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Published on August 20th, 2015 | by Guest Contributor


Upgrades To Texas Transmission Lines Slashes Wind Curtailment

August 20th, 2015 by  

Originally published on The Handleman Post.
By Clayton Handleman

It is August and that means the latest version of The Wind Technologies Market Report (WTMR) has been released by the US DOE’s Energy Efficiency and Renewable Energy (EERE) office. The WTMR is a chronicle of growth and economic and technology trends in the wind industry. Wind power has begun taking its place as a substantial contributor to electricity generation in the US. Due to its intermittent nature there is an increasing, and some suggest, premature, concern over limits on penetration. This is probably driven in large part by the large amounts of curtailment in Texas in 2009. The 2014 WTMR may put some of those concerns to rest. Data in the report show that in Texas, curtailment has been slashed from 17% in 2009 to 0.5% in 2014 (figure 1). This occurred despite the backdrop of increased wind generation in Texas. It was due in large part to bringing added transmission online.

wind-2014-curtailment-graphFigure 1:  Changes in wind curtailment by date.  Texas’ wind curtailment is labeled ERCOT.  WTMR p38

The improvement was no accident. As wind became valued as an important contributor to the Texas generation portfolio, it became apparent that to fully benefit from wind they would need to build transmission lines from where the best generation sites were to the population centers where it would be used. The Electric Reliability Council of Texas (ERCOT) set about defining Competitive Renewable Energy Zones (CREZ) and creating an electric transmission plan to assure that the electricity could get from the CREZs to point of use. The transmission lines have now been built and have nearly zeroed out the need to curtail wind generation.

ERCOT publishes quarterly progress reports for the CREZ program HERE. In the summary maps below (figures 1,2,3) it is easy to track progress over time of the transmission line build out. Comparing these to the data in figure 1 it is clear that the new transmission has successfully cleared the congestion that was limiting the use of wind generation. Perhaps most impressive is that the substantial reductions in curtailment occurred at the same time that wind energy generation increased by almost 100% (Figure 5 below).

wind-2014-crez-progressFigure 2:  CREZ transmission line project status  November 2014 – Complete – Public Utility Commission of Texas

wind-2013-crez-progressFigure 3: CREZ transmission line project status October 2013 – Partially Complete – Public Utility Commission of Texas

wind-2012-crez-progressFigure 4: CREZ transmission line project status October 2012 – Partially Complete – Public Utility Commission of Texas


Figure 5: Texas Wind Capacity and total generation.  EIA

Reprinted with permission.

About the Author: Clayton Handleman founded Heliotronics, Inc., to develop educational products that integrate live renewable energy data into curricula to teach about Science, Technology, Engineering, and Math (STEM) – See www.solarlearninglab.com and www.heliotronics.com

He blogs on renewable energy, Super Grid, and low-carbon transportation at https://handlemanpost.wordpress.com/ and is a guest blogger on other sites, including CleanTechnica, Greentech Media, RenewEconomy, and The Energy Collective

Clayton’s earlier work includes grid-interactive inverter design, related project management, and program management to develop and integrate data acquisition systems, web platforms, and related educational software. He holds multiple patents relating to inverter design. He has also written about macro trends including, 15 years ago, correctly predicting when PV would break the $1.00/Watt barrier.

Prior to his work in renewable energy, he did defense research and development at MIT Lincoln Laboratories. He has a B.A. in physics and minor in mathematics from Washington University and an M.S. Physics from Purdue University.

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  • globi

    Apparently improving grids is doable. Not just to improve reliability and to benefit from variable demand and with it variable pricing (as has been in the last 100+ years or so), but also for decentralized production.

  • Matt

    Note curtailment growing in ISO-NE and MISO. Need transmission there also?
    As for Texas, I don’t see any red or blue in the 2014 charts, so no new coming at the moment.

  • Adrian

    Interesting, it appears the biggest gains were realized from 2009-11, and after that generation has roughly tracked capacity 1:1. I suppose they addressed the biggest bottlenecks first.

  • Frank

    This is great, but Texas continues to add wind capacity. How much more can they add before they start having problems again, and are they planning more grid upgrades?

    • Shiggity

      The map doesn’t show the other export lines that are being built out into the southeast region. Much of the entire southeast could be powered by Texas energy. Texas dominance has always derived from energy exports. It doesn’t matter whether it’s wind or oil. Energy is king, that’s why utilities are freaking out so badly over people generating their own from solar / batteries.

      • JamesWimberley

        With the Tres Amigas interconnect stalled, SFIK the Texas grid is still isolated. It’s not easy to connect large grids. Either you have to match the frequency or use HVDC. Neither comes cheap.

        • Bob_Wallace

          There’s at least one line heading north out of Texas.

          With Oklahoma now selling wind-electricity into SE states I’m betting Texas money is going to want some of that business.

      • eveee

        Good point. Its hard to tell just where Texas wind capacity might need more transmission. Depends on exactly where capacity is added compared to where the transmission line expansions are.
        West Texas may send power West, but a whole lot more could happen if Tres Amigas happened.

    • eveee

      Texas is currently at 16GW. CREZ transmits 18.5GW. Existing grid must handle some also. So the amount is above that.


      Looks like Texas wind is expanding so fast that additional lines may be needed. Some existing single line transmission can be increased to double.

      Texas ERCOT March 2014 planning included 26.7 GW wind.


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