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Plunging Wind Into the Grid

The California ISO's intermittent resource program addresses a key market barrier to wind power: how to schedule wind energy in forward markets.
Fortnightly Magazine - June 15 2003

the data to understand how wind power best fits into California's power supply mix.

The goal is to be able to forecast the amount of wind energy production for each 10-minute segment going forward 90 minutes. As better data is collected, this goal will be reached over time. The main thrust is that there be no surprises. Impacts on transmission loading can be assessed and mitigated as needed by altering dispatch instructions to other generators. If an over-generation emergency exists, wind project operators will be instructed to adjust blades of individual wind turbines to reduce power output.

Once this program is in place, California can lay claim to a state-of-the-art wind production and transmission allocation system that makes use of new communication and weather forecasting technologies to boost efficiency and reduce costs for the ratepayer.

Next Steps in California and at FERC

The Participating Intermittent Resources Program consensus proposals were submitted to the California ISO board in October 2001. Tariff language was filed at FERC at end of January 2002. On March 27, 2002, FERC endorsed the Participating Intermittent Resources Program. "This order benefits customers by addressing a major obstacle to development of new wind and other intermittent generation. Encouraging the development of intermittent generation will increase diversity in the resource base, thereby improving system reliability as a whole," FERC said.

"It is difficult to overstate the importance of this to the wind energy industry," observed AWEA's Jim Caldwell. "FERC has found that wind energy's transmission needs can be met fairly, without extra costs for either the transmission system or for owners of other types of power plants. With this ruling, FERC has demonstrated that it understands the unique situation facing a variable energy source such as wind, and that it is willing to find ways to ensure that this new, clean, potentially huge source of electricity is not unfairly barred from the market," he says.

Adds Mark Smith, director of market affairs for FPL Energy, owners of the largest fleet of wind projects in the country: "The California ISO's Participating Intermittent Resources Program offers wind generation owners and energy consumers a rational and reasonable wholesale market structure. The previous California ISO market design was conceived with dispatchable resources in mind. Penalties in some regions-such as zero pay for generation above schedule and 150 percent financial penalties for deliveries short of schedule-were created to ensure that units managed their output very closely. A vast majority of wind energy is very difficult to accurately schedule in the timeframe required by grid operators. And once scheduled, wind energy production-as driven solely by the presence of the wind-is difficult to predict with certainty."

Smith goes on to say that the new California ISO approach "more accurately exposes the underlying value of wind generation and allows for reasonable development risk and cost of capital. It recognizes the inherent unpredictability of wind generation and counters with state-of-the-art wind forecasting and reasonable accommodations to the settlement of unavoidable scheduling errors."

There are still challenges remaining when it comes to transmission and wind power. For example, transmission planning is