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Green Blackouts?

Increasing renewable generation threatens reliability.

Fortnightly Magazine - August 2010

rapid frequency changes until the changes grow, and thereby to save wear-and-tear cost. By the same token, however, deadbands have been causing large frequency variability to increase on the interconnections by not responding to it immediately, and thereby have been increasing the need for more capability to respond to rapid frequency changes thanks to the reduction in that ability caused by the governor deadbands. This was demonstrated in a recent study of the Electric Reliability Council of Texas’ grid (see Figure 3).

Originally deadbands were justified when placed on mechanical governors controlling older power turbines to account for gear lash, which is the delay in gear re-engagement when the torque on the gears is countered or reversed. Most of those older turbines have since been retired, while current turbines don’t encounter the gear lash problem but use deadbanding software on their governors that is designed to reduce turbine maneuvering cost, not to compensate for mechanical characteristics. That application has furthered the commercial interest of the individual generator at the expense of the reliability of the grid.

Rational Standards

To reconcile the coming crisis in North American grids’ ability to stop sudden rapid deterioration in electrical frequency with the aggressive Obama renewable energy agenda, FERC issued an order on March 18. 2 That order required the continent’s legislatively designated electric reliability organization, the North American Electric Reliability Corp., to accelerate its current ANSI 3-certified industry-consensus process of developing an operating standard that assures that the two largest North American electric grids serving the United States achieve a reliable level of very rapid power fluctuation and response. FERC ordered that the process be concluded in six months. That deadline for solving a definitely 15-year-old problem was appealed 4 successfully, when on May 13, FERC ordered 5 a rehearing on the matter to be preceded by a technical conference with the industry at a so-far unspecified date. FERC appears to be waiting for NERC to post a draft standard soon for industry comment.

Meanwhile, the market economics of renewables might be slipping away. FERC’s Summer 2010 Energy Market & Reliability Assessment released on May 20 forecasted just 12.1 percent of U.S. wind power will be available on peak, a huge 4-percent drop from last year’s 15.2 percent of a 17-percent smaller capacity. The drop in peak availability is due to more experience with wind output among grid operators and improved forecasting. Add carbon capture and a vast natural gas supply coming into place in the Northeast, and alternative generation does not have an economic fighting chance of succeeding as presently funded, with wind development winding up as a government subsidized effort paying for MW output only—not development on an economic and market basis. So we might witness wind towers rusting in the plains. Add to this having wind pay its fair share of the reliability cost of stressing the grid, and administration energy policy faces much higher costs.

Moreover, since the mainland Canadian provinces except Quebec share the two largest of the North American power grids with the United States, their governments too have