Gas supply reliability

One of our core tasks is to transmit natural gas safely and reliably. Thankfully, outages of the gas grid are quite rare. In 2023, the average downtime for gas was found to be 44 seconds. This is slightly less (6 seconds) than in 2022. Failures in Moordrecht and Maassluis stood out (see boxes). Almost three quarters of failures are caused by an internal defect; obsolescence/corrosion and (past) installation errors. An average downtime of 44 seconds still equates to a delivery reliability of 99.9999%.

Annual average downtime for gas (in seconds)

  1. * Source: https://www.netbeheernederland.nl/_upload/Files/Resultaten_2022_-_Betrouwbaarheid_van_elektriciteitsnetten_in_Nederland__283.pdf

Gas grid safety

We intend to replace all our brittle gas pipelines (grey cast iron and asbestos cement) before 2028 in order to ensure the safety of our gas grid and because of the potentially profound social impact. In addition, the removal of brittle pipelines will help reduce CO2emissions. In 2023, we removed and/or replaced 212 km (2022: 200 km) of brittle pipelines and primary gas connection pipelines.

Failure in Moordrecht (Gas)

During work early in May, a contractor drove a sheet piling through a gas supply line. To be able to perform emergency repairs, we temporarily disconnected the gas main. This left around 160 homes in Moordrecht without a gas supply. Repair work was hampered by the fact that the location where the pipeline had been hit was under water. This meant that we could not finish the repair work while it was dark and had to wait until the next morning before completing the final part of the repair. As a result, the outage lasted nearly 17 hours in total.

Pipeline rupture in Maassluis

On 1 December, a water mains was hit during works in Maassluis. As a result of this rupture, water got into gas pipelines, leaving about 100 homes without gas. The electricity was still working, however. Furthermore,a part of the street was flooded and a flush hole (sink hole) of about three by four metres appeared. A water tapping point was set up for residents whose water had been disconnected. The first 40 homes were soon reconnected to the gas mains. Within a day, the gas supply was restored to all homes.

Smart, data-driven maintenance

In order to maintain the quality and safety of the gas grid, we constantly perform maintenance on – and inspections of – our gas grid. In 2023, we carried out 43,300 maintenance jobs and inspections, 96% of what we had scheduled. This is mainly due to the maintenance arising from those inspections (in this instance, less maintenance was required than expected) and to weather conditions in the last two quarters of the year.

Data-driven maintenance involves the use of data to pinpoint where maintenance is really needed and which elements need replacement. In addition to quality improvements, this yields annual savings. The following are a few examples of how we use data for maintenance:

  • We are continuing the roll-out of sensors for the protection of high-pressure gas pipelines. We use these sensors to measure the cathodic protection of our grids online. With continuous monitoring, we identify damage and therefore the risk of leaks at an early stage.

  • In 2023, we started a pilot with underground oil pressure cables. Currently, we use analogue manometers to monitor oil leaks. This involves around 80 connections, of 800 km in total. These meters cannot detect latent leaks in time. With the advent of digital pressure sensors with wireless communication options, we can continually monitor oil pressure and detect these leaks in time. This prevents environmental pollution.

What have we learnt about management?

Despite the growing pressure on our grids, we again managed to maintain a high level of supply reliability (over 99%) in 2023. Unfortunately, we did have a few more unwelcome lengthy failures. Our aim remains to minimise failures and thus minimise inconvenience to our customers.

Due to the growing number of solar panels, electric cars and heat pumps, we are increasingly encountering voltage problems on our electricity grid. We have observed that the grid, which has been laid out over the past one hundred years, is in some cases no longer suited to the new energy system.

By creating insight into the extent and cause of the voltage problems, we provide input to the construction organisation, which can tackle the root cause of the problem through initiatives such as the neighbourhood approach. Finally, we have established that the management organisation needs to scale up in order to absorb the increase in the number of stations and cables.

We will be building more and more in the coming years, and we need to make those new stations and cables last as long as possible. In short, management, in addition to more construction and better grid utilisation, remains as important as ever.