The incentive to use 100% renewable energy, for electricity, transport, or even total primary energy supply globally, has been motivated by global warming and other ecological as well as economic concerns. The Intergovernmental Panel on Climate Change has said that there are few fundamental technological limits to integrating a portfolio of renewable energy technologies to meet most of total global energy demand. Renewable energy use has grown much faster than even advocates anticipated.[148] At the national level, at least 30 nations around the world already have renewable energy contributing more than 20% of energy supply. Also, Professors S. Pacala and Robert H. Socolow have developed a series of "stabilization wedges" that can allow us to maintain our quality of life while avoiding catastrophic climate change, and "renewable energy sources," in aggregate, constitute the largest number of their "wedges".[149]
Renewable energy projects in many developing countries have demonstrated that renewable energy can directly contribute to poverty reduction by providing the energy needed for creating businesses and employment. Renewable energy technologies can also make indirect contributions to alleviating poverty by providing energy for cooking, space heating, and lighting. Renewable energy can also contribute to education, by providing electricity to schools.[140]
Large national and regional research projects on artificial photosynthesis are designing nanotechnology-based systems that use solar energy to split water into hydrogen fuel.[52] and a proposal has been made for a Global Artificial Photosynthesis project[53] In 2011, researchers at the Massachusetts Institute of Technology (MIT) developed what they are calling an "Artificial Leaf", which is capable of splitting water into hydrogen and oxygen directly from solar power when dropped into a glass of water. One side of the "Artificial Leaf" produces bubbles of hydrogen, while the other side produces bubbles of oxygen.[54]
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.

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The incentive to use 100% renewable energy, for electricity, transport, or even total primary energy supply globally, has been motivated by global warming and other ecological as well as economic concerns. The Intergovernmental Panel on Climate Change has said that there are few fundamental technological limits to integrating a portfolio of renewable energy technologies to meet most of total global energy demand. Renewable energy use has grown much faster than even advocates anticipated.[148] At the national level, at least 30 nations around the world already have renewable energy contributing more than 20% of energy supply. Also, Professors S. Pacala and Robert H. Socolow have developed a series of "stabilization wedges" that can allow us to maintain our quality of life while avoiding catastrophic climate change, and "renewable energy sources," in aggregate, constitute the largest number of their "wedges".[149]
In the next tutorial about Wind Turbine Generators we will look at DC machines and how we can use a DC Generator to produce electricity from the power of the wind. To learn more about “Wind Turbine Generators”, or obtain more wind energy information about the various wind turbine generating systems available, or to explore the advantages and disadvantages of wind energy, Click Here to get your copy of one of the top “Wind Turbine Guides” today direct from Amazon.
Subsequently, Spain, Italy, Greece—that enjoyed an early success with domestic solar-thermal installations for hot water needs—and France introduced feed-in tariffs. None have replicated the programmed decrease of FIT in new contracts though, making the German incentive relatively less and less attractive compared to other countries. The French and Greek FIT offer a high premium (EUR 0.55/kWh) for building integrated systems. California, Greece, France and Italy have 30–50% more insolation than Germany making them financially more attractive. The Greek domestic "solar roof" programme (adopted in June 2009 for installations up to 10 kW) has internal rates of return of 10–15% at current commercial installation costs, which, furthermore, is tax free.
In 2016, the city bought its way out of a contract providing energy derived from fossil fuels and arranged to get its power from a 97-unit windfarm in Adrian, Texas, about 500 miles away in the Texas Panhandle. Georgetown doesn’t own the farm, but its agreement allowed the owners to get the financing to build it. This spring, Georgetown is adding power from a 154-megawatt solar farm being built by NRG Energy in Fort Stockton, 340 miles to the west of the city.
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]

The picture the company is using to sell this on Amazon is not of the turbine they are selling, but a picture of the best-selling South-West Windpower Air X turbine and I bought this item believing it to be this turbine. I also have one of these turbines which has run faultlessly now for 7 years. I am very disappointed with the Sunforce and often feel like throwing into the sea! It's a piece of junk!!


