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]
On most horizontal wind turbine farms, a spacing of about 6–10 times the rotor diameter is often upheld. However, for large wind farms distances of about 15 rotor diameters should be more economical, taking into account typical wind turbine and land costs. This conclusion has been reached by research[62] conducted by Charles Meneveau of the Johns Hopkins University,[63] and Johan Meyers of Leuven University in Belgium, based on computer simulations[64] that take into account the detailed interactions among wind turbines (wakes) as well as with the entire turbulent atmospheric boundary layer.

From the end of 2004, worldwide renewable energy capacity grew at rates of 10–60% annually for many technologies. In 2015 global investment in renewables rose 5% to $285.9 billion, breaking the previous record of $278.5 billion in 2011. 2015 was also the first year that saw renewables, excluding large hydro, account for the majority of all new power capacity (134 GW, making up 53.6% of the total). Of the renewables total, wind accounted for 72 GW and solar photovoltaics 56 GW; both record-breaking numbers and sharply up from 2014 figures (49 GW and 45 GW respectively). In financial terms, solar made up 56% of total new investment and wind accounted for 38%.
Floatovoltaics are an emerging form of PV systems that float on the surface of irrigation canals, water reservoirs, quarry lakes, and tailing ponds. Several systems exist in France, India, Japan, Korea, the United Kingdom and the United States.[149][150][151][152] These systems reduce the need of valuable land area, save drinking water that would otherwise be lost through evaporation, and show a higher efficiency of solar energy conversion, as the panels are kept at a cooler temperature than they would be on land.[153] Although not floating, other dual-use facilities with solar power include fisheries.[154]
In 2016, the city bought its way out of a contract providing energy derived from fossil fuels and arranged to get its power from a 97-unit windfarm in Adrian, Texas, about 500 miles away in the Texas Panhandle. Georgetown doesn’t own the farm, but its agreement allowed the owners to get the financing to build it. This spring, Georgetown is adding power from a 154-megawatt solar farm being built by NRG Energy in Fort Stockton, 340 miles to the west of the city.
Some renewable power sources now cost somewhat more than conventional power, because the market for renewable energy is not fully developed and renewables have received fewer subsidies than fossil and nuclear fuels. Also, the damage to the environment and human health—otherwise known as externalities—caused by fossil fuels and nuclear power is not included in electricity prices. Renewable energy needs your support to overcome these barriers and become less expensive in the future. Look into becoming a green power consumer today!
While many renewable energy projects are large-scale, renewable technologies are also suited to rural and remote areas and developing countries, where energy is often crucial in human development.[13] Former 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] As most of renewables provide electricity, renewable energy deployment is often applied in conjunction with further electrification, which has several benefits: Electricity can be converted to heat (where necessary generating higher temperatures than fossil fuels), can be converted into mechanical energy with high efficiency and is clean at the point of consumption.[15][16] In addition to that electrification with renewable energy is much more efficient and therefore leads to a significant reduction in primary energy requirements, because most renewables don't have a steam cycle with high losses (fossil power plants usually have losses of 40 to 65%).[17]
The energy payback time (EPBT) of a power generating system is the time required to generate as much energy as is consumed during production and lifetime operation of the system. Due to improving production technologies the payback time has been decreasing constantly since the introduction of PV systems in the energy market.[128] In 2000 the energy payback time of PV systems was estimated as 8 to 11 years[129] and in 2006 this was estimated to be 1.5 to 3.5 years for crystalline silicon PV systems[121] and 1–1.5 years for thin film technologies (S. Europe).[121] These figures fell to 0.75–3.5 years in 2013, with an average of about 2 years for crystalline silicon PV and CIS systems.[130]
The time will arrive when the industry of Europe will cease to find those natural resources, so necessary for it. Petroleum springs and coal mines are not inexhaustible but are rapidly diminishing in many places. Will man, then, return to the power of water and wind? Or will he emigrate where the most powerful source of heat sends its rays to all? History will show what will come.[35]
If you regularly find your lawn furniture blown over, or have to collect it from the neighbour’s yard, your house needs to be repainted every year or two because it constantly gets sand-blasted, and where the trees have funny shapes (and not because your power company has been doing the pruning), that is when you know you live in a windy place where a wind turbine is likely to make economic sense.
With that in mind it makes a great deal of sense to use a tilt-up tower for your turbine. It makes maintenance and repairs much safer (on the ground) and cheaper. Crane fees, or having turbine installers hang off the top of a tower for long periods of time, tend to get very expensive. You should also budget for repairs, they will happen. Parts may be free under warranty, your installer’s time is not.
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.

