Energy & Green Tech

Biomass-driven technology allows for enhanced energy conversion

Organic waste—whether from households, agriculture or agroforestry—can be used as energy resource, but is often underexploited. A team of EPFL scientists has developed a methodology to better incorporate this resource ...

Energy & Green Tech

Africa's electricity unlikely to go green this decade

New research today from the University of Oxford predicts that total electricity generation across the African continent will double by 2030, with fossil fuels continuing to dominate the energy mix—posing potential risk ...

Energy & Green Tech

Team expands power grid planning to improve system resilience

In most animal species, if a major artery is cut off from the heart, the animal will struggle to survive. The same can be said for many of our critical infrastructure systems, such as electric power, water and communications. ...

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Energy

In physics, energy (from the Greek ἐνέργεια - energeia, "activity, operation", from ἐνεργός - energos, "active, working") is a scalar physical quantity that describes the amount of work that can be performed by a force, an attribute of objects and systems that is subject to a conservation law. Different forms of energy include kinetic, potential, thermal, gravitational, sound, light, elastic, and electromagnetic energy. The forms of energy are often named after a related force.

Any form of energy can be transformed into another form, but the total energy always remains the same. This principle, the conservation of energy, was first postulated in the early 19th century, and applies to any isolated system. According to Noether's theorem, the conservation of energy is a consequence of the fact that the laws of physics do not change over time.

Although the total energy of a system does not change with time, its value may depend on the frame of reference. For example, a seated passenger in a moving airplane has zero kinetic energy relative to the airplane, but non-zero kinetic energy relative to the Earth.

This text uses material from Wikipedia, licensed under CC BY-SA