Natural Gas Natural gas is a fossil fuel formed when layers of buried plants, gases, and animals are exposed to intense heat and pressure over thousands of years. The energy that the plants originally obtained from the sun is stored in the form of chemical bonds in natural gas. Natural gas is a nonrenewable resource because it cannot be replenished on a human time frame.[1] Natural gas is a hydrocarbon gas mixture consisting primarily of methane, but commonly includes varying amounts of other higher alkanes and even a lesser percentage of carbon dioxide, nitrogen, and hydrogen sulfide.[2] Natural gas is an energy source often used for heating, cooking, and electricity generation. It is also used as fuel for vehicles and as a chemical feedstock in the manufacture of plastics and other commercially important organic chemicals. Natural gas is found in deep underground rock formations or associated with other hydrocarbon reservoirs in coal beds and as methane clathrates. Sources[edit] Natural gas[edit]
Énergie renouvelable Un article de Wikipédia, l'encyclopédie libre. Les énergies renouvelables (EnR en abrégé) sont des sources d'énergies dont le renouvellement naturel est assez rapide pour qu'elles puissent être considérées comme inépuisables à l'échelle de temps humaine. L'expression énergie renouvelable est la forme courte et usuelle des expressions « sources d'énergie renouvelables » ou « énergies d'origine renouvelable » qui sont plus correctes d'un point de vue physique. Définitions Différents types d'énergies renouvelables. La chaleur interne de la Terre (géothermie) est assimilée à une forme d'énergie renouvelable, et le système Terre-Lune engendre les marées des océans et des mers permettant la mise en valeur de l'énergie marémotrice. L'énergie solaire comme la chaleur interne de la Terre proviennent de réactions nucléaires (fusion nucléaire dans le cas du Soleil, fission nucléaire dans celui de la chaleur interne de la Terre). Histoire Production de feu par friction à l'aide d'un archet. Biomasse Monde
Carbon neutral fuel Type of fuel which have no net greenhouse gas emissions Carbon-neutral fuel is fuel which produces no net-greenhouse gas emissions or carbon footprint. In practice, this usually means fuels that are made using carbon dioxide (CO2) as a feedstock. Proposed carbon-neutral fuels can broadly be grouped into synthetic fuels, which are made by chemically hydrogenating carbon dioxide, and biofuels, which are produced using natural CO2-consuming processes like photosynthesis.[1][2] The carbon dioxide used to make synthetic fuels may be directly captured from the air, recycled from power plant flue exhaust gas or derived from carbonic acid in seawater. If the combustion of carbon-neutral fuels is subject to carbon capture at the flue, they result in net-negative carbon dioxide emission and may thus constitute a form of greenhouse gas remediation. Production of synthetic hydrocarbons [edit] Hydrogen fuel is typically prepared by the electrolysis of water in a power to gas process.
Hydropower Facts and Information History Hydropower is electricity generated using the energy of moving water. Rain or melted snow, usually originating in hills and mountains, create streams and rivers that eventually run to the ocean. The energy of that moving water can be substantial, as anyone who has been whitewater rafting knows. Humans have been taking advantage of this source of energy for centuries. In the late 19th century, hydropower became a source for generating electricity. How it Works A typical hydro plant is a system with three parts: an electric plant where the electricity is produced, a dam that can be opened or closed to control water flow, and a reservoir where water can be stored. Where It's Used Hydroelectric power provides almost one-fifth of the world's electricity. The biggest hydro plant in the United States is located at the Grand Coulee Dam on the Columbia River in northern Washington. Drawbacks Hydropower is the cheapest way to generate electricity today.
