In 2011, the International Energy Agency said that "the development of affordable, inexhaustible and clean solar energy technologies will have huge longer-term benefits. It will increase countries' energy security through reliance on an indigenous, inexhaustible and mostly import-independent resource, enhance sustainability, reduce pollution, lower the costs of mitigating climate change, and keep fossil fuel prices lower than otherwise. These advantages are global. Hence the additional costs of the incentives for early deployment should be considered learning investments; they must be wisely spent and need to be widely shared".[49] Italy has the largest proportion of solar electricity in the world, in 2015 solar supplied 7.8% of electricity demand in Italy.[54] In 2016, after another year of rapid growth, solar generated 1.3% of global power.[55]
The U.S. Environmental Protection Agency (USEPA) Green Power Partnership is a voluntary program that supports the organizational procurement of renewable electricity by offering expert advice, technical support, tools and resources. This can help organizations lower the transaction costs of buying renewable power, reduce carbon footprint, and communicate its leadership to key stakeholders.[88]
Electricity for my off-grid cabin comes from solar and wind power stored in a bank of four 6-volt golf cart batteries wired for a 12-volt system. A charge controller and battery minder keep my system from under- or overcharging. The whole shebang cost me less than $1,000, and I have lights, fans, a television and stereo, refrigeration, and a disco ball that goes up for special occasions.
“University of Texas Study Highlights Wind’s Low Cost” • Wind, solar and natural gas have the lowest levelized cost of electricity in the majority of counties across the United States, according to a new report from The University of Texas at Austin’s Energy Institute, part of a series of white papers on the Full Cost of Electricity. [Into the Wind]
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.
In 2010, the United States led the world in geothermal electricity production with 3,086 MW of installed capacity from 77 power plants;[132] the largest group of geothermal power plants in the world is located at The Geysers, a geothermal field in California.[133] The Philippines follows the US as the second highest producer of geothermal power in the world, with 1,904 MW of capacity online; geothermal power makes up approximately 18% of the country's electricity generation.[132]
The energy it calculates is in kWh per year, the diameter of the wind turbine rotor is in meters, the wind speed is annual average for the turbine hub height in m/s. The equation uses a Weibull wind distribution with a factor of K=2, which is about right for inland sites. An overall efficiency of the turbine, from wind to electrical grid, of 30% is used. That is a reasonable, real-world efficiency number. Here is a table that shows how average annual wind speed, turbine size, and annual energy production relate:
Grid parity, the point at which the cost of photovoltaic electricity is equal to or cheaper than the price of grid power, is more easily achieved in areas with abundant sun and high costs for electricity such as in California and Japan.[80] In 2008, The levelized cost of electricity for solar PV was $0.25/kWh or less in most of the OECD countries. By late 2011, the fully loaded cost was predicted to fall below $0.15/kWh for most of the OECD and to reach $0.10/kWh in sunnier regions. These cost levels are driving three emerging trends: vertical integration of the supply chain, origination of power purchase agreements (PPAs) by solar power companies, and unexpected risk for traditional power generation companies, grid operators and wind turbine manufacturers.[81][dead link]
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.
Solar thermal power stations have been successfully operating in California commercially since the late 1980s, including the largest solar power plant of any kind, the 350 MW Solar Energy Generating Systems. Nevada Solar One is another 64MW plant which has recently opened.[34] Other parabolic trough power plants being proposed are two 50MW plants in Spain, and a 100MW plant in Israel.[35]
Research is also undertaken in this field of artificial photosynthesis. It involves the use of nanotechnology to store solar electromagnetic energy in chemical bonds, by splitting water to produce hydrogen fuel or then combining with carbon dioxide to make biopolymers such as methanol. Many large national and regional research projects on artificial photosynthesis are now trying to develop techniques integrating improved light capture, quantum coherence methods of electron transfer and cheap catalytic materials that operate under a variety of atmospheric conditions.[119] Senior researchers in the field have made the public policy case for a Global Project on Artificial Photosynthesis to address critical energy security and environmental sustainability issues.[120]
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.
