The International Geothermal Association (IGA) has reported that 10,715 MW of geothermal power in 24 countries is online, which is expected to generate 67,246 GWh of electricity in 2010.[131] This represents a 20% increase in geothermal power online capacity since 2005. IGA projects this will grow to 18,500 MW by 2015, due to the large number of projects presently under consideration, often in areas previously assumed to have little exploitable resource.[131]

Wind turbines need wind. Not just any wind, but the nicely flowing, smooth, laminar kind. That cannot be found at 30 feet height. It can usually not be found at 60 feet. Sometimes you find it at 80 feet. More often than not it takes 100 feet of tower to get there. Those towers cost as much or more, installed, as the turbine itself. How much tower you need for a wind turbine to live up to its potential depends on your particular site; on the trees and structures around it etc. Close to the ground the wind is turbulent, and makes a poor fuel for a small wind turbine.
Construction of the Salt Tanks which provide efficient thermal energy storage[103] so that output can be provided after the sun goes down, and output can be scheduled to meet demand requirements.[104] The 280 MW Solana Generating Station is designed to provide six hours of energy storage. This allows the plant to generate about 38 percent of its rated capacity over the course of a year.[105]
Renewable energy resources exist over wide geographical areas, in contrast to other energy sources, which are concentrated in a limited number of countries. Rapid deployment of renewable energy and energy efficiency is resulting in significant energy security, climate change mitigation, and economic benefits.[8] The results of a recent review of the literature[9] concluded that as greenhouse gas (GHG) emitters begin to be held liable for damages resulting from GHG emissions resulting in climate change, a high value for liability mitigation would provide powerful incentives for deployment of renewable energy technologies. In international public opinion surveys there is strong support for promoting renewable sources such as solar power and wind power.[10] At the national level, at least 30 nations around the world already have renewable energy contributing more than 20 percent of energy supply. National renewable energy markets are projected to continue to grow strongly in the coming decade and beyond.[11] Some places and at least two countries, Iceland and Norway generate all their electricity using renewable energy already, and many other countries have the set a goal to reach 100% renewable energy in the future. For example, in Denmark the government decided to switch the total energy supply (electricity, mobility and heating/cooling) to 100% renewable energy by 2050.[12]

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 percent of the country's automotive fuel. As a result of this, together with the exploitation of domestic deep water oil sources, Brazil, which years ago had to import a large share of the petroleum needed for domestic consumption, recently reached complete self-sufficiency in oil.[36][37][38]

If you regularly find your lawn furniture blown over, or have to collect it from the neighbour’s yard, your house needs to be repainted every year or two because it constantly gets sand-blasted, and where the trees have funny shapes (and not because your power company has been doing the pruning), that is when you know you live in a windy place where a wind turbine is likely to make economic sense.
Renewable energy technology has sometimes been seen as a costly luxury item by critics, and affordable only in the affluent developed world. This erroneous view has persisted for many years, but 2015 was the first year when investment in non-hydro renewables, was higher in developing countries, with $156 billion invested, mainly in China, India, and Brazil.[134]
Moving towards energy sustainability will require changes not only in the way energy is supplied, but in the way it is used, and reducing the amount of energy required to deliver various goods or services is essential. Opportunities for improvement on the demand side of the energy equation are as rich and diverse as those on the supply side, and often offer significant economic benefits.[60]
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.
Meanwhile, we enjoy life grid intertied here in northern California. Our daughters and their families are nearby using their independent living skills to make their own homes.  One daughter has designed and sold 300 off-grid or gridtie solar electric systems since the first of the year.  The other is baking bread today and figuring out what to do with the multitude of tomatillos, squash and eggplant that are spilling out of our garden.  I’m so proud of my tribe!
The generator, which is approximately 34% of the wind turbine cost, includes the electrical generator,[38][39] the control electronics, and most likely a gear box (e.g. planetary gear box),[40] adjustable-speed drive or continuously variable transmission[41] component for converting the low-speed incoming rotation to high-speed rotation suitable for generating electricity.
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.
Going forward, there is hope for the small wind future! Certification programs are under way in various places to provide real turbine performance data. In North America this is being spearheaded by the Small Wind Certification Council, which requires third-party certification of turbine performance in a standardized fashion. Manufacturers will no longer be able to fudge power curves, or specify ‘rated power’ at hurricane-force wind speeds. This will allow you, the consumer, to compare turbines on a much more even footing.

Innovative programs around the country now make it possible for all environmentally conscious energy consumers to support renewable energy directly by participating in the "green" power market. The willingness to pay for the benefits of increasing our renewable energy supplies can be tapped within any market structure and by any size or type of energy consumer.


