US Reliability: A Look at the Facts

In my last post, I touched on the failing reliability of the US electrical distribution system.  This failing should not be confused with power company claims that we need a new high voltage transmission system or “Super Grid” as claimed by land based wind cheerleader Al Gore.

So, let’s look at some facts about the reliability of the US distribution system.  In August 2012, the US Congressional Research Service published a report on storm related blackouts that includes some basic information about how the US distribution stacks up against the systems of European countries.  Here is that comparison:

Outage Rates in Other Countries

The United States is generally considered to have one of the industrial world’s most reliable electric power systems. However, when compared statistically to other nations, the U.S. grid does not necessarily meet those expectations.

There are two main indices generally used to measure reliability. The system average interruption duration index12 (SAIDI) represents the average amount of time per year that power supply to a customer is interrupted, expressed in minutes per customer per year. The system average interruption frequency index (SAIFI) represents the average number of times per year that the supply to a customer is interrupted, expressed as interruptions per customer per year. However,
there is a lack of consistency in how the inputs to these indices are measured, both domestically and internationally. Much of the discrepancy again concerns whether or how storm-related outage events are counted as outage events. Some jurisdictions, both in the United States and internationally, consider storm-related outages as “extreme” events, and thus are not included in power outage statistics. Additionally, what is considered as unusual weather in one region may not be counted as unusual in another region.

“It should be noted, however, that weather circumstances that occur occasionally should not be considered as exceptional events. For example, snowstorms are not an exceptional event in Sweden, but could be seen as an exceptional event in southern Greece. Similarly, very hot temperature for sustained periods of time is not an exceptional event in Greece, but could be considered so in Sweden. Lightning should not be treated as an exceptional event anywhere
in Europe.”14

SAIDI and SAIFI reliability indices for nine industrial countries are summarized in Table 2. As can be seen, the United States has the highest average annual outage time per customer, and the third-highest average annual number of supply outages per customer.

Here is Table 2, this table represents reliability indexes from 2007 –

Reliability comparison table

And here is the report’s conclusion about the current situation with the resiliency of the US distribution system.  This will be a real blow to FERC and power companies who are claiming our highest priority is new high voltage transmission investment.

However, the generally degraded condition of the U.S. electric grid’s infrastructure also likely contributes to the statistical quandary. The American Society of Civil Engineers (ASCE) has labeled the nation’s grid as a “patchwork system” that may ultimately break down without a massive investment of an estimated $673 billion by 2020.16 ASCE estimated that over the next decade, there is a gap between what it viewed as needed and current spending annually of $12.3 billion for power generation, $37.3 billion for transmission systems, and $57.4 billion for distribution systems. [emphasis mine]

Here is another graph from the report that shows clearly the increasing brittleness of the US distribution system, both in general and in terms of weather impacts –

blackout graph

And finally, we have a table from the report summarizing the causes of major blackouts in the US.

blackout table

Did you see any causes like “lack of transfer capacity at peak load” or “lack of transmission capacity”?  No, I didn’t either.  Look at “voltage reduction,” what PJM in its scare propaganda called “brownouts” – less than 7% of all events.  Maybe you could claim that PJM’s scare tactics included “supply shortage,” but that amounted to only 5.3% of incidents.  ALL of the major blackout causes were weather related or connected with equipment failure.  Here is clear evidence that there is not really any connection between real world blackouts and some claimed need for high voltage transmission lines.

As we know from reliability experts like George Loehr, the best way to increase system reliability is to keep electrical generation as close as possible to the places where electricity is consumed.  Building more and longer lines, of any kind, is the wrong way to go.  Building smaller generating systems IN our communities is the real source of resilient and effective power systems.

2 thoughts on “US Reliability: A Look at the Facts

  1. Hello, i have some question to owner these blog. I am from Poland and i would like to advise about quality of indices, like SAIDI, MAIFI and other in U.S or another country, if you have any information, which you can sharing with me. I put my address in framework below.
    I really count on your help.

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