The majority of green pricing programs charge a higher price per kilowatt-hour to support an increased percentage of renewable sources or to buy discrete kilowatt-hour blocks of renewable energy. Other programs have fixed monthly fees, round up customer bills, charge for units of renewable capacity, or offer renewable energy systems for lease or purchase.
Even with plans to grow as much as 80 percent over the next five years, the city expects to have plenty of energy from these renewable sources. (To be sure, about 2 percent of the time, the Georgetown utility draws electricity derived from fossil fuels. Ross says the city more than compensates at other times by selling excess renewable energy back to the grid—at a profit.)
Stop getting twisted!! Gold Plated Contacts Heavy 30 amp Per conductor slip ring total 180 amps....Great for even heavy 12 volt environment wind generators as used in our Cat 5 and Freedom II Dual PMA Turbines This rotating connector will be great for the wind generator. The current can be split up in DC applications by using two conductors to cut down on the resistance. If you have application specific questions feel free to ask me before buying. Has 3 mounting holes in collar and long wires for easy installation Shared Specifications Wires 6 Current 0~30A Voltage 600 VDC/VAC Max speed 250RPM Overall diameter 30mm Length 66mm Contact Material Precious Metal:gold-gold Contact Resistance <2mOhm Housing Material Plastics Torque 0.06N.
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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.
Because one obstacle to adopting wind and solar power is reliability—what happens on calm, cloudy days?—recent improvements in energy-storage technology, a.k.a. batteries, are helping accelerate adoption of renewables. Last May, for example, Tucson Electric Power signed a deal for solar energy with storage, which can mitigate (if not entirely resolve) concerns about how to provide power on gray days. The storage upped the energy cost by $15 per megawatt hour. By the end of the year, the Public Service Company of Colorado had been quoted a storage fee that increased the cost of a megawatt hour by only $3 to $7, a drop of more than 50 percent. In a landmark achievement, Tesla installed the world’s largest lithium-ion battery in South Australia last December, to store wind-generated power. But by then Hyundai Electric was at work in the South Korean metropolis of Ulsan on a battery that was 50 percent bigger.
Wave power, which captures the energy of ocean surface waves, and tidal power, converting the energy of tides, are two forms of hydropower with future potential; however, they are not yet widely employed commercially. A demonstration project operated by the Ocean Renewable Power Company on the coast of Maine, and connected to the grid, harnesses tidal power from the Bay of Fundy, location of world's highest tidal flow. Ocean thermal energy conversion, which uses the temperature difference between cooler deep and warmer surface waters, has currently no economic feasibility.
Our largest solar panel. Portable rugged and powerful. Our largest solar panel. Portable rugged and powerful. Designed for mobile base camps and die-hard adventurers a standard MC4 connector for third-party charge controllers and built-in charging cable for Sherpa Power Packs and Goal Zero Yeti Solar Generators. Can be chained in series or parallel to collect more power from ...  More + Product Details Close

There is no energy in the wind at those wind speeds, nothing to harvest for the turbine. While it may make you feel good to see your expensive yard toy spin, it is not doing anything meaningful in a breeze like that: To give you some idea, a wind turbine with a diameter of 6 meters (pretty large as small wind turbines go) can realistically produce just 120 Watt at 3.5 m/s wind speed. That same turbine would be rated at 6 kW (or more, see the next section), so energy production at cut-in really is just a drop in the bucket. What is more, due to the way grid-tie inverters work, you are about as likely to be loosing energy around cut-in wind speed to keep the inverter powered, as you are in making any energy, resulting in a net-loss of electricity production.
Usually however, renewable energy is derived from the mains electricity grid. This means that energy storage is mostly not used, as the mains electricity grid is organised to produce the exact amount of energy being consumed at that particular moment. Energy production on the mains electricity grid is always set up as a combination of (large-scale) renewable energy plants, as well as other power plants as fossil-fuel power plants and nuclear power. This combination however, which is essential for this type of energy supply (as e.g. wind turbines, solar power plants etc.) can only produce when the wind blows and the sun shines. This is also one of the main drawbacks of the system as fossil fuel powerplants are polluting and are a main cause of global warming (nuclear power being an exception). Although fossil fuel power plants too can be made emissionless (through carbon capture and storage), as well as renewable (if the plants are converted to e.g. biomass) the best solution is still to phase out the latter power plants over time. Nuclear power plants too can be more or less eliminated from their problem of nuclear waste through the use of nuclear reprocessing and newer plants as fast breeder and nuclear fusion plants.
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]

Last year, the tech giant matched 100 percent of its annual electricity consumption with renewable energy purchases, and has committed to continue doing so as the company grows. Last week, Google built on the 100 percent concept with the release of Carbon Heat Maps, which show that there are times and places where Google’s electricity profile is not yet fully carbon-free — which is what Google wants to be. 


