“[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.”
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]
Solar energy, radiant light and heat from the sun, is harnessed using a range of ever-evolving technologies such as solar heating, photovoltaics, concentrated solar power (CSP), concentrator photovoltaics (CPV), solar architecture and artificial photosynthesis.[49][50] Solar technologies are broadly characterized as either passive solar or active solar depending on the way they capture, convert and distribute solar energy. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light dispersing properties, and designing spaces that naturally circulate air. Active solar technologies encompass solar thermal energy, using solar collectors for heating, and solar power, converting sunlight into electricity either directly using photovoltaics (PV), or indirectly using concentrated solar power (CSP).
Coal is our dirtiest source of energy. It releases more harmful pollutants into the atmosphere than any other energy source and produces a quarter of the nation’s global warming emissions. If we are going to effectively reduce air pollution and address global warming, we need to shut down the oldest, dirtiest coal plants—and not build new ones to replace them.
It is unfortunate to see how well marketing for small wind turbines is working: I often see people post questions on forums, where they are looking for a wind turbine “with a low cut-in wind speed”. Depending on whom you ask, the cut-in wind speed is either the wind speed where the turbine starts turning, or the wind speed where it starts to produce some power. For most wind turbines it is around 2.5 – 3.5 m/s (5.5 – 8 mph), and it is an utterly meaningless parameter.

At Bodine-Scott, our renewable energy options have helped dozens of local homes and businesses reduce their utility bills and any negative environmental impact from the use of traditional energy sources. Our technicians are NABCEP-certified experts, and we keep all of our staff informed and up to date on the latest developments in the solar industries. Our average customer sees a 50 percent reduction in utility costs, to say nothing of the invaluable reduction in environmental impact that comes from using clean energy. If you are serious about making an investment in the future of your home and the Earth, contact us today to speak with one of our renewable energy experts.


As the section above shows, anything under 5 m/s annual average wind speed is not going to be worth-while if you want any economic benefit out of a wind turbine. Even with government incentives, you would be better off with solar for most places. Let us take this a bit further, and assume your backyard is pretty windy, a full 6 m/s (13.4 mph) annual average wind speed at 100′ height. You get a 6 kW wind turbine installed, and shell out $50,000 for that privilege. If the installer did her job properly, the turbine is spinning in nice, clean, laminar air, and it will produce around 13,000 kWh per year. You are the kind of person that wins the lottery on a regular basis, marries a beauty queen (or king), and has kids that all go to ivy-league universities; your wind turbine never breaks and you do not have to shell out a single buck for maintenance over 20 years. Now your turbine has produced around 260,000 kWh of electricity, which works out to 19.2 cents per kWh in cost. Maybe you pay more than for electricity and it is worth it, but your are likely not getting rich, and any repairs and maintenance will drive that price up in a hurry.
A subtype of Darrieus turbine with straight, as opposed to curved, blades. The cycloturbine variety has variable pitch to reduce the torque pulsation and is self-starting.[33] The advantages of variable pitch are: high starting torque; a wide, relatively flat torque curve; a higher coefficient of performance; more efficient operation in turbulent winds; and a lower blade speed ratio which lowers blade bending stresses. Straight, V, or curved blades may be used.[34]
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.

DOE selected six companies for its 2007 Green Power Supplier Awards, including Constellation NewEnergy; 3Degrees; Sterling Planet; SunEdison; Pacific Power and Rocky Mountain Power; and Silicon Valley Power. The combined green power provided by those six winners equals more than 5 billion kilowatt-hours per year, which is enough to power nearly 465,000 average U.S. households. In 2014, Arcadia Power made RECS available to homes and businesses in all 50 states, allowing consumers to use "100% green power" as defined by the EPA's Green Power Partnership.[86][87]
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.
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.
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]
The most common type of residential solar is called solar PV. The PV stands for “photovoltaic,” and a solar PV system is a electrical system that consists of solar panels, an inverter, a meter, and a few other components (mounting, cabling, etc.). A solar PV system requires little to no maintenance for years, and if you’re in a place with the right amount of sunlight, you can end up saving money, while also going green.

DOE selected six companies for its 2007 Green Power Supplier Awards, including Constellation NewEnergy; 3Degrees; Sterling Planet; SunEdison; Pacific Power and Rocky Mountain Power; and Silicon Valley Power. The combined green power provided by those six winners equals more than 5 billion kilowatt-hours per year, which is enough to power nearly 465,000 average U.S. households. In 2014, Arcadia Power made RECS available to homes and businesses in all 50 states, allowing consumers to use "100% green power" as defined by the EPA's Green Power Partnership.[86][87]
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:
×