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An introduction to energy resources
An introduction to energy resources

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S278_2 Glossary

S278_2 Glossary.
Thursday, 28 March 2024, 10:27 AM
Site: Open Learning
Course: An introduction to energy resources (S278_2)
Glossary: S278_2 Glossary
P

Photosynthesis

A chemical reaction in green plants in which carbon dioxide from the atmosphere combines with water to form carbohydrates, using the energy of solar radiation.

Photovoltaic (PV) effect

The result of electrons being freed from impurities in semiconductors by the quantum energy of light photons, so that the electrons move to generate both electrical potential and current. The principle behind solar cells.

Potential energy

Mechanical energy that exists by virtue of position or potential in a force field — usually that of gravity.

Power

The rate at which energy is delivered or work is done, measured in watts (W). One watt is equivalent to one joule per second.

Primary energy

The energy released by directly burning fossil fuels or consumed at source in electricity generation.
R

Renewable energy

Supplies of energy on Earth from internal and external processes that are continually available, whether they are used or not. They include solar, tidal, wave, wind, hydro and geothermal energy.

Residence time

The average time that carbon stays in a reservoir before moving to another reservoir, estimated by the amount in the reservoir divided by the transfer rate.

Respiration

The process where the organisms uses oxygen from air to react with the carbohydrates to liberate energy. Carbon dioxide and water are returned to the atmosphere during the respiration process.

S

Semiconductors

Poorly conductive materials doped with impurities, which act to increase electrical conductivity to a level intermediate between non-conductors and conductors. Bonded together in photovoltaic cells, they can generate an electrical current.

Solar energy

Solar radiation that reaches the Earth’s surface is potentially available as an energy resource as direct solar energy using photovoltaic cells.