The Green Button is …
Dynamic pricing is coming. Many of you are already under some kind of time of use billing basis with your power provider. Energy management, in its essence, is trading off the comfort of the occupants for the cost of energy. With dynamic pricing, a time-relative determinant of pricing will now become part of the calculus of how to make these tradeoffs.
The building controls industry has long relied on sub-optimal means of acquiring the needed actual energy usage of a facility for this purpose. Typically pulse meters are tapped to gain at least some measure of usage. Some utilities have begun to make available detailed usage from time of use meters on various bases.
Enter the Green Button. This initiative (see related news release, http://www.whitehouse.gov/administration/eop/ostp/pressroom/03222012), establishes a standardized format for the exchange of measurement data within the home, commercial, and industrial facilities. The Green Button originated with a White House “call to action”. However, Green Button is the result of a remarkable process of voluntary industry collaboration and adoption among stakeholders with only the facilitation by the White House Office of Science and Technology Policy (OSTP), the Department of Energy (DOE), and the National Institute of Standards (NIST) and their creation the Smart Grid Interoperability Panel (SGIP). The latter is a group of some several hundred stakeholder organizations that have come together to coordinate the development and deployment of standards on behalf of the Smart Grid.
The Green Button is three things primarily:
- It is a US government Policy initiative designed to inspire an ecosystem in the generation and consumption of Energy Usage Information (EUI) in the marketplace,
- It is a “Brand” that allows a recognition of the availability of this ecosystem and what is for and can do for the consumer,
- And, last but not least it is a collection of technologies that allow for the implementation of interoperating products and services. This includes standards, testing and certification, and reference open-source implementations.
The balance of this article will present some of the concepts and status of the Green Button.
What it’s for
The following figure illustrates the scope of the Green Button. Shown is the collaboration between customers owned devices from cell phones to thermostats, and, full-fledged energy management systems to utility meters and Web-portals.
The figure illustrates the three principal components of the Green Button data – usage profile which is a time delimited set of interval data; overall usage which are summary measurements of power and energy; and, cost attribution of the usage.
Green Button is implemented initially by the exchange of files that are formatted in XML according to the Green Button data format. It will be extended to fully automated exchanges from application to application as it builds in the marketplace.
Users of the EUI data exchanged by the Green Button collaborators can interpret this data and provide for:
Insight: entrepreneur-created web portals analyze energy usage and provide actionable tips;
Heating and Cooling: customized heating and cooling activities for savings and comfort;
Education: community and student energy efficiency competitions;
Retrofits: improved decision-support tools to facilitate energy efficiency retrofits;
Verification: measurement of energy efficiency investments;
Real Estate: provide energy costs for tenants and/or new home purchasers; and
Solar: optimize the size and cost-effectiveness of rooftop solar panels.
What it has
The figure below illustrates the composition of Green Button data. At the top of the data hierarchy is the UsagePoint. As you would guess, this is the point of usage for which Green Button data is provided. Probably the most important UsagePoint is at the service entrance represented by the revenue meter. However, additionally interesting UsagePoints will be inside the facility including submeters, subsystems such as chillers, all the way to specific devices or appliances such as large or even small loads.
The heart of the data measurements is the MeterReading. A UsagePoint can have zero or more MeterReadings each one of which can represent a unique kind of measurement – for example power (kW) or energy (kWh), or, voltage or temperature for that matter. The MeterReading is characterized by its ReadingType and is quantified by one or more IntervalReadings which contain measurement values, timestamps, and optionally cost attribution. IntervalReadings, themselves, are grouped into IntervalBlocks which help organize groups of readings into daily or monthly periods as desired. ReadingQuality allows tagging of specific readings with exceptional events such as power failures, estimations for missing measurements, etc…
Finally, the UsagePoint can carry two dashboards of summary information for the period. The ElectricPowerSummary contains summary information for a billing period. The ElectricPowerQualtiySummary contains some summary statistics on the nature of the power quality during the billing period.
So all in all, this data structure can be seen to be quite flexible at describing both current energy determinants, as well as, any number of other relevant measurements of interest to the facility owner.
Who is doing it
Initial utility exposition of Green Button data provides the basics – hourly load profile electric energy consumption. Other data will be evolving as experience and need dictate. Suffice it to say that the Green Button standard supports the present and future expectations of its usage.
Since its announcement in September of 2011, three major electric utilities announced support for Green Button and committed and successfully completed implementation within a 90 day goal. These were Pacific Gas & Electric Company, Southern California Edison, and San Diego Gas & Electric to provide the capability to millions households in 2012. Additionally, Oncor, Pepco Holdings Inc., Glendale Water and Power took up the challenge to release early in 2012. Most recently, the American Electric Power, Austin Energy, Baltimore Gas and Electric, Commonwealth Edison, NSTAR, PECO, Reliant, & Virginia Dominion Power have announced support.
In addition, the following suppliers to utilities and consuming product developers have begun to release products and services around the Green Button: Aclara, Tendril, Itron, OPower, Oracle, Silver Spring Networks, Belkin, Efficiency 2.0, EnergySavvy, FirstFuel, Honest Buildings, Lucid, Plotwatt, Schneider-Electric, Simple Energy, and Sunrun.
I will mention at this point that the apparent overnight success of the Green Button initiative was actually achieved through a multi-year effort at standardization and requirements gathering. Started as early as 2005, the UCA International User’s Group (UCAIug) embarked on an effort to develop requirements for standards around the customer interface to the Smart Grid. Today, the following organizations are pursuing the evolution and ongoing support of these activities around Green Button:
Standards — http://www.naesb.org/ESPI_Standards.asp
The Energy Service Provider Interface (ESPI) is the key underlying standard that defines the Green Button data format. Additionally, ESPI defines the orchestration of messaging for the dynamic exchange of Green Button data between “Data Custodians” (i.e. utilities) and “third parties”. The “file” exchange between Utilities and Retail Customers directly does not require this orchestration, but uses the standardize data format only.
User’s Group — http://osgug.ucaiug.org/sgsystems/OpenADE/default.aspx
Open Automated Data Exchange (OpenADE) is the requirements activity that fed the original standards development as well as the current evolution of testing and certification specifications for Green Button.
Open Source – http://www.openespi.org/
Open source implementations underway will provide a ready reference and starting point for implementations of Green Button sources and sinks.
SGIP Collaboration — http://collaborate.nist.gov/twiki-sggrid/bin/view/SmartGrid/GreenButtonInitiative
The NIST sponsored SGIP provides for the cooperative coordination of the various specification activities surrounding Green Button technology.
You can find additional details on how to get involved on the Green Button data Web site at http://www.greenbuttondata.org.