[Editor’s note: This story is the first in a series of overviews of the different types of renewable resources and how they fit into the generation mix.]
Western’s Renewable Energy Program is dedicated to helping our customers diversify their resource portfolios by providing information and technical assistance to evaluate their options. No single resource or mix works for every power provider, and even if two different utilities choose the same resource, each will gain different benefits and face different challenges. That being said, there is one renewable that leads the pack: wind.
Second only to hydropower in installed capacity, wind represents 27 percent of the nation’s renewable generation and supplies 4 percent of our total electricity. According to the Energy Information Administration (EIA) wind’s share of the nation’s electric power portfolio has increased 121 percent over the last three years, and is expected to continue as the fastest growing form of generation.
There are now 61,327 megawatts (MW) of installed wind capacity in the United States and more than 46,000 wind turbines. Installed capacity in Western’s territory alone totals more than 26,000 MW and includes the second- and third-largest wind producing states, California and Iowa respectively.
The top 10 rural electric cooperatives with wind capacity on their system are all generation and transmission cooperatives, including several Western customers. Basin Electric Power Cooperative placed first in 2012, with 716 MW of total wind capacity, and Great River Energy earned the number three spot on the list with 474 MW. Their successful wind programs have earned both utilities the Wind Cooperative of the Year award.
A standout resource
Some of the advantages wind power boasts are common to other types of renewables—low greenhouse gas emissions, free domestic fuel supply, local job creation—while others are unique to the resource. One feature of wind that does not get enough attention is that it uses far less water than many other types of generation. Water consumption per megawatt-hour for wind is almost zero (solar or dry-cooling gas plants are similar), compared to around 1,000 gallons for coal, oil or concentrating solar power with recirculating cooling.
(Artwork by the California Energy Commission)
A short explanation
The generator that turns wind into electricity is the wind turbine (not windmill), and it looks and acts something like a large toy pinwheel. Blowing wind spins the blades on the turbine. The blades are attached to a hub that is mounted on a turning shaft. The shaft goes through a gear transmission box that increases the turning speed. The transmission is attached to a high-speed shaft that turns a generator that makes electricity. In case of very high winds, the turbine has a brake to keep the blades from turning too fast and being damaged.
Cost is another factor that sets wind apart from other resources. It is one of the lowest-priced renewable energy technologies available, costing between two and six cents per kilowatt-hour, depending upon the wind resource and project financing and ownership structure of the particular project. Wind also offers economic development opportunities for rural areas. Growers can lease their land for turbines and still produce crops and livestock, since the towers have a relatively small footprint.
Like all forms of energy, both renewable and nonrenewable, wind has its share of challenges as well as benefits that each utility must assess based on individual circumstances.
Intermittency is the concern that most readily comes to mind for the average consumer, and it is certainly true that wind does not blow all the time. More accurate weather forecasting programs, affordable utility-scale storage and a more flexible grid would go a long way toward addressing the issue. Many research programs at national laboratories and universities are focusing on developing new technologies and improving existing systems to integrate wind onto the grid.
In the meantime, the utility industry is accustomed to dealing with the inherently variable nature of the power system. Those operational strategies are applied to wind, allowing the grid to balance constantly changing demand needs, whether the generation is coal, gas or wind. Some utilities are using demand response—cycling controlled loads on and off during peak demand—to match the load to the generation. Controlled super-insulated electric water heaters can use off-peak wind generation to heat water overnight and store it for use the next day. Plug-in electric vehicles may one day offer another load that can “bank” wind power.
In any case, the more wind we place on the system, the more complicated it becomes to balance load with resources cost effectively. Western and the industry are working hard to address these issues.
Perhaps a greater challenge to wind development is that many areas with the best resources are located far from the load. The American Recovery and Reinvestment Act of 2009 gave Western borrowing authority for transmission projects intended to connect renewable energy facilities to load demand. The Transmission Infrastructure Program (TIP) is currently partnering on several projects with at least one geographical point in Western’s territory.
Not a problem
Along with real challenges, wind is beset by several misconceptions that are ripe for a little myth-busting.
The belief that wind turbines are unusually harmful to birds is a persistent myth that scientific studies do not support. Most research indicates that urban sprawl, buildings, house cats and the climatic changes are bigger threats to bird habitats. The National Audubon Society has stated its strong support for wind power as a clean alternative energy source that reduces the threat of global warming.
Noise pollution, likewise, is a concern, but credible peer-reviewed scientific data and various government reports have not shown links between wind turbine noise and negative health impacts. Some opponents of wind power have pointed to infrasound, or sound below the threshold of human hearing, as a hazard. However, researchers at the University of Massachusetts found no credible evidence of physiological or psychological effects resulting from exposure to low-level noise.
To put turbine noise in context, at a distance of 300 meters, the turbine will have the sound pressure of 43 decibels. The average air conditioner can reach 50 decibels of noise, and most refrigerators run at around 40 decibels. For a person living half a mile from a wind turbine, the noise would blend in with other background noise, and a mile away, no noise would be heard.
None of these facts are intended to imply that wind power has no environmental impacts—all forms of generation do. However, renewable energy is at a stage where the technologies are rapidly evolving to become safer and more efficient. As the industry grows, so does its knowledge of the impacts and the ability to mitigate them.
A final word
Renewable resources are not a “one-size-fits-all” answer to energy independence. The purpose of Western’s Renewable Resource and Energy Services programs is to help our customers determine what resources are right for their needs.
Just a few factors that affect a utility’s choice include geographical location, state regulations and mandates, energy prices in the area and the makeup of its customer base. To learn more about renewable resources, contact Program Manager Randy Manion. For assistance with long-range portfolio planning, contact Energy Services Manager Ron Horstman or your regional Energy Services representative.