Sustaining a City in a Long-Term Power Outage

A few comments on this fascinating study from Pittsburgh (site of Carnegie Mellon, which is a center of excellence at studying critical infrastructure issues).  The key theme that emerges for me is the interaction of the liquid fuel system (particularly diesel) and the electricity system.  In a short outage, lots of critical infrastructure has diesel generator backup, and so the hospitals, 911-call centers, and so on can continue to operate.  However, they typically have limited fuel storage capacity (if for no other reason than that diesel doesn't keep indefinitely), and so in a long outage, the availability of diesel becomes critical to keeping everything together.

Hints of Climate Change Affecting the Electricity Grid

It's interesting reading the NERC 2013 Summer Reliability Assessment.  Although it's not a focus of the report, reading between the lines you can see that climate change is going to have complex effects on the grid, and all of them increase the stress on it:

1. Weather extremes, particular heat-waves, cause higher peak demands, and larger swings in power demand.  For example, p1 refers to challenges in the Texas interconnect (ERCOT) as follows: "The Anticipated Reserve Margin for ERCOT is 12.88 percent for summer 2013. This is below the 13.75 percent target for ERCOT. Sustained extreme weather could be a threat to supply adequacy this summer. ERCOT may need to declare Energy Emergency Alerts (EEA) if there are higher‐than‐normal forced generation outages or if record‐breaking weather conditions similar to the summer of 2011 lead to higher‐than‐expected peak demands."
2. Drought (expected to increase under climate change) can affect the operation of thermal generation plants (both nuclear and fossil-fuel powered).  Eg p4 says: "When water levels fall significantly, water intake structures may be exposed above the water surface, causing the plant to become nonoperational. Additionally, generators are less efficient as the temperature of cooling water increases and results in a reduction of the power capability of the plant. Along some bodies of water, regulatory limits are placed on the temperature of the cooling water system discharges, and power plants are not allowed to raise water temperatures above levels deemed safe for species of fish and other aquatic life. Again, no major system impacts are expected; however, in certain extreme cases, waivers may be needed to keep critical generation online."
3. Drought more obviously reduces available hydro-electric generation, eg in the midwest this year (p5): "For the upcoming summer season, the Missouri River main‐stem water levels are being monitored closely, as impacts to this water source may affect significant hydro generation. The U.S. Army Corps of Engineers predicts that 2013 will be a drought year, and electric energy produced from the Missouri River will be approximately 80 percent of the historical average."
4. Major storms appear to be worsening, and these can cause unpredictable damage to the grid, or the fuel sources required to run the grid.  For example, hurricane Sandy caused substantial outages in the northeast last year, and hurricanes in the Gulf of Mexico can cause loss of natural gas production required for electricity generation (p6).
5. Finally, the increase in solar and wind production (which is being undertaken to reduce the causes of climate change) itself is a grid-stressor as these sources are intermittent and mostly not under the control of the grid operators.  The larger the mix of these sources becomes, the more we will demand of the transmission grid.

Of course, none of these things need be fatal to the reliable production of electricity.  But it's clear that it's going to take significant additional investment to keep the grid working reliably in the face of climate change.  Given human inertia, one might imagine that we will be slow to make all the necessary investments and be prone to run the grid in a stressed and vulnerable manner.

International Power Outage Comparisons

Terrorism and the Electric Power Delivery System

I am currently reading Terrorism and the Electric Power Delivery System.  From the summary:

The electric power delivery system that carries electricity from large central generators to customers could be severely damaged by a small number of well-informed attackers. The system is inherently vulnerable because transmission lines may span hundreds of miles, and many key facilities are unguarded. This vulnerability is exacerbated by the fact that the power grid, most of which was originally designed to meet the needs of individual vertically integrated utilities, is now being used to move power between regions to support the needs of new competitive markets for power generation. Primarily because of ambiguities introduced as a result of recent restructuring of the industry and cost pressures from consumers and regulators, investment to strengthen and upgrade the grid has lagged, with the result that many parts of the bulk high-voltage system are heavily stressed.

A terrorist attack on the power system would lack the dramatic impact of the attacks in New York, Madrid, or London. It would not immediately kill many people or make for spectacular television footage of bloody destruction. But if it were carried out in a carefully planned way, by people who knew what they were doing, it could deny large regions of the country access to bulk system power for weeks or even months. An event of this magnitude and duration could lead to turmoil, widespread public fear, and an image of helpless- ness that would play directly into the hands of the terrorists. If such large extended outages were to occur during times of extreme weather, they could also result in hundreds or even thousands of deaths due to heat stress or extended exposure to extreme cold.

The largest power system disruptions experienced to date in the United States have caused high economic impacts. Considering that a systematically designed and executed terrorist attack could cause disruptions that were even more widespread and of longer duration, it is no stretch of the imagination to think that such attacks could entail costs of hundreds of billions of dollars—that is, perhaps as much as a few percent of the U.S. gross domestic product (GDP), which is currently about $12.5 trillion.

Electric systems are not designed to withstand or quickly recover from damage inflicted simultaneously on multiple components. Such an attack could be carried out by knowl- edgeable attackers with little risk of detection or interdiction. Further well-planned and coordinated attacks by terrorists could leave the electric power system in a large region of the country at least partially disabled for a very long time.

Alert readers may note that the $12.5 trillion figure for GDP is inconsistent with the 2012 publication date of this National Academies of Science report.  Apparently it was written in the 2004-2007 timeframe, but then classified until last year.

Extreme Weather Possibly Increasing Power Outages?

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