12 Month Financing: For a limited time, purchase $599 or more using the Amazon.com Store Card and pay no interest for 12 months on your entire order if paid in full in 12 months. Interest will be charged to your account from the purchase date if the promotional balance is not paid in full within 12 months. Minimum monthly payments required. Subject to credit approval. Apply now.
Concentrator photovoltaics (CPV) systems employ sunlight concentrated onto photovoltaic surfaces for the purpose of electrical power production. Contrary to conventional photovoltaic systems, it uses lenses and curved mirrors to focus sunlight onto small, but highly efficient, multi-junction solar cells. Solar concentrators of all varieties may be used, and these are often mounted on a solar tracker in order to keep the focal point upon the cell as the sun moves across the sky.[147] Luminescent solar concentrators (when combined with a PV-solar cell) can also be regarded as a CPV system. Concentrated photovoltaics are useful as they can improve efficiency of PV-solar panels drastically.[148]
A wind turbine is made up of two major components and having looked at one of them, the rotor blade design in the previous tutorial, we can now look at the other, the Wind Turbine Generator or WTG’s which is the electrical machine used to generate the electricity. A low rpm electrical generator is used for converting the mechanical rotational power produced by the winds energy into usable electricity to supply our homes and is at the heart of any wind power system.
As suppliers of inverters for turbines good, bad, and just plain ugly, we have pretty well seen it all when it comes to turbine failure. We can tell you unequivocally that you get what you pay for. Depending on your sense of adventure that can be good or bad; if you plan to go cheap, plan on (you) being the manufacturer’s R&D department and test center. Being a really good do-it-yourselfer with an understanding of wind turbines, alternators, and all things electric will come in very handy too. Just in case you do not believe us, you can read about it in this Green Power Talk thread. There are more threads with similar content on the forum, just browse around a little.
Micro-hydro configured into mini-grids also provide power. Over 44 million households use biogas made in household-scale digesters for lighting and/or cooking, and more than 166 million households rely on a new generation of more-efficient biomass cookstoves.[26] Clean liquid fuel sourced from renewable feedstocks are used for cooking and lighting in energy-poor areas of the developing world. Alcohol fuels (ethanol and methanol) can be produced sustainably from non-food sugary, starchy, and cellulostic feedstocks. Project Gaia, Inc. and CleanStar Mozambique are implementing clean cooking programs with liquid ethanol stoves in Ethiopia, Kenya, Nigeria and Mozambique.[139]
This is a wind map of the lands south of the border (the US) for 30 meters (100′) height, a very common height for small wind turbine installations. Anything green or yellow is not a good wind resource location. Here in Canada the distribution is similar, in that the good places are in the mid-west and very close to the shores of the great lakes and oceans.
Current Texas solar incentives include generous rebates for solar electric and solar hot water systems.  When combined with Federal solar rebates your solar panel installation will be approximately 50% less because of the incentives!  Our solar installers will be happy to answer your questions and explain the benefits of solar power.  Simply click the image below, fill in the form, and a certified solar installer will contact you by phone at your convenience.
Wind turbines are used to generate electricity from the kinetic power of the wind. Historical they were more frequently used as a mechanical device to turn machinery. There are two main kinds of wind generators, those with a vertical axis, and those with a horizontal axis. Wind turbines can be used to generate large amounts of electricity in wind farms both onshore and offshore. The articles on this page are about wind turbines.

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.
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]
By 2040, renewable energy is projected to equal coal and natural gas electricity generation. Several jurisdictions, including Denmark, Germany, the state of South Australia and some US states have achieved high integration of variable renewables. For example, in 2015 wind power met 42% of electricity demand in Denmark, 23.2% in Portugal and 15.5% in Uruguay. Interconnectors enable countries to balance electricity systems by allowing the import and export of renewable energy. Innovative hybrid systems have emerged between countries and regions.[27]

