That omission is interesting. Michael Taylor from IRENA, based in Bonn (but originally from Australia), spoke at the Open Power System Data (OPSD) workshop on 21 November 2016 in Berlin, Germany. IIRC, he noted that his views were personal not official, but he was very supportive of open models and open data. Perhaps you could write to him or alternatively, contact him before drafting your letter. Not only is it open models that need coverage, it is open data too.
Regarding the question of writing on openmod issues. Do we need some process for endorsement by the openmod community. Long ago, I worked with a New Zealand NGO called the Sustainable Energy Forum (SEF) and they had some quite good protocols for developing letters, press releases, and submissions that were sent out under their name. Do we need something similar?