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Note that this is enabled by Iceland implementing the RES Directive on 8 July for entry into force on 1st September. The EEA Standing Committee of the EFTA States has confirmed that Directive 2001/77/EC entered into force in Iceland on 31st July 2006 (see http://secretariat.efta.int/Web/EuropeanEconomicArea/EEAAgreement/listofjcds/list2005.pdf, item 102 (pp 46) for 2005).
Relevant Legislation
Letter appointing Statnett as GoO Issuing Body (Norwegian)
Letter appointing Statnett as GoO Issuing Body (English)
Information about GoO implementation in Norway
EEA Agreement
EEA Agreement - Annex 4: Energy
Lists of adopted Joint Committee Decisions
Norway is in the process of modifying the Energy Act; this modification will be approved by the Parliament this spring. The "new" Energy Act, will be unfortunately only in Norwegian this time. The new clause handling GoOs (opprinnelsesgarantier in Norwegian) is § 4-3 (below), which says that the "party responsible for settlement (Statnett) also have the duty of issuing Guarantees of Origin" - more or less the same text as in the letter from the Ministry.
§ 4-3 nytt fjerde ledd skal lyde:

Den avregningsansvarlige som nevnt i annet ledd plikter å utstede opprinnelsesgarantier (GoO) etter anmodning fra berettigede produsenter av elektrisk energi. Departementet gir forskrifter om utforming og gjennomføring av ordningen med opprinnelsesgarantier, herunder om berettiget produksjon, utstedelse av og innhold i opprinnelsesgarantier, gebyr for utstedelse, rapportering og kontroll mv.

"New" Energy Act