An article that appeared recently in a new energy trade publication, Energy AOL, purported to show "the reality of wind" by extensively quoting negative comments from Kevin Gaden, a spokesperson for the Municipal Energy Agency of Nebraska (MEAN).
Here are some facts that contradict Mr. Gaden’s remarks and that should have been included in the story:
Reserve costs: Utility system operators constantly adjust the output of power plants and other resources to accommodate changes in electricity demand and supply. Large amounts of wind energy can marginally add to the variability that is already on the system, causing an modest increase in the need for these resources, which grid operators refer to as reserves.
Nebraska’s utilities teamed up in 2009 and 2010 to study the impacts of adding wind power to the grid. The utilities’ study, available here, found that Nebraska and the entire region could obtain 40% of its electricity from wind farm plants without any negative impact on grid reliability. The study found the cost of the additional reserves needed to accommodate this extremely high level of wind turbines were about $2/MWh (megawatt-hour, 1,000 kilowatt-hours) of wind, and the costs at lower penetrations were a fraction of that. For context, in that part of the Midwest, a MWh of wind energy is typically sold for around $40-60, so this additional cost is literally pennies on the dollar for the value created by wind.
More importantly, the cost of accommodating wind power on the utility system is less than the cost of integrating many other types of power plants. For example, large nuclear and fossil power plants experience unexpected and instantaneous outages on a fairly frequent basis. As a result, system operators must maintain 1,000+ MW (megawatts) of reserve generation, enough for a large city, standing by at all times and ready to be deployed quickly if needed. The nationwide cost of maintaining these reserves is in the billions of dollars, and this is something we all pay through our electric bills to subsidize large fossil and nuclear plants. In contrast, it takes many hours for the combined output of wind plants spread across a region like the Midwest to change significantly, and system operators use weather forecasts to predict when that will happen. As a result, grid operators can accommodate changes in wind output using slower-acting reserves that typically cost 1/40 as much as the faster-acting reserves that they use for conventional power plants.
Baseload plants: It makes sense that wind farms can sell their power at a lower cost than other power plants, as wind plants’ fuel is free. As a result, it should not be a surprise that market forces dictate that fossil-fired power plants should reduce their output before wind farms do, since fossil plants have to pay for the fuel they are burning, while wind farms do not. In fact, the significant fuel, emissions, and cost savings that result from wind farms causing fossil-fired power plants to reduce their output or turn off are the reasons why we build wind farms in the first place. Fortunately, there is a great deal of flexibility built into the power system to accommodate the fact that electric demand varies by a factor of three or more depending on the time of day or year, so fossil-fired plants are already designed to reduce their output when their power is not needed, whether that is due to electric demand being low or wind energy output being high.
Emissions savings: A large body of data collected by the government and by utility system operators confirms that adding wind to the grid results in major reductions in fossil fuel use and emissions. In almost all cases, every MWh of electricity produced by a wind farm displaces a MWh of electricity that would have been produced by a fossil-fired power plant. Moreover, many analyses indicate that the emissions savings resulting from adding wind to the utility system have been even larger than expected. For example, a 2010 study by the National Renewable Energy Laboratory found that if the Eastern U.S. obtained 20% of its electricity from wind energy, carbon dioxide emissions would be reduced by 25%. This is because the oldest fossil-fired power plants on the utility system tend to be the highest emitting as well as the most expensive to run, and so they are the first to be turned off when low-cost wind is available.
By Tom Gray, www.awea.org/blog/
