Reliability of our grids
On average, customers were not supplied with electricity for 20.03 minutes in 2019 - a deterioration compared with 2018, when downtime averaged 17.01 minutes.
The average downtime for gas was 87 seconds in 2019, compared with 69 seconds in 2018. The main cause of the increased average downtime for gas is a number of major failures, such as the one in Heenvliet in May.
Average downtime for electricity and gas in 2019
Annual average downtime for electricity (in minutes)
Causes of downtime for electricity (in per cent)
Annual average downtime for gas (in seconds)
Causes of downtime for gas (in per cent)
Supply reliability (in per cent)
Excavation activities
Excavation activities are often the cause of disruptions. The volume of excavation activities has increased for several years, rising by no less than 11% in 2019. This increase also leads to more excavation damage, resulting in a higher incidence of related disruptions. The growth in excavation activities is partly attributable to an expansion in constructionwork and demand for optical fibre. Roughly a quarter of excavation damage is the result of work to lay optical fibre.
Dig safe
In spring 2019, we launched a campaign together with the other grid managers aimed at creating awareness among consumers about the consequences of digging: 'Dig safe'. In the campaign, the grid managers give consumers and gardening contractors tips on avoiding damage to cables as well as pipelines; for instance, when sinking a post in the ground, or using an auger or spade. The campaign had a positive effect, with the number of recorded instances of excavation damage among consumers decreasing by more than 10% in the spring.
Smart, risk-based maintenance
In 2019, we took steps to make our grids even smarter. These steps had a positive impact on maintenance in particular: we use data to pinpoint where maintenance is really needed and where it is not essential. Mindful of our financial responsibility, we do all that we can to exploit our assets as long as possible in order to keep the social costs for the energy supply at a minimum. We refer to this notion as the 'risk reduction per euro'. This approach has resulted in savings of more than 4 million euros. In addition, data help to improve the quality of the grid and increase safety.
From 2019, we use data for maintenance in the following projects:
- Using the 'Condition assessment' ['Toestandwaardig'] method, we automatically calculate the condition of a medium-voltage station based on 10 indicators, including ground or soil type and age. This information tells us exactly for how long a medium-voltage station will remain operational. Whereas it used to be standard practice for them to be replaced after five years , we now know that they can remain in service for far longer; as much as twice as long in some cases.
- Subsidence is an indication of the potential risk of pipeline subsidence and hence whether a pipeline will begin to leak. We can map this subsidence using satellite imagery. Now, we are able to do so with greater precision than previously. We test suspect pipelines by means of a Partial Discharge measurement. This measurement involves using an inspection vehicle that can accurately determine the condition of the pipelines, which enables us to set priorities as well as replace sections locally.
- Stedin has developed an improved model for estimating the likelihood of pipeline failure over a period of 50 years. This model provides important input for risk assessment, and hence for maintenance and investment planning. More information is now available for less effort. In addition, the results of the model are easier to visualise in our geographic information system. This system ensures that the data are widely accessible across Stedin.
Cast iron gas pipeline explosion in The Hague
On 27 January 2019, a gas explosion rocked the residential area of Jan van der Heijdenstraat in The Hague. Ten people were injured in the explosion, one of whom had to wait for eight hours to be rescued from the rubble of the building. Three homes were completely destroyed and a further six were seriously damaged. Stedin assisted the emergency services by disconnecting the gas pipelines and electricity at the site. The immediate priority after the explosion was to care for the residents affected. An investigation into the possible cause of the explosion started a day later.
The Public Prosecution Service (OM) and the State Supervision of Mines (SodM), as the regulatory authority, investigated the cause of this serious incident. Specialists from research institute Kiwa were asked by the Public Prosecution Service to assist with the technical aspects of the investigation. Since a gas leak was identified as a possible cause of the explosion, Stedin gave evidence as a witness. Stedin was not permitted to conduct its own on-site investigation at this stage.
The Public Prosecution Service concluded the criminal investigation on 6 June 2019 and published its conclusion. At the same time, the State Supervision of Mines published the findings of its investigation. The investigation into the circumstances surrounding the gas explosion found that it was a tragedy for which no party can be held criminally liable. A crack was found in the gas pipeline under the street where the homes were located. While the investigations were unable to determine the cause of this crack, it was concluded that Stedin had done everything possible in advance to prevent the incident.
Impact of gas pipeline explosion in The Hague
The explosion made a profound impression on Stedin's employees. We consider the incident to be the low point of 2019. Although independent investigations found that Stedin was not to blame, we feel a sense of social involvement with the incident and we sympathise deeply with everyone who was injured or affected. For this exceptional situation, Stedin appointed a case manager who supported them and helped them navigate the handling processes for insurance as well as claims.
