Energy is the capacity to do work. Energy comes in various forms, such as motion, heat, light, electrical, chemical, nuclear energy, and gravitational. Total energy is the sum of all forms of the energy a system possesses. In the absence of magnetic, electrical and surface tension effects, the total energy of a system consists of the kinetic, potential, and internal energies. The internal energy of a system is made up of sensible, latent, chemical, and nuclear energies. The sensible internal energy is due to translational, rotational, and vibrational effects of atoms and molecules.
Thermal energy is the sensible and latent forms of internal energy. The classification of energy into different ‘‘types’’ often follows the boundaries of the fields of study in the natural sciences. For example, chemical energy is the kind of potential energy stored in chemical bonds, and nuclear energy is the energy stored in interactions between the particles in the atomic nucleus. Microscopic forms of energy are related to the molecular structure of a system and they are independent
of outside reference frames.
Primary energy is the energy extracted or captured directly from the environment.
Three distinctive groups of primary energy are:
• Nonrenewable energy (fossil fuels): coal, crude oil, natural gas, nuclear fuel.
• Renewable energy: hydropower, biomass, solar energy, wind, geothermal, and
Potential energy is associated with forces that act on a body in such a way that depending on the initial and final positions of the body, the amount of work done on the body can be calculated. These forces, known as potential forces, can be represented at any point in space by vectors that are gradients of the scalar quantity known as potential.
Kinetic energy is something that can be transferred between objects and changed into other kinds of energy. For example, a flying squirrel might bump into a stationary pigeon. After the collision, there would be an initial kinetic energy of the squirrel that gets transferred into the pigeon or transformed to some other form of it.
Kinetic energy is a scalar quantity, so it does not have a set direction. Contrary to velocity, force, acceleration, and momentum, the kinetic energy of an object is all about the magnitude alone. Just like work and potential energy, the standard metric unit of measurement for kinetic energy is the Joule.
3. Geothermal Energy
Geothermal energy is the heat originating from the original formation of the planet, from radioactive decay of minerals, from volcanic activity, and from solar energy absorbed at the surface. The geothermal gradient, which is the difference in temperature between the core of the planet and its surface, drives a continuous conduction of thermal energy in the form of heat from the core to the surface.
Hydrogen has the highest energy content of any common fuel by weight (about three times more than gasoline), but the lowest energy content by volume. Hydrogen transports energy in a useable form from one place to another. Like electricity, hydrogen is an energy carrier. Hydrogen burns cleanly, producing water H2O. When burned in an engine or; used a fuel cell, it is converted
to water only. To make hydrogen a renewable fuel it should use renewable energy, such as wind power or solar power, for production.
5. Wind Energy
Wind power is a totally renewable energy source with no greenhouse gas emissions, but due to its
unpredictability has problems integrating with national grids. One of the front-runners of the renewable energy march is wind. Wind power is the use of air flow through wind turbines to mechanically power generators for electric power. Wind power, as an alternative to burning fossil fuels, is plentiful, renewable, widely distributed, clean, produces no greenhouse gas emissions during operation, consumes no water, and uses the little land. The net effects on the environment are far less problematic than those of non-renewable power sources. Availability of transmission capacity helps large-scale deployment by reducing the cost of delivered wind energy.