Can Wind Power Plug into the Grid?

By Kathleen Davis, Associate Editor

The buzz on wind power continues to grow in the U.S., with even the end-consumer becoming interested in the possibility of making their energy choices more “green.” But, problems remain in making those consumer visions a reality-problems with technology, storage, regulations and, most importantly to us here at Utility Automation & Engineering T&D, getting that power onto the grid, often referred to as “wind on the wires.”

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To find out more about this issue, we spoke to Charlie Smith, the executive director of the Utility Wind Integration Group, an organization with the sole mission to accelerate wind integration. In late May, we spoke to Charlie about all the details and hurdles of making that green dream a reality.

UA: Which is more of a “sticky wicket” for wind integration: putting bulk wind into the transmission system or connecting a turbine or two to a distribution system?

Charlie Smith: It all depends. Injecting wind power at a weak point in either a transmission system or on a distribution feeder can be a challenge. It is always easier to inject wind power at a strong point on the grid.

UA: What is the single largest technology hurdle that needs to be addressed when connecting wind farms to the grid?

CS: There are three significant interface issues that have to be dealt with. The first is the ability to assist with voltage regulation during normal system conditions; the second is the ability to provide low voltage ride-thru (LVRT) during a normally cleared fault and contribute to the post-fault voltage recovery; the third is to provide a wind plant SCADA interface appropriate to the needs of the system operator.

UA: How do transmission planning processes need to change to accommodate wind energy?

CS: In general, the transmission planning process needs to become more transparent and more proactive in dealing with the needs of wind plants. With the short lead times of two years typical for wind plants today, and the five- to seven-year transmission planning horizon, there is a serious mismatch between the needs of the wind plant developer and the current transmission planning timeline. There is a growing recognition of this problem at the federal and state levels, and steps are being taken to deal with it. Regarding the details of the planning process, transmission planners have historically planned transmission for capacity resources, ensuring that the full capacity of the generation was deliverable at the time of system peak for reliability purposes. With wind being an energy resource as opposed to a capacity resource, new transmission planning methods will need to take into account the fact that it will not always be economical to build transmission rated for the full output of all the wind plants simultaneously.

UA: UWIG works with the DOE and the NREL on their wind program. What positive changes have been made-in regards to hooking wind to the grid-since you began working with them? Is it a symbiotic relationship, or are you fighting a lot about incentives and regulations?

CS: UWIG enjoys a very positive working relationship with the DOE/NREL wind program, which it has had since its inception in 1989. The federal program has always had a very sincere interest in understanding the needs of utilities when it comes to interconnecting and operating wind power plants on utility systems. This desire has formed the basis of a strong partnership in the area of interconnecting wind plants and integrating them into the utility planning and operating process. UWIG and DOE/NREL were pioneers in the early modeling efforts behind the interconnection studies for large wind plants, and DOE/NREL has always been very receptive to input to the wind program from UWIG members.

UA: How do you juggle the competing interests of all the people involved in the process-transmission organizations, regulatory bodies, utility and transmission planners, wind farm investors? Are their interests “at odds,” or are they becoming more cohesive?

CS: The UWIG has a very strong technical focus. We seek to understand the technical issues at hand, and identify solutions which are workable and acceptable to a broad range of interests. There is always some tension among the competing interests of the parties, ranging from the uncompromising system reliability requirements of the utility system operators to the financial drivers of the investment community, but generally we find that people of goodwill working together can come up with solutions that all parties can live with. We also find that the technical focus of our diverse membership, including utilities, transmission providers, developers, manufacturers, and consultants leads to a better understanding of our respective roles and responsibilities, and a deeper appreciation of the various challenges faced within the different sectors of the industry.

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UA: Costs are always a concern to investors, utilities and even end users. How expensive will it be to smoothly integrate wind into the grid? Where do those costs come from-technology, fees, and charges-and who will foot the bill?

CS: Much of our focus has been on investigating technical wind integration costs, to make sure that we understand exactly how much those costs are and where they come from. Others have paid more attention to the benefits. We have found costs ranging up to half a cent per kilowatt-hour to integrate up to 20 percent or 25 percent of wind energy into the delivered energy mix. These costs are typically less than 10 percent of the cost of the wind energy. More recently, people are beginning to examine the additional benefits of wind energy associated with its value as a hedge against volatile fossil fuel price, and carbon risk. At the end of the day, the customer generally pays.