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.
Nearly all the gasoline sold in the United States today is mixed with 10% ethanol,[128] and motor vehicle manufacturers already produce vehicles designed to run on much higher ethanol blends. Ford, Daimler AG, and GM are among the automobile companies that sell "flexible-fuel" cars, trucks, and minivans that can use gasoline and ethanol blends ranging from pure gasoline up to 85% ethanol. By mid-2006, there were approximately 6 million ethanol compatible vehicles on U.S. roads.[129]

A report by the United States Geological Survey estimated the projected materials requirement in order to fulfill the US commitment to supplying 20% of its electricity from wind power by 2030. They did not address requirements for small turbines or offshore turbines since those were not widely deployed in 2008, when the study was created. They found that there are increases in common materials such as cast iron, steel and concrete that represent 2–3% of the material consumption in 2008. Between 110,000 and 115,000 metric tons of fiber glass would be required annually, equivalent to 14% of consumption in 2008. They did not see a high increase in demand for rare metals compared to available supply, however rare metals that are also being used for other technologies such as batteries which are increasing its global demand need to be taken into account. Land, whbich might not be considered a material, is an important resource in deploying wind technologies. Reaching the 2030 goal would require 50,000 square kilometers of onshore land area and 11,000 square kilometers of offshore. This is not considered a problem in the US due to its vast area and the ability to use land for farming and grazing. A greater limitation for the technology would be the variability and transmission infrastructure to areas of higher demand.[54]
Biomass can be converted to other usable forms of energy such as methane gas or transportation fuels such as ethanol and biodiesel. Rotting garbage, and agricultural and human waste, all release methane gas – also called landfill gas or biogas. Crops, such as corn and sugarcane, can be fermented to produce the transportation fuel, ethanol. Biodiesel, another transportation fuel, can be produced from left-over food products such as vegetable oils and animal fats.[69] Also, biomass to liquids (BTLs) and cellulosic ethanol are still under research.[70][71] There is a great deal of research involving algal fuel or algae-derived biomass due to the fact that it's a non-food resource and can be produced at rates 5 to 10 times those of other types of land-based agriculture, such as corn and soy. Once harvested, it can be fermented to produce biofuels such as ethanol, butanol, and methane, as well as biodiesel and hydrogen. The biomass used for electricity generation varies by region. Forest by-products, such as wood residues, are common in the United States. Agricultural waste is common in Mauritius (sugar cane residue) and Southeast Asia (rice husks). Animal husbandry residues, such as poultry litter, are common in the United Kingdom.[72]
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]
Most installers overrate the available wind resource. The majority of small wind turbine installations underperforms their predictions, often by a wide margin. Since wind speed is the most important parameter for turbine energy production, getting that wrong has large consequences (the power in the wind goes with the cube of the wind speed, so double the wind speed and the power in it is 2 * 2 * 2 = 8x as much). You have to be realistic about your annual average wind speed.
Renewable energy variability is a problem for corporate buyers. But what is undesirable to buyers is attractive for insurance companies, whose core business revolves around managing weather-related risks. VFAs sit on top of a new or existing PPA and are effectively designed to pay the corporate buyer when they’re getting less renewable power than they contracted for, and give money to the insurer when there’s more.

