Energy is the ability to do work. It comes in different forms thermal (heat), radiant (light), mechanical, electrical, chemical, and nuclear energy. Energy is in everything.
Internationally accepted unit of measurement for energy is the SI unit of energy, the joule. Power is the rate at which energy is transferred and it is usually measured in watts.
Energy is most often used in the context of energy resources, their development, consumption, depletion, and conservation. Since economic activities such as manufacturing and transportation can be energy intensive, energy efficiency, energy dependence, energy security and price are key concerns.
Renewable energy sources are solar energy, wind energy, geothermal energy, hydropower, bioenergy (bioethanol, biodiesel), ocean energy (tidal power, wave energy, Ocean Thermal Energy Conversion -OTEC). Renewable energy sources are often marked as sustainable energy sources.
Non-renewable energy sources are fossil fuels (oil, coal, natural gas) and nuclear energy. Fossil fuels are the main energy source in today's world. Non-renewable energy sources are often marked as non-sustainable energy sources.
We use energy to do everything we do, from making a jump shot to baking our favorite cookies to sending astronauts into space - energy is there, making sure we have the power to do it all.
Food is stored energy. It is stored as a chemical with potential energy. When your body uses that stored energy to do work, it becomes kinetic energy.
Matter can be turned into energy, and energy into matter. One of Einstein's great insights was to realize that matter and energy are really different forms of the same thing. The deep connection Einstein discovered between energy and mass is expressed in the equation E=mc2. Here E represents energy, m represents mass, and c2 is a very large number, the square of the speed of light.
Scientists from Columbia University, New York, and Lawrence Berkeley National Laboratory, Berkeley, California have concluded that more energy is being absorbed from the sun than is emitted back to space, throwing the Earth's energy "out of balance" and warming the globe.
In physics, the law of conservation of energy states that the total amount of energy in any isolated system remains constant but cannot be recreated, although it may change forms.
According to law of conservation of energy, energy can neither be created (produced) nor destroyed itself. It can only be transformed. So, whenever one measures the total energy of a system of particles whose interactions do not depend explicitly on time, it is found that the total energy of the system always remains constant.
In physics and engineering, energy transformation or energy conversion, is any process of transforming one form of energy to another. Usually we transform unusable energy into usable with range of different machines (cars, heaters …).
Sustainable energy is the provision of energy such that it meets the needs of the present without compromising the ability of future generations to meet their needs. Sustainable Energy has two key components: renewable energy and energy efficiency. By some other definition, sustainable energy is energy which is replenishable within a human lifetime and causes no long-term damage to the environment.
Alternative energy is typically defined as coming from sources that do not deplete natural resources or harm the environment. Typical examples of alternative energy are wind power and solar power.
Ordinary fossil fuel power plants convert between 36% and 48% of the fuel's energy into electricity, with the remainder being lost as waste heat.
Energy storage is the storing of some form of energy that can be drawn upon at a later time to perform some useful operation. A device that stores energy is sometimes called an accumulator. Hydroelectric dams are one type of energy accumulator. Batteries are also energy accumulators.
In physical cosmology, dark energy is a hypothetical exotic form of energy that permeates all of space and tends to increase the rate of expansion of the universe.
Energy security has become essential to the functioning of modern economies. Because of that, almost all wars in past 20 or so years are mostly wars for control over energy sources (direct energy source control, control over energy transport routes, control over energy rich countries …).