There are three separate issues here.
First of all, this is a very active forum and it often comes up near the top during general home automation searches on Google. But the forum is in fact for people who are using the Samsung SmartThings home automation platform. So all the answers you will get here will be in the context of that specific platform, which means the first thing that we need to ask is which SmartThings hub model you have and which SmartThings app you are using, because the features and options do vary somewhat from model to model.
If you don’t have a SmartThings hub, people will still try to help if they can, but you may get very few responses as that’s not really the context in which our discussions take place.
Second, the Zigbee Standard allows for the use of many different profiles, and they don’t all talk to each other. Since the specific feature you linked to mentions it works with the smart meter in the home, it’s very unlikely that it is using the profile that SmartThings uses. So you wouldn’t be able to get any direct integration with the SmartThings hub. 
Finally, SmartThings itself doesn’t have a HomeKit integration, so even if that particular device did work with HomeKit, it wouldn’t work with SmartThings. Again, placing it out of scope for this particular forum.
There is an unofficial method for getting some integration between SmartThings and HomeKit, but it requires using yet an additional device as a server and quite a bit of technical skill. So it might be able to help if you could connect the zigbee device to SmartThings, but since it’s the wrong zigbee profile, that’s not an option in this particular case.
Sorry we can’t be of more help. Your best bet is probably just to contact the utility company and ask them directly if they have any plans for HomeKit integration.