On February 26, 2008, a drop in wind generation by about 1400 MW over ten minutes, coupled with an increase in demand of 4412 MW due to colder weather, and lower-than scheduled production from other power suppliers, led ERCOT, the Texas grid operator to cut 1100 MW of power to interruptible customers for about 90 minutes.
All these facts come from a Reuters article misleadingly titled "Loss of wind causes Texas power grid emergency." I was dismayed a few weeks ago when this misleading reporting led the generally insightful Master Resource Report to conclude "This is a clear example of why solutions to storage and transmission are going to become increasingly critical as sources such as wind and solar become increasing parts of the generation mix. This doesn’t invalidate renewable power; it just means that the country has plenty of work to do and that there are plenty of investment opportunities besides just wind turbines and solar cells." [link to pdf]
It may be surprising to readers that I find anything objectionable in a call for more storage or transmission, although I’m a stronger proponent of transmission, which I consider more cost effective, even if there are far fewer barriers to adding storage.
However, the lesson of the 2008 Texas emergency is that while we need more transmission, and, eventually, storage, there are other, cheaper and easier steps we can take to integrate wind and solar to considerably higher levels of penetration..
Not A "Wind" Emergency
The first thing to note about the incident is that the increase in electric demand was more than three times as large as the decrease in supply from wind. Presumably, ERCOT had been dealing with such fluctuations in demand since long before wind came onto the system. Part of the problem was that other power suppliers (presumably natural gas and coal, usually considered "reliable") were not delivering what they had promised. Hence, the drop in wind production was probably only 20% of the overall problem, not 100%, as the headline led readers to believe.
Hero: The Smart Grid
The next conclusion we can draw is that Demand Response (DR), in the form of interruptible service to large customers, prevented power outages. Demand response an early form of the Smart Grid which is already working today. It allows the grid operator to cut power consumption by other users who have previously agreed to such cuts in return for lower electricity rates or cash payments. According to a 2005 study of DR programs from the American Council for an Energy Efficient Economy, the median cost of DR programs studied was $29 per kWh, and the average cost was $86 which compares quite favorably to the $500 or more per kW cost of a peaking gas turbine. Demand Response was the hero of February 6, 2008, even if wind was not the villain.
Before we look for investments in energy storage or even transmission, we should be looking to even more cost effective resources for the integration of variable energy sources, such as Demand Response and other variations of the Smart Grid. Both EnerNOC (ENOC) and Comverge (COMV) provide demand response services to utilities, and this is also one use for Smart Grid technology from such companies as Echelon (ELON), RuggedCom (RUGGF.PK), Telvent (TLVT), and Itron (ITRI).
Villain: The Dumb Grid
During the discussion at a January 21 seminar sponsored by the National Renewable Energy Laboratory and the National Oceanic and Atmospheric Administration, featuring speakers from wind forecasting companies 3Tier, WindLogics, and AWS Truewind, the speakers mentioned that the weather forecasters had been telling the system operator of the incoming cold front and likely drop in wind production, but that the system operators chose to make no preparations before the fact. Had they done so, they could have ramped up standby generation before the cold front hit, and would not have needed to call on the interruptible power resources.
Given that much of the heating in Texas is electric, system operators must have known that a cold front would raise demand. Why would system operators choose not to heed forecasters’ warnings? There may be many reasons, but in the end, they all probably come back to incentives. Preparing for a predicted increase in demand would have been the intelligent response, but regulated utilities have very little incentive to use their resources intelligently. After all, a regulated utility makes most of its profits based on an authorized return on capital based on the investments it can justify to the regulator as necessary to keep the system up and running. If the utility is, for whatever reason, unable to use those resources effectively, it becomes easier to argue that more resources are needed, which will lead to more profit for utility shareholders, and a less stressful job for system operators..
In other words, regulated utilities have an incentive to use as little brainpower (for which they do not earn a return on capital) and as much capital investment as possible. They have an incentive to be dumb. Given such incentives, is it any surprise that they ignore warnings, and then blame the problem on the variability of wind?
Tom Konrad, Ph.D.
DISCLOSURE: Tom Konrad owns ENOC, COMV, ELON, RUGGF, and ITRI
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