Many industrialized nations have installed significant solar power capacity into their grids to supplement or provide an alternative to conventional energy sources while an increasing number of less developed nations have turned to solar to reduce dependence on expensive imported fuels (see solar power by country). Long distance transmission allows remote renewable energy resources to displace fossil fuel consumption. Solar power plants use one of two technologies:
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.
^ 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.
Smart grid refers to a class of technology people are using to bring utility electricity delivery systems into the 21st century, using computer-based remote control and automation.[65] These systems are made possible by two-way communication technology and computer processing that has been used for decades in other industries. They are beginning to be used on electricity networks, from the power plants and wind farms all the way to the consumers of electricity in homes and businesses. They offer many benefits to utilities and consumers—mostly seen in big improvements in energy efficiency on the electricity grid and in the energy users’ homes and offices.[65]
With feed-in tariffs, the financial burden falls upon the consumer. They reward the number of kilowatt-hours produced over a long period of time, but because the rate is set by the authorities, it may result in perceived overpayment. The price paid per kilowatt-hour under a feed-in tariff exceeds the price of grid electricity. Net metering refers to the case where the price paid by the utility is the same as the price charged.
Since you are working hard to read this rather lengthy article, here is some entertainment. The ‘intermission’ if you like. So, put your feet up and enjoy the next picture: It’s a prime example of much that is wrong with the small wind world. The fact that an installer would even consider installing in a place like that. Customers that are too uninformed to know better (and their installer clearly is not interested in educating them). Turbine manufacturers that deliver standard towers that are much too short to be effective; this tower plus turbine is just 23 feet tall! Then there is the claim by the manufacturer (dutifully parroted by the installer) that this turbine will offset “up to 30%” of their electricity bill. The last one is not really a lie I suppose: If in reality it offsets just 2% of the owners bill, technically that still falls within that “up to 30%”…

In 2010, the International Energy Agency predicted that global solar PV capacity could reach 3,000 GW or 11% of projected global electricity generation by 2050—enough to generate 4,500 TWh of electricity.[40] Four years later, in 2014, the agency projected that, under its "high renewables" scenario, solar power could supply 27% of global electricity generation by 2050 (16% from PV and 11% from CSP).[2]
Several refineries that can process biomass and turn it into ethanol are built by companies such as Iogen, POET, and Abengoa, while other companies such as the Verenium Corporation, Novozymes, and Dyadic International[163] are producing enzymes which could enable future commercialization. The shift from food crop feedstocks to waste residues and native grasses offers significant opportunities for a range of players, from farmers to biotechnology firms, and from project developers to investors.[164]
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.

Then the faster the coil of wire rotates, the greater the rate of change by which the magnetic flux is cut by the coil and the greater is the induced emf within the coil. Similarly, if the magnetic field is made stronger, the induced emf will increase for the same rotational speed. Thus: emf ∝ Φn. Where: “Φ” is the magnetic-field flux and “n” is the speed of rotation. Also, the polarity of the generated voltage depends on the direction of the magnetic lines of flux and the direction of movement of the conductor.
The locations with highest annual solar irradiance lie in the arid tropics and subtropics. Deserts lying in low latitudes usually have few clouds, and can receive sunshine for more than ten hours a day.[86][87] These hot deserts form the Global Sun Belt circling the world. This belt consists of extensive swathes of land in Northern Africa, Southern Africa, Southwest Asia, Middle East, and Australia, as well as the much smaller deserts of North and South America.[88] Africa's eastern Sahara Desert, also known as the Libyan Desert, has been observed to be the sunniest place on Earth according to NASA.[89][90]