Other cities won’t have it so easy. Take Atlanta. Residents buy energy from Georgia Power, which is owned by investors. As things stand, Atlantans have no control over how their power is generated, though that may change. In 2019, Georgia Power, by state law, has to update its energy plan. Ted Terry, director of the Georgia chapter of the Sierra Club, says the nonprofit is working with Atlanta officials to incorporate renewables, primarily solar, into the state’s plan. Developing such energy sources on a scale that can power a metro area with 5.8 million people, as in Atlanta, or 7.68 million in the San Francisco Bay Area, or 3.3 million in San Diego, will prove challenging. But it doesn’t seem impossible. In 2015, California set a goal of deriving 50 percent of its energy from renewable sources by 2030. Its three investor-owned utilities—Pacific Gas & Electric, Southern California Edison and San Diego Gas & Electric—are poised to achieve that goal just two years from now, or ten years early.
Conventional hydroelectricity works very well in conjunction with solar power, water can be held back or released from a reservoir behind a dam as required. Where a suitable river is not available, pumped-storage hydroelectricity uses solar power to pump water to a high reservoir on sunny days then the energy is recovered at night and in bad weather by releasing water via a hydroelectric plant to a low reservoir where the cycle can begin again.[109] However, this cycle can lose 20% of the energy to round trip inefficiencies, this plus the construction costs add to the expense of implementing high levels of solar power.
Single small turbines below 100 kilowatts are used for homes, telecommunications dishes, or water pumping. Small turbines are sometimes used in connection with diesel generators, batteries, and photovoltaic systems. These systems are called hybrid wind systems and are typically used in remote, off-grid locations where a connection to the utility grid is not available.
How accurate are these numbers? This is the energy production a good horizontal-axis wind turbine can reach, if installed at the perfect site and height. These are the upper limit though, if your turbine produces anywhere near the number predicted by this table you should be doing your happy-dance! Most small wind turbine installations underperform significantly, in fact, the average seems to be about half of the predicted energy production (and many do not even reach that). There can be many reasons for the performance shortfall; poor site selection,  with more turbulent air than expected often has much to do with it. The reports in the ‘real world’ section following below illustrate this point. Many small wind turbines do not reach 30% overall efficiency, some are close to 0% (this is no joke!), so these numbers have only one direction to go. For off-grid battery charging wind turbines you should deduct 20 – 30% of the predicted numbers, due to the lower efficiency of a turbine tied to batteries, and the losses involved in charging batteries.

Markets for second-generation technologies are strong and growing, but only in a few countries. The challenge is to broaden the market base for continued growth worldwide. Strategic deployment in one country not only reduces technology costs for users there, but also for those in other countries, contributing to overall cost reductions and performance improvement.


Features:Low wind speed start-up(2m/s), high wind power utilization, light,cute, low vibration.Human-friendly design,easy to install and maintain.Blades using reinforced glass fiber, helped with optimized structure and aerodynamic shape, it enhanced wind power coefficient and power generating capacity.Using patented permanent magnet generator and special stator, it effectively reduces torque resistance and guarantees the stability.The 24V DC 400W wind turbine is an eco.
At Bodine-Scott, our renewable energy options have helped dozens of local homes and businesses reduce their utility bills and any negative environmental impact from the use of traditional energy sources. Our technicians are NABCEP-certified experts, and we keep all of our staff informed and up to date on the latest developments in the solar industries. Our average customer sees a 50 percent reduction in utility costs, to say nothing of the invaluable reduction in environmental impact that comes from using clean energy. If you are serious about making an investment in the future of your home and the Earth, contact us today to speak with one of our renewable energy experts.
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 energy in the wind goes up with the cube of the wind speed. Double the wind speed and you have 2 * 2 * 2 = 8 times the energy! Sit back and let the full weight of that sink in for a moment: It means that even a small difference in annual average wind speed will make a BIG difference in how much your wind turbine will produce: Putting that turbine in a place that has just 10% more wind will net you 1.1 * 1.1 * 1.1 = 1.33 = a full 33% more energy!