2010 was a record year for green energy investments. According to a report from Bloomberg New Energy Finance, nearly US $243 billion was invested in wind farms, solar power, electric cars, and other alternative technologies worldwide, representing a 30 percent increase from 2009 and nearly five times the money invested in 2004. China had $51.1 billion investment in clean energy projects in 2010, by far the largest figure for any country.[155]
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
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.
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.

Due to increased technology and wide implementation, the global glass fiber market might reach US$17.4 billion by 2024, compared to US$8.5 billion in 2014. Since it is the most widely used material for reinforcement in composites around the globe, the expansion of end use applications such as construction, transportation and wind turbines has fueled its popularity. Asia Pacific held the major share of the global market in 2014 with more than 45% volume share. However China is currently the largest producer. The industry receives subsidies from the Chinese government allowing them to export it cheaper to the US and Europe. However, due to the higher demand in the near future some price wars have started to developed to implement anti dumping strategies such as tariffs on Chinese glass fiber.[58]
Renewable energy, after its generation, needs to be stored in a medium for use with autonomous devices as well as vehicles. Also, to provide household electricity in remote areas (that is areas which are not connected to the mains electricity grid), energy storage is required for use with renewable energy. Energy generation and consumption systems used in the latter case are usually stand-alone power systems.
Projections vary. The EIA has predicted that almost two thirds of net additions to power capacity will come from renewables by 2020 due to the combined policy benefits of local pollution, decarbonisation and energy diversification. Some studies have set out roadmaps to power 100% of the world’s energy with wind, hydroelectric and solar by the year 2030.
Environmental impact of wind power includes effect on wildlife, but can be mitigated if proper monitoring and mitigation strategies are implemented.[76] Thousands of birds, including rare species, have been killed by the blades of wind turbines,[77] though wind turbines contribute relatively insignificantly to anthropogenic avian mortality. For every bird killed by a wind turbine in the US, nearly 500,000 are killed by each of feral cats and buildings.[78] In comparison, conventional coal fired generators contribute significantly more to bird mortality, by incineration when caught in updrafts of smoke stacks and by poisoning with emissions byproducts (including particulates and heavy metals downwind of flue gases). Further, marine life is affected by water intakes of steam turbine cooling towers (heat exchangers) for nuclear and fossil fuel generators, by coal dust deposits in marine ecosystems (e.g. damaging Australia's Great Barrier Reef) and by water acidification from combustion monoxides.
A more reliable grid: Even if we're not ready to completely transition to renewable energy sources of power, supplementing the grid with green electricity helps increase grid reliability. You can also produce your own green electricity by installing solar panels or wind turbines at home. If the grid goes down for some reason, you may be able to keep your power on using your on-site renewable power generation system.
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.
It all started in Vermont in 1997. Our passion for protecting the environment led us to our mission: to use the power of consumer choice to change the way power is made. Today, as the longest-serving renewable energy retailer, we remain committed to sustainability every step of the way. By offering only products with an environmental benefit and operating with a zero-carbon footprint, we’re living our promise to the planet, inside and out.
Single small turbines below 100 kilowatts are used for homes, telecommunications dishes, or water pumping. Small turbines are sometimes used in connection with diesel generators, batteries, and photovoltaic systems. These systems are called hybrid wind systems and are typically used in remote, off-grid locations where a connection to the utility grid is not available.
There are different types of inverters for solar use (string, central, micro). If you’re hoping to install the solar PV system yourself, selecting the best inverter will require serious research and careful planning. If you work through a professional solar installer, on the other hand, the company should help take care of inverter selection for you.
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.
Thirty years ago Bergey pioneered the radically-simple “Bergey design” that has proven to provide the best reliability, performance, service life, and value of all of the hundreds of competitive products that have come and gone in that time. With only three moving parts and no scheduled maintenance necessary, the Bergey 10 kW has compiled a service record that no other wind turbine can match. We back it up with the longest warranty in the industry.
Solar panels converts the sun's light in to usable solar energy using N-type and P-type semiconductor material.  When sunlight is absorbed by these materials, the solar energy knocks electrons loose from their atoms, allowing the electrons to flow through the material to produce electricity. This process of converting light (photons) to electricity (voltage) is called the photovoltaic (PV) effect.  Currently solar panels convert most of the visible light spectrum and about half of the ultraviolet and infrared light spectrum to usable solar energy.

