Environmental Management

Methane emissions

The distribution network for natural gas comprises about 34,000 kms of mains, excluding connecting pipes. Methane emissions occur because mains and connections are not fully sealed. Digging work or degeneration of mains and connections can also cause leakage in the mains system. Though leaks are immediately repaired and the networks are regularly checked, a certain amount of gas still escapes. As natural gas contains 80% methane, this is referred to as methane emissions. 

In accordance with the protocol of the Ministry of Housing, Spatial Planning and the Environment (VROM), methane emissions are calculated according to the length of the networks and the average size of the leaks occurring in these networks. In this respect, a higher emission factor is used for cast-iron mains as this material tends to be more prone to leaks.
By replacing cast-iron pipes with pipes made of other materials, the emissions from the networks are reduced. At the same time, the network is expanded annually due to the construction of new mains, which serves to increase the emissions. The methane emissions are about one tenth of a percentage of the total amount of distributed natural gas. Methane is a greenhouse gas and the emissions are expressed in kg CO2 equivalents. The greenhouse impact of methane is 21 times greater than that of CO2. To permit a proper comparison of the impact of the various gases, the emissions are converted to CO2 equivalents. In 2007 the methane emissions came to the equivalent of 92,233 tons of CO2, which is slightly lower than in 2006 despite the expansion of the network in 2007. This is mainly attributable to the replacement of network sections with a higher emission factor with network sections with a lower factor.  

Replacement of PCB-polluted transformers

The Ministry of Housing, Spatial Planning and the Environment (VROM) published the guidelines for the implementation of the PCB regulations for transformers at year-end 2004. Since the eighties the Netherlands’ policy and regulations on PCBs have been aimed at banishing polluted equipment from the Netherlands. The expectation was that a large portion of the PCBs present in the Netherlands would be found in transformers. In 2001 the transformer clean-up operation had still made insufficient progress. In consultation with EnergieNed, VROM then decided to proceed with the phased enforcement of the regulations to achieve the removal of all potentially polluted transformers before 1 January 2004. During the discussions between VROM and EnergieNed, the transformers present at the grid manager were subdivided into 3 groups:

1. Construction year 1986 or later. These are deemed to be PCB-free.
2. Pollution suspects. These are transformers from 1985 or earlier and of a brand which had already been found to contain excess PCB pollution levels.
3. The group of unspecified transformers. This group required further investigation.  

The transformers from group 1 are analysed for the presence of PCBs at the end of their useful life, the transformers from group 2 had to be removed before 01-01-2004. The transformers from group 3 were subjected to random tests. 

Nuon/Continuon has met the demands from the VROM directive. All polluted/suspect transformers were replaced before 1 January 2004. All other transformers will be analysed at the time of replacement.

Decontamination of gas plant sites

Nuon has opted for a solution-oriented approach to decontaminating polluted gas plant sites. Our aim is to complete the decontamination of all our gas plant sites by 2015. To this end, we are seeking optimal cooperation with municipalities, provinces and other parties such as project developers so that after the soil decontamination operations the old gas plant sites can be redeveloped wherever possible. The soil remediation and redevelopment of a number of gas plant sites has already started up in the provinces of North Holland and Gelderland, while a former gasholder site (Maresingelterrein) now forms part of the Nieuw Leyden residential project in Leiden. A total of 28 projects at former gas plant sites that are (co-)owned by Nuon have been set in motion. Nuon expects to spend € 40 million on the remediation of all sites, of which EUR 23.8 million has meanwhile been realised.

NWS Environmental Help Desk

The Environmental Help Desk of Network Services has been operational since 2006 in order to answer the environmental questions of employees within the Network Services Division. The aim of the Environmental Help Desk is to provide accessible and adequate operational support to employees of NWS. In 2007 the Environmental Help Desk recorded a total of 75 questions and requests. Requests varied from environmental support when working in contaminated soil to conflicts with authorities and the performance of audits. Most questions concerned soil and permits. Priorities for 2007 were to increase the awareness of the Environmental Help Desk within NWS and to give customers an even better service. To this end, a 24-hour emergency service was put in place in cooperation with the Technical Service Centre.