Catalyst with Shayle Kann
Catalyst with Shayle Kann

Frontier Forum: How VPPs earn grid-scale trust [partner content]

Can a grid operator tell the difference between a virtual power plant and a traditional one? That’s the idea behind the Huels Test, a framework developed by EnergyHub to answer a simple but consequential question: when does a distributed fleet of customer devices become reliable enough to function l

Featured Speakers

Seth Frader-Thompson GuestStacey Phillips Guest

Topics Discussed

Episode Summary

Executive Summary: This Frontier Forum explores how virtual power plants (VPPs) are shifting from simple demand response into grid-critical infrastructure. Duke Energy and EnergyHub argue that connected customer devices—thermostats, batteries, EV chargers, and water heaters—can now be forecast, dispatched, and trusted like power plants, helping manage winter peaks, reduce costs, and support planning, operations, and decarbonization.

Main Topics: VPPs as grid infrastructure, not just peak response (Priority: 5/5): The discussion frames VPPs as a mature resource that can replace or defer peaker plants and increasingly participate in day-to-day grid operations, not just emergency events. Winter reliability and Duke Energy's demand management (Priority: 5/5): Duke describes extreme winter weather, record peaks, and massive crew mobilization, while simultaneously deploying flexible customer resources to reduce outage and supply stress. Trust, forecasting, and repeatability at scale (Priority: 5/5): A major theme is that VPPs have become more reliable through scale, telemetry, and better forecasting, making operators more willing to rely on them repeatedly. VPP maturity model and the Hewletts test (Priority: 4/5): EnergyHub presents a four-level maturity framework plus the Hewletts test, which asks whether an operator could distinguish a VPP from a conventional power plant. Utility planning and integrated resource plans (Priority: 5/5): Duke says customer resources are already embedded in IRPs and used to ‘shrink the challenge’ before centralized generation is planned, making them foundational to long-term planning. Customer value, friction, and affordability (Priority: 4/5): The speakers emphasize that programs succeed when customer participation is easy, repeatable, and valuable, because system benefits flow to all customers through avoided infrastructure and lower costs. Single pane of glass and operational integration (Priority: 4/5): Duke is working toward unified control software so operators can dispatch varied resources from one interface, a prerequisite for scaling from pilot programs to routine use.

Key Arguments: Scale improves reliability: with 160,000+ devices, Duke can statistically forecast output and tolerate some customer nonparticipation without losing grid value. Modern VPPs are more trustworthy because two-way data, IoT connectivity, and real-time telemetry let utilities measure and verify actual response instead of guessing after the fact. Customer resources are already a core planning input at Duke, helping planners reduce the amount of centralized generation and infrastructure they need to build. Batteries and EVs expand VPP usefulness beyond legacy one-way switches because they can respond more frequently and with less customer friction. The industry should shift from thinking about VPPs as occasional emergency assets to treating them as dispatchable, repeatable grid tools that can be used dozens or hundreds of times per year. The Hewletts test is meant to eliminate ambiguity for operators and regulators by setting a North Star: if a VPP behaves like a power plant, it should be treated like one. Level 4 VPPs go beyond power-plant equivalence by also solving distribution constraints, customer savings, and bulk-system needs simultaneously. Duke argues that software should follow deployment, not precede it; utilities can start with existing tools and improve integration over time rather than waiting for perfect systems. Customer participation and low friction matter as much as technology sophistication; programs that customers dislike will not scale or earn operator trust. Regulatory recognition is lagging technology, so the industry needs clearer frameworks and crediting mechanisms for different DER capabilities and durations.

Data Points: Crew mobilization: 18,000 crew members - Utility restoration response across Duke territories during the winter storm period Crew geographic coverage: 27 states, including Canada - External crews brought in to restore power in the Carolinas Flexible capacity deployed: 180 megawatts - EnergyHub says it deployed this much flexible capacity during recent winter events Thermostat-program capacity: 120 megawatts - Portion of deployed flexible capacity from a traditional thermostat program Duke customer device count: 160,000 devices - Seth cites the scale of Duke's participating devices as a source of reliability and forecastability Duke VPP winter capability: 2 gigawatts - Stacey says Duke has this much winter capability across all utilities Duke VPP summer capability: 2.5 gigawatts - Stacey says Duke has this much summer capability across all utilities Duke customer base: 1 million customers - Stacey says this many customers participate in Duke programs Battery program capacity: 45 megawatts - Duke says it built this battery program in 18 months Planned utility investment: $100 million - Duke expects to invest this over five years for data centers and advanced manufacturing support Program operating window change: 1 hour at a time - Duke says it reduced switch event duration to avoid customer complaints and attrition Legacy event duration: 3 to 4 hours - How long Duke historically ran one-way switch programs before shortening events Peak-use frequency: Dozens per year moving toward hundreds per year - How often repeatable VPP resources may be used operationally over time Integration timeline: 18 months - Time it took Duke to stand up the 45 MW battery program VPP maturity target for level 4: 5-year goal - Seth says level 4 widespread capability is closer to five years than ten Utilities served by EnergyHub: More than 160 utilities - Company description at the end of the episode

Pivotal Quotes: "What’s cool about VPPs is they are both a genuinely practical, effective resource that can replace a peaker power plant, but it’s also an opportunity for the sort of average customer to participate in a way." — Seth Frader-Thompson: On why VPPs matter both operationally and for customer participation "We use the customer resources to shrink the challenge." — Stacey Phillips: On how Duke’s planning process incorporates flexible demand before building centralized generation "They don’t want to see the difference. We need to deliver to them streamlined decision making." — Seth Frader-Thompson: On the Hewletts test and the need for operator-friendly integration

Implications: VPPs are moving into mainstream grid planning. Utilities that invest in telemetry, forecasting, and operator integration can use customer devices as dependable capacity, improve affordability, and reduce the need for peakers and upgrades.

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