I see the Green Button data standard on greenbuttondata.org. But I am trying to figure out which geographic regions have the standard ALREADY deployed.
The Department of Energy's Green Button website offers a list of companies who have implemented it:
The Green Button initiative was officially launched in January 2012. To date, a total of 35 utilities and electricity suppliers have signed on to the initiative. In total, these commitments ensure that 36 million homes and businesses will be able to securely access their own energy information in a standard format. This number will continue to grow as utilities nation-wide voluntarily make energy data more available to their customers in this common, machine-readable format.
The following utilities have already committed to Green Button: American Electric Power, Austin Energy, Baltimore Gas & Electric, CenterPoint Energy, Chattanooga EPB, Commonwealth Edison, Glendale Water and Power, National Grid, NSTAR, Oncor, Pacific Power, Pepco Holdings, PG&E, PECO, Portland General Electric, PPL Electric Utilities, Reliant, Rocky Mountain Power, SDG&E, Southern California Edison, TXU Energy, and Virginia Dominion Power.
... there is also a much more substantial list of companies who have have expressed interest in supporting it.
OpenEI from the National Renewable Energy Lab (NREL) maintains a list of both the utilities participating and a map as well as other Green Button apps.
Thank you Jeanne for providing an answer. I do want to point one thing out, the correct URL to visit in order to reach OpenEI's list is: http://en.openei.org/wiki/Green_Button#Participating_Green_Button_Utility_Providers
An alternate page view is: http://en.openei.org/wiki/List_of_Green_Button_Utility_Providers
This list was recently updated to include the most recent changes and additions. The status column identifies those that have implemented the Green Button from those that have committed. Utilities that have implemented also have a Green Button next to the name that will navigate users to the company's Green Button page when possible, or to the account login page in the event a user must be logged in to access that page.
It is important to note that the utility company names on OpenEI are derived from the EIA-861 form. In some cases these names may appear a bit different than those in the lists found on Energy.gov or greenbuttondata.org. This is in part because the official operating name may differ slightly from the publicly identifiable name. Also, there are instances where it may be because the individual subsidiaries are listed separately rather than by the parent holding company or corporation, such as with American Electric Power, Pacificorp and Pepco Holdings.
To address the other question here posted by Nick; the difference between Green Button Download My Data and Green Button Connect My Data is that download allows users to do just that, download their energy usage data in a standardized format. Connect My Data allows users to provide authenticated direct access by third parties, such as apps and developers, to their energy usage data. This access is set up for a determined period of time and the user retains the right to revoke access at any time. Downloaded data may still be used with most Green Button apps and services, as long as the user provides it for them.
Currently, utilities on the aforementioned list are not identified by the type of Green Button access they provide (Download, Connect or both). At the moment, Download is more commonly found than Connect. Stay tuned to OpenEI for updates, perhaps the type of data access will be provided in the future.