Concentrating solar power plants with wet-cooling systems, on the other hand, have the highest water-consumption intensities of any conventional type of electric power plant; only fossil-fuel plants with carbon-capture and storage may have higher water intensities.[135] A 2013 study comparing various sources of electricity found that the median water consumption during operations of concentrating solar power plants with wet cooling was 810 ga/MWhr for power tower plants and 890 gal/MWhr for trough plants. This was higher than the operational water consumption (with cooling towers) for nuclear (720 gal/MWhr), coal (530 gal/MWhr), or natural gas (210).[134] A 2011 study by the National Renewable Energy Laboratory came to similar conclusions: for power plants with cooling towers, water consumption during operations was 865 gal/MWhr for CSP trough, 786 gal/MWhr for CSP tower, 687 gal/MWhr for coal, 672 gal/MWhr for nuclear, and 198 gal/MWhr for natural gas.[136] The Solar Energy Industries Association noted that the Nevada Solar One trough CSP plant consumes 850 gal/MWhr.[137] The issue of water consumption is heightened because CSP plants are often located in arid environments where water is scarce.

A solar power tower uses an array of tracking reflectors (heliostats) to concentrate light on a central receiver atop a tower. Power towers can achieve higher (thermal-to-electricity conversion) efficiency than linear tracking CSP schemes and better energy storage capability than dish stirling technologies.[14] The PS10 Solar Power Plant and PS20 solar power plant are examples of this technology.


Among sources of renewable energy, hydroelectric plants have the advantages of being long-lived—many existing plants have operated for more than 100 years. Also, hydroelectric plants are clean and have few emissions. Criticisms directed at large-scale hydroelectric plants include: dislocation of people living where the reservoirs are planned, and release of significant amounts of carbon dioxide during construction and flooding of the reservoir.[16]

In terms of ocean energy, another third-generation technology, Portugal has the world's first commercial wave farm, the Aguçadora Wave Park, under construction in 2007. The farm will initially use three Pelamis P-750 machines generating 2.25 MW.[44][45] and costs are put at 8.5 million euro. Subject to successful operation, a further 70 million euro is likely to be invested before 2009 on a further 28 machines to generate 525 MW.[46] Funding for a wave farm in Scotland was announced in February, 2007 by the Scottish Executive, at a cost of over 4 million pounds, as part of a £13 million funding packages for ocean power in Scotland. The farm will be the world's largest with a capacity of 3 MW generated by four Pelamis machines.[47] (see also Wave farm).

Nuclear power. After coal, the next largest source of our electricity is nuclear power. While nuclear plants don't cause air pollution, they do create radioactive waste, which must be stored for thousands of years. As accidents at Three Mile Island and Chernobyl proved, nuclear plants also carry the risk of catastrophic failure. And nuclear power can be very expensive.
Biomass is biological material derived from living, or recently living organisms. It most often refers to plants or plant-derived materials which are specifically called lignocellulosic biomass.[65] As an energy source, biomass can either be used directly via combustion to produce heat, or indirectly after converting it to various forms of biofuel. Conversion of biomass to biofuel can be achieved by different methods which are broadly classified into: thermal, chemical, and biochemical methods. Wood remains the largest biomass energy source today;[66] examples include forest residues – such as dead trees, branches and tree stumps –, yard clippings, wood chips and even municipal solid waste. In the second sense, biomass includes plant or animal matter that can be converted into fibers or other industrial chemicals, including biofuels. Industrial biomass can be grown from numerous types of plants, including miscanthus, switchgrass, hemp, corn, poplar, willow, sorghum, sugarcane, bamboo,[67] and a variety of tree species, ranging from eucalyptus to oil palm (palm oil).

Throughout the country, more than half of all U.S. electricity customers now have an option to purchase some type of green power product from a retail electricity provider. Roughly one-quarter of the nation's utilities offer green power programs to customers, and voluntary retail sales of renewable energy in the United States totaled more than 12 billion kilowatt-hours in 2006, a 40% increase over the previous year.