Solar energy, radiant light and heat from the sun, is harnessed using a range of ever-evolving technologies such as solar heating, photovoltaics, concentrated solar power (CSP), concentrator photovoltaics (CPV), solar architecture and artificial photosynthesis.[49][50] Solar technologies are broadly characterized as either passive solar or active solar depending on the way they capture, convert and distribute solar energy. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light dispersing properties, and designing spaces that naturally circulate air. Active solar technologies encompass solar thermal energy, using solar collectors for heating, and solar power, converting sunlight into electricity either directly using photovoltaics (PV), or indirectly using concentrated solar power (CSP).
A recent UK Government document states that "projects are generally more likely to succeed if they have broad public support and the consent of local communities. This means giving communities both a say and a stake".[194] In countries such as Germany and Denmark many renewable projects are owned by communities, particularly through cooperative structures, and contribute significantly to overall levels of renewable energy deployment.[195][196]
SquareTrade Protection Plans are only valid for new or Amazon certified refurbished products purchased at Amazon in the last 30 days. By purchasing this Protection Plan you agree to the Protection Plan Terms & Conditions (http://www.squaretrade.com/terms-standard). Your Protection Plan Terms & Conditions will be delivered via email within 24 hours of purchase
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.

There is no energy in the wind at those wind speeds, nothing to harvest for the turbine. While it may make you feel good to see your expensive yard toy spin, it is not doing anything meaningful in a breeze like that: To give you some idea, a wind turbine with a diameter of 6 meters (pretty large as small wind turbines go) can realistically produce just 120 Watt at 3.5 m/s wind speed. That same turbine would be rated at 6 kW (or more, see the next section), so energy production at cut-in really is just a drop in the bucket. What is more, due to the way grid-tie inverters work, you are about as likely to be loosing energy around cut-in wind speed to keep the inverter powered, as you are in making any energy, resulting in a net-loss of electricity production.
Since 2013 the world's highest-situated wind turbine was made and installed by WindAid and is located at the base of the Pastoruri Glacier in Peru at 4,877 meters (16,001 ft) above sea level.[94] The site uses the WindAid 2.5 kW wind generator to supply power to a small rural community of micro entrepreneurs who cater to the tourists who come to the Pastoruri glacier.[95]
Floatovoltaics are an emerging form of PV systems that float on the surface of irrigation canals, water reservoirs, quarry lakes, and tailing ponds. Several systems exist in France, India, Japan, Korea, the United Kingdom and the United States.[149][150][151][152] These systems reduce the need of valuable land area, save drinking water that would otherwise be lost through evaporation, and show a higher efficiency of solar energy conversion, as the panels are kept at a cooler temperature than they would be on land.[153] Although not floating, other dual-use facilities with solar power include fisheries.[154]
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.
Permanent magnets for wind turbine generators contain rare earth metals such as Nd, Pr, Tb, and Dy. Systems that use magnetic direct drive turbines require higher amounts of rare metals. Therefore, an increase in wind production would increase the demand for these resources. It is estimated that the additional demand for Nd in 2035 may be 4,000 to 18,000 tons and Dy could see an increase of 200 to 1200 tons. These values represent a quarter to half of current production levels. However, since technologies are developing rapidly, driven by supply and price of materials these estimated levels are extremely uncertain.[55]

All electrical turbine generators work because of the effects of moving a magnetic field past an electrical coil. When electrons flow through an electrical coil, a magnetic field is created around it. Likewise, when a magnetic field moves past a coil of wire, a voltage is induced in the coil as defined by Faraday’s law of magnetic induction causing electrons to flow.


There are more specific questions you’ll have to ask yourself about your location and home—e.g., is my next-door neighbor’s oak tree going to block all my sunlight? You’ll also have to take local weather conditions into consideration. Luckily, there are plenty of other resources to help you find your solar potential. See our Tools section for more info.
When energy is purchased from the electricity network, the power reaching the consumer will not necessarily be generated from green energy sources. The local utility company, electric company, or state power pool buys their electricity from electricity producers who may be generating from fossil fuel, nuclear or renewable energy sources. In many countries green energy currently provides a very small amount of electricity, generally contributing less than 2 to 5% to the overall pool. In some U.S. states, local governments have formed regional power purchasing pools using Community Choice Aggregation and Solar Bonds to achieve a 51% renewable mix or higher, such as in the City of San Francisco.[76]
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.