Biofuel A biofuel is a fuel that contains energy from geologically recent carbon fixation. These fuels are produced from living organisms. Examples of this carbon fixation occur in plants and microalgae. These fuels are made by a biomass conversion (biomass refers to recently living organisms, most often referring to plants or plant-derived materials). This biomass can be converted to convenient energy containing substances in three different ways: thermal conversion, chemical conversion, and biochemical conversion. Bioethanol is an alcohol made by fermentation, mostly from carbohydrates produced in sugar or starch crops such as corn, sugarcane, or sweet sorghum. Biodiesel can be used as a fuel for vehicles in its pure form, but it is usually used as a diesel additive to reduce levels of particulates, carbon monoxide, and hydrocarbons from diesel-powered vehicles. Liquid fuels for transportation[edit] First-generation biofuels[edit] Ethanol[edit] Biodiesel[edit] Other bioalcohols[edit]
Énergie hydroélectrique Un article de Wikipédia, l'encyclopédie libre. L'énergie hydroélectrique, ou hydroélectricité, est une énergie électrique renouvelable obtenue par conversion de l'énergie hydraulique, des différents flux d'eau naturels[1], en électricité. L'énergie cinétique du courant d'eau est transformée en énergie mécanique par une turbine hydraulique, puis en énergie électrique par un alternateur. En 2011, l’énergie hydroélectrique représente environ 16,2 %[2] de la production mondiale d’électricité et possède de nombreux atouts. Quatrième source de production d'électricité mondiale, l’énergie hydroélectrique est amenée à se développer en intégrant la protection des ressources piscicoles et en s’articulant avec d’autres énergies renouvelables comme l’éolien ou d’autres systèmes hybrides (par exemple avec l’hydrogène). Principes[modifier | modifier le code] Il existe quatre grands types de turbines. Historique[modifier | modifier le code] Entrée monumentale de l'exposition de 1925 On distingue ainsi :
Geothermal electricity Geothermal electricity is electricity generated from geothermal energy. Technologies in use include dry steam power plants, flash steam power plants and binary cycle power plants. Geothermal electricity generation is currently used in 24 countries,[1] while geothermal heating is in use in 70 countries.[2] Estimates of the electricity generating potential of geothermal energy vary from 35 to 2,000 GW.[2] Current worldwide installed capacity is 10,715 megawatts (MW), with the largest capacity in the United States (3,086 MW).[3] El Salvador, Kenya, the Philippines, Iceland and Costa Rica generate more than 15% of their electricity from geothermal sources. Geothermal power is considered to be sustainable because the heat extraction is small compared with the Earth's heat content.[4] The emission intensity of existing geothermal electric plants is on average 122 kg of CO 2 per kilowatt-hour (kW·h) of electricity, about one-eighth of a conventional coal-fired plant.[5] Resources[edit]
Hydroelectric Power Generation Hydroelectric Power Hydro-electric power, using the potential energy of rivers, now supplies 17.5% of the world's electricity (99% in Norway, 57% in Canada, 55% in Switzerland, 40% in Sweden, 7% in USA). Apart from a few countries with an abundance of it, hydro capacity is normally applied to peak-load demand, because it is so readily stopped and started. It is not a major option for the future in the developed countries because most major sites in these countries having potential for harnessing gravity in this way are either being exploited already or are unavailable for other reasons such as environmental considerations. Growth to 2030 is expected mostly in China and Latin America. Hydro energy is available in many forms, potential energy from high heads of water retained in dams, kinetic energy from current flow in rivers and tidal barrages, and kinetic energy also from the movement of waves on relatively static water masses. Water Turbines Turbine Power Output Turbine Types Pmax =½ηρQv2
Types of Alternative Energy Énergie marémotrice Un article de Wikipédia, l'encyclopédie libre. L'énergie marémotrice est issue des mouvements de l'eau créés par les marées et causés par l'effet conjugué des forces de gravitation de la Lune et du Soleil. Elle est utilisée soit sous forme d'énergie potentielle - l'élévation du niveau de la mer, soit sous forme d'énergie cinétique - les courants de marée[1] . L'énergie marémotrice n'est pas nouvelle : des moulins à marée ont été construits dès le XIIe siècle sur l'Adour. Principe[modifier | modifier le code] Principe d'une usine marémotrice Article détaillé : Marée. Le phénomène de marée est dû à la différence de temps de rotation entre la Terre (24 heures) et la Lune (28 jours) qui est donc relativement fixe par rapport à celle-ci. L'énergie dite marémotrice constitue donc une récupération de l'énergie cinétique de la rotation de la Terre. L'énergie correspondante peut être captée sous deux formes : Origine de l'énergie des marées[modifier | modifier le code]
Wind power in Alaska Wind power in Alaska has the potential to provide all of the electricity used in the U.S. state of Alaska. From its installation in July 2009 though October 2012, the Pillar Mountain Wind 4.5 MW wind farm has saved the use of almost 3,000,000 gallons of diesel fuel in Kodiak, Alaska.[1] Potential[edit] Alaska wind resources In early 2010, the National Renewable Energy Laboratory released the first comprehensive update of wind energy potential by state since 1993, showing that Alaska has the potential to install 494,700 MW of wind power, capable of generating 1,620,000 million kWh/year.[2] Alaska used 6,291 million kWh in 2011, so Alaska has the potential to generate all energy used in the state from windpower.[3] Projects[edit] Eva Creek Wind ProjectFire Island Wind Project[4]Pillar Mountain Wind Project See also[edit] Wind power in the United States References[edit] External links[edit] Renewable Energy Projects
How Geothermal Energy Works Heat from the earth can be used as an energy source in many ways, from large and complex power stations to small and relatively simple pumping systems. This heat energy, known as geothermal energy, can be found almost anywhere—as far away as remote deep wells in Indonesia and as close as the dirt in our backyards. Many regions of the world are already tapping geothermal energy as an affordable and sustainable solution to reducing dependence on fossil fuels, and the global warming and public health risks that result from their use. For example, as of 2013 more than 11,700 megawatts (MW) of large, utility-scale geothermal capacity was in operation globally, with another 11,700 MW in planned capacity additions on the way [1]. These geothermal facilities produced approximately 68 billion kilowatt-hours of electricity, enough to meet the annual needs of more than 6 million typical U.S. households. Iceland's Nesjavellir geothermal power station. The geothermal resource References: [2] U.S.