Why Energy is Required in Every Aspect of Human Activity and forms of Energy

 

WHAT IS ENERGY AND WHY IS ENERGY REQUIRED IN EVERY ASPECT OF HUMAN ACTIVITY?

What is Energy?

The term energy can be generally defined as the amount of force or power when applied can move one object from one position to another, or it defines the capacity of a system to do the work. The energy can have many forms such as kinetic, potential, electromagnetic, nuclear, sound, light or photoenergy, and gravitational. The most important characteristic of energy is the possibility to convert one of its forms to another. This can be done naturally (e.g. chemical reactions) or artificially through man-made energy technologies (e.g. hydropower generators). In the later energy conversions, the energy technologies convert a naturally available form of energy to a specific desired form such as electricity or heat.

    Why is Energy Required in Every Aspect of Human Activity?

Energy is one of the most important needs of humans in daily lives and has been for decades, perhaps millenniums. Once the things we cannot do without energy is considered, energy becomes of great importance and is becoming increasingly vital as technology advances progressively. We divide our energy use among four economic sectors:

Ø Residential,

Ø Commercial,

Ø Transportation, and

Ø Industrial.

 

Heating and cooling our homes, lighting office buildings, driving cars and moving freight, and manufacturing the products we rely on in our daily lives are all functions that require energy. If projections are correct, we’re going to keep needing more.

 

v Home & Work:

We use energy in homes and commercial buildings in similar ways. We keep rooms at a comfortable temperature, illuminate our spaces, heat water for bathing and laundry, and depend on computers, copiers, appliances, and other technologies.

v Transportation:

The transportation sector includes many modes, from personal vehicles and large trucks to public transportation (buses, trains) to airplanes, freight trains, ships and barges, and pipelines. By far the largest share is consumed by cars, light trucks, and motorcycles, followed by other trucks, aircraft, boats and ships, and trains and buses as well as Pipelines.

v Industry:

Every product on which we rely—from gasoline and automobiles to food, buildings, machinery, and appliances—takes energy to produce. The use of energy in industry affects every single citizen directly through the cost of goods and services, the quality of manufactured products, the strength of the economy, and the availability of jobs.

The industrial sector uses energy in many ways. One major application involves raising the temperature of components in the manufacturing process, which is called process heating. Refining crude oil, where heat is used to separate various distillates, is an example of this. Another common use of energy in industry is to heat a boiler that generates steam or hot water.

A few industries use a very large share of energy in the industrial sector. Petroleum refining is the principal consumer, with the chemical industry a close second. Those users, plus the paper and metal industries, account for 78% of total industrial energy use.

Industry and manufacturing rely heavily on natural gas, petroleum  and other liquids, and electricity, with coal, renewables, and biofuels  making up the rest.

 

THE VARIOUS FORMS OF ENERGY AVAILABLE TO MAN, HOW THEY ARE HARNESSED AND UTILIZED.

Many forms of energy exist, but they all fall into two basic categories:

Ø     Potential energy

Ø     Kinetic energy

POTENTIAL ENERGY:

Potential energy is stored energy and the energy of position. The following forms of energy fall into the potential energy category;

Chemical energy is energy stored in the bonds of atoms and molecules. Batteries, biomass, petroleum, natural gas, and coal are examples of chemical energy. Chemical energy is converted to thermal energy when people burn wood in a fireplace or burn gasoline in a car's engine.

Mechanical energy is energy stored in objects by tension. Compressed springs and stretched rubber bands are examples of stored mechanical energy.

Nuclear energy is energy stored in the nucleus of an atom—the energy that holds the nucleus together. Large amounts of energy can be released when the nuclei are combined or split apart.

Gravitational energy is energy stored in an object's height. The higher and heavier the object, the more gravitational energy is stored. When a person rides a bicycle down a steep hill and picks up speed, the gravitational energy is converting to motion energy. Hydropower is another example of gravitational energy, where gravity forces water down through a hydroelectric turbine to produce electricity.

KINETIC ENERGY:

Kinetic energy is the motion of waves, electrons, atoms, molecules, substances, and objects. The following forms of energy fall into the Kinetic energy category;

Radiant energy is electromagnetic energy that travels in transverse waves. Radiant energy includes visible light, x-rays, gamma rays, and radio waves. Light is one type of radiant energy. Sunshine is radiant energy, which provides the fuel and warmth that make life on earth possible.

