Report: Warming threatens Southwest's power grid

Wildfires, drought, higher demand could stress electric supply
2013-05-03T00:00:00Z 2014-07-15T17:49:20Z Report: Warming threatens Southwest's power gridTony Davis Arizona Daily Star Arizona Daily Star
May 03, 2013 12:00 am  • 

The Southwest's power grid could become more vulnerable to climate change over the coming decades, says a new report led by University of Arizona researchers.

A growing number of future extreme heat and drought incidents could increase threats to electricity supplies, says the report on Southwest climate change, coordinated by UA and released Thursday. The 500-page report was prepared by 120 scientists around the nation, with five UA researchers as lead editors.

Specific risks to power systems listed in the report include:

• More demand for air conditioning could overload power plants, transformers and transmission lines.

• High temperatures could reduce efficiency of power plants, and the capacity of power lines, substations and transformers to carry electricity.

• Reduced flows in rivers due to droughts could reduce power production at reservoirs, including lakes Mead and Powell.

• Wildfires, which have increased in the past two decades and are expected to increase more from hotter weather, could destroy or damage power lines, poles and other electric infrastructure. Wildfires' threat could also come from soot, heat or chemicals used to fight wildfires, said Vincent Tidwell, a Sandia National Laboratories scientist and lead author of the report's chapter on energy.

While most threats outlined in the report are relatively limited by themselves, "when you start putting them all together, they begin to add up," said Tidwell, a hydrologist.

Tucson Electric Power says it's already dealing with extreme weather conditions, and "we're confident that we'd be well prepared to deal with whatever conditions we may have to face in the future," said Joe Barrios, a TEP spokesman.

"Because we are a regulated utility, we have to design and build systems that satisfy environmental requirements, many of which obviously are intended to address the issue of climate change," Barrios said. "We also have to build systems that are safe and reliable and systems that meet demand requirements. As we look forward and design our systems, there's a lot of balancing going on."

It's not clear if grid threats are imminent or far off, Tidwell said.

"It's hard to say when that next very strong drought is going to hit, or how vulnerable we are. Is it two years off or 20 years off? I can't answer that," Tidwell said. "We've seen some very strong droughts recently in the Midwest, and Texas got close to a few brownouts during their drought (two years ago)."

An example of the problems that researches expect to increase happened in September 2011, Tidwell said, when high demand load due to hot temperatures tripped a transformer and transmission line near Yuma. Power was cut off to 2.7 million San Diego County customers in California for up to 12 hours.

Another example occurred in the San Diego area in October 2007, when a wildfire damaged two dozen power lines covering 35 miles, cutting off power to nearly 80,000 customers, some for several weeks, Tidwell said.

More electric blackouts and/or brownouts are possible if society doesn't take steps to deal with these problems, such as increasing buildings' energy efficiency or acting to manage or reduce electricity demand, Tidwell said.

"Certainly, we work hard to avoid those problems," Tidwell said, adding, "The vulnerabilities are there."

Another solution is to look at a region's overall electrical generating system and its susceptibility to limited water availability, Tidwell said. Certain kinds of power plants, led by nuclear energy and followed by coal, require a lot of water. Large-scale, solar thermal plants that heat water or other fluids or generate electricity through a steam cycle can also be high water users, compared to small-scale, home-based PV panel systems, he said.

Finally, when people use more air conditioning to keep cool as the heat builds, the energy used by the air conditioners can increase CO2 and other greenhouse gas emissions, making the climate changes worse, he said.

The report's chapter on energy raises a lot of issues that are important to TEP when it plans for the future, utility spokesman Barrios said.

"Starting today, if we do nothing to maintain our system to make improvements, some portion of our system eventually will fail," Barrios said. "It requires constant maintenance. It requires re-evaluation and sometimes it requires building new facilities. The effort on our part to (provide) reliable service is continuous."

On StarNet: Reporter Tony Davis live blogged from the event. Read the transcript at live.azstarnet.com

"Starting today, if we do nothing to maintain our system to make improvements, some portion of our system eventually will fail. It requires constant maintenance. It requires re-evaluation and sometimes it requires building new facilities. The effort on our part to (provide) reliable service is continuous."

Joe Barrios, a TEP spokesman

COMING SATURDAY

Other findings of the Southwest climate change report

Contact reporter Tony Davis at tdavis@azstarnet.com or 806-7746.

Copyright 2014 Arizona Daily Star. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

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