Most cars on the road today in the U.S. can run on blends of up to 10% ethanol, and motor vehicle manufacturers already produce vehicles designed to run on much higher ethanol blends. Ford, DaimlerChrysler, and GM are among the automobile companies that sell "flexible-fuel" cars, trucks, and minivans that can use gasoline and ethanol blends ranging from pure gasoline up to 85% ethanol (E85). By mid-2006, there were approximately six million E85-compatible vehicles on U.S. roads.[39]
The market for renewable energy technologies has continued to grow. Climate change concerns and increasing in green jobs, coupled with high oil prices, peak oil, oil wars, oil spills, promotion of electric vehicles and renewable electricity, nuclear disasters and increasing government support, are driving increasing renewable energy legislation, incentives and commercialization.[10] New government spending, regulation and policies helped the industry weather the 2009 economic crisis better than many other sectors.[24][197]
Nuclear power. After coal, the next largest source of our electricity is nuclear power. While nuclear plants don't cause air pollution, they do create radioactive waste, which must be stored for thousands of years. As accidents at Three Mile Island and Chernobyl proved, nuclear plants also carry the risk of catastrophic failure. And nuclear power can be very expensive.
There are two main reasons for this, according to Kevin Haley, BRC program manager. First, there’s been strong continued support from major tech companies with large electricity loads. Facebook and AT&T, for instance, have procured the most new renewable energy capacity in 2018, with other large deals from Microsoft, Apple and Walmart. The second reason is that the pool of corporate customers is starting to expand.
Anaerobic digestion, geothermal power, wind power, small-scale hydropower, solar energy, biomass power, tidal power, wave power, and some forms of nuclear power (ones which are able to "burn" nuclear waste through a process known as nuclear transmutation, such as an Integral Fast Reactor, and therefore belong in the "Green Energy" category). Some definitions may also include power derived from the incineration of waste.
UN Conference on the Human Environment (Stockholm 1972) Brundtlandt Commission Report (1983) Our Common Future (1987) Earth Summit (1992) Rio Declaration on Environment and Development Agenda 21 (1992) Convention on Biological Diversity (1992) ICPD Programme of Action (1994) Earth Charter Lisbon Principles UN Millennium Declaration (2000) Earth Summit 2002 (Rio+10, Johannesburg) United Nations Conference on Sustainable Development (Rio+20, 2012) Sustainable Development Goals
Biofuels - Rather than burning biomass to produce energy, sometimes these renewable organic materials are transformed into fuel. Notable examples include ethanol and biodiesel. Biofuels provided 2.7 percent of the world's fuels for road transport in 2010, and have the potential to meet more than 25 percent of world demand for transportation fuels by 2050.

However, it has been found that high emissions are associated only with shallow reservoirs in warm (tropical) locales, and recent innovations in hydropower turbine technology are enabling efficient development of low-impact run-of-the-river hydroelectricity projects.[17] Generally speaking, hydroelectric plants produce much lower life-cycle emissions than other types of generation. Hydroelectric power, which underwent extensive development during growth of electrification in the 19th and 20th centuries, is experiencing resurgence of development in the 21st century. The areas of greatest hydroelectric growth are the booming economies of Asia. China is the development leader; however, other Asian nations are installing hydropower at a rapid pace. This growth is driven by much increased energy costs—especially for imported energy—and widespread desires for more domestically produced, clean, renewable, and economical generation.
As of 2014, offshore wind power amounted to 8,771 megawatt of global installed capacity. Although offshore capacity doubled within three years (from 4,117 MW in 2011), it accounted for only 2.3% of the total wind power capacity. The United Kingdom is the undisputed leader of offshore power with half of the world's installed capacity ahead of Denmark, Germany, Belgium and China.