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 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]

^ Jump up to: a b Werner, Jürgen H. (2 November 2011). "Toxic Substances In Photovoltaic Modules" (PDF). postfreemarket.net. Institute of Photovoltaics, University of Stuttgart, Germany - The 21st International Photovoltaic Science and Engineering Conference 2011 Fukuoka, Japan. p. 2. Archived from the original (PDF) on 23 September 2014. Retrieved 23 September 2014.


With investment subsidies, the financial burden falls upon the taxpayer, while with feed-in tariffs the extra cost is distributed across the utilities' customer bases. While the investment subsidy may be simpler to administer, the main argument in favour of feed-in tariffs is the encouragement of quality. Investment subsidies are paid out as a function of the nameplate capacity of the installed system and are independent of its actual power yield over time, thus rewarding the overstatement of power and tolerating poor durability and maintenance. Some electric companies offer rebates to their customers, such as Austin Energy in Texas, which offers $2.50/watt installed up to $15,000.[96]
Solar energy is a flexible energy technology: it can be built as distributed generation (located at or near the point of use) or as a central-station, utility-scale solar power plant (similar to traditional power plants). Both of these methods can also store the energy they produce for distribution after the sun sets, using cutting edge solar + storage technologies.
Another situation where a small wind turbine can make good sense is in case your province, state, or country has rebates or other incentives that make it cheap to install one (just keep ongoing maintenance and repair cost in mind as well). While we would like to advocate responsible spending of government money, the small wind industry needs many more customers to mature. It takes time and installation numbers for manufacturers to work out the bugs, make better turbines, and make them cheaper.
UN Conference on the Human Environment (Stockholm 1972) Brundtlandt Commission Report (1983) Our Common Future (1987) Earth Summit (1992) Rio Declaration on Environment and Development Agenda 21 (1992) Convention on Biological Diversity (1992) ICPD Programme of Action (1994) Earth Charter Lisbon Principles UN Millennium Declaration (2000) Earth Summit 2002 (Rio+10, Johannesburg) United Nations Conference on Sustainable Development (Rio+20, 2012) Sustainable Development Goals
There are different types of inverters for solar use (string, central, micro). If you’re hoping to install the solar PV system yourself, selecting the best inverter will require serious research and careful planning. If you work through a professional solar installer, on the other hand, the company should help take care of inverter selection for you.

Environmental impact of wind power includes effect on wildlife, but can be mitigated if proper monitoring and mitigation strategies are implemented.[76] Thousands of birds, including rare species, have been killed by the blades of wind turbines,[77] though wind turbines contribute relatively insignificantly to anthropogenic avian mortality. For every bird killed by a wind turbine in the US, nearly 500,000 are killed by each of feral cats and buildings.[78] In comparison, conventional coal fired generators contribute significantly more to bird mortality, by incineration when caught in updrafts of smoke stacks and by poisoning with emissions byproducts (including particulates and heavy metals downwind of flue gases). Further, marine life is affected by water intakes of steam turbine cooling towers (heat exchangers) for nuclear and fossil fuel generators, by coal dust deposits in marine ecosystems (e.g. damaging Australia's Great Barrier Reef) and by water acidification from combustion monoxides.
“Hurricane-Broken Air Power Base Has an Alternative to Rebuild for Resilience” • Rebuilding the hurricane-wrecked Tyndall Air Force Base in Florida will come with a massive price tag, but experts say it offers a chance to make the base more resilient to the effects of extreme weather. Hurricane Michael hit Tyndall as a Category 4 storm. [Infosurhoy]
The advantage of this approach in the United States is that many states offer incentives to offset the cost of installation of a renewable energy system. In California, Massachusetts and several other U.S. states, a new approach to community energy supply called Community Choice Aggregation has provided communities with the means to solicit a competitive electricity supplier and use municipal revenue bonds to finance development of local green energy resources. Individuals are usually assured that the electricity they are using is actually produced from a green energy source that they control. Once the system is paid for, the owner of a renewable energy system will be producing their own renewable electricity for essentially no cost and can sell the excess to the local utility at a profit.

