Energy & Green Tech

Interest rates are a decisive factor for competitive renewables

Renewable energy has become competitive—and one often-overlooked reason is the reduced cost of financing. Researchers from ETH Zurich and the Potsdam Institute for Climate Impact Research (PIK) have modeled different scenarios ...

Energy & Green Tech

Solar array feeds railway route in the UK

How well is the UK doing to seal a future of solar powered trains? Will connecting solar power directly to rail networks help meet a good enough share of electricity needs? Eyes are on a pilot scheme going on now and it ...

Energy & Green Tech

Energizing buildings

A solar façade developed at ETH Zurich combines electricity production with intelligent shading to achieve optimal energy balance.

Energy & Green Tech

New rechargeable aqueous battery challenges lithium-ion dominance

A new rechargeable high voltage manganese dioxide zinc battery, exceeding the 2 V barrier in aqueous zinc chemistry, is the latest invention by City College of New York researchers. With a voltage of 2.45-2.8V, the alkaline ...

Engineering

The future of 'extremely' energy-efficient circuits

Data centers are processing data and dispensing the results at astonishing rates, and such robust systems require a significant amount of energy—so much energy, in fact, that information communication technology is projected ...

Energy & Green Tech

Ocean power: A green option failing to make waves

The tidal power plant on the Rance river in Brittany, France, stands as a reminder of the underexploited potential of energy generation from ocean tides, waves and warmth.

Energy & Green Tech

The long road to clean energy

The vital transition to a zero-carbon economy is likely to be a long and rocky road. So-called green energy is booming, but not fast enough to curb climate change, which is accelerating at an alarming pace as oil, gas and ...

Engineering

Using smart sensor technology in building design

Have lights turned on automatically when you walk into a room? Does the air conditioner in the conference room turn on when a certain number of people enter the room?

Energy & Green Tech

Photovoltaics could cool our homes with the power of the sun

The International Energy Agency has dubbed increased global cooling demand as one of the most critical blind spots in today's energy debate. A new study titled "Meeting Increased Global Cooling Demand with Photovoltaics during ...

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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