Some of you may have seen an article in the NY Times last week addressing the speculation that the growing integration of renewables in general, and wind power in particular may be creating big problems for the utilities that run the electric power network in the future.
This is not the first time the issue has come up. In fact, it was a particular area of interest and study back in my days as a researcher at Pacific Gas and Electric during the 1990's.
In recent years I've seen many technical articles and whitepapers addressing the concern. To grossly oversimplify, there are circumstances whereby the generators on the wind turbines (if you have enough of them) are thought to be able to adversely interact with the grid to drive voltages and or frequency out of allowed tolerances, causing a big outage.
One analogy might be watching a new driver learning to handle the clutch pedal. In the fits and starts of applying and removing gas to the engine and torque to the wheels, it is possible to kill the motor. "Killing the motor" of the grid should be avoided!
Some Canadian utilities have put a temporary upper limit on how much wind power they'll accept. Others around the world are considering the same. I recently had a chance to speak to an old colleague, a transmission system engineer from my PG&E R&D days. He currently works for the the State of California and spends a lot of time studying these problems. With California's aggressive plans for renewable energy integration, it is clearly a question that needs to be answered. "What WILL happen when we put all of this renewable energy into the grid?"
His reply surprised me. It seems that integrating big wind farms into the transmission grid is not a big concern in California. The ability to predict output from wind farms is pretty good on an hour by hour basis with relatively little minute-by-minute changes. The system operators have good telemetry on those sites. The types of problems that might be caused by adverse interactions between the generators and the grid are well understood. There are readily available devices that can be put at the interconnection point to mitigate for any such interactions. In short, it is an engineering problem with engineering solutions.
What startled me was he went on to say "I'm more concerned about is what happens when all of Gov. Schwarzenegger's million solar roofs come on line." He added, "no one at the utility knows where they are. The distribution system has very little telemetry. Solar power output can quickly and dramatically change with cloud cover. The distribution system has always been hard to model with its inherent complexity of customers, branches and interconnections. Now with the introduction of thousands of "hidden" generators, we don't have a good handle on if or how it may cause problems. I don't THINK that there is a problem with distributed PV, but we know that we need to keep an eye on this issue."
Somewhere, out there, a PV developer-entrepreneur is reading this, shaking his fist in the air and yelling "FEAR ME, utilities!"
