German grid more stable in 2013
It’s bad news for the folks insisting that renewables are wreaking havoc on the grid – last year, the average number of minutes of power outages in Germany fell below the already leading level of 2012 and below the average over the past seven years. Craig Morris looks into the situation.
On Friday, Germany’s Network Agency announced (press release in German) that the SAIDI value for the country fell from 15.91 minutes in 2012 to 15.32 minutes last year. Though not without its critics, SAIDI has become the internationally recognized way of measuring grid reliability. In this calculation, power outages must last at least three minutes to be counted, and natural disasters are not included.
In 2006, Germany began using SAIDI as a way of reporting grid reliability as a part of an EU-wide effort to facilitate data comparisons. The average from 2006 to 2012 for Germany is 16.91 minutes, roughly 10 percent above the level in 2013 (low numbers are better).
Despite the overall improvement, the press release also states that “interruptions due to feedback effects” from both the underlying low-voltage and superordinate high-voltage grids increased considerably at the medium-voltage level for the third year in a row. These interruptions could be the result of the increase in distributed renewables, with most wind power connected to the medium-voltage grid and most PV connected to low-voltage lines.
But the press release denies any detrimental effects from the Energiewende, explaining instead that these feedback effects can also come from “consumption systems or an interruption in power supply from power plants.” “No considerable influence of the Energiewende and the concomitant increase in distributed generation capacity on supply quality was detected in the year under review,” the president of the Network Agency Jochen Homann states in the press release, which attributes the SAIDI improvement to a decrease in outages caused by third parties (vehicles, construction work, etc. disturbing power lines and cables). “German power supply remains very reliable, even in comparison to other European countries,” Homann adds.
It also remains very reliable in comparison to the US, though the Network Agency does not make that comparison – probably for a lack of data. The US does not collect reliable power outage statistics – SAIDI or otherwise – but all indications are that Americans easily put up with 10 times as many minutes of power outages on average per year.
In other words, since 2006 we have witnessed a stabilization of Germany’s impressively reliable grid even as some 35 gigawatts of solar and 35 gigawatts of wind were installed on a grid with peak demand of generally around 60-70 gigawatts. Clearly, installing the equivalent of 100 percent of peak demand as wind and solar capacity does not bring down the grid. At the same time, the main correlation with low SAIDI seems to be the amount of underground cabling (as opposed to overhead lines), not the share of renewables, as I explained last year.
The news may come as a surprise to international critics of the Energiewende. The same day of the press release, the Institute for Energy Research (IER) – an organization that seems afraid the German energy transition might work – posted an article on Canada Free Press arguing that “the outcome [of the Energiewende] for Germans will be a higher potential for blackouts” based on the skyrocketing number of grid intervention events, which roughly increased fourfold from 2010 to 2012.
There may yet be something to this concern, however. I once provocatively asked a representative of a transit grid operator to explain what a “grid intervention” on the part of a grid operator means: “so instead of merely sitting there looking at screens, the engineers now have to press buttons?” “Yes,” the expert answered with a wry smile, “and each time they have to do so, there is a slight chance of an error, especially human error.”