvements in efficiency.

Multiple parallel efforts will be needed, and that recognition has prompted intense interest in a wide variety of new technologies.

Some will require substantial improvements—or even research breakthroughs—to have a major impact on our energy budget. The following are some of the options. Consortia of companies are working with the Nuclear Regulatory Commission to secure federal approval for these types of nuclear power plants, and several utilities recently requested approval of a combined construction and operating license.

Longer term advances could broaden the desirability and future use of nuclear energy. The goals of these efforts are to improve the economics, safety, fuel-cycle waste management, and proliferation resistance of nuclear reactors, as well as widen their applications. DOE is pursuing the demonstration of one such design, a very-high temperature reactor, through its Next Generation Nuclear Plant program, and the facility is scheduled to begin operations by In theory, it could be much more.

In practice, it will require considerable scientific and engineering progress in the two ways of converting the energy of sunlight into usable forms. Photovoltaic PV systems exploit the photoelectric effect discovered more than a century ago. In certain materials, the energy of incoming light kicks electrons into motion, creating a current.

Sheets of these materials are routinely employed to power a host of devices from orbiting satellites to pocket calculators, and many companies make roof-sized units for homes and office buildings. At the present time, however, the best commercial PV systems produce electricity at five to six times the cost of other generation methods. Furthermore, unless PV energy is consumed immediately, it must be stored in batteries or by some other method.

Adequate and cost-effective storage solutions await development. One factor favoring PV systems is that they produce maximum power close to the time of peak loads, which are driven by air-conditioning. Transporting and storing Uses of hydrocarbon gas liquids Imports and exports Prices. Also in Natural gas explained Natural gas Delivery and storage Natural gas pipelines Liquefied natural gas Where our natural gas comes from Imports and exports How much gas is left Use of natural gas Prices Factors affecting natural gas prices Natural gas and the environment Customer choice programs.

Also in Coal explained Coal Mining and transportation Where our coal comes from Imports and exports How much coal is left Use of coal Prices and outlook Coal and the environment. Renewable sources. Renewable energy. Biofuels: Ethanol and Biomass-based diesel. Also in Hydropower explained Hydropower Where hydropower is generated Hydropower and the environment Tidal power Wave power Ocean thermal energy conversion.

Also in Biofuels explained Biofuels Ethanol Use and supply of ethanol Ethanol and the environment Biomass-based diesel fuels Use of biomass-based diesel fuel Biomass-based diesel and the environment. Also in Wind explained Wind Electricity generation from wind Where wind power is harnessed Types of wind turbines History of wind power Wind energy and the environment.

Also in Geothermal explained Geothermal Where geothermal energy is found Use of geothermal energy Geothermal power plants Geothermal heat pumps Geothermal energy and the environment. Also in Solar explained Solar Photovoltaics and electricity Where solar is found and used Solar thermal power plants Solar thermal collectors Solar energy and the environment.

Secondary sources. Also in Electricity explained Electricity The science of electricity Magnets and electricity Batteries, circuits, and transformers Measuring electricity How electricity is generated Electricity in the United States Generation, capacity, and sales Delivery to consumers Use of electricity Prices and factors affecting prices Electricity and the environment. Also in Hydrogen explained Hydrogen Production of hydrogen Use of hydrogen. Energy is the ability to do work Scientists define energy as the ability to do work.

There are many different forms of energy, including Heat Light Motion Electrical Chemical Gravitational These forms of energy can be grouped into two general types of energy for doing work: Potential or stored energy Kinetic or working energy Energy can be converted from one form to another. Energy sources can be categorized as renewable or nonrenewable There are many different sources of energy , which can be divided into two basic categories: Renewable energy sources that can be easily replenished Nonrenewable energy sources that cannot be easily replenished Renewable and nonrenewable energy sources can be used as primary energy sources to produce useful energy such as heat, or they can used to produce secondary energy sources such as electricity and hydrogen.