Portal:Energy
Main page | New articles & Tasks |
The Energy Portal Welcome to Wikipedia's Energy portal, your gateway to energy. This portal is aimed at giving you access to all energy related topics in all of its forms.
|
Page contents: Selected article • Selected image • Selected biography • Did you know? • General images • Quotations • Related portals • Wikiprojects • Major topics • Categories • Help • Associated Wikimedia |
Introduction
In physics, energy (from Ancient Greek ἐνέργεια (enérgeia) 'activity') is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of heat and light. Energy is a conserved quantity—the law of conservation of energy states that energy can be converted in form, but not created or destroyed. The unit of measurement for energy in the International System of Units (SI) is the joule (J).
Common forms of energy include the kinetic energy of a moving object, the potential energy stored by an object (for instance due to its position in a field), the elastic energy stored in a solid object, chemical energy associated with chemical reactions, the radiant energy carried by electromagnetic radiation, and the internal energy contained within a thermodynamic system. All living organisms constantly take in and release energy.
Due to mass–energy equivalence, any object that has mass when stationary (called rest mass) also has an equivalent amount of energy whose form is called rest energy, and any additional energy (of any form) acquired by the object above that rest energy will increase the object's total mass just as it increases its total energy.
Human civilization requires energy to function, which it gets from energy resources such as fossil fuels, nuclear fuel, or renewable energy. The Earth's climate and ecosystems processes are driven by the energy the planet receives from the Sun (although a small amount is also contributed by geothermal energy). (Full article...)
Selected article
The use of coal dates back to the Bronze Age, but it was the Industrial Revolution that led to its large-scale use, as the steam engine took over from the water wheel. Today world coal consumption is about 5.3 billion tonnes annually, of which about 75% is used to produce electricity. The region including the China and India uses about 1.7 billion tonnes annually, forecast to exceed 2.7 billion tonnes by 2025. The United States consumes about 1.0 billion tons annually. Almost one-third of all coal used was supplied by China in 2005.
Coal mining causes a number of harmful effects, including the pollution of water sources by sulfuric acid caused by a chemical reaction between water and iron sulfide in the coal. In common with other fossil fuels, the burning coal produces carbon dioxide and nitrogen oxides. It also produces sulfur dioxide, the cause of acid rain. Coal contains traces of uranium, thorium, and other naturally-occurring radioactive isotopes which, due to the vast quantities of coal used, cause more radioactive contamination than nuclear power plants. To eliminate CO2 emissions from coal plants, carbon capture and storage technology has been proposed but has yet to be commercially used.
Selected image
Photo credit: From an image by Arnold Paul
Coal-fired power stations transform chemical energy into 36%-48% electricity and 52%-64% waste heat.
Did you know?
- According to research by the IPCC, government funding for most energy research programmes has been flat or declining for nearly 20 years, and is now about half the 1980 level?
- Renewable energy in Iceland provides over 70% of the country's primary energy needs, and 99.9% of Iceland's electricity?
- The Rance tidal power plant in France was the world's 1st electrical generating station powered by tidal energy?
- A tropical cyclone (example pictured) can release heat energy at the rate of 50 to 200 trillion joules per day, roughly 200 times the world-wide electrical generating capacity?
- Ordinary fossil fuel power plants convert between 36% and 48% of the fuel's energy into electricity, with the remainder being lost as waste heat, about half of which is unavoidable due to the second law of thermodynamics?
- Burning biomass indoors leads to between 1.5 and 2 million deaths each year from indoor air pollution in developing nations?
- Over 50% of world small hydroelectricity generating capacity is in China?
- Charles Fritts developed the first solar cell in 1884, although its efficiency was less than 1%?
Selected biography
In 1831, Faraday began his great series of experiments in which he discovered electromagnetic induction. He established that a changing magnetic field produces an electric field, a relation mathematically modelled by Faraday's law. Faraday later used the principle to construct the electric dynamo, the ancestor of modern power generators. He went on to investigate the fundamental nature of electricity, concluding in 1839 that, contrary to opinions at the time, only a single "electricity" exists, and the changing values of quantity and intensity (voltage and charge) would produce different groups of phenomena.
Some historians refer to Faraday as the best experimentalist in the history of science. Despite this his mathematical ability did not extend so far as trigonometry or any but the simplest algebra. He nevertheless possessed the ability to present his ideas in clear and simple language. During his lifetime, Faraday rejected a knighthood and twice refused to become President of the Royal Society.
In the news
- 1 June 2024 – Russian invasion of Ukraine
- Russia launches missile and drone strikes across Ukraine, injuring at least four people and damaging critical infrastructure, including energy facilities. Ukraine says that it shot down 35 of 53 missiles and 46 of 47 drones. (Reuters)
General images
Quotations
- "If we already have the Kyoto protocol, why invent another proposal and not just implement one that already exists? If a country is incapable of implementing the result of an international treaty that has established rules and regulations, it won't end up implementing those rules voluntarily."" – Luiz Inácio Lula da Silva, 2007
- "Climate change is a challenge China must cope with to realize sustainable development... Implementing a climate change containment policy may cost a fortune, but the cost will be even higher if we delay. Early action is imperative." – Ma Kai, 2007
- "The consequences of restricting the development of developing nations will be much more serious than the consequences of global warming." – Ma Kai, 2007
Related portals
WikiProjects
WikiProjects connected with energy:
Other WikiProjects that may be of interest:
Major topics
Major categories
National energy supply, use & conservation
National electricity sector
Politics, economics, environment
- Climate change
- Energy conservation
- Energy economics
- Energy crises
- Energy development
- Energy policy
- Peak oil
Energy sources
- Fuels
- Biofuels
- Fossil fuels
- Fusion power
- Nuclear technology
- Renewable energy
- Energy conversion
- Electric power
- Energy storage
Energy-related design
Scientific usage
Category browser
Help
Puzzled by energy?
Can't answer your question?
Don't understand the answer?
- Ask at the reference desk
- Read the Wikipedia help pages
For further ideas, to leave a comment, or to learn how you can help improve and update this portal, see the talk page.
Associated Wikimedia
The following Wikimedia Foundation sister projects provide more on this subject:
-
Commons
Free media repository -
Wikibooks
Free textbooks and manuals -
Wikidata
Free knowledge base -
Wikinews
Free-content news -
Wikiquote
Collection of quotations -
Wikisource
Free-content library -
Wikiversity
Free learning tools -
Wiktionary
Dictionary and thesaurus