Geothermal energy is produced by tapping into the thermal energy created and stored within the earth. It arises from the radioactive decay of an isotope of potassium and other elements found in the Earth's crust.[144] Geothermal energy can be obtained by drilling into the ground, very similar to oil exploration, and then it is carried by a heat-transfer fluid (e.g. water, brine or steam).[144] Geothermal systems that are mainly dominated by water have the potential to provide greater benefits to the system and will generate more power.[145] Within these liquid-dominated systems, there are possible concerns of subsidence and contamination of ground-water resources. Therefore, protection of ground-water resources is necessary in these systems. This means that careful reservoir production and engineering is necessary in liquid-dominated geothermal reservoir systems.[145] Geothermal energy is considered sustainable because that thermal energy is constantly replenished.[146] However, the science of geothermal energy generation is still young and developing economic viability. Several entities, such as the National Renewable Energy Laboratory[147] and Sandia National Laboratories[148] are conducting research toward the goal of establishing a proven science around geothermal energy. The International Centre for Geothermal Research (IGC), a German geosciences research organization, is largely focused on geothermal energy development research.[149]
The Nomad 20 Solar Panel combines highly efficient The Nomad 20 Solar Panel combines highly efficient monocrystalline technology in a foldable portable plug-and-play form. With a built-in junction box and innovative smart chip the Nomad 20 can directly charge handheld USB and 12-Volt devices directly from the sun just as fast as the wall. Combine the Nomad 20 ...  More + Product Details Close

Geothermal energy is produced by tapping into the thermal energy created and stored within the earth. It arises from the radioactive decay of an isotope of potassium and other elements found in the Earth's crust.[144] Geothermal energy can be obtained by drilling into the ground, very similar to oil exploration, and then it is carried by a heat-transfer fluid (e.g. water, brine or steam).[144] Geothermal systems that are mainly dominated by water have the potential to provide greater benefits to the system and will generate more power.[145] Within these liquid-dominated systems, there are possible concerns of subsidence and contamination of ground-water resources. Therefore, protection of ground-water resources is necessary in these systems. This means that careful reservoir production and engineering is necessary in liquid-dominated geothermal reservoir systems.[145] Geothermal energy is considered sustainable because that thermal energy is constantly replenished.[146] However, the science of geothermal energy generation is still young and developing economic viability. Several entities, such as the National Renewable Energy Laboratory[147] and Sandia National Laboratories[148] are conducting research toward the goal of establishing a proven science around geothermal energy. The International Centre for Geothermal Research (IGC), a German geosciences research organization, is largely focused on geothermal energy development research.[149]

The time will arrive when the industry of Europe will cease to find those natural resources, so necessary for it. Petroleum springs and coal mines are not inexhaustible but are rapidly diminishing in many places. Will man, then, return to the power of water and wind? Or will he emigrate where the most powerful source of heat sends its rays to all? History will show what will come.[35]


There are numerous organizations within the academic, federal, and commercial sectors conducting large scale advanced research in the field of renewable energy. This research spans several areas of focus across the renewable energy spectrum. Most of the research is targeted at improving efficiency and increasing overall energy yields.[157] Multiple federally supported research organizations have focused on renewable energy in recent years. Two of the most prominent of these labs are Sandia National Laboratories and the National Renewable Energy Laboratory (NREL), both of which are funded by the United States Department of Energy and supported by various corporate partners.[158] Sandia has a total budget of $2.4 billion[159] while NREL has a budget of $375 million.[160]
A typical home uses approximately 10,932 kilowatt-hours (kWh) of electricity per year (about 911 kWh per month).[1] Depending on the average wind speed in the area, a wind turbine rated in the range of 5 to 15 kW would be required to make a significant contribution to this demand. A 1.5-kW wind turbine will meet the needs of a home requiring 300 kWh per month in a location with a 14 MPH (6.26 meters per second) annual average wind speed.[2] The manufacturer, dealer, or installer can provide you with the expected annual energy output of the turbine as a function of annual average wind speed. The manufacturer will also provide information about any maximum wind speeds at which the turbine is designed to operate safely. Most turbines have automatic overspeed-governing systems to keep the rotor from spinning out of control in extremely high winds.

