1 / 14

Shrinkage Forum 04 June 2013

Shrinkage Forum 04 June 2013. Roy Malin. Best Practice - Areas of Inconsistency. Licence Obligations – Shrinkage and Leakage Model. DNs have a Licence obligation to maintain a Shrinkage and Leakage Model The inclusion of Shrinkage is a new addition for the RIIO price control period

giacomo-allen
Download Presentation

Shrinkage Forum 04 June 2013

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Shrinkage Forum 04 June 2013 Roy Malin

  2. Best Practice - Areas of Inconsistency

  3. Licence Obligations – Shrinkage and Leakage Model • DNs have a Licence obligation to maintain a Shrinkage and Leakage Model • The inclusion of Shrinkage is a new addition for the RIIO price control period • Need to expand current model to include Theft of Gas (ToG) and Own Use Gas (OUG) • Propose that the current ToG and OUG processes are adopted into the Shrinkage and Leakage Model • Propose that this be done alongside the proposed Low Pressure Service Model changes

  4. Low Pressure Service Model Modification • In February 2012, National Grid published a consultation on a proposed revision to the Leakage Model in respect of the calculation of leakage from low pressure services • For leakage estimation purposes, services are split into four categories: Steel Service to Metallic Main, PE Service to Metallic Main, Steel Service to PE Main and PE service to PE main. • 2002/03 National Leakage Tests established that only service connections to metallic mains leak • Establish a new ‘baseline’ estimate of the number of services in each of the categories (using mains replacement data) • Update model to capture the impact on leakage of service transfers (model previously updated to capture the impact of service relays)

  5. Impact of LP ServiceModel Change • Impact is consistent with that already published for 2013/14 Initial Shrinkage Proposals • Establish a new ‘baseline’ estimate of the number of services • The RIIO Shrinkage and Leakage Baselines based on v1.3 Model • Impact determined by comparing the 2010/11 v1.3 Model output with that from the revised model for the same year • Impact will be the same for each year of the RIIO Price Control Period • Inclusion of Service Transfers • Average no transfers/km x anticipated mains replacement length x leakage rate • Impact will be cumulative from 2011/12 and over the RIIO Period • Change has no significant impact on incentives for DNs: • Re-baseline to 2010/11 - Baselines and Actual quantities will adjust by the same amount • Service Transfers – Baseline will be adjusted by an amount based on average transfer workload, whereas Actual quantity will be based actual transfer workload

  6. Impact of Model Change – Re-baseline 2010/11

  7. Impact of Model Change – Service Transfers

  8. Impact of Model Change – Combined (GWh)

  9. AGI Venting - Current Model • Current Methodology • ‘Fixed’ values based on a 1994 Watt Committee report • National estimate • Derivation unknown • National value apportioned across LDZs at time of Network Sale • Approximately 5% of over all emissions

  10. AGI Venting - Background • Two routinely venting components • Positioners • Controllers • Venting occurs both in steady state and during control actions • Each AGI usually has a number of Positioners and Controllers • Positioners and Controllers originally designed to work with compressed air but modified to work with gas, as readily available on site.

  11. AGI Venting - Proposal • Proposed Methodology • ‘Activity’ based estimation • Based on number of Positioners and Controllers • Estimate of Steady-state Venting • Manufacturers Data • Estimate of Operational Venting

  12. AGI Venting – IFI Project • Key deliverables • Verify Manufacturers Data • Establish relationship between venting rate and control system operating pressure for steady-state venting • Identify levels of venting in operation • Investigate the potential to relate operational venting to telemetered flow and pressure data • The viability of this will be assessed when data is available

  13. AGI Venting – Verification Manufacturers Data • Bristol Babcock Controller • 0.05cfm @ 20 PSI • Verified by lab tests • Linear relationship between control pressure and venting • Fisher Positioner • 0.3cfm @ 100 PSI • Verified by lab tests • Linear relationship between control pressure and venting

  14. AGI Venting – Next Steps • End of July – Complete IFI Work • August – Complete inventory of existing equipment • September – Issue Consultation on AGI Venting • October – Report on Consultation issued to Ofgem • December – Ofgem decision (in time for 2014/15 Shrinkage Proposals)

More Related