Add National Grid Support to Opower Integration

National Grid is using Opower, and it’d be great to have the electric and gas usage data available in Home Assistant. They also recently started rolling out “smart meters” which provide users with “near” real-time electric usage data (usage data is available in 15-minute chunks/intervals), so it’d be nice if that could populate the energy dashboard in HA.

I’m happy to help contribute however I can or help with testing. I looked into the Opower integration code to see if it’s something I could potentially add myself, but I couldn’t see how the auth actually works for the different utility companies.