The energy number that is left over should be a good approximation of what you can expect from that VAWT. Compare the resulting numbers with those mentioned in just about all sales brochures of VAWT type turbines and it should be immediately clear that their marketing people are smoking The Good Stuff. There is no relation to physical reality in their numbers, they are consistently much too high. Keep in mind that the energy production numbers calculated here are ‘best case’; for a turbine in nice, smooth air. Most VAWTs are placed very close to the ground, or on buildings, where there is little wind and lots of turbulence. Under those conditions they will do much, much worse than predicted.
Most current solar power plants are made from an array of similar units where each unit is continuously adjusted, e.g., with some step motors, so that the light converter stays in focus of the sun light. The cost of focusing light on converters such as high-power solar panels, Stirling engine, etc. can be dramatically decreased with a simple and efficient rope mechanics.[55] In this technique many units are connected with a network of ropes so that pulling two or three ropes is sufficient to keep all light converters simultaneously in focus as the direction of the sun changes.
FEATURES: Integrated automatic braking system to protect from sudden and high wind speed. Easy DIY installation methods with all materials provided. Can be used in conjunction with solar panels. MPPT Maximum power point tracking built into the wind turbine generator. Made with high quality Polypropylene and Glass Fiber material with a weather resistant seal.

With advanced technology being developed, cellulosic biomass, such as trees and grasses, are also used as feedstocks for ethanol production. Ethanol can be used as a fuel for vehicles in its pure form, but it is usually used as a gasoline additive to increase octane and improve vehicle emissions. Bioethanol is widely used in the United States and in Brazil. The energy costs for producing bio-ethanol are almost equal to, the energy yields from bio-ethanol. However, according to the European Environment Agency, biofuels do not address global warming concerns.[75] Biodiesel is made from vegetable oils, animal fats or recycled greases. It can be used as a fuel for vehicles in its pure form, or more commonly as a diesel additive to reduce levels of particulates, carbon monoxide, and hydrocarbons from diesel-powered vehicles. Biodiesel is produced from oils or fats using transesterification and is the most common biofuel in Europe. Biofuels provided 2.7% of the world's transport fuel in 2010.[76]
Responsible development of all of America’s rich energy resources -- including solar, wind, water, geothermal, bioenergy & nuclear -- will help ensure America’s continued leadership in clean energy. Moving forward, the Energy Department will continue to drive strategic investments in the transition to a cleaner, domestic and more secure energy future.
It is possible to use any type of solar thermal panel (sheet and tubes, roll-bond, heat pipe, thermal plates) or hybrid (mono/polycrystalline, thin film) in combination with the heat pump. The use of a hybrid panel is preferable because it allows covering a part of the electricity demand of the heat pump and reduce the power consumption and consequently the variable costs of the system.

Most small wind turbines do not perform quite as well as their manufacturers want you to believe. That should come as no surprise at this point. What may be surprising is that even the turbines of the more honourable manufacturers that are honest about performance fall short, more often than not. The likely cause is turbulence and improper site selection.


The New Zealand Parliamentary Commissioner for the Environment found that the solar PV would have little impact on the country's greenhouse gas emissions. The country already generates 80 percent of its electricity from renewable resources (primarily hydroelectricity and geothermal) and national electricity usage peaks on winter evenings whereas solar generation peaks on summer afternoons, meaning a large uptake of solar PV would end up displacing other renewable generators before fossil-fueled power plants.[127]

