A Fresh Look at Wind
Reflections on Where We are Going
I have been told by many people, both friends and strangers, that this themed biennial issue of IEEE Power & Energy Magazine, devoted to the integration and interconnection of wind plants on power systems, has been a very helpful and educational resource for them, as well as for a great number of their colleagues and less technical industry players. This is important to me, and it is one of the many reasons that I continue to serve as the guest editor for this reoccurring theme issue.
My colleague Brian Parsons from the National Renewable Energy Laboratory (NREL), who recently retired, was my supporting coeditor for the first four issues, in 2005, 2007, 2009, and 2011. I am now joined by Charlton Clark, a colleague who heads the wind integration activities in the U.S. Department of Energy. Their help and support, which helps makes this issue possible, has been another source of inspiration for me. They have been great supporters and contributors to the Utility Variable-Generation Integration Group (UVIG), and working together with a broad cross section of the industry through UVIG, we have been able to make great strides in the field of wind integration in the past ten years. I feel incredibly fortunate to be working with them and so many other really great people during this period of time. It is without a doubt the most exciting time in the power business in the past 50 years. .
I have been doing a fair amount of reflection lately, looking at where we have come from, where we are going, and how much remains to be done in terms of the integration of renewable energy into the electric power system. My reflection has been partly due to the banner year the wind and solar industries experienced last year, with 45 GW of wind and over 20 GW of solar installed globally. My participation in the IEA Wind Annex Task 25 report on global best practices for the integration of wind energy on power systems has provided opportunity for reflection as well. While solar photovoltaics projected to continue its growth this year, wind is expected to have a significant slow down in the United States and, to a lesser extent, globally. This starts me thinking about what we have learned during the first 300 GW of wind power plant installations and how to distill and pass that knowledge on to help pave the way for the next 300 GW, and the next 300 GW after that, in successively shorter periods of time.
The question always comes up: what are the limits? As far as I can tell, there aren’t any technical ones, only economic ones. As a realistic engineer, I feel that we have to consider both. And I think that comes through in all of the things that we do. A year ago, NREL published a rather large report on the renewable electricity futures (REF) study, which looked at the feasibility of operating the power system with a range of annual renewable energy from 30 to 90% and focused in on 80%, thus the nickname “The 80% Study.” (The report can be found at http://www.nrel.gov/analysis/re_futures/.) It included not just wind and solar in the renewable sources but also biomass, geothermal, and hydro. In the 80% scenario, 45% of the total energy came from wind and solar; 35% from biomass, geothermal and hydro; and the remainder from fossil and nuclear. An hourly unit commitment and production cost simulation for the year 2050 showed that the system operation was feasible. A related challenge to the system operation is the design and operation of competitive electricity markets to handle this ever-growing share of near-zero marginal cost energy, a challenge that is being felt around the world and deserves to receive a much-increased share of our attention in the near future. Today’s markets never anticipated this situation when they were designed 10–15 years ago.
There are challenges but we are up to meeting them. I accept it as a personal challenge, a game of wits, to keep coming up with new solutions for new problems! So with the goal of identifying and addressing these challenges, we provide a global update to our last wind integration issue of two years ago.
We have been fortunate to obtain the participation of an outstanding cast of authors and coauthors, with over 50 representatives from 11 countries. They provide updates on the status and challenges of a broad cross section of wind integration activities from much of the globe, covering a range of important topics from many different perspectives. This issue consists of a selection of seven articles, which we would now like to introduce.
First is an update on the work of the Western Wind and Solar Integration Study (WWSIS) Phase 2, “Finding Flexibility,” led by Debbie Lew of NREL. This article provides a look at the impact of high levels of wind and solar penetration on the wear and tear costs on the conventional fleet and on the associated emissions reductions.
Next is a look at a wind and solar integration study at the other end of the size spectrum, the island of Oahu in Hawaii, “Catching Some Rays,” led by Matt Schuerger, an independent consultant who helped manage the study process.
In both of these studies, wind plant output forecasting and accessing sources of flexibility in the system are critical to successful integration strategies. Our next article, “Knowledge Is Power,” led by Mark Ahlstrom of Windlogics, provides an up-to-date look at the role of wind forecasting in integrating large volumes of wind energy into electricity markets.
The following article, “The Flexibility Workout,” led by Hannele Holttinen of VTT in Finland, addresses the topic of system flexibility. Holttinen serves as chair of the IEA Wind Annex Task 25 on Integration of Large Volumes of Wind Energy into Electricity Systems, an international collaboration of 14 countries, the work of which serves as the basis for this article.
The next two topics of system dynamics and grid codes reflect the growing application of traditional power engineering considerations into the wind integration process. Nick Miller of GE led the article “Emergency Response,” which by necessity deals with interconnection-wide phenomena, in this case both the Eastern Interconnection and the Western Interconnection in the United States. This article contains fascinating insight into the ancillary services of inertial response and frequency response that can be provided by wind power plants.
Next we look at the rapid evolution of grid codes, or interconnection requirements, around the world, at both the transmission and distribution level, in “Code Shift,” led by Thomas Ackermann of Energy-nautics in Germany. Ackermann has been a frequent contributor to this series over the years.
Just as we had an article two years ago on the situation in China, this year we have an article recognizing the rapid growth of offshore wind power in Europe and the importance of offshore network design. We are fortunate to have a contribution led by Antje Orths from the Danish TSO Energinet.dk, “Connecting the Dots.” This article provides a fascinating insight into the cooperation necessary to get a dozen or more countries working together on a truly international project, as well as the system planning and high-voltage dc technology development required for offshore wind.
We also include a book review of Wind Power in Power Systems, second edition, edited by Thomas Ackermann and reviewed by Aidan Tuohy of EPRI. This is followed by the thought-provoking column “In My View” from Prof. Mark O’Malley and his students from University College Dublin in Ireland, on the question of does the smart grid have a role in wind integration? The answer may surprise you!
Both Charlton and I feel very fortunate to work with this fine group of wonderful people from around the world on such an important topic as the integration of renewable energy into the electric power system. Personally, I have been in electric power engineering for over 40 years, and this is clearly the most exciting time of my career. And it is a wonderful time for someone just beginning a career in electric power. As we discussed, there are plenty of challenges and addressing them will make for an exciting time for many years to come. I look forward to addressing them with you! And I thank all of those who have contributed to this special issue to make it possible, especially to my colleague and friend Mel Olken, the editor of the magazine, for his encouragement and support, which makes all of this possible.