Depending on the stress of the grid, some #OhmHours are more demanding than others. Environmental #OhmHours are called when demand on the grid is not critical, but conservation can be helpful to the environment. You won't earn or lose any points for this type of #OhmHour, but saving energy could keep a dirty power plant turned off!
Do keep in mind, your streak will be broken if you consume more power than your forecast.
You'll always be informed if it's an Environmental #OhmHour in your #OhmHour text and email notifications, and after the event, you can see them appear on your dashboard like this:
That being said, these types of #OhmHours are rare and will not be called all the time. You will most likely get a normal #OhmHour with points for your next event.