We manage an inherited portfolio of historically contaminated land including former manufactured gas plants, industrial landfills, former and current gas holders and electricity substations on our transmission and distribution networks. Sites can sometimes have a complex mix of contamination dating back over 100 years.
National Grid manages land contamination issues on 709 sites, the majority of which were previously used for gas production. In the US, this includes obligations in relation to land owned by third parties. During 2010/11, environmental work stages were completed on 342 sites of which 39 included remediation.
We measure the number of contaminated sites by including those where we anticipate significant spend on investigation, risk assessment or remediation works. As part of our proactive management programme and to respond to enquiries from stakeholders, including environmental regulators, we are seeing an increasing need to undertake desk based reviews to update our assessments, even where we have concluded that no remediation work is required. Including all of this work would overstate the number of contaminated sites, so this year we have introduced a financial threshold for reporting purposes. .
During 2010/11, in addition to continuing to manage and decontaminate the former gas manufacturing sites that we own, we also completed a high level review of 364 sites owned and operated by National Grid Electricity Transmission (NGET) in the UK. We will use this information to continue to investigate and manage the portfolio on a prioritised basis. In the interim, we have adopted a working assumption for reporting purposes that 110 of these sites will require some degree of intervention.
Particularly in the UK, reclaiming brownfield land continues to be crucial in promoting urban regeneration and protecting the countryside from over-development. National Grid is widely regarded as one of the UK’s leading experts in the clean-up of former gasworks.
No two pieces of land are identical, and National Grid maintains its record for using a combination of established and innovative technologies when cleaning up brownfield sites. We are continuously looking for ways to improve, exploring how new technologies can contribute to National Grid’s ambitious sustainability goals. Our aim is to minimise the amount of contaminated soils we dispose of at landfill using techniques that allow treated soils to be recycled and re-used on the site of origin or at another location in the portfolio. We also seek to work with environmental regulators to ensure that regulatory frameworks support the most sustainable outcomes.