Accelerated replacement of cast iron
In the past, grey cast iron pipes were used as mains in the gas distribution network. This situation was also the case at Jan van der Heijdenstraat. Over the years, more modern materials became available, which are now commonly used for laying and replacing gas mains. The grid managers in the Netherlands launched a remediation programme during 2010 to replace all the grey cast iron gas mains in the country. In the light of the incident and the subsequent investigation, the State Supervision of Mines made four recommendations for Stedin and the sector as a whole. The State Supervision of Mines calls for a significant acceleration of the existing remediation programme for grey cast iron gas mains. The grid managers take the recommendations from the State Supervision of Mines very seriously. Among other things, these recommendations have resulted in the decision to speed up the replacement of all the cast iron mains in our service area. These mains were originally scheduled to be replaced by 2030, but this deadline has now been brought forward to 2028. A total of 53% have already been replaced.
Transition together
Proactive pre-investment in Houten
Pre-investment based on future scenarios is becoming increasingly important. Houten-Oost is a case in point. Here, we identified a capacity bottleneck, which was brought to light by the finding that up to eight applications for solar farms had been filed with the municipality of Houten. Instead of adapting existing stations, we held discussions with the applicants concerned. These discussions resulted in the decision to build a new transformer station close to the solar farms. We anticipate that this station will enable us to minimise the social costs. Since the road only needs to be dug up once, we will also avoid any unnecessary inconvenience.
High-voltage projects involving Stedin and Enduris
Stedin is involved in a large number of projects related to high voltage. An example is the proposed widening of the A27 motorway. In order to reduce traffic congestion, the Directorate-General for Public Works and Water Management (Rijkswaterstaat) has proposed to widen a large section of the A27. Since many of Stedin's networks are located along or nearby the motorway, they need to be moved or altered before the motorway can be widened. Work to widen the A27 between Utrecht-Noord and the Eemnes junction as well as the necessary re-routing have been completed. Re-routing activities for the section from Hooipolder to the Lekbrug bridge at Vianen are next in line. The work is scheduled to continue until 2024.
In the province of Zeeland, Enduris carried out the renovation of the 380kV station at Dodewaard commissioned by TenneT. The work consisted of replacing the severely outdated operating and security systems. This work was completed in November 2019.
Roll-out of new fibre-optic network in all regions
Stedin took a new fibre-optic network (Stedin Telecom Network STN2020) into use in October 2018. This modern telecommunications network establishes a data link between all the station automation systems in transmission stations and the larger medium-voltage distribution stations in Stedin's area. The first data services started to run over the network in 2019. They included station security and data communication, improving our Network Operation Center's insight into the functioning of the energy grid. This network has now been implemented in The Hague and parts of Rotterdam. The aim is to have realised full service implementation across Stedin's entire area in two years' time.
Investments in our grids
Investments have increased in all areas over recent years.
The investments are € 39 million (6%) higher than in 2018 and comprise 99% of the budgeted amount (2019: € 650 million).
Customer demand for smart meters stabilised in 2019. A shortage of gas meters also meant that fewer gas meter replacements were carried out last year than planned. You can read more about this matter in High-quality products and services'.
Our grid-driven investments in 2019 are in line with our long-term planning to achieve a sustainable improvement in the quality of the grid. Regarding gas replacements, more than 27,000 primary gas connections, 147 NEN 1059 control stations and over 120 kilometres of brittle pipelines were replaced. We also largely attained our target as regards electricity replacements through the replacement of 94 COQ/MIPAK stations.
It is our expectation that the customer-driven investments will remain substantial in the coming years, driven by the pace of the energy transition to which Stedin contributes and changing customer needs. This trend makes planning and adjusting investments more challenging than in the past. Several multi-year efficiency programmes were launched in 2018, aimed at ensuring that we retain our financial health and our ability to fund the investments required by the energy transition as well as keeping those investments affordable in the long term. By improving our work efficiency and making our investment planning more risk-based, among other things, we were able to achieve a saving on investments of more than € 14 million in 2019.
The other investments increased as a result of the investments in the property at Nijverheidsweg in Utrecht due to the review of the real estate portfolio. In accordance with the strategic real estate plan, Stedin Holding N.V. purchased the building at Nijverheidsweg in Utrecht on 1 March 2019. This purchase enhances flexibility for the optimum utilisation of real estate, enabling savings to be achieved on the overall real estate portfolio in the future as well.