Green energy, however, utilizes energy sources that are readily available all over the world, including in rural and remote areas that don't otherwise have access to electricity. Advances in renewable energy technologies have lowered the cost of solar panels, wind turbines and other sources of green energy, placing the ability to produce electricity in the hands of the people rather than those of oil, gas, coal and utility companies.
Conventional hydroelectricity works very well in conjunction with solar power, water can be held back or released from a reservoir behind a dam as required. Where a suitable river is not available, pumped-storage hydroelectricity uses solar power to pump water to a high reservoir on sunny days then the energy is recovered at night and in bad weather by releasing water via a hydroelectric plant to a low reservoir where the cycle can begin again.[109] However, this cycle can lose 20% of the energy to round trip inefficiencies, this plus the construction costs add to the expense of implementing high levels of solar power.
Interest in recycling blades varies in different markets and depends on the waste legislation and local economics. A challenge in recycling blades is related to the composite material, which is made of a thermosetting matrix and glass fibers or a combination of glass and carbon fibers. Thermosetting matrix cannot be remolded to form new composites. So the options are either to reuse the blade and the composite material elements as they are found in the blade or to transform the composite material into a new source of material. In Germany, wind turbine blades are commercially recycled as part of an alternative fuel mix for a cement factory.

Green energy, however, utilizes energy sources that are readily available all over the world, including in rural and remote areas that don't otherwise have access to electricity. Advances in renewable energy technologies have lowered the cost of solar panels, wind turbines and other sources of green energy, placing the ability to produce electricity in the hands of the people rather than those of oil, gas, coal and utility companies.
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.
A study of the material consumption trends and requirements for wind energy in Europe found that bigger turbines have a higher consumption of precious metals but lower material input per kW generated. The current material consumption and stock was compared to input materials for various onshore system sizes. In all EU countries the estimates for 2020 exceeded and doubled the values consumed in 2009. These countries would need to expand their resources to be able to meet the estimated demand for 2020. For example, currently the EU has 3% of world supply of fluorspar and it requires 14% by 2020. Globally, the main exporting countries are South Africa, Mexico and China. This is similar with other critical and valuable materials required for energy systems such as magnesium, silver and indium. In addition, the levels of recycling of these materials is very low and focusing on that could alleviate issues with supply in the future. It is important to note that since most of these valuable materials are also used in other emerging technologies, like LEDs, PVs and LCDs, it is projected that demand for them will continue to increase.[53]
The conversion of sunlight into electricity is made possible with the special properties of semi-conducting materials. It can be harnessed through a range of ever-evolving technologies like solar heating, photovoltaics, solar thermal energy, solar architecture, molten salt power plants, and artificial photosynthesis. Learn more about solar solutions from IGS Solar.
Over $1 billion of federal money has been spent on the research and development of hydrogen and a medium for energy storage in the United States.[150] Both the National Renewable Energy Laboratory[151] and Sandia National Laboratories[152] have departments dedicated to hydrogen research. Hydrogen is useful for energy storage, and for use in airplanes and ships, but is not practical for automobile use, as it is not very efficient, compared to using a battery — for the same cost a person can travel three times as far using a battery electric vehicle.[153]
The stator is the “stationary” (hence its name) part of the machine and can have either a set of electrical windings producing an electromagnet or a set of permanent magnets within its design. The rotor is the part of the machine that “rotates”. Again, the rotor can have output coils that rotate or permanent magnets. Generally, generators and alternators used for wind turbine generators are defined by how they make generate their magnetism, either electromagnets or permanent magnets.
The ability of biomass and biofuels to contribute to a reduction in CO2 emissions is limited because both biomass and biofuels emit large amounts of air pollution when burned and in some cases compete with food supply. Furthermore, biomass and biofuels consume large amounts of water.[200] Other renewable sources such as wind power, photovoltaics, and hydroelectricity have the advantage of being able to conserve water, lower pollution and reduce CO2 emissions.
Several initiatives are being proposed to mitigate distribution problems. First and foremost, the most effective way to reduce USA’s CO2 emissions and slow global warming is through conservation efforts. Opponents of the current US electrical grid have also advocated for decentralizing the grid. This system would increase efficiency by reducing the amount of energy lost in transmission. It would also be economically viable as it would reduce the amount of power lines that will need to be constructed in the future to keep up with demand. Merging heat and power in this system would create added benefits and help to increase its efficiency by up to 80-90%. This is a significant increase from the current fossil fuel plants which only have an efficiency of 34%.[92]
We now know that the electrical generator provides a means of energy conversion between the mechanical torque generated by the rotor blades, called the prime mover, and some electrical load. The mechanical connection of the wind turbine generator to the rotor blades is made through a main shaft which can be either a simple direct drive, or by using a gearbox to increase or decrease the generator speed relative to the rotational speed of the blades.
In conclusion, I would say that however great the scientific importance of this discovery may be, its practical value will be no less obvious when we reflect that the supply of solar energy is both without limit and without cost, and that it will continue to pour down upon us for countless ages after all the coal deposits of the earth have been exhausted and forgotten.[36]

Renewable energy power plants do provide a steady flow of energy. For example, hydropower plants, ocean thermal plants, osmotic power plants all provide power at a regulated pace, and are thus available power sources at any given moment (even at night, windstill moments etc.). At present however, the number of steady-flow renewable energy plants alone is still too small to meet energy demands at the times of the day when the irregular producing renewable energy plants cannot produce power.


