Wind on the Wires1 - Smart Grid (R) Evolution: Electric Power Struggles - page 146

ERCOT electricity system has also forced grid operators to change how they manage the
system to ensure reliability.
6.4.3 Integrating Wind into ERCOT
The scaling up of wind power in Texas has had a strong impact on regional grid operations
and management. ERCOT operates a deregulated wholesale electricity market, so wind
impacts electricity prices at different locations or “nodes,” as well as other generators on
the system (Public Utility Commission of Texas 2008 ) . The variability of wind and its
predictability both impact grid operations. When ERCOT commissioned GE and AWS
Truewind to examine the effects of wind on power reliability needs with different levels
of wind and load, their report modeled multiple scenarios: a 5,000 MW scenario, two
10,000 MW scenarios with wind resources sited at different parts of the state, and a 15,000
MW scenario. These different levels of system penetration were designed to help ERCOT
better understand the operating requirements of different levels of wind development. The
study found that high wind power penetrations would increase the need for flexibility and
responsiveness in other generation sources. For example, to accommodate the increased
wind power, the system would need to increase the capacity of fossil fuel power plants
to ramp up more quickly; this could affect costs of grid operation and maintenance. The
PUCT found this to be acceptable and focused on the report's claim that having wind on
the system would reduce the overall spot price of electricity in electricity markets (Public
Utilities Commission of Texas 2008 ). Other studies examined how wind would change
the management of the grid to ensure reliability and evaluated how new wind forecasting
methods could facilitate grid operations.
The PUCT also evaluated integration and reliability, and stated their belief in ERCOT's
ability to integrate 18,000 MW of wind on the system by 2017. This represents 23 percent
of projected peak system load. The PUCT also questioned how higher levels of wind
integration would impact system reliability. In its decision to support the transmission for
this high level of wind, the PUCT focused on system reliability but also cited positive
impacts on strained water resources and reductions in criteria air pollutants (like oxides
of sulfur or nitrogen) that would be associated with incorporating more wind into the
electricity grid.
Along the way, Texas struggled with some high-profile challenges of integrating wind
into the grid. A confluence of events on the afternoon of February 26, 2008 exposed the
needtoaltermarketschedulingandsystemoperationstoaccommodate largelevelsofwind
power generation. That day, several conventional generators were offline when the wind on
the system dropped and load increased faster than expected in the afternoon. This caused
ERCOT to call up its interruptible industrial and commercial clients - Loads acting as