A researcher at Marshall University says there are still hurdles to overcome in adjusting the traditional, inflexible electrical grid to accept wind energy in Appalachia.
Wind, a relatively small contributor to the state’s energy portfolio, has recently experienced some growth in the state. Increasing concerns about cost to the system and other hurdles have slowed the proliferation of wind generators in the state and nationwide.
“As the amount of installed wind has increased, it has been observed that the marginal costs of wind to the system are greater than the marginal cost of turbine operation due to the variable nature of wind and the resulting dependence on other generators in the system for balance,” the report states, citing the Federal Energy Regulatory Commission.
The report further states that much of the literature argues that integrating wind successfully is not a question of reliability, but cost and efficiency. Reliability, the report states, is a surmountable energy requirement, thought energy efficient wind integration is more challenging.
Christine Risch, director of research at the Marshall University Center for Business and Economic Research, created the review of recommendations on the integration of wind and electrical supply. Some of her findings were presented Oct. 26 at the Southern Appalachian Regional Wind Energy Institute annual meeting.
“Research is not complete on it by anybody, and all the major players and electric suppliers are still looking at it,” she said. “There will be so much information coming out on this topic over the next couple of years.”
“If some protocols and policies aren’t put in place, we won’t get the wind we want, and we hope that we will,” Risch said.
The good news for wind is that reliability, Risch said, has not really been affected by wind incorporation, a finding supported by the North American Electric Reliability Corporation.
“They do have some pretty strong recommendations if wind is going to increase as a share of electricity generation,” Risch said. “(NERC) is strongly recommending that the system becomes more flexible. We have this sort of incumbent system that’s not very flexible on many levels, especially during the light load times of the day.”
The problem with integrating wind is that it only produces when the wind is blowing at the correct speed. Compounding the issue is that demand for electricity also fluctuates from peak to low demand.
“When there is low load the system is more inflexible than during the day when the load is increasing and generators are coming online to serve the increasing load,” Risch said.
At night, when wind is strong, Risch said, it can’t always be utilized. Dialing down traditional power plants typically results in some sort of efficiency loss or increased emissions, which is contradictory to the benefits gained by wind energy.
Natural gas and some newer coal plants, Risch said, are becoming more flexible. Being able to decrease generation of electricity without efficiency loss would be essential to more widespread integration of wind, due to its intermittency.
The other option – battery storage of wind during times wind is out-producing demand – can be costly.
“There’s a lot of ways to make a system more flexible, but putting into practice may not be as easy as just writing it down on paper,” Risch said. ” … Large batteries can be very expensive.”
Storage is being used on a small-scale basis, but is not yet being widely used, Risch said. Focusing more on shifting electrical load and demand would make non-baseload energy sources more viable, she added.
In addition to storage, further development of demand-side technology, on-turbine technology and a number of other developments will be necessary for widespread wind integration. Altering components in wind turbines to make them act in a manner similar to conventional generators is being talked about in academic circles, Risch said, but not much anywhere else.
“Moving peak times from mid-day to more of the midnight hours would solve some of the problems,” Risch said. “It’s very hard to shift heating and cooling demand, though. For residential, that’s our biggest load.”
If wind is not integrated correctly and traditional power plants are asked to make up for the difference during wind’s intermittency, emissions may actually increase and efficiency may go down, and the benefit of wind may not be realized, Risch said.
Fossil fuel prices are also directly tied to the success of wind energy.
“As wind penetration increases, the existing fleet of baseload plants is likely to be forced to operate below their preferred levels of output more frequently than before,” the report states. “Wind is expected to displace conventional generation, but not at a megawatt-per-megawatt basis. As wind expands, more generation capacity, or responsive load, will be needed to respond to more potential output fluctuation.”
Low natural gas prices encourage power companies to use natural gas plants, which tend to be more flexible and adaptable to the intermittency of wind.
“The past couple years we’ve had more gas, which is good for wind,” Risch said.
Wind’s challenges are shared by other renewable sources as well. Solar energy intermittency tends to be more aligned with peak demand times.
The impact of the wind turbines being introduced into the system still needs further study, Risch said. She said there are some technologies being recommended to reduce some of the pitfalls of wind energy and its costs on the traditional system.
“What are those costs? How do you measure them?” researchers are asking, Risch said. “Are they being assigned accurately or not? There are some questions that when you make these calculations, are you ignoring the contributions that wind plants make?”
Risch said at the end of the year, or shortly after, West Virginia will have about 10 megawatts of wind-generated energy capacity. Wind developments are slowing down, but will likely grow slowly, Risch said.
“I think people are being a little more cautious because of this integration issue,” Risch said. “No one wants to waste fossil fuel to integrate, even though it is renewable energy. Then there’s the issue of bats, which are pretty important.”
Fatalities of bats are a common occurrence and environmental concern associated with wind energy development.
Studying the issue further, which many institutions are currently doing, may yield more solutions, many of which could be needed to effectively integrate wind into the grid.
“In our region, wind is a pretty small share of generation and generation capacity right now,” Risch said. “So, it’s really not an important issue for us right now in the Atlantic region. It’s bigger in Texas and Washington state and the Midwest because they have higher shares of wind. We are heavily connected, though, particularly to the Midwest, so it affects us.”
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