†Offer is available to Texas residential customers who enroll using the Promotion Code “NIGHTSFREE”. Plan bills a monthly Base Charge, an Energy Charge, and passes through Utility Transmission and Distribution delivery charges. Energy Charges for usage consumed between 9pm and 7am each day is credited back on your bill. The utility charges, including delivery charges for night time hours, are passed through at cost and aggregated on your bill. See Electricity Facts Label for details.

Due to data transmission problems, structural health monitoring of wind turbines is usually performed using several accelerometers and strain gages attached to the nacelle to monitor the gearbox and equipments. Currently, digital image correlation and stereophotogrammetry are used to measure dynamics of wind turbine blades. These methods usually measure displacement and strain to identify location of defects. Dynamic characteristics of non-rotating wind turbines have been measured using digital image correlation and photogrammetry.[44] Three dimensional point tracking has also been used to measure rotating dynamics of wind turbines.[45]
As local wind speed increases, so does the power output. Since this type of generator uses wind as 'fuel', it is important to choose an appropriate site for mounting the turbine. The ideal location for a wind generator is 20 feet above any surrounding object within a 250-foot radius. Wind speed increases with height above ground, so a taller mast can provide significant gains in energy production.
Most horizontal axis turbines have their rotors upwind of its supporting tower. Downwind machines have been built, because they don't need an additional mechanism for keeping them in line with the wind. In high winds, the blades can also be allowed to bend which reduces their swept area and thus their wind resistance. Despite these advantages, upwind designs are preferred, because the change in loading from the wind as each blade passes behind the supporting tower can cause damage to the turbine.
Geothermal power plants can operate 24 hours per day, providing base-load capacity, and the world potential capacity for geothermal power generation is estimated at 85 GW over the next 30 years. However, geothermal power is accessible only in limited areas of the world, including the United States, Central America, East Africa, Iceland, Indonesia, and the Philippines. The costs of geothermal energy have dropped substantially from the systems built in the 1970s.[10] Geothermal heat generation can be competitive in many countries producing geothermal power, or in other regions where the resource is of a lower temperature. Enhanced geothermal system (EGS) technology does not require natural convective hydrothermal resources, so it can be used in areas that were previously unsuitable for geothermal power, if the resource is very large. EGS is currently under research at the U.S. Department of Energy.
Geothermal energy - Just under the earth's crust are massive amounts of thermal energy, which originates from both the original formation of the planet and the radioactive decay of minerals. Geothermal energy in the form of hot springs has been used by humans for millennia for bathing, and now it's being used to generate electricity. In North America alone, there's enough energy stored underground to produce 10 times as much electricity as coal currently does.
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]
Wind turbines allow us to harness the power of the wind and turn it into energy. When the wind blows, the turbine's blades spin clockwise, capturing energy. This triggers the main shaft, connected to a gearbox within the nacelle, to spin. The gearbox sends that energy to the generator, converting it to electricity. Electricity then travels down the tower to a transformer, where voltage levels are adjusted to match with the grid.
Between maintenance and repairs, it would greatly help and keep your cost down if you can do some of the work yourself: Being able to safely tilt the turbine tower up or down will save you money. Understanding how the turbine works, how to stop it safely, how to trouble-shoot at least the minor issues can keep you in the black. We understand that installing a wind turbine is not for everyone. In fact, towers are dangerous, and for a good installation the devil is in the details. An experienced installer can make a real difference in putting up a turbine that will work better, and be more reliable over time. We really encourage you to have a professional installer to do the initial installation. However, throwing up your hands and calling your installer for routine maintenance, or every time there is a minor issue, will likely make you an unhappy wind turbine owner (even if it is your installer’s dream).
The political purpose of incentive policies for PV is to facilitate an initial small-scale deployment to begin to grow the industry, even where the cost of PV is significantly above grid parity, to allow the industry to achieve the economies of scale necessary to reach grid parity. The policies are implemented to promote national energy independence, high tech job creation and reduction of CO2 emissions. Three incentive mechanisms are often used in combination as investment subsidies: the authorities refund part of the cost of installation of the system, the electricity utility buys PV electricity from the producer under a multiyear contract at a guaranteed rate, and Solar Renewable Energy Certificates (SRECs)
The windwheel of Hero of Alexandria (10 AD – 70 AD) marks one of the first recorded instances of wind powering a machine in history.[2][3] However, the first known practical wind power plants were built in Sistan, an Eastern province of Persia (now Iran), from the 7th century. These "Panemone" were vertical axle windmills, which had long vertical drive shafts with rectangular blades.[4] Made of six to twelve sails covered in reed matting or cloth material, these windmills were used to grind grain or draw up water, and were used in the gristmilling and sugarcane industries.[5]

There is one more area where buyers may get a false sense of security: Several states in the US have lists of “approved” wind turbines for their rebate programs. An example of this is the California list. The problem is that approval for this list, and the performance data provided (such as rated power and energy production) are essentially self-certified. The less-scrupulous manufacturers can ‘manufacture’ data and submit it under the pretence that it was measured.  The only value of those lists is in telling you what rebates are available, they do not provide reliable turbine information.
The comments stand in contrast to those made by Trump administration representatives also speaking at the energy summit, which is known as CERAWeek. Rick Perry, the energy secretary, on Wednesday criticized what he described as the “mind-set of the Paris agreement” that he contends supports renewable energy to the exclusion of other energy sources. And he took aim at countries pledging to phase out coal use.
As of 2018, American electric utility companies are planning new or extra renewable energy investments. These investments are particularly aimed at solar energy, thanks to the Tax Cuts and Jobs Act of 2017 being signed into law. The law retained incentives for renewable energy development. Utility companies are taking advantage of the federal solar investment tax credit before it permanently goes down to 10% after 2021. According to the March 28 S&P Global Market Intelligence report summary, "NextEra Energy Inc., Duke Energy Corp., and Dominion Energy Inc.’s utilities are among a number of companies in the sector contemplating significant solar investments in the near-term. Other companies, including Xcel Energy Inc. and Alliant Energy Corp., are undertaking large wind projects in the near-term, but are considering ramping up solar investments in the coming years."[96]
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.
Many industrialized nations have installed significant solar power capacity into their grids to supplement or provide an alternative to conventional energy sources while an increasing number of less developed nations have turned to solar to reduce dependence on expensive imported fuels (see solar power by country). Long distance transmission allows remote renewable energy resources to displace fossil fuel consumption. Solar power plants use one of two technologies:
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