Thermal energy, or heat, is the energy that comes from the movement of atoms and molecules in a substance. Heat increases when these particles move faster. Geothermal energy is the thermal energy in the earth.

Motion energy is energy stored in the movement of objects. The faster they move, the more energy is stored. It takes energy to get an object moving, and energy is released when an object slows down. Wind is an example of motion energy. A dramatic example of motion energy is a car crash—a car comes to a total stop and releases all of its motion energy at once in an uncontrolled instant.

Sound is the movement of energy through substances in longitudinal (compression/rarefaction) waves. Sound is produced when a force causes an object or substance to vibrate. The energy is transferred through the substance in a wave. Typically, the energy in sound is smaller than in other forms of energy.

Electrical energy is delivered by tiny charged particles called electrons, typically moving through a wire. Lightning is an example of electrical energy in nature.

2.1  How Are These Energies Harnessed And Utilized?

Geothermal

Geothermal energy is produced by the heat of Earth’s molten interior. This energy is harnessed to generate electricity when water is injected deep underground and returns as steam (or hot water, which is later converted to steam) to drive a turbine on an electric power generator.

 

Moderate- to low-temperature geothermal resources are also used to heat buildings directly and to provide space heating through district heating systems in which heat is distributed to residences and commercial buildings from a central source.

Wind

Wind energy is an indirect form of solar energy created by a combination of factors, including the uneven heating of Earth’s atmosphere by solar radiation, variations in topography, and the rotation of Earth. People have been putting wind energy to use throughout history to propel sail boats, mill flour from grain, and pump water. Today the wind-induced mechanical power of huge multi-blade rotors—sweeping circles in the air as much as 100 meters in diameter—is routed to generators that produce electricity.

Solar

Sunlight is Earth’s most abundant energy source and is delivered free of charge. Yet harnessing sunlight’s energy content directly—rather than indirectly in fossil fuels, wind, or hydroelectric power—makes only a small contribution to humanity’s energy supply. In practice, it will require considerable scientific and engineering progress in the two ways of converting the energy of sunlight into usable forms.

Photovoltaic Photovoltaic (PV) Cell sometimes referred to as a solar cell, a device that utilizes the photoelectric effect to convert incident sunlight directly into electricity. This can be distinguished from solar thermal energy, which is sometimes used to create electricity indirectly. (PV) systems work because PV materials absorb the energy in photons of certain wavelengths and release electrons, which can be collected into 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. The current capacity is limited by two factors. One is the efficiency of PV materials, the other is the cost of PV modules.

However, PV is an intermittent source, available only when the Sun is shining. 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 demand, which is driven by air conditioning. Peak power is much more expensive than average power. With the advent of time-of-day pricing for power, PV power could grow more economical. Sunlight can also be focused and concentrated by mirrors and the resulting energy employed to heat liquids that drive turbines to create electricity—a technique called solar thermal generation. Unlike PV chips, which only respond to certain wavelengths in sunlight, solar thermal generation uses the entire solar spectrum. Existing systems produce electricity at about twice the cost of fossil-fuel sources.

Biomass

Biomass is biological matter that can be used as fuel or for industrial production, and it makes a major contribution to the nation’s renewable energy portfolio. Although the term is perhaps most familiar in the context of corn ethanol that is added to gasoline, biomass has many applications.

Wood, which makes up about half of all biomass employed for energy, has been used by people for thousands of years to cook food and to keep warm. Grasses, agricultural crops (such as corn and sugar cane), landfill waste, and manure are other examples of biomass. Used for a variety of purposes, biomass provides energy to produce electricity, heat, chemicals, and transportation fuels (biofuels). It makes small contributions to each of the economic sectors, but the majority of this energy source goes to industry.

Hydroelectric

Hydroelectric energy depends on the availability of suitable waterways and facilities. There are several benefits that make hydropower appealing. For example, unlike other renewable energy sources, such as wind and solar, hydropower is not intermittent.

Future hydropower technologies may include devices which can harness energy from waves, tides, ocean currents, and marine thermal gradients. However, attempts to tap wide swaths of ocean or coastal straits and embayments for harvesting energy will run into challenging social or economic barriers (e.g., entrenched uses such as fisheries and shipping lanes or environmentally sensitive areas) as well as technology, materials, and engineering issues (e.g., proximity to utility infrastructure, survivability).

The current contribution of such technologies to our energy supply system, however, is extremely small. Nevertheless, the promise of expanding our hydropower resources to include these additional renewable, non-intermittent, and emissions-free sources of energy remains very appealing.