Active Creosote Extraction (ACE)

Objectives

The objectives of the project are to:

• Develop an extraction method that can extract creosote from wood poles at a length of 2.5m.
• To determine the best type of extraction method that can be used for creosote extraction.
• To develop an extraction method that can extract creosote from wood poles at a length of 5.0m
• To determine the best type of extraction method that can be used for creosote extraction.
• To develop the extraction method further to enable a carbon recovery unit within the extraction loop.
• To create a disposal method where wood poles can be deemed as non-hazardous waste.
• To assess the commercial validity of the extraction method.

Problem(s)

Decarbonisation is a fundamental and complex challenge for any business looking to achieve a goal of net zero, a goal National Grid have set to achieve by 2028. Creosote, a preservative used in wood poles that support overhead lines on National Grids, other DNOs and BTs network, is a carbonaceous material which when disposed of can only be done in a facility in South Yorkshire, through an incendiary process as the poles are treated as hazardous waste. This accounts for roughly 10% of National Grids’ redundant poles. The other 90% is left on landowners’ property. However, environmental restrictions and legislation is beginning to become more stringent and it is apparent that the activity of leaving poles for landowners is becoming less feasible and a restrictive method of disposing of redundant wood poles.

Method(s)

The project will compromise of 4 Work Packages.

• The first work package will involve procurement of the extraction system, test equipment and preparation of the test area before the extraction methods can be tested.
• Work package 2 will involve testing the extraction system on a wood pole cut to 2.5 metres in length. This work package will test multiple methods of extracting the creosote. The best method identified will be taken on in work package 3.
• Work package 3 will involve modification to the extraction unit so that it can be used for a 5 metre wood pole.
• Work package 4 will aim to test methods of recycling the generated CO₂. This will be after a go/no go stage due to possible high financial costs associated that can only be confirmed closer to the time. Upon closure of the project, an assessment will be made to deduce its commercial validity.

• Scope

  Across all four license areas National Grid Electricity Distribution currently has 1,377,000 treated wood poles facilitating the electricity distribution network. Annually 27,000 of these poles are replaced with redundant poles either being left for landowners or returned back to the local depot site.  Poles which are returned to depot account for approximately 10% of the total poles replaced, therefore currently 90% are being left on site for landowners. As environmental restrictions and legislation become more stringent it is apparent that the activity of leaving poles for landowners is becoming less feasible and a restrictive method of disposing of redundant wood poles.

  Due to their creosote content, all returned redundant poles must be disposed of as hazardous waste and historically have been disposed of to landfill. The redundant poles cannot be reused nor can they be ‘donated’ in bulk to other organisations. Since 2014, and in line with the waste hierarchy, the poles have been taken to a waste to energy incinerator facility in South Yorkshire for disposal, the only facility in the UK licensed to incinerate treated wood.

  In 2016/17 National Grid spent £253,320 on the disposal of returned poles at the South Yorkshire facility, and the most current disposal figures, between November 2019 and October 2020, shows 840 tonnes of treated poles were sent for incineration at a cost of £185k. National Grid is reliant on the continued operation of the South Yorkshire site to accept and dispose of all treated waste poles (currently only approximately 10% of all replaced wood poles), the volume of which is likely to increase in the near future as stated above.

  The project’s main non-financial benefit will be creating a new and commercial method of disposing of creosote impregnated wood poles. This new method will significantly reduce the carbon emissions compared to the current incineration process. This method will create a new pathway for wood pole disposal and will also avoid any impact on the business if changes in legislation are made in the future. If the wood poles are deemed non-hazardous waste, they will be able to be re purposed, such as being donated to charities and being used for playgrounds and parks. This project will make a major contribution in meeting National Grid Electricity Distribution's target of a net zero business by 2028.

• Success criteria

  The success criteria for the project include:

  • Extraction tests carried out for a 2.5m pole.
  • Identification of best extraction method.
  • Extraction tests carried out for a 5m pole.
  • An assessment will be carried out on the commercial validity of the system.
  • Creating a method that can deem poles that have had creosote extracted from them as non-hazardous waste.
• Potential for new learning

  The learning from the project will be contained in work package reports, capturing all relevant details about the work undertaken in the corresponding work stream. It is also expected that dissemination will be carried out through presenting learning at the environment committee, the first of which will be in Q1 of 2022. The expectations on the learning will be details of how exactly the extraction system works.

• Documents and links

  Project Registration and PEA document

  Annual Progress Report 2022 

  Six Monthly Project Progress Report - November 2021 - April 2022

  Extraction System Report - November 2022

  D2.2 Pole Extraction Test Methodology - November 2022

  D2.1 Baseline Analysis of Untreated Poles 

  D1.1 Servicing Calibration and Installation of Analytical Equipment 

• Monthly updates

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