Small wind turbines may be used for a variety of applications including on- or off-grid residences, telecom towers, offshore platforms, rural schools and clinics, remote monitoring and other purposes that require energy where there is no electric grid, or where the grid is unstable. Small wind turbines may be as small as a fifty-watt generator for boat or caravan use. Hybrid solar and wind powered units are increasingly being used for traffic signage, particularly in rural locations, as they avoid the need to lay long cables from the nearest mains connection point.[60] The U.S. Department of Energy's National Renewable Energy Laboratory (NREL) defines small wind turbines as those smaller than or equal to 100 kilowatts.[61] Small units often have direct drive generators, direct current output, aeroelastic blades, lifetime bearings and use a vane to point into the wind.
Reliance on rare earth minerals for components has risked expense and price volatility as China has been main producer of rare earth minerals (96% in 2009) and had been reducing its export quotas of these materials.[56] In recent years, however, other producers have increased production of rare earth minerals and China has removed its reduced export quota on rare earths leading to an increased supply and decreased cost of rare earth minerals, increasing the viability of the implementation of variable speed generators in wind turbines on a large scale.[57]

A few localities have exploited the attention-getting nature of wind turbines by placing them on public display, either with visitor centers around their bases, or with viewing areas farther away.[59] The wind turbines are generally of conventional horizontal-axis, three-bladed design, and generate power to feed electrical grids, but they also serve the unconventional roles of technology demonstration, public relations, and education.
Jump up ^ Schröder, K.-P.; Smith, R.C. (2008). "Distant future of the Sun and Earth revisited". Monthly Notices of the Royal Astronomical Society. 386 (1): 155–163. arXiv:0801.4031. Bibcode:2008MNRAS.386..155S. doi:10.1111/j.1365-2966.2008.13022.x. See also Palmer, J. (2008). "Hope dims that Earth will survive Sun's death". New Scientist. Retrieved 24 March 2008.
It is possible to use any type of solar thermal panel (sheet and tubes, roll-bond, heat pipe, thermal plates) or hybrid (mono/polycrystalline, thin film) in combination with the heat pump. The use of a hybrid panel is preferable because it allows covering a part of the electricity demand of the heat pump and reduce the power consumption and consequently the variable costs of the system.
These residential renewable energy plans are sourced from 100% wind power generation. In addition, a Green Power plan lets you lock in a secure, fixed energy rate with the same key benefits as Champion Energy’s traditional electricity plans. This is an ideal choice for customers looking for ways to preserve the environment, conserve natural resources and promote the growth of renewable energy infrastructure.