UA: When looking at the higher cost-per-MWh of wind energy, can changes in grid structure help make it more competitive to fossil fueled-power?

CS: In some areas of the country, wind energy is already cheaper than energy from new fossil fuel plants. Reinforcing the grid generally provides both reliability benefits to the system and economic benefits to customers. Strengthening the grid is beneficial to wind, as it provides additional capacity to move wind energy to market, relieve bottlenecks, and enable energy and ancillary service markets to operate more efficiently. It is difficult to allocate the benefits of expanded grid infrastructure between wind and conventional generators.

UA: Give us three suggestions you have for regulators to make markets more “wind friendly.”

CS: The biggest impediment to broader participation of wind in competitive electricity markets has been addressed in the recent FERC Order 890, the removal of imbalance penalties associated with the difference between day-ahead scheduled deliveries and actual deliveries of wind energy, in favor of a cost-based system. The second is to allow system balancing across broad geographical areas, oftentimes more broad than the boundaries represented by current balancing areas, which are an historical artifact. The third is to actually support the creation of competitive, deep, liquid, well-functioning wholesale electricity markets for energy and ancillary services. Implementation of these three steps will go a long ways toward improving the ability of wind plants to effectively compete in the marketplace.

UA: The Cal ISO has a “participating intermittent resource program” that keeps wind generators from incurring imbalances charges when the delivered amount of energy differs from the scheduled amount. Do you support this program, and would you like to see it expanded into other states?

CS: The CA PIRP program allows hourly wind energy imbalances to be netted out on a monthly basis and settled at cost instead of with penalties. With a good wind energy forecast, the imbalance energy at the end of the month is quite small, so the financial impact on the wind plant operator is small. This program was quite novel when it was first introduced, and addressed a very important problem. With the new Order 890, the need for it is greatly reduced. A good wind forecasting system and a well-functioning balancing market will solve the problem.

UA: The recent Midwest Wind Integration study found that wind could be incorporated into the Minnesota power mix up to a 25 percent level and with quite a low cost (approx. 4.5 cents a kWh). Do you agree with the findings, and could the basics of that study be applied to the U.S. as a whole?

CS: Actually, the wind integration cost from the latest MN study was only .45 cents/kWh! The Minnesota Wind Integration Study benefited from a very robust stakeholder review process through the creation of a Technical Review Committee (TRC), in which I had the opportunity to participate. The primary concern of the MN Department of Commerce, which supported the study, was that the study be done with the best available study techniques and tools, and that the results be as technically rigorous as possible. A broad range of utility and other stakeholders participated in the process, and all had their voices heard and their concerns addressed to the maximum extent possible, and I think that everyone was generally satisfied with the outcome, myself included. The study requires a massive amount of data to be generated, particularly with regards to the modeling of the wind plant output. The basic methods are being extended to ever larger geographical regions of the country, and within a few years, we should have an answer to that question.

UA: Do you see wind energy pushing even beyond 25 percent in some states? To 30 percent? Even 40 percent?

CS: In a strong interconnected system, I think we will certainly see wind penetrations reach beyond 25 percent in some regions. Western Denmark has already achieved such penetration on an annual basis, and in some operating hours, numbers in excess of 100 percent with wind exports. The next step of wind penetration being planned by the Danish grid operator is 50 percent by 2025. Significant changes will have to be made in the market design and with the development of price responsive load and energy storage, but the Danes are actively working to achieve it. The Europeans have been leading the way regarding the integration of large amounts of renewable energy into electric grids, but there is fundamentally no reason that we cannot do the same. There is good cooperation between the European and North American utilities, manufacturers, and developers through UWIG, and a lot of good sharing of knowledge and experience. The power system engineers with whom I speak in both North America and Europe are excited by the challenge. I believe it’s only a matter of time.

UA: Can wind energy be “baseload,” or will it forever be peak power-only connected in to “help” and never fully relied upon? Is changing that view of wind as secondary source as simple as changing the look of system reliability plans and understanding more complex load-carrying calculations? Or will wind always be relegated to the “backseat” when it comes to power?

