A statistic you probably don’t know is SAIDI, system average interruption duration index. It means the average number of minutes per year for which the customers of an electricity network are deprived of power, not counting short interruptions of 1-5 minutes, planned interruptions, or “extreme weather events”. It’s one of the two main internationally agreed indicators for grid reliability. Its sibling SAIFI is an indicator of power cut frequency, and is less significant for most customers.

What is it in the USA?

Surprise, surprise, US energy reliability statistics are an uncoordinated mess. The most recent analysis I could find dates to 2008 and the DoE does not (according to Google) publish national SAIDI or other reliability indicators. The latest number I could find is an independent estimate of 240 for 2007. That’s four hours of power cuts a year before the utilities can blame them on ice storms, hurricanes or terrorists.

I thought my Spanish supply was unreliable but the latest SAIDI for Spain is 89. A graph of European SAIDI trends from an authoritative source, the Council of European Energy Regulators (5th benchmarking report, 2011, Figure 2.1. page 27. Data table page 115.) Sorry for the poor screenshot resolution.

So raising the reliability of US electricity to the Greek level of 134 would be a considerable improvement.
Average and best European practice is far below that. The reliability leader is not surprisingly Germany, at 15.3 minutes in 2011.

Notice the way that the arrival of lots of intermittent wind and solar energy in Denmark, Germany, and Spain has been making their grids less reliable? Me neither. The two seem entirely uncorrelated. Intermittent doesn’t mean unpredictable, and competent grid managers have found ways of coping.

It might be an idea for American journalists to actually look at Germany instead of writing stuff like this, from James Conca in Forbes:

The grid can’t handle it [the German renewable energy plan], the transmission system is not there, and the power disruptions and brownouts are wreaking havoc on the country’s energy reliability.

Craig Morris at the German-based Renewables International blog (h/t for my topic) has fun with this nonsense.

The better performance of Europe in general over the USA, and the general trend to improvement, are satisfactorily explained by European coordination and regulatory pressure. It’s still an interesting question why German electricity is at the top. It isn’t formal centralisation. In contrast to the national grid monopolies of Britain, France, and Spain, Germany counts four regional high-voltage grid operators (map here) and a staggering total of 864 network operators.

It would be worthwhile for US policymakers and regulators to find out how this federalised patchwork – rather like their own – works. Non-exclusive hypotheses: the regulator is tough and uncaptured; German technicians and engineers are exceptionally well-trained and competent; operators buy high-quality German equipment; the four large regional networks – the smallest covers a population of 10 million Baden-Württemburgers – impose high standards on the many tadpoles; German consumers have a strong preference for reliability and are willing to pay for it – the average retail price is 23c per kwh); perhaps the law provides for effective compensation for cuts.

A quicker route to progress in the US would be for Steven Chu to publish a reliability league table for electricity, by state and by utility. The shaming effect at the bottom would I think be pretty strong; and a race might also start at the top, once the lag with Europe becomes well known.

I take the opportunity of reposting my favourite pylon snap of an expensive but stunning French design, here on a 400kv line crossing the Somme. SFIK Germany lags in grid aesthetics.

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