As the section above shows, anything under 5 m/s annual average wind speed is not going to be worth-while if you want any economic benefit out of a wind turbine. Even with government incentives, you would be better off with solar for most places. Let us take this a bit further, and assume your backyard is pretty windy, a full 6 m/s (13.4 mph) annual average wind speed at 100′ height. You get a 6 kW wind turbine installed, and shell out $50,000 for that privilege. If the installer did her job properly, the turbine is spinning in nice, clean, laminar air, and it will produce around 13,000 kWh per year. You are the kind of person that wins the lottery on a regular basis, marries a beauty queen (or king), and has kids that all go to ivy-league universities; your wind turbine never breaks and you do not have to shell out a single buck for maintenance over 20 years. Now your turbine has produced around 260,000 kWh of electricity, which works out to 19.2 cents per kWh in cost. Maybe you pay more than for electricity and it is worth it, but your are likely not getting rich, and any repairs and maintenance will drive that price up in a hurry.
Among sources of renewable energy, hydroelectric plants have the advantages of being long-lived—many existing plants have operated for more than 100 years. Also, hydroelectric plants are clean and have few emissions. Criticisms directed at large-scale hydroelectric plants include: dislocation of people living where the reservoirs are planned, and release of significant amounts of carbon dioxide during construction and flooding of the reservoir.[16]
Due to data transmission problems, structural health monitoring of wind turbines is usually performed using several accelerometers and strain gages attached to the nacelle to monitor the gearbox and equipments. Currently, digital image correlation and stereophotogrammetry are used to measure dynamics of wind turbine blades. These methods usually measure displacement and strain to identify location of defects. Dynamic characteristics of non-rotating wind turbines have been measured using digital image correlation and photogrammetry.[44] Three dimensional point tracking has also been used to measure rotating dynamics of wind turbines.[45]
By participating in a green energy program a consumer may be having an effect on the energy sources used and ultimately might be helping to promote and expand the use of green energy. They are also making a statement to policy makers that they are willing to pay a price premium to support renewable energy. Green energy consumers either obligate the utility companies to increase the amount of green energy that they purchase from the pool (so decreasing the amount of non-green energy they purchase), or directly fund the green energy through a green power provider. If insufficient green energy sources are available, the utility must develop new ones or contract with a third party energy supplier to provide green energy, causing more to be built. However, there is no way the consumer can check whether or not the electricity bought is "green" or otherwise.

Taken together, the generation and distribution of electric power in the United States is an astonishingly complex undertaking. Utilities may generate their own power or buy it from other utilities; that power travels over a grid of transformers and high- and low-voltage lines to your house. Ownership of utilities varies from nonprofits to cooperatives to for-profits. Federal regulators ultimately oversee the grid. Amazingly, when you flip a switch, electricity is there.

Index of solar energy articles List of concentrating solar thermal power companies List of photovoltaics companies List of photovoltaic power stations List of pioneering solar buildings List of rooftop photovoltaic installations List of solar car teams List of solar powered products List of solar thermal power stations People associated with solar power

