What are the main forms of energy?
17327#6
Energy occurs in many forms, including chemical energy, thermal energy, electromagnetic radiation, gravitational energy, electric energy, elastic energy, nuclear energy, and rest energy. These can be categorized in two main classes: potential energy and kinetic energy. Kinetic energy is the movement energy of an object. Kinetic energy can be transferred between objects and transformed into other kinds of energy.
Kinetic energy
9649#4
The total energy of a system can be subdivided and classified into potential energy, kinetic energy, or combinations of the two in various ways. Kinetic energy is determined by the movement of an object – or the composite motion of the components of an object – and potential energy reflects the potential of an object to have motion, and generally is a function of the position of an object within a field or may stored in the field itself.
Energy
9649#36
Examples of energy transformation include generating electric energy from heat energy via a steam turbine, or lifting an object against gravity using electrical energy driving a crane motor. Lifting against gravity performs mechanical work on the object and stores gravitational potential energy in the object. If the object falls to the ground, gravity does mechanical work on the object which transforms the potential energy in the gravitational field to the kinetic energy released as heat on impact with the ground. Our Sun transforms nuclear potential energy to other forms of energy; its total mass does not decrease due to that in itself (since it still contains the same total energy even if in different forms), but its mass does decrease when the energy escapes out to its surroundings, largely as radiant energy.
Energy
9649#1
Common forms of energy include the kinetic energy of a moving object, the potential energy stored by an object's position in a force field (gravitational, electric or magnetic), the elastic energy stored by stretching solid objects, the chemical energy released when a fuel burns, the radiant energy carried by light, and the thermal energy due to an object's temperature.
Energy
39221#6
The basic definition of "energy" is a measure of a body's (in thermodynamics, the system's) ability to cause change. For example, when a person pushes a heavy box a few meters forward, that person exerts mechanical energy, also known as work, on the box over a distance of a few meters forward. The mathematical definition of this form of energy is the product of the force exerted on the object and the distance by which the box moved (Work=Force x Distance). Because the person changed the stationary position of the box, that person exerted energy on that box. The work exerted can also be called "useful energy". Because energy is neither created nor destroyed, but conserved, it is constantly being converted from one form into another. For the case of the person pushing the box, the energy in the form of internal (or potential) energy obtained through metabolism was converted into work in order to push the box. This energy conversion, however, is not linear. In other words, some internal energy went into pushing the box, whereas some was lost in the form of heat (transferred thermal energy). For a reversible process, heat is the product of the absolute temperature "T" and the change in entropy "S" of a body (entropy is a measure of disorder in a system). The difference between the change in internal energy, which is Δ"U", and the energy lost in the form of heat is what is called the "useful energy" of the body, or the work of the body performed on an object. In thermodynamics, this is what is known as "free energy". In other words, free energy is a measure of work (useful energy) a system can perform at constant temperature. Mathematically, free energy is expressed as:
Thermodynamic free energy
827528#3
ISO 13600 series (ISO 13600, ISO 13601 and ISO 13602) are intended to be used as tools to define, describe, analyse and compare technical energy systems (TES) at micro and macro levels:In the field of energetics, an energy carrier corresponds only to an energy form (not an energy system) of energy input required by the various sectors of society to perform their functions. Energy carriers (EC) are produced by the energy sector using primary energy sources (PES). The distinction between "Energy Carriers" and "Primary Energy Sources" is extremely important since these two labels refer to energy forms of different quality so that they cannot be aggregated: 1 megajoule (MJ) of EC is not the same as 1 MJ of PES. Sunlight is a main form of primary energy, which can be transformed into plants and then into coal, oil and gas. Solar power and wind power are other derivatives of sunlight. Note that although coal, oil and natural gas are derived from sunlight, they are considered primary energy sources which are extracted from the earth (fossil fuels). Natural uranium is also a primary energy source extracted from the earth but does not come from the decomposition of organisms (mineral fuel).