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]
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.
Several groups in various sectors are conducting research on Jatropha curcas, a poisonous shrub-like tree that produces seeds considered by many to be a viable source of biofuels feedstock oil.[117] Much of this research focuses on improving the overall per acre oil yield of Jatropha through advancements in genetics, soil science, and horticultural practices. SG Biofuels, a San Diego-based Jatropha developer, has used molecular breeding and biotechnology to produce elite hybrid seeds of Jatropha that show significant yield improvements over first generation varieties.[118] The Center for Sustainable Energy Farming (CfSEF) is a Los Angeles-based non-profit research organization dedicated to Jatropha research in the areas of plant science, agronomy, and horticulture. Successful exploration of these disciplines is projected to increase Jatropha farm production yields by 200-300% in the next ten years.[119]

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.
Between maintenance and repairs, it would greatly help and keep your cost down if you can do some of the work yourself: Being able to safely tilt the turbine tower up or down will save you money. Understanding how the turbine works, how to stop it safely, how to trouble-shoot at least the minor issues can keep you in the black. We understand that installing a wind turbine is not for everyone. In fact, towers are dangerous, and for a good installation the devil is in the details. An experienced installer can make a real difference in putting up a turbine that will work better, and be more reliable over time. We really encourage you to have a professional installer to do the initial installation. However, throwing up your hands and calling your installer for routine maintenance, or every time there is a minor issue, will likely make you an unhappy wind turbine owner (even if it is your installer’s dream).
Wind turbines allow us to harness the power of the wind and turn it into energy. When the wind blows, the turbine's blades spin clockwise, capturing energy. This triggers the main shaft, connected to a gearbox within the nacelle, to spin. The gearbox sends that energy to the generator, converting it to electricity. Electricity then travels down the tower to a transformer, where voltage levels are adjusted to match with the grid.
United Nations' Secretary-General Ban Ki-moon has said that renewable energy has the ability to lift the poorest nations to new levels of prosperity.[14] In October 2011, he "announced the creation of a high-level group to drum up support for energy access, energy efficiency and greater use of renewable energy. The group is to be co-chaired by Kandeh Yumkella, the chair of UN Energy and director general of the UN Industrial Development Organisation, and Charles Holliday, chairman of Bank of America".[147]
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.
Solar energy is the cleanest and most abundant renewable energy source available, and the U.S. has some of the richest solar resources in the world. Solar technologies can harness this energy for a variety of uses, including generating electricity, providing light or a comfortable interior environment, and heating water for domestic, commercial, or industrial use.
The trouble with rated power is that it does not tell you anything about energy production. Your utility company charges you for the energy you consume, not power. Likewise, for a small wind  turbine you should be interested in the energy it will produce, for your particular site, with your particular annual average wind speed. Rated power of the turbine does not do that. To find out about energy production take a look at the tables presented earlier.
Despite these diverse developments, developments in fossil fuel systems almost entirely eliminated any wind turbine systems larger than supermicro size. In the early 1970s, however, anti-nuclear protests in Denmark spurred artisan mechanics to develop microturbines of 22 kW. Organizing owners into associations and co-operatives lead to the lobbying of the government and utilities and provided incentives for larger turbines throughout the 1980s and later. Local activists in Germany, nascent turbine manufacturers in Spain, and large investors in the United States in the early 1990s then lobbied for policies that stimulated the industry in those countries.
A heat pump is a device that provides heat energy from a source of heat to a destination called a "heat sink". Heat pumps are designed to move thermal energy opposite to the direction of spontaneous heat flow by absorbing heat from a cold space and releasing it to a warmer one. A solar-assisted heat pump represents the integration of a heat pump and thermal solar panels in a single integrated system. Typically these two technologies are used separately (or only placing them in parallel) to produce hot water.[180] In this system the solar thermal panel performs the function of the low temperature heat source and the heat produced is used to feed the heat pump's evaporator.[181] The goal of this system is to get high COP and then produce energy in a more efficient and less expensive way.
