Hello @hvanderweijde Interesting. Some responses and recent references follow.
Unfortunately I cannot say much but there will be a significant report on open electricity data made public in early September 2018 which should cover a number of the points you raise.
Smart metered data from households almost certainly classifies as personal information under the GDPR. In which case, the Right to Data Portability (RtDP) (GDPR article.20) also applies. Spatially aggregated smart meter data should not present privacy issues but, as you indicate, may well be politically difficult to obtain. For many modeling purposes, distribution transformer logs should suffice together with suitable downscaling techniques.
Data standards can be specific or general. See here for an emerging energy sector metadata standard. There is also work underway to develop an energy sector ontology (systematized knowledge) being led by @ludwig.huelk
Not sure I agree with your impressions regarding proprietary versus open source support. My experiences in relation to open source support are favorable (for instance, I recently got an unsolicited personal introduction to the lead designer of Julia).
Regarding model longevity, I think open source has much to offer here. Besides some long established closed models are going open incrementally, with one example being MESSAGEix.
In terms of meeting in London, I am sure the openmod community would like to develop better contacts with UK researchers (currently mostly limited to ICL). You might well consider hosting an openmod workshop in due course?
References
European Commission (December 2017). Legal opinion: legal aspects of European energy data — Output 2 of the “Study on the quality of electricity market data”. Brussels, Belgium: European Commission.
Hirth, Lion, Jonathan Mühlenpfordt, and Marisa Bulkeley (1 September 2018). “The ENTSO-E Transparency Platform: a review of Europe’s most ambitious electricity data platform”. Applied Energy. 225: 1054–1067. ISSN 0306-2619. doi:10.1016/j.apenergy.2018.04.048. Creative Commons CC-BY-4.0 license.
Postscript
Just to comment on your “increasingly be legally owned by the consumer” remark for household metered data. As far as I am aware, there is no legal ownership in such datasets. The GDPR is very intentionally formulated under human rights and not property rights doctrines. Nor is such data is covered by any intellectual property right. It is not authored, so copyright does not apply. It is a spin-off from provision and billing, so a database right does not apply. It has no competitive value to the householder (who is not engaged in commerce in any case) and therefore does not class as a trade secret. I am not aware of any special legislation in the United Kingdom that grants property rights to household electricity data. Or am I missing something? Google suggests not.