These high strength magnets are usually made from rare earth materials such as neodymium iron (NdFe), or samarium cobalt (SmCo) eliminating the need for the field windings to provide a constant magnetic field, leading to a simpler, more rugged construction. Wound field windings have the advantage of matching their magnetism (and therefore power) with the varying wind speed but require an external energy source to generate the required magnetic field.
Turbines used in wind farms for commercial production of electric power are usually three-bladed. These have low torque ripple, which contributes to good reliability. The blades are usually colored white for daytime visibility by aircraft and range in length from 20 to 80 meters (66 to 262 ft). The size and height of turbines increase year by year. Offshore wind turbines are built up to 8(MW) today and have a blade length up to 80 meters (260 ft). Usual tubular steel towers of multi megawatt turbines have a height of 70 m to 120 m and in extremes up to 160 m.
^ Jump up to: a b c d Alsema, E.A.; Wild – Scholten, M.J. de; Fthenakis, V.M. Environmental impacts of PV electricity generation – a critical comparison of energy supply options Archived 6 March 2012 at the Wayback Machine. ECN, September 2006; 7p. Presented at the 21st European Photovoltaic Solar Energy Conference and Exhibition, Dresden, Germany, 4–8 September 2006.
Wave power, which captures the energy of ocean surface waves, and tidal power, converting the energy of tides, are two forms of hydropower with future potential; however, they are not yet widely employed commercially. A demonstration project operated by the Ocean Renewable Power Company on the coast of Maine, and connected to the grid, harnesses tidal power from the Bay of Fundy, location of world's highest tidal flow. Ocean thermal energy conversion, which uses the temperature difference between cooler deep and warmer surface waters, has currently no economic feasibility.
Ross, something of a libertarian at heart, entered politics because he was ticked off that the municipal code prohibited him from paving the driveway to his historic home entirely in period-appropriate brick. (The code required some concrete.) He joined the city council in 2008 and was elected to his first term as mayor in 2014. He often likens the city to “Mayberry R.F.D.,” and it does have a town square with a courthouse, a coffee shop where you’re bound to run into people you know and a swimming hole. But it also has Southwestern University, and in 2010 university officials, following a student initiative, told the city council they wanted their electricity to come from renewable sources. The city had already set a goal of getting 30 percent of its power that way, but now, Ross and his colleagues saw their opportunity.
It all started in Vermont in 1997. Our passion for protecting the environment led us to our mission: to use the power of consumer choice to change the way power is made. Today, as the longest-serving renewable energy retailer, we remain committed to sustainability every step of the way. By offering only products with an environmental benefit and operating with a zero-carbon footprint, we’re living our promise to the planet, inside and out.
The life-cycle greenhouse-gas emissions of solar power are in the range of 22 to 46 gram (g) per kilowatt-hour (kWh) depending on if solar thermal or solar PV is being analyzed, respectively. With this potentially being decreased to 15 g/kWh in the future.[121] For comparison (of weighted averages), a combined cycle gas-fired power plant emits some 400–599 g/kWh,[122] an oil-fired power plant 893 g/kWh,[122] a coal-fired power plant 915–994 g/kWh[123] or with carbon capture and storage some 200 g/kWh, and a geothermal high-temp. power plant 91–122 g/kWh.[122] The life cycle emission intensity of hydro, wind and nuclear power are lower than solar's as of 2011 as published by the IPCC, and discussed in the article Life-cycle greenhouse-gas emissions of energy sources. Similar to all energy sources were their total life cycle emissions primarily lay in the construction and transportation phase, the switch to low carbon power in the manufacturing and transportation of solar devices would further reduce carbon emissions. BP Solar owns two factories built by Solarex (one in Maryland, the other in Virginia) in which all of the energy used to manufacture solar panels is produced by solar panels. A 1-kilowatt system eliminates the burning of approximately 170 pounds of coal, 300 pounds of carbon dioxide from being released into the atmosphere, and saves up to 105 gallons of water consumption monthly.[124]
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.
^ Jump up to: a b c Fridleifsson,, Ingvar B.; Bertani, Ruggero; Huenges, Ernst; Lund, John W.; Ragnarsson, Arni; Rybach, Ladislaus (11 February 2008). O. Hohmeyer and T. Trittin, ed. "The possible role and contribution of geothermal energy to the mitigation of climate change" (PDF). Luebeck, Germany: 59–80. Archived from the original (pdf) on 22 July 2011. Retrieved 6 April 2009.
With investment subsidies, the financial burden falls upon the taxpayer, while with feed-in tariffs the extra cost is distributed across the utilities' customer bases. While the investment subsidy may be simpler to administer, the main argument in favour of feed-in tariffs is the encouragement of quality. Investment subsidies are paid out as a function of the nameplate capacity of the installed system and are independent of its actual power yield over time, thus rewarding the overstatement of power and tolerating poor durability and maintenance. Some electric companies offer rebates to their customers, such as Austin Energy in Texas, which offers $2.50/watt installed up to $15,000.[96]
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