The Wisdom of Wind

Wind has come a long way since the 1980s in terms of the power industry and wind powerLooking up at wind turbine - with logo. It’s hard to believe that many of the wind turbines we put into action in 1982 were able to generate only about 100 kilowatts of energy, maybe enough to power about 36 homes when the wind was blowing at our first wind farm at Altamont Pass. Soon we will have giant turbines that can put out almost 2 megawatts (MW) of power each, enough to power 730 homes, and they’re more efficient (taking up less space for more power).

Plus they are a clean, green source of electricity.

The Altamont Pass location has changed in recent years. Towers now can be 100 feet or more in height, utilizing wind that is stronger and more consistent than breezes closer to the ground. Lattice support towers that encouraged bird nesting are being replaced by towers designed without nesting opportunities and bird collisions have been significantly reduced as modern turbine blades over 100 feet in diameter turn slower than those on older windmills.

The U.S. Department of Energy says that most windmills in the country are started when wind speeds are between 8 and 16 miles per hour and turned off when winds exceed 55 mph. Higher winds can damage the windmills, so operators remotely stop them from spinning.

Today we can generate almost 200 MW from wind for local distribution, using turbines at Altamont as well as power from wind farms in Washington and Southern California (see our energy resources map). Combining that wind energy with the electricity generated by solar, hydroelectric, geothermal and landfill gas resources, we’re able to keep our power generation for our Santa Clara customers over 40 percent carbon free.

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Wind Power Winning the Day for Electricity Users

Did you know that wind power is actually considered a type of solar power by the U.S. Department of Energy (DOE)? Wind farm - with logo

In an explanation of how wind turbines work, the DOE points out that winds are caused by the heating of the atmosphere by the sun, the rotation of the Earth, and the Earth’s surface irregularities. Maybe we can add “earth spin power” to our list of renewable energy sources.

At SVP we have the potential use of almost 200 megawatts (MW) of peak wind power for our customers. The actual amount utilized at any one time usually depends on when and where the wind is blowing. As of Dec. 31, 2015, California had 6,108 megawatts (MW) of wind power potential, according to the DOE. The DOE states there are 74,472 megawatts of wind power capable of being generated overall in the U.S.

Wind power is here to stay, and for good reason.

So how does wind add up? The advantages as well as the challenges associated with wind power include:

  • It’s a green renewable energy source. Turbines don’t emit atmospheric pollutants.
  • It’s sustainable. As long as the sun shines and the wind blows, power can be harnessed and distributed to the grid.
  • Wind turbines can be built on existing farms or ranches. Some of the best wind farm sites are in rural areas. Since wind turbines use very little land, farmers and ranchers can continue working their land while at the same time earning extra income from renting their land to power companies.
  • Wind helps the economy and creates jobs. U.S. wind power projects in 2014 employed more than 73,000 workers and resulted in more than $8 billion of private capital entering the economy, according to the American Wind Energy Association. The DOE’s Wind Vision Report says by 2050, wind power might support more than 600,000 jobs in manufacturing, installation, maintenance, and support services.

There are also challenges for wind power.

Other sources of electricity can be cheaper than wind power. Some fossil-fueled generation sources can sometimes provide electricity more cheaply than wind farms. Also, the initial investment for wind power technology is higher than the investment needed for conventional resources.

  • Rural sites are good for wind but they can be far from populations needing the electricity. This requires transmission lines to deliver the power from a remote location.
  • A wind farm development might not be the most profitable use of the land. Other types of development not related to power generation may be more profitable for owners of land suitable for a wind project.
  • Turbines might cause noise and aesthetic pollution. Concern exists over the noise produced by the turbine blades and visual impacts to the landscape.
  • Turbine blades could damage local wildlife. There is concern about turbine blades killing and injuring birds. The Audubon Society has long supported wind power while encouraging new wind farm location parameters and continued improvement in pole design. Slower turbines, improved monitoring of bird behavior and flight paths, and sensitivity to bird migration routes have all played a role in reducing impacts of wind turbines on birds. In fact, a good portion of turbines are shut down for two months during the bird migration season at Altamont Pass, where we are also working toward replacing the smaller, faster-spinning small turbines with new large units.

The Workings of Wind Power

wind turbine with logoHow in the world do those windmills we see on the hills around the Bay Area generate and deliver electricity?

That’s a common question posed to us, so let’s take a minute to explain the inner workings of a wind turbine that’s capable of producing up to 1.8 megawatts of power when the wind is blowing. That’s enough to power 500 homes. Take a look at the graphic animation from the U.S. Department of energy that shows the different working parts. (Be sure to click through the slide show to see all of the different working parts described below.)

First of all, there are the blades. Most turbines have two or three blades that are attached to the rotor, or hub. That connects to the main shaft, which spins to power a generator. The electricity from that turbine is fed into the grid for widespread distribution.

You can see from the graphic that there are more components, especially as turbines get larger. Turbines are designed to spin facing either upwind or downwind. The one pictured in the animation is an upwind type, facing the wind with the aid of a yaw drive that keeps it headed into the wind. Downwind turbines are naturally spun by the wind to face away from the wind and do not require the yaw drive.

Most modern turbines have blades connected to a pitch system much like that of a propeller-driven airplane. The blades can be turned, or pitched, to control how much wind they utilize to spin the windmill or to minimize the impact of wind when the turbine needs to be turned off, such as when winds exceed 55 miles-per-hour. A brake may complete the stopping process.

Sometimes you’ll see some or all the turbines on a wind farm stopped even when the wind is blowing. Electric utility customers are probably getting all the power they need from other sources. Since electricity is an on-demand source of energy, there is no place for the wind power to go. In the future when power storage battery technology has advanced to the point where saving excess energy is feasible, we may see this change.