Consumer & Gadgets

Smart devices need to get smarter to help save energy

As the growth in connected devices outstrips that of conventional home appliances, consumers will find it increasingly more difficult to understand which electrical devices are consuming the most power in their homes, and ...

Energy & Green Tech

Scientists develop novel biophotovoltaics system

Researchers from the Institute of Microbiology of the Chinese Academy of Sciences have reported a novel biophotovoltaics (BPV) system based on a synthetic microbial consortium with constrained electron flow. This BPV system ...

Energy & Green Tech

Scorching growth for renewables thanks to solar: IEA

Growth in the renewable electricity generation sector has returned to a double-digit pace thanks to a surge in the installation of solar photovoltaic (PV) panels, the International Energy Agency said Friday.

Energy & Green Tech

Why don't we have electric aircraft?

Electric cars, trains, trams and boats already exist. That logically leads to the question: why are we not seeing large electric aircraft? And will we see them any time soon?

Energy & Green Tech

Google green energy buys boost 'carbon-free' portfolio

Google on Thursday announced a record-high boost to its green electricity purchases, saying the deals will spur construction of millions of solar panels and hundreds of wind turbines.

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.

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