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Solar Constant

The intensity of the Sun’s radiation at the distance of Earth, measured at the top of the atmosphere, approximately 1360 W/m².

Solar Insolation

The power per unit area of sunlight actually reaching Earth’s surface after passing through the atmosphere.

Energy Payback Time

The length of time a solar panel must operate to generate the energy used in its manufacture, typically around 2 years for modern crystalline silicon panels.

Hydropower

High-quality mechanical energy derived from water that can be converted to electricity with very high efficiency.

N-type Semiconductor

Silicon doped with pentavalent impurities like phosphorus or arsenic, resulting in excess free electrons.

P-type Semiconductor

Silicon doped with trivalent elements such as boron or gallium, creating holes as positive charge carriers.

Concentration Ratio

The ratio of focused sunlight intensity at the receiver to the incident direct sunlight intensity.

Power Towers

A solar thermal power system that uses a field of heliostats reflecting sunlight onto a central receiver at the top of a tower.

Electrolysis

A process that uses electric current to split water into hydrogen and oxygen, typically with about 75% efficiency.

Betz Power Coefficient

The theoretical maximum fraction of wind energy a turbine can extract, equal to 59%.

Ohm’s Law

The law states that voltage (V) equals current (I) times resistance (R): V = I·R.

Transformer

An AC device that steps voltage up or down using electromagnetic induction between coils.

Fuel Cells

Devices that convert a fuel and an oxidizer into electricity, water, and heat through electrochemical reactions.

Current (Amperes)

The flow rate of electric charge, measured in Amperes (A).

Voltage

The electrical potential difference between two points, measured in Volts (V).

Electrical Resistance

The opposition to the flow of electric current, measured in Ohms (Ω).

Wind Power

The energy available in the wind, which varies with the cube of wind speed.

Hydropower Efficiency

The efficiency of converting hydropower to electricity, often exceeding 90%.

Latitudinal Effect on Insolation

Solar insolation varies with latitude due to Earth’s curvature; higher insolation near the equator and lower near the poles.

Seasonal Variation of Solar Constant

The solar constant itself does not vary with location but can experience small seasonal changes due to Earth's elliptical orbit.

Indirect Solar Energy

Energy obtained from solar energy sources such as wind and hydropower.

Semiconductor

A material with conductivity between a conductor and an insulator, whose conductivity can be controlled.

Solar Thermal Power System Components

Includes concentrators, heat engines, and generators for converting solar energy into electricity.

Passive Solar Design

A design relying on materials and architectural features to collect, distribute, and store solar energy.

Electromagnetic Composition of Solar Energy

Solar energy at the upper atmosphere has about 50% in infrared, 40% in visible light, and 10% in ultraviolet.

Doping

The process of adding impurities to semiconductors to modify their electrical properties.

Mechanical Energy

Energy derived from mechanical processes, such as movement or the position of an object.

Hydropower Plants Advantage

Their ability to quickly adjust output to match electricity demand, useful for peak load balancing.

Concentrator

A component in solar thermal power systems that focuses sunlight to generate high temperatures.

Turbines

Devices that convert fluid energy (such as water or wind) into mechanical energy.

Altitude Effect on Insolation

Higher elevations can receive slightly more solar insolation due to thinner atmosphere.

Chemical Hydrogen

Hydrogen that must be produced from other sources as it does not exist freely in nature.

Electromagnetic Induction

The principle that allows a transformer to change the voltage of an AC current.

Hydrogens Production Methods

Methods include steam reforming, electrolysis, thermal splitting, and photolysis.

Solar Energy Surplus

The amount of solar energy incident on Earth is roughly 10,000 times greater than current human energy consumption.

Electrochemical Fuel Cells Efficiency

PEMFCs typically operate at 50-60% efficiency in converting hydrogen energy to electricity.

Solar Energy Definition

Energy obtained from the Sun, which can be harnessed through various technologies for electricity generation.

High Voltage Transmission

Minimizing power loss in electric transmission by using high voltage and low current.

Renewable Energy Types

Sources of energy that can be replenished naturally, including solar, wind, and hydropower.

N-type vs P-type Semiconductors

N-type has more electrons, while P-type has more holes, both critical for electronics functionality.

Power Loss Determinants

Power loss in transmission lines is proportional to the square of the current and the resistance of the line.