There is a youtube video describing the data that is sent by smart meters. While it is not clear exactly how much data is transfered, it seems to be quite a bit, it changes channels every half second and the content appeared to be fairly dense hexadecimal encoded data.
The video appears to be based in America, and he went to fairly long and legally questionable lengths to decode this data. As someone who lives under the jurisdiction of the GDPR my first thought is that one should be able to request all this data under Article 15 of the GDPR. From a google, the UK govenment appears to think the GDPR applies to this data at least in regard to giving it to a third party:
As noted above, a number of routes are available to consumers in terms of being able to access their own energy consumption data. This would then enable them to pass it directly to third parties, should they wish to do so. Additionally, the new data protection regime provides consumers with a right to ‘data portability’, which could [17] apply to energy consumption data and would enable consumers to request the transfer of their data to third party organisations.
[17] The extent to which the right to data portability afforded under the GDPR applies will depend on the manner in which the energy consumption data was collected and the legal basis under which processing was conducted. The right to data portability is additionally limited to data ‘provided to the data controller’ and would not extend to any analysis conducted on the raw data. Further information on the right to data portability is available here: https://ico.org.uk/for-organisations/guide-to-the-general-data-protection-regulation-gdpr/individual-rights/right-todata-portability/ [dead link but similar to this] https://ico.org.uk/for-organisations/uk-gdpr-guidance-and-resources/individual-rights/individual-rights/right-to-data-portability/
This is not clear to me how ones right of access under Art 15 is limited by the manner of data collection or the legal basis under which processing was conducted, unlike for example Art. 14 Art. 15 has no explicit exceptions.
Is a smart meter company obligated to provide all data transmitted by a smart meter if requested under Article 15 of the GDPR? The primary use cases of this data would be analysis of ones energy consumption with an eye to reducing it and being aware of potential security implications with the data transferred.