Dutch natural-gas networks are becoming more susceptible to disruptions. Despite the fact that households and businesses are facing gas-network disruptions more often, the natural-gas network continues to experience relatively few disruptions compared with the electricity networks in the Netherlands. But when a disruption does occur, it usually is an extended interruption. The number of minutes that Dutch members of the public are not supplied any natural gas because of unexpected interruptions increased from 23 seconds in 2009 to slightly over a minute in 2013.
These conclusions have been drawn in the Quality Factsheets 2013 by the Netherlands Authority for Consumers and Markets (ACM) as the energy regulator in the Netherlands. With these factsheets, ACM wishes to present an objective and broad picture of the quality that the regional network operators of electricity and natural-gas networks provide.
Henk Don, Member of the Board of ACM, explains: ‘What we see is that 40 percent of the disruptions in the gas networks are caused by deterioration with age or wear and tear. In the next few years, ACM will continue to keep a very close watch on the reliability of the gas networks. We do so by, for example, examining the reports on quality and capacity, which the network operators are required to draw up every two years. Network operators continue to be responsible themselves for investing enough to maintain the reliability of their gas networks. Within the regulation of their tariffs, network operators are given room to be able to make the necessary investments in their gas networks.’
Gas networks of network operator DELTA have longest interruptions per customer
In 2013, on average, 24 in 1,000 households in the southern Dutch province of Zeeland were hit by unexpected interruptions in the gas networks, while the national average is 7 in 1,000 customers. Moreover, the interruptions of DELTA Netwerkbedrijf, which is the network operator in Zeeland, lasted in 2013 much longer than the national average: 550 minutes compared with 150 minutes. A big contributing factor to this figure was a major interruption in the town of Yerseke on 23 April 2013.
Pipes from gray cast iron are progressively being replaced
Since 2009, network operators have already replaced one third of the gas pipes made from gray cast iron. Such pipes cannot withstand the stress caused by, for example, rapidly sinking ground. In such situations, pipes can suddenly burst, and they have a higher probability for leakages than do pipes made from other materials. That is why, in April 2009, following several incidents, the Dutch Safety Board (Onderzoeksraad voor Veiligheid) recommended the acceleration of replacing the pipes made from gray cast iron. The total length of gray cast iron pipes subsequently decreased by a third from 7,188 kilometers in 2009 to 4,828 kilometers in 2013. As part of the effort to share responsibility over safety regulation of gas networks, ACM and the State Supervision of Mines oversee the replacement works.
Interruptions in electricity networks are short
In 2013, Dutch households had no electricity for, on average, 23 minutes as a result of unforeseen interruptions in the regional networks. The interruption duration in 2013 was thus slightly lower than the average of 25 minutes in the past few years. Digging damage turns out to be the cause behind a quarter of all interruptions in the electricity networks. The Netherlands has one of the most reliable electricity networks in Europe.