Energy & Green Tech

Improving solar cell efficiency with a bucket of water

Looking at your cell phone, you realize the battery is low, which means you have to make another long walk into town to pay money to charge the device. By the time you get home, it's getting dark. You light the kerosene lamp ...

Energy & Green Tech

A new water-splitting technique to generate clean hydrogen

Electrolytic hydrogen production entails the generation of hydrogen from water using electrical power, which should ideally come from renewable power sources such as sunlight and wind. Although this method of producing hydrogen ...

Energy & Green Tech

Experiments show dramatic increase in solar cell output

In any conventional silicon-based solar cell, there is an absolute limit on overall efficiency, based partly on the fact that each photon of light can only knock loose a single electron, even if that photon carried twice ...

Engineering

AI-designed heat pumps consume less energy

In Switzerland, 50 to 60 percent of new homes are equipped with heat pumps. These systems draw in thermal energy from the surrounding environment—such as from the ground, air, or a nearby lake or river—and turn it into ...

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 ...

Energy & Green Tech

Pollution-free hydrogen: green energy breakthrough?

Scientists said Tuesday they have developed a way of extracting hydrogen from oil without releasing greenhouse gases—a breakthrough they hailed as a "silver bullet" for cleaner energy and the climate.

Energy & Green Tech

Malta energy storage system is looking forward to first pilot

Malta has received a round of funding and is graduated from "project" to group that can sail. The Cambridge, MA-based company is focused on the storage of electro-thermal energy and the funding put the group in celebration ...

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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