Wind turbines need wind. Not just any wind, but the nicely flowing, smooth, laminar kind. That cannot be found at 30 feet height. It can usually not be found at 60 feet. Sometimes you find it at 80 feet. More often than not it takes 100 feet of tower to get there. Those towers cost as much or more, installed, as the turbine itself. How much tower you need for a wind turbine to live up to its potential depends on your particular site; on the trees and structures around it etc. Close to the ground the wind is turbulent, and makes a poor fuel for a small wind turbine.
We harness the earth’s most abundant resources – the strength of the wind, the heat of the sun and the force of water – to power the world’s biggest economies and the most remote communities. Combining onshore and offshore wind, hydro and innovative technologies, GE Renewable Energy has installed more than 400+ gigawatts capacity globally to make the world work better and cleaner.
Green-e is a voluntary certification program for renewable electricity products. The Green-e program establishes consumer protection and environmental standards for electricity products, and verifies that these products meet the standards. The Green-e logo certifies that at least half the power supplied is from renewable sources. Many products will carry the Green-e logo, and the best way to find the most environmentally sensitive providers is by doing some comparison research. To find out which Green-e certified products are available in your state, visit Green-e's electric choices page. Questions about particular providers can be directed to the Center for Resources Solutions, which administers the Green-e program, at (415) 561-2100.
Green energy is the term used to describe sources of energy that are considered to be environmentally friendly and non-polluting, such as geothermal, wind, solar, and hydro. Sometimes nuclear power is also considered a green energy source. Green energy sources are often considered "green" because they are perceived to lower carbon emissions and create less pollution.
Green energy is commonly thought of in the context of electricity, mechanical power, heating and cogeneration. Consumers, businesses, and organizations may purchase green energy in order to support further development, help reduce the environmental impacts of conventional electricity generation, and increase their nation’s energy independence. Renewable energy certificates (green certificates or green tags) have been one way for consumers and businesses to support green energy.
What? You are still reading? If we did not talk you out of a wind turbine by now there may still be hope! There certainly are situations where a small wind turbine makes perfect sense: If you are off-grid you should definitely consider adding a wind turbine. Wind and solar tend to complement each other beautifully; the sunny days tend to be not very windy, while the windy days tend to have little sun. Wind turbines generally produce most energy in the winter, when solar panels fall short.
As competition in the wind market increases, companies are seeking ways to draw greater efficiency from their designs. One of the predominant ways wind turbines have gained performance is by increasing rotor diameters, and thus blade length. Retrofitting current turbines with larger blades mitigates the need and risks associated with a system-level redesign. As the size of the blade increases, its tendency to deflect also increases. Thus, from a materials perspective, the stiffness-to-weight is of major importance. As the blades need to function over a 100 million load cycles over a period of 20–25 years, the fatigue life of the blade materials is also of utmost importance. By incorporating carbon fiber into parts of existing blade systems, manufacturers may increase the length of the blades without increasing their overall weight. For instance, the spar cap, a structural element of a turbine blade, commonly experiences high tensile loading, making it an ideal candidate to utilize the enhanced tensile properties of carbon fiber in comparison to glass fiber.[47] Higher stiffness and lower density translates to thinner, lighter blades offering equivalent performance. In a 10 (MW) turbine—which will become more common in offshore systems by 2021—blades may reach over 100 m in length and weigh up to 50 metric tons when fabricated out of glass fiber. A switch to carbon fiber in the structural spar of the blade yields weight savings of 20 to 30 percent, or approximately 15 metric tons.[48]
Other cities won’t have it so easy. Take Atlanta. Residents buy energy from Georgia Power, which is owned by investors. As things stand, Atlantans have no control over how their power is generated, though that may change. In 2019, Georgia Power, by state law, has to update its energy plan. Ted Terry, director of the Georgia chapter of the Sierra Club, says the nonprofit is working with Atlanta officials to incorporate renewables, primarily solar, into the state’s plan. Developing such energy sources on a scale that can power a metro area with 5.8 million people, as in Atlanta, or 7.68 million in the San Francisco Bay Area, or 3.3 million in San Diego, will prove challenging. But it doesn’t seem impossible. In 2015, California set a goal of deriving 50 percent of its energy from renewable sources by 2030. Its three investor-owned utilities—Pacific Gas & Electric, Southern California Edison and San Diego Gas & Electric—are poised to achieve that goal just two years from now, or ten years early.
As competition in the wind market increases, companies are seeking ways to draw greater efficiency from their designs. One of the predominant ways wind turbines have gained performance is by increasing rotor diameters, and thus blade length. Retrofitting current turbines with larger blades mitigates the need and risks associated with a system-level redesign. As the size of the blade increases, its tendency to deflect also increases. Thus, from a materials perspective, the stiffness-to-weight is of major importance. As the blades need to function over a 100 million load cycles over a period of 20–25 years, the fatigue life of the blade materials is also of utmost importance. By incorporating carbon fiber into parts of existing blade systems, manufacturers may increase the length of the blades without increasing their overall weight. For instance, the spar cap, a structural element of a turbine blade, commonly experiences high tensile loading, making it an ideal candidate to utilize the enhanced tensile properties of carbon fiber in comparison to glass fiber.[47] Higher stiffness and lower density translates to thinner, lighter blades offering equivalent performance. In a 10 (MW) turbine—which will become more common in offshore systems by 2021—blades may reach over 100 m in length and weigh up to 50 metric tons when fabricated out of glass fiber. A switch to carbon fiber in the structural spar of the blade yields weight savings of 20 to 30 percent, or approximately 15 metric tons.[48]

There are numerous organizations within the academic, federal, and commercial sectors conducting large scale advanced research in the field of renewable energy. This research spans several areas of focus across the renewable energy spectrum. Most of the research is targeted at improving efficiency and increasing overall energy yields.[157] Multiple federally supported research organizations have focused on renewable energy in recent years. Two of the most prominent of these labs are Sandia National Laboratories and the National Renewable Energy Laboratory (NREL), both of which are funded by the United States Department of Energy and supported by various corporate partners.[158] Sandia has a total budget of $2.4 billion[159] while NREL has a budget of $375 million.[160]
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.

Alternatively, SRECs allow for a market mechanism to set the price of the solar generated electricity subsity. In this mechanism, a renewable energy production or consumption target is set, and the utility (more technically the Load Serving Entity) is obliged to purchase renewable energy or face a fine (Alternative Compliance Payment or ACP). The producer is credited for an SREC for every 1,000 kWh of electricity produced. If the utility buys this SREC and retires it, they avoid paying the ACP. In principle this system delivers the cheapest renewable energy, since the all solar facilities are eligible and can be installed in the most economic locations. Uncertainties about the future value of SRECs have led to long-term SREC contract markets to give clarity to their prices and allow solar developers to pre-sell and hedge their credits.
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