Like solar radiation, the ocean is another widely available and distributed energy source. The energy in the ocean is in part kinetic energy in the form of tides, currents, and waves, and part thermal energy from the sun stored as heat. The quantity of energy stored in the ocean is enormous but can be quite diffuse; in some cases, it is about the same as from solar radiation and, as a result, it is difficult to harness. Marine energy systems can be classified into four main groups: (more…)

It is often useful to know how much energy is being changed from one form to another. For example, natural gas companies need to have a way to measure the fuel demands of their customers so they can provide enough natural gas when it is most needed.

In most scientific experiments, there is some form of energy measurement. A meter is an instrument that measures energy—such as the power and gas meters located on the sides of houses—and the standard unit of energy in the metric system is called a joule (J).

Energy can be measured in many different units. A calorie is defined as the amount of heat energy needed to raise the temperature of 2.2 pounds (1 kilogram) of water by 1.8°F (1°C). Joule conversion to calorie: 1 Joule is approximately 0.2390 calorie. Power is simply the rate at which the energy is changed. (more…)