{
  "url": "https://openlegislation.uk/eu-regulation-2012-601/annex-IV/division-8/division-B/division-2",
  "json_url": "https://openlegislation.uk/eu-regulation-2012-601/annex-IV/division-8/division-B/division-2.json",
  "legislation": "eur/2012/601",
  "legislation_title": "Commission Regulation (EU) No 601/2012 of 21 June 2012 on the monitoring and reporting of greenhouse gas emissions pursuant to Directive 2003/87/EC of the European Parliament and of the Council (Text with EEA relevance) (repealed)",
  "legislation_url": "https://openlegislation.uk/eu-regulation-2012-601",
  "path": "annex/IV/division/8/division/B/division/2",
  "kind": "division",
  "number": "Calculation Method B —",
  "heading": "Overvoltage Method",
  "text": "Where the anode effect overvoltage is measured, the operator shall use the following equations for the determination of PFC emissions:\nCF4 emissions [t] = OVC × (AEO/CE) × PrAl × 0,001\nC2F6 emissions [t] = CF4 emissions × FC2F6\nWhere:\nOVC Overvoltage coefficient (‘emission factor’) expressed as kg CF4 per tonne of aluminium produced per mV overvoltage;\nAEO Anode effect overvoltage per cell [mV] determined as the integral of (time × voltage above the target voltage) divided by the time (duration) of data collection;\nCE Average current efficiency of aluminium production [%];\nPrAl Annual production of primary Aluminium [t];\nFC2F6 Weight fraction of C2F6 (t C2F6/t CF4);\nThe term AEO/CE (Anode effect overvoltage/current efficiency) expresses the time-integrated average anode effect overvoltage [mV overvoltage] per average current efficiency [%].\nEmission factor The emission factor for CF4 (‘overvoltage coefficient’ OVC) shall express the amount [kg] of CF4 emitted per tonne of aluminium produced per millivolt overvoltage [mV]. The emission factor of C2F6 (weight fraction FC2F6) shall express the amount [t] of C2F6 emitted proportionate to the amount [t] of CF4 emitted.\nTier 1 The operator shall apply technology-specific emission factors from Table 2 of this section of Annex IV.\nTier 2 The operator shall use installation-specific emission factors for CF4 [(kg CF4/t Al)/(mV)] and C2F6 [t C2F6/t CF4] established through continuous or intermittent field measurements. For the determination of those emission factors, the operator shall use the most recent version of the guidance mentioned under tier 3 of section 4.4.2.4 of the 2006 IPCC Guidelines. The operator shall determine the emission factors with a maximum uncertainty of ± 15 % each.\nThe operator shall determine the emission factors at least every three years or earlier where necessary due to relevant changes at the installation. Relevant changes shall include a change in the distribution of anode effect duration or a change in the control algorithm affecting the mix of the types of anode effects or the nature of the anode effect termination routine.\nTable 2:\nTechnology-specific emission factors related to overvoltage activity data\nTechnology\nEmission factor for CF4[(kg CF4/t Al)/mV]\nEmission factor for C2F6[t C2F6/t CF4]\nCentre Worked Prebake (CWPB)\n1,16\n0,121\nVertical Stud Søderberg (VSS)\nN.A.\n0,053",
  "extent": "E+W+S+N.I.",
  "status": null,
  "version": "current",
  "annotations": [],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/eur/2012/601/annex/IV/division/8/division/B/division/2",
    "retrieved_at": "2026-11-01T14:49:20.227833+00:00"
  },
  "licence": "Open Government Licence v3.0",
  "licence_url": "https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/",
  "attribution": "Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives."
}