Making Wind Fit

Location: New York
Author: Bill Opalka
Date: Tuesday, August 14, 2007

With the public's demand for green energy growing and favorable tax policies in place at least through the end of next year, wind energy's upward draft shows no sign of abating. In fact, in its first-quarter 2007 market report, the American Wind Energy Association projected another 3,000 megawatts of capacity being built this year and thousands of megawatts remain on the drawing board in the ensuing years.

So that means that solutions to the traditional impediments to wind development -- intermittency and lack of transmission access -- will continue to be challenges, operationally and logistically. Some of the largest players in wind-driven power generation -- and smaller ones, too -- are creating ways to alleviate these concerns through a range of efforts, from technical advances to massive capital expenditures.

The fact that wind doesn't always blow when it's needed, or it blows at times when customers are using less electricity, impeded acceptance of wind-driven power for many years. The variable output that accompanies strong gusts followed by light breezes would create challenges for grid stability if wind was to occupy a larger share of the electric generators' portfolio. But with state mandates to increase the amount of clean energy in the mix, integrating wind is not merely desirable, it's a requirement.

Proponents say its apparent shortcomings are not enough to stifle its continued growth. The challenge and opportunity exists by reasonably managing its output but partly by having realistic expectations of what it can provide to the electric grid.

Transmission planning and operations are what will lead to greater acceptance. Managing the output plays a role, and so does setting realistic expectations of what wind-driven generators can provide to the electric grid.

Suitable transmission planning and operations will lead to greater acceptance. Managing this asset is well under way in many of regions of the United States where wind energy is most abundant. The common challenge is to move generation from areas where it is most prolific, through the Great Plains and Midwest regions, to load centers in large cities, often hundreds of miles distant.

In fact, the Holy Grail of the wind-power industry in America, tapping the vast resource from North Dakota to Texas and efficiently sending the energy to the load centers closer to the coasts or to population centers in the nation's midsection, is already technically feasible and is approaching economic viability.

To that end, AEP embarked on a decade-long $7 billion build-out unveiled in April before the Public Utility Commission of Texas in which wind-driven power will play a significant part. Texas has a well-known transmission-line bottleneck west of McCamey such that power generated by wind from west Texas cannot always reach load centers in the eastern sections of Texas -- and this, in a state that is becoming a leader in wind-driven power generation capacity.

An 11-state utility, AEP is a large purchaser of wind energy, and to a lesser extent an owner and operator of some facilities. It has 2,200 megawatts of wind power on its transmission system in Texas and Oklahoma. Mike Heycek, senior vice president for transmission for the Columbus, Ohio-based utility, said one technical challenge has been overcome. "Voltage support is required, and that is a problem that is certainly solvable now," he said. In fact, a 765-kilovolt line can now sustain transmission into the hundreds of miles without significant leakage. AEP even envisions wind generation from the central plains as cost-effective and available to as far east as Chicago.

Operationally, the integration of wind is the subject of ongoing efforts in the Pacific Northwest. The federal Bonneville Power Administration (BPA) is a participant in a "Northwest Wind Integration Action Plan," along with numerous other stakeholders. That collaborative process includes the BPA, investor-owned utilities, municipals, co-ops and environmental groups. This spring it released a framework to integrate wind into the overall power generation and distribution mix in the northwestern states.

Hydropower generation capacity has been used to smooth out the ups-and-downs of wind variability in the Pacific Northwest. But hydropower in that region is at its limit, and peaking generation is often produced in the same way it is in the rest of the country through expensive gas-fired generation. The cost advantage of hydro is therefore lost.

Wind power's value is as a peaking source and not meant as a base load resource. Elliott Mainzer, manager of transmission strategy and planning, says, "The primary value of displacing fossil fuel generation and reducing the carbon footprint." Wind fits into the generation portfolio by avoiding the operation of expensive natural gas plants.

But associated operational costs increase as the higher degree of wind penetration into the overall portfolio mix increases. "In general, the studies have found that wind integration costs are a significant, but not dominating portion of total wind resource costs, up to wind nameplate penetration levels of 20 to 30 percent of peak load."

A remaining challenge is the size of the control area in which the resources are located: the larger the area, the more readily wind generation from geographically distant plants are integrated. With 16 control areas served by BPA, coordination is essential to lessen the costs associated with integrating wind. "Short of actual control area consolidation, the two most significant steps toward realizing this benefit are the development of expanded wholesale markets for control area services and greater operating-area revenue sharing."

Studies in the United States and Canada have demonstrated that thousands of megawatts of wind power can be accommodated by the power grid with minimal disruption. GE Energy performed a study in New York that showed the state could contain 3,300 megawatts of wind generation. Similarly, a GE study for the Ontario Power Authority found that there were minimal system operation impacts for levels of wind capacity up to 5,000 megawatts. A separate study in the Northwest showed that system has no operational or physical constraints to prevent 6,000 megawatts from being generated.

As in much of life, timing is everything. Public demand for clean energy will continue to grow the technical and cost impediments to wind generation are being addressed, but the transmission build-out needed to make this resource more readily available will have to accelerate significantly to make it all work.