CS: This is the age-old question of how much capacity does an energy resource provide. It is difficult to be an energy resource in a capacity world. Traditionally, our attention has been focused on capacity because of our focus on system reliability. We need sufficient capacity to meet the peak load with a high degree of probability. The capacity value of a wind plant can be calculated with a fair degree of accuracy using probabilistic reliability assessment tools. The number could be anywhere between 5 percent and 40 percent, depending on the existing generation mix, and the degree of coincidence between the load shape and the wind plant output. Once the capacity value of the wind plant has been determined, the system planner simply gets on with the job of planning for sufficient capacity to meet the reliability needs of the system. The wind is valuable as an energy resource in its own right, and that is why it is being purchased by utilities. It displaces expensive fossil fuels, and it provides a hedge against fossil fuel price volatility and carbon risk. If it has any capacity value, that’s an added bonus, but it is small compared to the value of the energy.

UA: When you look into the future for wind energy-when you stare into your crystal ball and see 10 years ahead-how important is wind to power production here in the U.S. and how have we changed the grid and markets to accommodate it? Or, have we?

CS: We face a very uncertain future on many fronts, one of which is energy. There is no silver bullet that is going to solve our energy problems. I believe that renewable energy in general, and wind energy in particular, have a bright future, both in the U.S. and worldwide. Wind has been growing at an annual rate of about 25 percent for the past 5 years, and everything that I read says that with the proper policy support, we can expect that to continue. Whether that policy support is a PTC, or an RPS, or a carbon cap-and-trade system is anybody’s guess, but it looks like wind is here to stay. DOE and AWEA are examining a scenario that leads to 20 percent of our national electricity consumption coming from wind by 2030, and that looks achievable, given some sort of policy support and the necessary market changes, which include broad geographical markets, expanded balancing areas, and new transmission. I expect wind to be an important part of our energy future, but certainly not the only part

The Utility Wind Integration Group (UWIG), has more than 100 members spanning the United States, Canada and Europe, including investor-owned, public power, and rural electric cooperative utilities; transmission system operators; and associate member corporate, government, and academic organizations. Find out more on the web at www.uwig.org.

Sampling of Proposed/Planned Wind Projects (by State)

  • Alaska: Kotzebue Wind Project. 0.3 MW.
  • Arizona: Sunshine Wind Energy Park. 60 MW.
  • California: Pine Tree Wind Project. 120 MW.
  • Colorado: Cedar Creek. 220 MW.
  • Hawaii: Kama’oa Wind Farm. 20.5 MW.
  • Idaho: Cotterel Mountain. 80-100 MW.
  • Illinois: Blackstone Wind Farm. 300-600 MW.
  • Iowa: Pocahontas County Wind Project. 123 MW.
  • Maine: Redington Mountain. 60-90 MW.
  • Maryland: Savage Mt Wind Energy Project. 40 MW.
  • Massachusetts: Berkshire Wind Farm. 15 MW.
  • Michigan: Noble Thumb Wind Park. 48 MW.
  • Minnesota: Prairie Star. 100.65 MW.
  • Missouri: Bluegrass Ridge Project. 56.7 MW.
  • Montana: Fort Peck. 0.66 MW.
  • Nevada: Desert Queen Wind Ranch. 80 MW.
  • New York: LIPA Offshore Project. 144 MW.
  • North Dakota: Dakota I Power Partners. 19.5 MW.
  • Oklahoma: Centennial Wind Energy Project (2007 portion). 60 MW.
  • Oregon: Elkhorn wind Power Project. 140 MW.
  • Pennsylvania: Freedom Wind Energy. 100 MW.
  • South Dakota: Pine Ridge Reservation. 200-400 MW.
  • Texas: Buffalo Gap, Phase II. 232.5 MW.
  • Vermont: Searsburg. 30-40 MW.
  • Washington: Marengo Wind Power Project. 140.4 MW.
  • West Virginia: Mount Storm. 300 MW.
  • Wisconsin: Forward Wind Energy Project. 200 MW.
  • Wyoming: Bridger Butte Wind Project. 201 MW.

Notes:

(1.) This is not a complete list, only a sampling. Many states had numerous proposed sites.

(2.) If the state is missing from this list, we could not find a proposed wind project for that state at press time. That does not, however, mean that one isn’t under consideration.

(3.) MW information is taken from AWEA sources.

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