“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]
Prior to the development of coal in the mid 19th century, nearly all energy used was renewable. Almost without a doubt the oldest known use of renewable energy, in the form of traditional biomass to fuel fires, dates from 790,000 years ago. Use of biomass for fire did not become commonplace until many hundreds of thousands of years later, sometime between 200,000 and 400,000 years ago.[31] Probably the second oldest usage of renewable energy is harnessing the wind in order to drive ships over water. This practice can be traced back some 7000 years, to ships in the Persian Gulf[32] and on the Nile.[33] Moving into the time of recorded history, the primary sources of traditional renewable energy were human labor, animal power, water power, wind, in grain crushing windmills,[32] and firewood, a traditional biomass. A graph of energy use in the United States up until 1900 shows oil and natural gas with about the same importance in 1900 as wind and solar played in 2010.
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.
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]
Geothermal energy is produced by tapping into the thermal energy created and stored within the earth. It arises from the radioactive decay of an isotope of potassium and other elements found in the Earth's crust.[144] Geothermal energy can be obtained by drilling into the ground, very similar to oil exploration, and then it is carried by a heat-transfer fluid (e.g. water, brine or steam).[144] Geothermal systems that are mainly dominated by water have the potential to provide greater benefits to the system and will generate more power.[145] Within these liquid-dominated systems, there are possible concerns of subsidence and contamination of ground-water resources. Therefore, protection of ground-water resources is necessary in these systems. This means that careful reservoir production and engineering is necessary in liquid-dominated geothermal reservoir systems.[145] Geothermal energy is considered sustainable because that thermal energy is constantly replenished.[146] However, the science of geothermal energy generation is still young and developing economic viability. Several entities, such as the National Renewable Energy Laboratory[147] and Sandia National Laboratories[148] are conducting research toward the goal of establishing a proven science around geothermal energy. The International Centre for Geothermal Research (IGC), a German geosciences research organization, is largely focused on geothermal energy development research.[149]
“Climate Change Helped Make California a Tinder Box for its Record-Setting Wildfires” • Camp Fire, which is devastating Sierra Nevada foothills, has become the most destructive wildfire in California’s history. By the evening of November 10, it had scorched 105,000 acres of land and killed 23 people, with more than 100 people still unaccounted for. [Quartz]
Jump up ^ Noth, André (July 2008). "History of Solar Flight" (PDF). Autonomous Systems Lab. Zürich: Swiss Federal Institute of Technology. p. 3. Archived from the original (PDF) on 1 February 2012. Retrieved 8 July 2010. Günter Rochelt was the designer and builder of Solair I, a 16 m wingspan solar airplane ... 21st of August 1983 he flew in Solair I, mostly on solar energy and also thermals, during 5 hours 41 minutes.
With advanced technology being developed, cellulosic biomass, such as trees and grasses, are also used as feedstocks 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 United States and in Brazil. The energy costs for producing bio-ethanol are almost equal to, the energy yields from bio-ethanol. However, according to the European Environment Agency, biofuels do not address global warming concerns.[75] Biodiesel is made from vegetable oils, animal fats or recycled greases. It can be used as a fuel for vehicles in its pure form, or more commonly 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. Biofuels provided 2.7% of the world's transport fuel in 2010.[76]
The overwhelming majority of electricity produced worldwide is used immediately, since storage is usually more expensive and because traditional generators can adapt to demand. However both solar power and wind power are variable renewable energy, meaning that all available output must be taken whenever it is available by moving through transmission lines to where it can be used now. Since solar energy is not available at night, storing its energy is potentially an important issue particularly in off-grid and for future 100% renewable energy scenarios to have continuous electricity availability.[106]
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