Public Utilities Fortnightly's GreenUtility website recently carried an interview with Kurt Yeager, a former President of the Electric Power Research Institute (EPRI) on the topic of a “smart grid” and Mr. Yeager's contention that it is necessary for substantial use of renewable energy sources to generate electricity.
While Mr. Yeager does get many points right, like the urgent need to invest in our grid to make it more reliable, more efficient, and provide consumers with access to larger quantities of lower cost energy resources like wind energy, several points need to be made to correct misconceptions presented in the interview.
Mr. Yeager says, “I served on a National Academy renewable energy study a couple of years ago. We concluded that getting more than single digit percentages from intermittent renewable energy sources is really not possible in today’s grid. We would have to build so much backup gas power or storage capacity that it doesn’t make sense.”
Wind energy is being reliably and efficiently integrated onto the grid today. In Europe, Denmark now obtains more than 20% of its electricity from wind, Portugal more than 15%, Spain and Ireland more than 10%, and Germany around 7%. These countries have wind resources that are far less diverse than ours and their power grids are not as large, making the task of integrating wind there far more challenging than it is in the U.S., and yet these countries still have not experienced any major challenges or any negative impacts on reliability. In fact, many of these countries plan to increase their wind penetrations several times over after conducting studies indicating that there would be no negative impacts on reliability from doing so.
In the U.S., Texas obtained almost 8% of its electricity from wind energy in 2010, and Iowa over 15%. Wind integration studies in the U.S. have found that wind penetrations can be increased at least 10-20 times beyond current levels with no challenges for power system reliability. For links to these studies, see http://www.uwig.org/opimpactsdocs.html .
Nowhere in Europe or in the U.S. have storage resources or dedicated backup resources been added as a result of the addition of wind energy, and it is unfortunate to hear Mr. Yeager reference that old myth about wind energy. Wind energy needs backup or storage no more than any other generator on the power system, and in many ways the gradual and predictable variability in the output of wind plants is far easier to manage than that of large power plants that trip offline instantaneously when they experience a forced outage.
On the power system, the output of wind plants is combined with all other sources of supply and demand, which is important because it means that all changes in electricity supply and demand that are occurring across the entire region are aggregated together. Even though many of those sources of supply and demand are changing (think of factories coming on and offline, people turning air conditioners on and off, fossil-fired power plants breaking down unexpectedly) together their combined output is stable and manageable. There is no need to “back up” wind output as claimed, since the gradual and predictable changes that occur in wind output as weather systems move across the region are largely canceled out by other changes in electricity supply and demand. At very high wind penetrations, the total power system variability and thus the need for reserves can increase, but that variability is mostly confined to the 30+ minute timeframe and is readily managed by inexpensive, mostly non-polluting, non-spinning reserves. In fact, it would be far more appropriate to talk about the need to back up large fossil and nuclear power plants, as they are the ones that experience large, immediate, and unexpected outages, requiring grid operators to keep fast acting, expensive, and inefficient reserve generation ready 24/7/365 in case one of those plants goes down.
The focus on microgrids and “smart grid” technology misses the point about what is really needed for our power system to be able to provide consumers with more reliable, more affordable, and cleaner electricity–building more transmission lines and upgrading the capacity of the ones we have. In parts of the country where consumers are denied access to lower cost and cleaner generation, the problem is not a lack of a smart grid, but rather a lack of a grid at all. Many of the nation's best wind energy resources are stranded in rural parts of the middle of the country with very small populations and no transmission system at all. If our country's massive wind energy resources are to be put to use, we need to invest in transmission lines that can move that power to the consumers who want it.
Building transmission that increases our ability to move power from region to region is critical for avoiding blackouts and other reliability problems and minimizing their impact when they do happen, as well as for providing consumers with greater choice for energy sources that protects them from volatility in the price of any one fuel. Higher-capacity transmission lines are also far more efficient than the overloaded low-voltage lines that carry most of the nation's power today, so by reducing line losses with new transmission, we can save consumers money and reduce emissions. While Mr. Yeager is correct that we need to invest in our grid for a number of reasons, his prescription for how that investment should be made misses the mark.