While renewables have been very successful in their ever-growing contribution to electrical power there are no countries dominated by fossil fuels who have a plan to stop and get that power from renwables. Only Scotland and Ontario have stopped burning coal, largely due to good natural gas supplies. In the area of transportation, fossil fuels are even more entrenched and solutions harder to find.[198] It's unclear if there are failures with policy or renewable energy, but twenty years after the Kyoto Protocol fossil fuels are still our primary energy source and consumption continues to grow.[199]
For a 6 kW wind turbine to produce that much energy per average year, you need an annual average wind speed of close to 5 m/s (11 mph) blowing at turbine hub height. It may not sound like much, but that is a reasonably windy place. Much of North America does not have that much wind at 100′ or below. Keep in mind, you need that much wind just to break even in energy production vs. solar. To outweigh the disadvantages of small turbines you better have more!
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.

A wide range of concentrating technologies exists: among the best known are the parabolic trough, the compact linear Fresnel reflector, the Stirling dish and the solar power tower. Various techniques are used to track the sun and focus light. In all of these systems a working fluid is heated by the concentrated sunlight, and is then used for power generation or energy storage.[11] Thermal storage efficiently allows up to 24-hour electricity generation.[12]
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The array of a photovoltaic power system, or PV system, produces direct current (DC) power which fluctuates with the sunlight's intensity. For practical use this usually requires conversion to certain desired voltages or alternating current (AC), through the use of inverters.[4] Multiple solar cells are connected inside modules. Modules are wired together to form arrays, then tied to an inverter, which produces power at the desired voltage, and for AC, the desired frequency/phase.[4]
“[The maps] suggest that our 100 percent renewable energy purchasing goal — which relies on buying surplus renewable energy when it’s sunny and windy, to offset the lack of renewable energy supply in other situations — is an important first step toward achieving a fully carbon-free future,” Michael Terrell, Google’s head of energy markets, wrote in a blog post. “Ultimately, we aspire to source carbon-free energy for our operations in all places, at all times.”
While the material cost is significantly higher for all-glass fiber blades than for hybrid glass/carbon fiber blades, there is a potential for tremendous savings in manufacturing costs when labor price is considered. Utilizing carbon fiber enables for simpler designs that use less raw material. The chief manufacturing process in blade fabrication is the layering of plies. By reducing the number of layers of plies, as is enabled by thinner blade design, the cost of labor may be decreased, and in some cases, equate to the cost of labor for glass fiber blades.[51]
^ 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.
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]
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.
Besides the greening of fossil fuel and nuclear power plants, another option is the distribution and immediate use of power from solely renewable sources. In this set-up energy storage is again not necessary. For example, TREC has proposed to distribute solar power from the Sahara to Europe. Europe can distribute wind and ocean power to the Sahara and other countries. In this way, power is produced at any given time as at any point of the planet as the sun or the wind is up or ocean waves and currents are stirring. This option however is probably not possible in the short-term, as fossil fuel and nuclear power are still the main sources of energy on the mains electricity net and replacing them will not be possible overnight.

What is a small wind turbine? Anything under, say, 10 meters rotor diameter (30 feet) is well within the “small wind” category. That works out to wind turbines with a rated power up to around 20 kW (at 11 m/s, or 25 mph). For larger wind turbines the manufacturers are usually a little more honest, and more money is available to do a good site analysis. The information in this article is generic: The same applies to all the other brands and models, be they of the HAWT (Horizontal Axis Wind Turbine) or VAWT (Vertical Axis Wind Turbine) persuasion.

“[The maps] suggest that our 100 percent renewable energy purchasing goal — which relies on buying surplus renewable energy when it’s sunny and windy, to offset the lack of renewable energy supply in other situations — is an important first step toward achieving a fully carbon-free future,” Michael Terrell, Google’s head of energy markets, wrote in a blog post. “Ultimately, we aspire to source carbon-free energy for our operations in all places, at all times.”
Enhanced geothermal systems (EGS) are a new type of geothermal power technologies that do not require natural convective hydrothermal resources. The vast majority of geothermal energy within drilling reach is in dry and non-porous rock.[161] EGS technologies "enhance" and/or create geothermal resources in this "hot dry rock (HDR)" through hydraulic stimulation. EGS and HDR technologies, such as hydrothermal geothermal, are expected to be baseload resources which produce power 24 hours a day like a fossil plant. Distinct from hydrothermal, HDR and EGS may be feasible anywhere in the world, depending on the economic limits of drill depth. Good locations are over deep granite covered by a thick (3–5 km) layer of insulating sediments which slow heat loss.[162] There are HDR and EGS systems currently being developed and tested in France, Australia, Japan, Germany, the U.S. and Switzerland. The largest EGS project in the world is a 25 megawatt demonstration plant currently being developed in the Cooper Basin, Australia. The Cooper Basin has the potential to generate 5,000–10,000 MW.
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.
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.
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]
Bioethanol is an alcohol made by fermentation, mostly from carbohydrates produced in sugar or starch crops such as corn, sugarcane, or sweet sorghum. Cellulosic biomass, derived from non-food sources such as trees and grasses is also being developed as a feedstock for ethanol production. Ethanol can be used as a fuel for vehicles in its pure form, but it is usually used as a gasoline additive to increase octane and improve vehicle emissions. Bioethanol is widely used in the USA and in Brazil. Biodiesel can be used as a fuel for vehicles in its pure form, but it is usually used as a diesel additive to reduce levels of particulates, carbon monoxide, and hydrocarbons from diesel-powered vehicles. Biodiesel is produced from oils or fats using transesterification and is the most common biofuel in Europe.
The Stirling solar dish combines a parabolic concentrating dish with a Stirling engine which normally drives an electric generator. The advantages of Stirling solar over photovoltaic cells are higher efficiency of converting sunlight into electricity and longer lifetime. Parabolic dish systems give the highest efficiency among CSP technologies.[18] The 50 kW Big Dish in Canberra, Australia is an example of this technology.[14]
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