Another situation where a small wind turbine can make good sense is in case your province, state, or country has rebates or other incentives that make it cheap to install one (just keep ongoing maintenance and repair cost in mind as well). While we would like to advocate responsible spending of government money, the small wind industry needs many more customers to mature. It takes time and installation numbers for manufacturers to work out the bugs, make better turbines, and make them cheaper.
There have been "not in my back yard" (NIMBY) concerns relating to the visual and other impacts of some wind farms, with local residents sometimes fighting or blocking construction.[192] In the United States, the Massachusetts Cape Wind project was delayed for years partly because of aesthetic concerns. However, residents in other areas have been more positive. According to a town councilor, the overwhelming majority of locals believe that the Ardrossan Wind Farm in Scotland has enhanced the area.[193]
Consumers throughout the United States have a third green power option: Renewable Energy Certificates (RECs or sometimes "green tags"). A REC represents the environmental attributes or benefits of renewable electricity generation (usually one credit = one kilowatt-hour). RECs can be purchased in almost any quantity and are usually available from someone other than your electricity provider. What you pay for is the benefit of adding clean, renewable energy generation to the regional or national electricity grid. The overall environmental benefit of purchasing a green pricing or green marketing product versus RECs is exactly the same. RECs provide a "green" option for people in any state, but are ideal for people who live in states where green pricing and green marketing options are not available. 
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.
The use of a gearbox allows for better matching of the generator speed to that of the turbine but the disadvantage of using a gearbox is that as a mechanical component it is subjected to wear and tear reducing the efficiency of the system. Direct drive however may be more simple and efficient, but the generators rotor shaft and bearings are subjected to the full weight and rotational force of the rotor blades.

Some people, including Greenpeace founder and first member Patrick Moore,[67][68][69] George Monbiot,[70] Bill Gates[71] and James Lovelock[72] have specifically classified nuclear power as green energy. Others, including Greenpeace's Phil Radford[73][74] disagree, claiming that the problems associated with radioactive waste and the risk of nuclear accidents (such as the Chernobyl disaster) pose an unacceptable risk to the environment and to humanity. However, newer nuclear reactor designs are capable of utilizing what is now deemed "nuclear waste" until it is no longer (or dramatically less) dangerous, and have design features that greatly minimize the possibility of a nuclear accident. These designs have yet to be commercialized. (See: Molten salt reactor)
The electrical machine most commonly used for wind turbines applications are those acting as generators, with synchronous generators and induction generators (as shown) being commonly used in larger wind turbine generators, while smaller and home made wind turbines tend to use a low speed DC generator or Dynamo as they are small, cheap and a lot easier to connect up.
Jump up ^ James, Paul; Magee, Liam; Scerri, Andy; Steger, Manfred B. (2015). Urban Sustainability in Theory and Practice:. London: Routledge.; Liam Magee; Andy Scerri; Paul James; Jaes A. Thom; Lin Padgham; Sarah Hickmott; Hepu Deng; Felicity Cahill (2013). "Reframing social sustainability reporting: Towards an engaged approach". Environment, Development and Sustainability. Springer.
The home wind Generator systems are designed for reliable power output for the next 30 years or so. With every price increase of the utility company power your investment gets better all the time. Utility costs are rising all over and will accelerate over the next few years. We expect the cost of electricity to rise and double over Obamas term in office due to cap and trade and increased regulation and market pressure.
Small-scale turbines are expensive (one manufacturer says a typical system costs $40,000 to $60,000 to install), though some of that outlay can be offset by federal and local tax credits. Experts recommend that you buy one certified by the Small Wind Certification Council. Turbine manufacturers include Bergey Wind Power, Britwind and Xzeres Wind; look on their websites for local dealers.

Wind-to-rotor efficiency (including rotor blade friction and drag) are among the factors impacting the final price of wind power.[16] Further inefficiencies, such as gearbox losses, generator and converter losses, reduce the power delivered by a wind turbine. To protect components from undue wear, extracted power is held constant above the rated operating speed as theoretical power increases at the cube of wind speed, further reducing theoretical efficiency. In 2001, commercial utility-connected turbines deliver 75% to 80% of the Betz limit of power extractable from the wind, at rated operating speed.[17][18][needs update]

For several years, worldwide growth of solar PV was driven by European deployment, but has since shifted to Asia, especially China and Japan, and to a growing number of countries and regions all over the world, including, but not limited to, Australia, Canada, Chile, India, Israel, Mexico, South Africa, South Korea, Thailand, and the United States.