A hybrid system combines (C)PV and CSP with one another or with other forms of generation such as diesel, wind and biogas. The combined form of generation may enable the system to modulate power output as a function of demand or at least reduce the fluctuating nature of solar power and the consumption of non renewable fuel. Hybrid systems are most often found on islands.

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.

Low Temperature Geothermal[29] refers to the use of the outer crust of the earth as a Thermal Battery to facilitate Renewable thermal energy for heating and cooling buildings, and other refrigeration and industrial uses. In this form of Geothermal, a Geothermal Heat Pump and Ground-coupled heat exchanger are used together to move heat energy into the earth (for cooling) and out of the earth (for heating) on a varying seasonal basis. Low temperature Geothermal (generally referred to as "GHP") is an increasingly important renewable technology because it both reduces total annual energy loads associated with heating and cooling, and it also flattens the electric demand curve eliminating the extreme summer and winter peak electric supply requirements. Thus Low Temperature Geothermal/GHP is becoming an increasing national priority with multiple tax credit support[60] and focus as part of the ongoing movement toward Net Zero Energy.[61][30] New York City has even just passed a law[62] to require GHP anytime is shown to be economical with 20 year financing including the Socialized Cost of Carbon.[63][64]

A Darrieus type vertical axis wind turbine (the egg-beater type) can in theory work almost as good as a horizontal axis turbine. Actual measurement of one of the better designs out there, the UGE VisionAir5, does not bear that out though: It measures in at a pitiful 11% efficiency at 11 m/s wind speed, while a Bergey Excel-6 HAWT clocks in at 22% efficiency for that same wind speed, twice as much. You can read about it in Paul Gipe’s article.  Besides efficiency issues, a Darrieus VAWT unfortunately has a number of inherent issues that put them at a disadvantage: Since they are usually tall and relatively narrow structures the bending forces on their main bearing (at the bottom) are very large. There are similar issues with the forces on the blades. This means that to make a reliable vertical axis turbine takes more material, and more expensive materials, in comparison to a horizontal type turbine. For comparison, that same UGE VisionAir5 weighs 756 kg vs. the Bergey Excel-6 at 350 kg. Keep in mind that the UGE turbine only sweeps about half the area of the Bergey, the latter is a much larger turbine! This makes VAWTs inherently more expensive, or less reliable, or both.


This discussion is mainly about factory-made grid-tie wind turbines. The off-grid crowd has an entirely different set of decisions and goals. The main ones are that for off-grid use economic viability in comparison with the electrical grid is not an issue, and a wind turbine can make up for the loss of sunlight (and PV electricity) in the winter months. For the DIY group there are several good turbine designs available; Hugh Piggott and the two Dans have written books that outline this step-by-step. Building your own turbine can be a great hobby, and some of the topics touched below apply (such as proper site selection), but this discussion is not about those. The decisions involved in making your own turbine, and the cost basis, have little overlap with a the process of having an installer put a factory-made turbine in your backyard.
If you do install an anemometer and measure the wind over one or more years, you should compare the annual average wind speed obtained from your anemometer data to the annual average of the nearest airport or meteo-station for that same year. This will tell you if your site is more or less windy than that airport or meteo-station, and by how much. Then compare that year’s data  to the long-term annual average wind speed, and you will know what to expect over the long term, corrected for your particular site. It will not be exact, but it will make your short-term anemometer data much more useful.

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.


Outline of energy Energy Units Conservation of energy Energetics Energy transformation Energy condition Energy transition Energy level Energy system Mass Negative mass Mass–energy equivalence Power Thermodynamics Quantum thermodynamics Laws of thermodynamics Thermodynamic system Thermodynamic state Thermodynamic potential Thermodynamic free energy Irreversible process Thermal reservoir Heat transfer Heat capacity Volume (thermodynamics) Thermodynamic equilibrium Thermal equilibrium Thermodynamic temperature Isolated system Entropy Free entropy Entropic force Negentropy Work Exergy Enthalpy
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]
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.
The Vestas V164 has a rated capacity of 8 MW,[79] later upgraded to 9.5 MW.[80][81] The wind turbine has an overall height of 220 m (722 ft), a diameter of 164 m (538 ft), is for offshore use, and is the world's largest-capacity wind turbine since its introduction in 2014. The conventional drive train consist of a main gearbox and a medium speed PM generator. Prototype installed in 2014 at the National Test Center Denmark nearby Østerild. Series production began end of 2015.
Outline of energy Energy Units Conservation of energy Energetics Energy transformation Energy condition Energy transition Energy level Energy system Mass Negative mass Mass–energy equivalence Power Thermodynamics Quantum thermodynamics Laws of thermodynamics Thermodynamic system Thermodynamic state Thermodynamic potential Thermodynamic free energy Irreversible process Thermal reservoir Heat transfer Heat capacity Volume (thermodynamics) Thermodynamic equilibrium Thermal equilibrium Thermodynamic temperature Isolated system Entropy Free entropy Entropic force Negentropy Work Exergy Enthalpy
Solar electricity is inherently variable and predictable by time of day, location, and seasons. In addition solar is intermittent due to day/night cycles and unpredictable weather. How much of a special challenge solar power is in any given electric utility varies significantly. In a summer peak utility, solar is well matched to daytime cooling demands. In winter peak utilities, solar displaces other forms of generation, reducing their capacity factors.
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]

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]

The conversion of the rotational mechanical power generated by the rotor blades (known as the prime mover) into useful electrical power for use in domestic power and lighting applications or to charge batteries can be accomplished by any one of the following major types of rotational electrical machines commonly used in a wind power generating systems:
^ 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.
The W03083 Firman generator is perfect in and The W03083 Firman generator is perfect in and around the RV on the campsite while powering small appliances or while at home. Its Fuel Economy Mode reduces fuel consumption and promotes engine efficiency. It uses an OHV electric start engine (Max-Pro Series) for longer life higher performance and lower maintenance. ...  More + Product Details Close
I wouldn’t consider myself a creative type.  Never painted a picture, never felt confident in color or fabric choices.  But I did get a real creativity boost living off-grid in northern New Mexico, raising children on one income in a home with caught water, gardening at 7600 feet in a climate that gets REALLY cold.  We built a house called an earthship from recycled materials and earth. 
Green Energy Corp’s™ Microgrid as a Service (MaaS) package is a cloud based, subscription service enabling third party developers to utilize GreenBus® and Green Energy Corp expertise in financing, building and deploying microgrids. Included in the MaaS package is the microgrid toolset comprised of software, design and engineering packages, equipment recommendations, construction methods, operations and maintenance support, and financial instruments all delivered from a hosted environment.
Materials that are typically used for the rotor blades in wind turbines are composites, as they tend to have a high stiffness, high strength, high fatigue resistance, and low weight.[46] Typical resins used for these composites include polyester and epoxy, while glass and carbon fibers have been used for the reinforcing material.[47] Construction may use manual layup techniques or composite resin injection molding. As the price of glass fibers is only about one tenth the price of carbon fiber, glass fiber is still dominant.

Photovoltaics were initially solely used as a source of electricity for small and medium-sized applications, from the calculator powered by a single solar cell to remote homes powered by an off-grid rooftop PV system. Commercial concentrated solar power plants were first developed in the 1980s. The 392 MW Ivanpah installation is the largest concentrating solar power plant in the world, located in the Mojave Desert of California.
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