In an electricity system without grid energy storage, generation from stored fuels (coal, biomass, natural gas, nuclear) must be go up and down in reaction to the rise and fall of solar electricity (see load following power plant). While hydroelectric and natural gas plants can quickly follow solar being intermittent due to the weather, coal, biomass and nuclear plants usually take considerable time to respond to load and can only be scheduled to follow the predictable variation. Depending on local circumstances, beyond about 20–40% of total generation, grid-connected intermittent sources like solar tend to require investment in some combination of grid interconnections, energy storage or demand side management. Integrating large amounts of solar power with existing generation equipment has caused issues in some cases. For example, in Germany, California and Hawaii, electricity prices have been known to go negative when solar is generating a lot of power, displacing existing baseload generation contracts.[107][108]
Even if you can’t directly purchase and install a solar system because you rent your home, have inadequate solar resources, or lack financing, you may still benefit from switching to solar electricity, and there numerous business models that make solar easier, cheaper, and more accessible. Options such as community or shared solar programs, solar leases, and power-purchase agreements allow millions of households to take advantage of solar energy. Learn about the various ways you can go solar.

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]
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]
U.S. President Barack Obama's American Recovery and Reinvestment Act of 2009 includes more than $70 billion in direct spending and tax credits for clean energy and associated transportation programs. Leading renewable energy companies include First Solar, Gamesa, GE Energy, Hanwha Q Cells, Sharp Solar, Siemens, SunOpta, Suntech Power, and Vestas.[142]
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]

Renewable energy and energy efficiency are sometimes said to be the "twin pillars" of sustainable energy policy. Both resources must be developed in order to stabilize and reduce carbon dioxide emissions. Efficiency slows down energy demand growth so that rising clean energy supplies can make deep cuts in fossil fuel use. If energy use grows too fast, renewable energy development will chase a receding target. A recent historical analysis has demonstrated that the rate of energy efficiency improvements has generally been outpaced by the rate of growth in energy demand, which is due to continuing economic and population growth. As a result, despite energy efficiency gains, total energy use and related carbon emissions have continued to increase. Thus, given the thermodynamic and practical limits of energy efficiency improvements, slowing the growth in energy demand is essential.[61] However, unless clean energy supplies come online rapidly, slowing demand growth will only begin to reduce total emissions; reducing the carbon content of energy sources is also needed. Any serious vision of a sustainable energy economy thus requires commitments to both renewables and efficiency.[62]


^ 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.
The most common type of residential solar is called solar PV. The PV stands for “photovoltaic,” and a solar PV system is a electrical system that consists of solar panels, an inverter, a meter, and a few other components (mounting, cabling, etc.). A solar PV system requires little to no maintenance for years, and if you’re in a place with the right amount of sunlight, you can end up saving money, while also going green.
Biomass, biogas and biofuels are burned to produce heat/power and in doing so harm the environment. Pollutants such as sulphurous oxides (SOx), nitrous oxides (NOx), and particulate matter (PM) are produced from this combustion; the World Health Organisation estimates that 7 million premature deaths are caused each year by air pollution.[102] Biomass combustion is a major contributor.[102][103][104]
Solar panels converts the sun's light in to usable solar energy using N-type and P-type semiconductor material.  When sunlight is absorbed by these materials, the solar energy knocks electrons loose from their atoms, allowing the electrons to flow through the material to produce electricity. This process of converting light (photons) to electricity (voltage) is called the photovoltaic (PV) effect.  Currently solar panels convert most of the visible light spectrum and about half of the ultraviolet and infrared light spectrum to usable solar energy.

Dale Ross, the mayor of Georgetown, Texas, has a big smile, a big handshake and a big personality. In last year’s election, he won big, with 72 percent of the vote. The key to his success? “Without being too self-reflective,” he says, “I just like people.” He’s a Republican, and his priorities are party staples: go light on regulation, be tough on crime, keep taxes low. But the thing that is winning him international renown is straight out of the liberal playbook—green power. Thanks to his (big) advocacy, Georgetown (pop. 67,000) last year became the largest city in the United States to be powered entirely by renewable energy.
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
Turbines used in residential applications can range in size from 400 Watts to 100 kW (100 kW for very large loads), depending on the amount of electricity you want to generate. For residential applications, you should establish an energy budget and see whether financial incentives are available. This information will help determine the turbine size you will need. Because energy efficiency is usually less expensive than energy production, making your house more energy efficient will probably be more cost effective and will reduce the size of the wind turbine you need (see How Can I Make My Home More Energy Efficient?). Wind turbine manufacturers, dealers, and installers can help you size your system based on your electricity needs and the specifics of your local wind resource and micro-siting.
Where the reputable, and more expensive manufacturers are good in honouring their warranties, you are likely on your own with the cheap stuff. Even with a good warranty, take our word for it that you would much rather not make use of it. Even if the manufacturer supplies replacement parts, it is still expensive to install them. Not to mention that your turbine will not be making energy meanwhile.
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.
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