Energy carrier
41447629#8
The main forms of renewable energy used in Mexico are hydropower, biomass, geothermal, solar power and wind. While all of these are assisting in lowering the fossil fuel count and carbon emissions.
Renewable energy in Mexico
533487#67
All forms of energy are either potential energy (e.g. Chemical, gravitational, electrical energy, temperature differential, latent heat, etc.) or kinetic energy (e.g. momentum). Some technologies provide only short-term energy storage, and others can be very long-term such as power to gas using hydrogen or methane and the storage of heat or cold between opposing seasons in deep aquifers or bedrock. A wind-up clock stores potential energy (in this case mechanical, in the spring tension), a battery stores readily convertible chemical energy to operate a mobile phone, and a hydroelectric dam stores energy in a reservoir as gravitational potential energy. Ice storage tanks store ice (thermal energy in the form of latent heat) at night to meet peak demand for cooling. Fossil fuels such as coal and gasoline store ancient energy derived from sunlight by organisms that later died, became buried and over time were then converted into these fuels. Even food (which is made by the same process as fossil fuels) is a form of energy stored in chemical form.
Energy development
491955#1
Energy in food comes from three sources: fat, protein, and carbohydrates. A typical energy bar weighs between 45 and 80 g and is likely to supply about 200–300 Cal (840–1,300 kJ), 3–9 g of fat, 7–15 g of protein, and 20–40 g of carbohydrates.
In order to provide energy quickly, most of the carbohydrates are various types of sugars like fructose, glucose, maltodextrin and others in various ratios, combined with complex carbohydrate sources like oats and barley. Proteins come mostly in the form of fast digesting whey protein. Energy bars generally don't contain sugar alcohols, since these bars, due to type of carbohydrate content, don't require low calorie sweeteners to improve their taste. Fats in energy bars are kept to minimum and their main sources are often cocoa butter and dark chocolate.
Energy bar
3043836#30
Iron nuclei are the most stable nuclei (in particular iron-56), and the best sources of energy are therefore nuclei whose weights are as far removed from iron as possible. One can combine the lightest ones—nuclei of hydrogen (protons)—to form nuclei of helium, and that is how the Sun generates its energy. Or else one can break up the heaviest ones—nuclei of uranium or plutonium—into smaller fragments, and that is what nuclear power reactors do.
Nuclear binding energy
1413688#7
Primary energy sources are transformed in energy conversion processes to more convenient forms of energy that can directly be used by society, such as electrical energy, refined fuels, or synthetic fuels such as hydrogen fuel. In the field of energetics, these forms are called energy carriers and correspond to the concept of "secondary energy" in energy statistics.
Primary energy
9058630#3
In 2011, expenditures on energy totalled over 6 trillion USD, or about 10% of the world gross domestic product (GDP). Europe spends close to one-quarter of the world's energy expenditures, North America close to 20%, and Japan 6%.
World total primary energy supply (TPES), or "primary energy" differs from the world final energy consumption because much of the energy that is acquired by humans is lost as other forms of energy during the process of its refinement into usable forms of energy and its transport from its initial place of supply to consumers. For instance, when oil is extracted from the ground it must be refined into gasoline, so that it can be used in a car, and transported over long distances to gas stations where it can be used by consumers. World final energy consumption refers to the fraction of the world's primary energy that is used in its final form by humanity.
World energy consumption
5638#3
Fires occur naturally, ignited by lightning strikes or by volcanic products. Combustion (fire) was the first controlled chemical reaction discovered by humans, in the form of campfires and bonfires, and continues to be the main method to produce energy for humanity. Usually, the fuel is carbon, hydrocarbons or more complicated mixtures such as wood that contains partially oxidized hydrocarbons. The thermal energy produced from combustion of either fossil fuels such as coal or oil, or from renewable fuels such as firewood, is harvested for diverse uses such as cooking, production of electricity or industrial or domestic heating. Combustion is also currently the only reaction used to power rockets. Combustion is also used to destroy (incinerate) waste, both nonhazardous and hazardous.
Combustion