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Current Thinking: Integrating Wind by Dick Watson NW Current, August 1, 2006

Wind power is enjoying an explosion of development. According to data compiled by Jeff King of the Northwest Power and Conservation Council, the Northwest will have over 1,400 megawatts (MW) of wind generating capacity in service by the end of this year. That's a jump from less than 100 MW in 2000. And that's not likely to be the end of it.

Jeff's data shows that there are 428 MW of wind capacity under construction, nearly 1,200 MW that has been permitted, and 1,500 MW that is actively being planned. If all that development goes forward, the total would be over 4,500 MW, or approximately 1,500 average megawatts (aMW) of energy. The region would be well on its way to achieving the 6,000 megawatts called for developing over the next 20 years in the council's 2005 plan. That's a good thing, right?

I think it's a good thing. Wind power has zero fuel costs and zero carbon emissions. Those will be increasingly important characteristics in the years ahead.

When the council was developing its Fifth Power Plan, it subjected hundreds of alternative resource plans to an expected cost-versus-risk analysis against over 750 possible "futures," i.e., alternative scenarios for how the future might unfold. These scenarios addressed a number of interdependent factors like load growth, fuel prices, hydro conditions, environmental regulation (in particular, efforts to control carbon emissions), and the market price of electricity. When the smoke cleared from the computers, wind, with its low carbon and low cost-volatility, played a significant role over a wide range of possible futures. It contributed significantly to reducing risk without too great a cost penalty.

But at some point there might be too much wind, at least with current technologies. The Fifth Power Plan's conclusions were affected by a number of the analyses and estimates that support them. In particular, the estimates regarding the cost of integrating a variable output resource like wind into the power system are subject to some uncertainty, particularly as more and more wind is brought into the system.

The electricity system is unique in that its instantaneous production and consumption must be in balance at all times. Wind is not dispatchable, i.e. you don't have control of the output. When the wind blows hard, you have high levels of production. When there is no wind, you get no production, and there are all points in between. The utility control area operators who are responsible for that balancing act have to have dispatchable generators under their control that they can ramp up or down quickly enough to maintain that balance. They have to do this on a second-to-second basis (termed regulation) and on an hour-ahead and longer basis (load following). The costs of integration are a legitimate additional cost of wind and other intermittent resources.

In addition, there is the problem of transmission. Transmission is a capacity issue. If you want to get the full output of a wind project to market, you have to have access to transmission capacity equal to the full output of the project, even though on average you might be utilizing only a third of that capacity. As transmission constraints have become more prevalent, this issue has assumed greater importance.

It would seem that the Northwest has the ideal system with which to integrate wind, given the capacity and flexibility of the hydroelectric system. And indeed, Bonneville Power Administration, PacifiCorp and others have successfully offered integration products. But that system is increasingly constrained, and it may be limited in its capability. Utilities expressed concern about wind integration during the plan's public review process. And while it is the utilities that are purchasing the wind power, their concerns have perhaps increased as the likely penetration of wind has increased.

There is a lot of work going on to understand the integration issues and how, for example, they might be affected by greater installed wind capacity, larger individual wind projects, greater geographic diversity, better wind forecasting and so on. There is, however, still a lot to learn.

Because of these issues, the council included several items in its Five Year Action Plan intended to confirm the wind resource and the ability of the power system to transmit the power and integrate it. Initially, work on the action items has gone on through the Northwest Power Pool's Northwest Transmission Assessment Committee (NTAC) Wind Integration Study Group. This group has compiled a great deal of useful information on the actual performance of Northwest wind projects. Still, there has not been a high-level policy focus on the issues of wind integration.

This is about to change. Recently, the Bonneville Power Administration and the Northwest Power and Conservation Council announced a process to resolved the issues surrounding wind integration. Specifically, they are working on an action plan that, according to Jeff King and Bonneville's Elliot Mainzer, intends to develop "a) a package of specific, measurable and pragmatic strategies to address the operational, infrastructure and policy issues associated with increasing renewables penetration, and b) to define the commitments needed from utility and regulatory decision makers to implement them."

Examples of specific products could include:

• Development of a centralized wind forecasting network.
• Development of a formal plan for pooling regulating reserves.
• Recommendations on specific transmission paths requiring upgrades to enhance the geographic diversity of renewable development, as well as estimates of the potential cost and methods of allocating those costs.
• Recommendations for ways to meet future dispatchable resource needs with resources that have the flexibility to ramp up and down to accommodate a large amount of wind generation

Staff is hard at work developing a work plan to present to the Steering Committee at its first meeting within a few weeks. I plan to be there.

Related Pages:
GE Opens Wind Turbine Assembly Facility In China by Clean Edge News, 7/5/6