Photovoltaics (PV) uses solar cells assembled into solar panels to convert sunlight into electricity. It's a fast-growing technology doubling its worldwide installed capacity every couple of years. PV systems range from small, residential and commercial rooftop or building integrated installations, to large utility-scale photovoltaic power station. The predominant PV technology is crystalline silicon, while thin-film solar cell technology accounts for about 10 percent of global photovoltaic deployment. In recent years, PV technology has improved its electricity generating efficiency, reduced the installation cost per watt as well as its energy payback time, and has reached grid parity in at least 30 different markets by 2014.[115] Financial institutions are predicting a second solar "gold rush" in the near future.[116][117][118]
“What Changes Will Maine’s New Government Bring to Your Life?” • Swept to sizable majorities in last week’s elections, Maine’s Democrats will be in full control of state government for the first time since 2010. They are likely to look for ways to address a number of pressing issues, one of which is climate change. [Kennebec Journal & Morning Sentinel]
In 2007, the US Congress directed the Department of Energy to report on ways to reduce water consumption by CSP. The subsequent report noted that dry cooling technology was available that, although more expensive to build and operate, could reduce water consumption by CSP by 91 to 95 percent. A hybrid wet/dry cooling system could reduce water consumption by 32 to 58 percent.[138] A 2015 report by NREL noted that of the 24 operating CSP power plants in the US, 4 used dry cooling systems. The four dry-cooled systems were the three power plants at the Ivanpah Solar Power Facility near Barstow, California, and the Genesis Solar Energy Project in Riverside County, California. Of 15 CSP projects under construction or development in the US as of March 2015, 6 were wet systems, 7 were dry systems, 1 hybrid, and 1 unspecified.
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]
Through collaboration, smaller buyers can benefit from economies of scale, while larger buyers can continue to see cost benefits while achieving their renewable energy goals. Aggregation allows companies to procure in a mutually beneficial way with relatively little give and take. For that reason, RMI believes this marks “the beginning of a trend,” Haley said.  
Wind power first appeared in Europe during the Middle Ages. The first historical records of their use in England date to the 11th or 12th centuries and there are reports of German crusaders taking their windmill-making skills to Syria around 1190.[6] By the 14th century, Dutch windmills were in use to drain areas of the Rhine delta. Advanced wind turbines were described by Croatian inventor Fausto Veranzio. In his book Machinae Novae (1595) he described vertical axis wind turbines with curved or V-shaped blades.
A heat pump is a device that provides heat energy from a source of heat to a destination called a "heat sink". Heat pumps are designed to move thermal energy opposite to the direction of spontaneous heat flow by absorbing heat from a cold space and releasing it to a warmer one. A solar-assisted heat pump represents the integration of a heat pump and thermal solar panels in a single integrated system. Typically these two technologies are used separately (or only placing them in parallel) to produce hot water.[180] In this system the solar thermal panel performs the function of the low temperature heat source and the heat produced is used to feed the heat pump's evaporator.[181] The goal of this system is to get high COP and then produce energy in a more efficient and less expensive way.
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Renewable energy technologies are getting cheaper, through technological change and through the benefits of mass production and market competition. A 2011 IEA report said: "A portfolio of renewable energy technologies is becoming cost-competitive in an increasingly broad range of circumstances, in some cases providing investment opportunities without the need for specific economic support," and added that "cost reductions in critical technologies, such as wind and solar, are set to continue."[99]

This solar resource map provides a summary of the estimated solar energy available for power generation and other energy applications. It represents the average daily/yearly sum of electricity production from a 1 kW-peak grid-connected solar PV power plant covering the period from 1994/1999/2007 (depending on the geographical region) to 2015. Source: Global Solar Atlas]