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Designing Consumer Metrics for Grid-Connected Devices

A couple walks into a local big box store, looking for a new water heater to replace their existing unit. Within the large appliances section, they are confronted with multiple options. Should they choose a traditional electric resistance model or a more capable but more expensive heat pump? How do they translate their “wish list” of features and capabilities into a brand and model to buy? What about incentives? Overwhelmed by the options and thoroughly confused by misleading google searches, the couple picks a unit randomly.

This scenario is unfortunately too familiar in the rapidly-changing marketplace of grid-connected devices. Less than 1% of all devices have real-time grid information, thereby limiting their value to the utility or the customer. The real-time availability of price signals, as well as the timeliness and accuracy of such signals, determines the device’s value.

The smart grid consumer device market is still quite new, and independent consumer-centric metrics do not yet exist. However, as device capabilities and offerings expand, the need for these metrics increases. Independent consumer metrics can help customers more meaningfully evaluate options, as well as help accelerate market acceptance and scale.

The promise of the smart home

Don’t reinvent the wheel
One tried and true method for addressing this need stems from car magazine new vehicle test reviews. These articles typically contain standardized, industry-accepted objective and subjective metrics to help guide new car shoppers in their purchasing decisions. Examples of objective metrics for vehicles can include 0-60 mph and quarter mile times, 60-0mph braking distances, estimated EPA mpg, interior noise dBA levels at highway speed, etc.

Subjective notes from magazine editors can characterize steering crispness, braking feel, or styling cues of nostalgic nods to past models. Combined, the subjective and objective information helps readers identify, understand, and evaluate new products and buying preferences.

Providing value beyond consumers
When purchasing smart grid devices, consumers face a wide range of choices, each providing tradeoffs between functionality, performance, safety, aesthetics, sustainability and cost. In some cases, this equipment may introduce privacy or security risks. Furthermore, these devices need to interoperate with various communication networks and/or cloud services, potentially incurring additional costs. Consumer-centric metrics must incorporate all of these factors so that customers can understand the various tradeoffs.

The availability of vetted customer-centric metrics will also help vendors and grid operators analyze their products and programs, allowing them to develop more consumer-friendly offerings. These metrics can also serve as a basis for models to measure performance and as a foundation for regulators.

Categories of metrics 
In recognition of the need for consumer metrics, the Customer Grid Edge Working Group, convened by the Smart Electric Power Alliance (SEPA) has developed (below) an initial set of ten objective metrics and five subjective metric categories for consideration.

These high-level metrics will need further definition to match precise representative conditions or scenarios, including different geographic areas or regulatory environments. They will also need to be reevaluated over time to track evolving economic, environmental, regulatory, human behavior and technological factors, all of which can affect the end performance metrics of these systems.

Note: the working group determined that objective metrics should be repeatable and ideally quoted with their accuracy or error bars, or a range of likely values that are found upon repeated measurements.

All metrics would eventually map onto Red, Amber, Green.

Potential objective metric categories
Features Matrix: This could include individual device features such as comfort sliders where consumers can adjust between comfort and cost, capabilities to connect to demand response programs or respond to time-of-use rates, ancillary services that the technologies provides, emergency notifications, inputs for weather or other inputs for custom response.

Load flexibility (kWh): The flexibility in when the device uses energy and how much it uses.

Environmental impact: This could include measures for CO2 impact and measuring air quality, such as particulates per unit volume (cars sold in Europe have this label).

Financial impact:
For customers this could include:

    • Monthly saving based on use profile
    • Possible household insurance discounts

For utilities this could include:

    • Capital savings by cost avoidance or deferment of infrastructure upgrades
    • Operating costs/savings

Reliability: Mean time between failures (MTBF) in normal and emergency situations.

Integration: Interoperability & compatibility with standards, as well as with other devices and systems (to avoid susceptibility to other devices or systems).

Adaption: Time & actions required to adapt to changes in

    • New appliances
    • Infrastructure
    • Energy sources
    • Regulatory & economic factors

Privacy and security: This could include measures on likelihood of a private information breach (companies currently have ratings for this metric) and time to detect and recover from a breach.

Flexibility for customer preferences: Customer can select priorities for

    • Comfort
    • Environmental impact
    • Cost savings
    • Convenience
    • Control

Other established metrics: (EPA energy star, etc.)

Potential subjective metric categories

    • Value for money (opinion of tester)
    • Ease of installation and use
    • Effectiveness on stated performance goals of product/services
    • Overall rating & impressions
    • Other

The path forward
Greater penetration, adoption, and optimal use of smart grid systems will reduce carbon and other emissions, provide value to utilities and end use customers, increase energy resilience and reliability, and improve customer comfort and convenience. In order to achieve these goals and fulfill the promises of the smart connected grid, consumers, grid operators, regulatory agencies, and vendors need established and well-vetted metrics to evaluate and report on the performance of smart grid systems.

The promise of the smart grid

As the industry continues to innovate and new demand response technologies roll off the manufacturing line, SEPA envisions a future where customers can review these metrics at the point of sale. Manufacturers, solution providers, regulators, third-party reviewers, and other energy stakeholders will need to collaborate to build out, validate, standardize, and implement these metrics for the mass market.

SEPA foresees four future scenarios for building out this important capability. First, established organizations with qualified metrics and credibility, such as EnergyStar, could adopt smart grid consumer metrics. Second, a new organization could be created to provide these services. Third, solution providers and vendors seeking to differentiate their products could set a new standard for informing customers, and lead in the development of metrics. Fourth, third-party reviewers, such as Consumer Reports, could establish their own assessment criteria to inform consumers, particularly for subjective metrics.

However, the right home for these metrics may vary. For example, security companies could potentially derive the privacy and security scores. Organizations that measure and track CO2 and other particulate emissions, such as the U.S. EPA, could potentially score the CO2 impact. Utilities could provide data to support metrics on demand response program interoperability. Additionally, the inputs to these metrics may be derived directly from technology manufacturers or independently validated and/or tested.

The path forward will likely involve a combination of all these options. Ultimately, consumers and vendors will benefit from widespread industry collaboration and consensus. Organizations such as SEPA and other industry forums, can help to refine the metrics, accelerate development and spur adoption.

This blog identifies and proposes 15 key categories of metrics that define technological, environmental, financial and subjective characteristics of grid-connected devices. SEPA’s Customer Grid Edge Working Group will continue to refine and socialize these proposed metrics.

If you are interested in getting involved, we encourage you to access or join the working group at For more information, contact [email protected]

About the Authors
Jackson Wang is President at e-Radio Inc.
Linda M. Zeger is Founder & Principal Consultant at Auroral LLC
Brenda Chew is a Senior Manager, Research at SEPA
Ben Ealey is the Principal, Grid Integration at SEPA.