As of 2014, offshore wind power amounted to 8,771 megawatt of global installed capacity. Although offshore capacity doubled within three years (from 4,117 MW in 2011), it accounted for only 2.3% of the total wind power capacity. The United Kingdom is the undisputed leader of offshore power with half of the world's installed capacity ahead of Denmark, Germany, Belgium and China.
So how do wind turbines make electricity? Simply stated, a wind turbine works the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity. View the wind turbine animation to see how a wind turbine works or take a look inside.
As part of the Paris agreement nearly 200 countries, rich and poor, pledged to cut or curb the greenhouse gas emissions they produce through the burning of fossil fuels or the cutting of forests. Countries also pledged to create the Green Climate Fund, mobilizing $100 billion by 2020 from both public funds and private industry to help the poorest nations.
The heat that is used for geothermal energy can be from deep within the Earth, all the way down to Earth's core – 4,000 miles (6,400 km) down. At the core, temperatures may reach over 9,000 °F (5,000 °C). Heat conducts from the core to surrounding rock. Extremely high temperature and pressure cause some rock to melt, which is commonly known as magma. Magma convects upward since it is lighter than the solid rock. This magma then heats rock and water in the crust, sometimes up to 700 °F (371 °C).[58]
In 2014 global wind power capacity expanded 16% to 369,553 MW.[83] Yearly wind energy production is also growing rapidly and has reached around 4% of worldwide electricity usage,[84] 11.4% in the EU,[85] and it is widely used in Asia, and the United States. In 2015, worldwide installed photovoltaics capacity increased to 227 gigawatts (GW), sufficient to supply 1 percent of global electricity demands.[86] Solar thermal energy stations operate in the United States and Spain, and as of 2016, the largest of these is the 392 MW Ivanpah Solar Electric Generating System in California.[87][88] The world's largest geothermal power installation is The Geysers in California, with a rated capacity of 750 MW. Brazil has one of the largest renewable energy programs in the world, involving production of ethanol fuel from sugar cane, and ethanol now provides 18% of the country's automotive fuel. Ethanol fuel is also widely available in the United States.
In conclusion, I would say that however great the scientific importance of this discovery may be, its practical value will be no less obvious when we reflect that the supply of solar energy is both without limit and without cost, and that it will continue to pour down upon us for countless ages after all the coal deposits of the earth have been exhausted and forgotten.[36]
The Solar updraft tower is a renewable-energy power plant for generating electricity from low temperature solar heat. Sunshine heats the air beneath a very wide greenhouse-like roofed collector structure surrounding the central base of a very tall chimney tower. The resulting convection causes a hot air updraft in the tower by the chimney effect. This airflow drives wind turbines placed in the chimney updraft or around the chimney base to produce electricity. Plans for scaled-up versions of demonstration models will allow significant power generation, and may allow development of other applications, such as water extraction or distillation, and agriculture or horticulture. A more advanced version of a similarly themed technology is the Vortex engine which aims to replace large physical chimneys with a vortex of air created by a shorter, less-expensive structure.
“California Invests in ‘By Location’ Distributed Energy Resources” • California leads the US with several pilot projects to reward rooftop solar energy generators and other distributed energy resources in specific locations as an alternative to having utilities meet needs by investing in upgrading their electricity generation networks. [CleanTechnica]
Renewable energy (and energy efficiency) are no longer niche sectors that are promoted only by governments and environmentalists. The increased levels of investment and the fact that much of the capital is coming from more conventional financial actors suggest that sustainable energy options are now becoming mainstream.[63] An example of this would be The Alliance to Save Energy's Project with Stahl Consolidated Manufacturing, (Huntsville, Alabama, USA) (StahlCon 7), a patented generator shaft designed to reduce emissions within existing power generating systems, granted publishing rights to the Alliance in 2007.
Last year, the tech giant matched 100 percent of its annual electricity consumption with renewable energy purchases, and has committed to continue doing so as the company grows. Last week, Google built on the 100 percent concept with the release of Carbon Heat Maps, which show that there are times and places where Google’s electricity profile is not yet fully carbon-free — which is what Google wants to be. 

Also, the output voltage and power demand depends entirely upon the appliances you have and how you wish to use them. In addition, the location of the wind turbine generator, would the wind resource keep it constantly rotating for long periods of time or would the generator speed and therefore its output vary up and down with variations in the available wind.


This is a wind map of the lands south of the border (the US) for 30 meters (100′) height, a very common height for small wind turbine installations. Anything green or yellow is not a good wind resource location. Here in Canada the distribution is similar, in that the good places are in the mid-west and very close to the shores of the great lakes and oceans.
The terms wind energy or wind power describe the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power can be used for specific tasks (such as grinding grain or pumping water) or a generator can convert this mechanical power into electricity.
At GE, product evolution is at our core, and we are continuously working to develop the next generation of wind energy. Beginning in 2002 with one wind turbine model, we now offer a full suite of turbines created for a variety of wind environments. We offer increased value to customers with proven performance, reliability, and availability. Our portfolio of turbines feature rated capacities from 1.7 MW to 5.3 MW (Onshore) and 6 MW to 12 MW (Offshore), we are uniquely suited to meet the needs of a broad range of wind regimes. 
Setting up a solar electric system is easy. The new source of power will integrate seamlessly with your existing utilities. Apart from settimg up the solar energy equipment, there will be no need to reconfigure or rewire your home. Our offerings include several pre-engineered, packaged systems for both residential and commercial applications, so there’s sure to be something that fits the needs of your home or business. Most solar panels last about 30 years, which means you will see the benefits of this new source of energy for decades to come.

A wide range of concentrating technologies exists: among the best known are the parabolic trough, the compact linear Fresnel reflector, the Stirling dish and the solar power tower. Various techniques are used to track the sun and focus light. In all of these systems a working fluid is heated by the concentrated sunlight, and is then used for power generation or energy storage.[11] Thermal storage efficiently allows up to 24-hour electricity generation.[12]
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