Wind turbines are generally inexpensive. They will produce electricity at between two and six cents per kilowatt hour, which is one of the lowest-priced renewable energy sources.[72] And as technology needed for wind turbines continues to improve, the prices will decrease as well. In addition, there is no competitive market for wind energy, as it does not cost money to get ahold of wind.[72] The main cost of wind turbines are the installation process. The average cost is between $48,000 and $65,000 to install. However, the energy harvested from the turbine will offset the installation cost, as well as provide virtually free energy for years after.[73]

One issue that has often raised concerns is the use of cadmium (Cd), a toxic heavy metal that has the tendency to accumulate in ecological food chains. It is used as semiconductor component in CdTe solar cells and as buffer layer for certain CIGS cells in the form of CdS.[141] The amount of cadmium used in thin-film PV modules is relatively small (5–10 g/m²) and with proper recycling and emission control techniques in place the cadmium emissions from module production can be almost zero. Current PV technologies lead to cadmium emissions of 0.3–0.9 microgram/kWh over the whole life-cycle.[121] Most of these emissions arise through the use of coal power for the manufacturing of the modules, and coal and lignite combustion leads to much higher emissions of cadmium. Life-cycle cadmium emissions from coal is 3.1 microgram/kWh, lignite 6.2, and natural gas 0.2 microgram/kWh.

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The journal, Renewable Energy, seeks to promote and disseminate knowledge on the various topics and technologies of renewable energy systems and components. The journal aims to serve researchers, engineers, economists, manufacturers, NGOs, associations and societies to help them keep abreast of new developments in their specialist fields and to apply alternative energy solutions to current practices.

Globally, the long-term technical potential of wind energy is believed to be five times total current global energy production, or 40 times current electricity demand, assuming all practical barriers needed were overcome. This would require wind turbines to be installed over large areas, particularly in areas of higher wind resources, such as offshore. As offshore wind speeds average ~90% greater than that of land, so offshore resources can contribute substantially more energy than land stationed turbines.[44] In 2014 global wind generation was 706 terawatt-hours or 3% of the worlds total electricity.[45]
A typical house usually requires a home wind turbine with a 5 kW generating capacity to meet all its energy requirements. A turbine that offers this much power would have to be around 13 to 18 feet in diameter and positioned in an area where strong winds often pass through. There are also plenty of smaller, cheaper turbines, but these variants produce less power and are less reliable than their more expensive counterparts.
Julia Pyper is a Senior Editor at Greentech Media covering clean energy policy, the solar industry, grid edge technologies and electric mobility. She previously reported for E&E Publishing, and has covered clean energy and climate change issues across the U.S. and abroad, including in Haiti, Israel and the Maldives. Julia holds degrees from McGill and Columbia Universities. Find her on Twitter @JMPyper.
“California Looks to Stationary Energy Storage as a Solution to Peaker Plants” • Central California electric utility Pacific Gas & Electric is planning to replace three old natural gas power plants in its network with stationary energy storage installations from Tesla. California is looking to add 1.3 GW of storage to its power grid by 2020. [CleanTechnica]
Previously, the largest U.S. city fully powered by renewables was Burlington, Vermont (pop. 42,000), home to Senator Bernie Sanders, the jam band Phish and the original Ben & Jerry’s. Georgetown’s feat is all the more dramatic because it demolishes the notion that sustainability is synonymous with socialism and GMO-free ice cream. “You think of climate change and renewable energy, from a political standpoint, on the left-hand side of the spectrum, and what I’ve done is toss all those partisan political thoughts aside,” Ross says. “We’re doing this because it’s good for our citizens. Cheaper electricity is better. Clean energy is better than fossil fuels.”
Power Scorecard is a web tool that rates the environmental quality of electricity offered to customers in California, New Jersey, New York, Pennsylvania, and Texas. It will help identify products that have the lowest overall environmental impact on our air, land, and water, and those that will lead to the development of the most new renewable energy generation. Power Scorecard will be expanding into other states in the near future.
Many residential PV systems are connected to the grid wherever available, especially in developed countries with large markets.[10] In these grid-connected PV systems, use of energy storage is optional. In certain applications such as satellites, lighthouses, or in developing countries, batteries or additional power generators are often added as back-ups. Such stand-alone power systems permit operations at night and at other times of limited sunlight.