Converting energy from one form (fuel) into another form (movement).

The current at which maximum power is available from a module.

Generic term for any power supply located near the point where the power is used. Opposite of central power. See stand-alone systems.

The use of flowing water to produce electrical energy.

History of Hydropower

People have been harnessing water to perform work for thousands of years. The Greeks used water wheels for grinding wheat into flour more than 2,000 years ago.

Besides grinding flour, the power of water was used to saw wood and power textile mills and manufacturing plants.

For more than a century, the technology for using falling water to create hydroelectricity has existed. The evolution of the modern hydropower turbine began in the mid-1700s when a French hydraulic and military engineer, Bernard Forest de Bélidor wrote Architecture Hydraulique. In this four volume work, he described using a vertical-axis versus a horizontal-axis machine.

During the 1700s and 1800s, water turbine development continued. In 1880, a brush arc light dynamo driven by a water turbine was used to provide theater and storefront lighting in Grand Rapids, Michigan; and in 1881, a brush dynamo connected to a turbine in a flour mill provided street lighting at Niagara Falls, New York. These two projects used direct-current technology.

Alternating current is used today. That breakthrough came when the electric generator was coupled to the turbine, which resulted in the world's, and the United States', first hydroelectric plant located in Appleton, Wisconsin, in 1882.

Means of a power conditioning unit that automatically operates the photovoltaic generator at its maximum power point under all conditions.

The point on the current-voltage (I-V) curve of a module under illumination, where the product of current and voltage is maximum.

For a typical silicon cell, this is at about 0.45 volts.

Operating a photovoltaic array at the peak power point of the array's I-V curve where maximum power is obtained. Also called "peak power tracking".

Amperes produced by a photovoltaic module or array operating at the voltage of the I-V curve that will produce maximum power from the module.

Operating point of the I-V (current-voltage) curve for a solar cell or photovoltaic module where the product of the current value times the voltage value is a maximum.

The process of modifying the characteristics of electrical power; for example, inverting direct current to alternating current.

Electrical equipment, or power electronics, used to convert power from a photovoltaic array into a form suitable for subsequent use.

A collective term for inverter, converter, battery charge regulator, and blocking diode.

The ratio of output power to input power of the inverter.

The ratio of the power available from a battery to its mass (W/kg) or volume (W/l).

The ratio of actual power being used in a circuit, expressed in watts or kilowatts, to the power that is apparently being drawn from a power source, expressed in volt-amperes or kilovolt-amperes.

Rated power of the inverter; however, some units can not produce rated power continuously.

See duty rating for additional information.

The sine of the phase angle between the current and voltage waveforms in an alternating current system.

See power factor for additional information.

The ability of a telescope to separate two closely spaced sources of radiation; such as, stars.

Concept for providing large amounts of electricity for use on the earth from one or more satellites in geosynchronous earth orbit.

A very large array of solar cells on each satellite would provide electricity, which would be converted to microwave energy and beamed to a receiving antenna on the ground. There, it would be reconverted into electricity and distributed the same as any other centrally generated power, through a grid.

The designation of a power supply providing continuous uninterruptible service.

The uninterruptible power supply will contain batteries.

The voltage at which maximum power is available from a photovoltaic module.