Virtual power plant (VPP) platform profile
OATI: a utility DERMS that reaches wholesale markets
How OATI’s webSmartEnergy DERMS runs demand response and VPP programs for 225+ utilities, and why its grid and market software sets it apart.
VPP Economics has no affiliation with, sponsorship from, or endorsement by any utility, aggregator, platform, or device maker named here.
The short answer
- OATI is a DERMS provider with a much wider footprint. Open Access Technology International, founded in 1995 in Minnesota, sells the webSmartEnergy distributed energy resource management system (DERMS) to utilities, and also runs trading, transmission and market software used by every major North American grid operator (OATI).
- It is the most widely deployed utility DERMS by count. More than 225 utilities use it, including 11 of the 60 U.S. generation and transmission (G&T) cooperatives (PR Newswire); more than 150 cooperatives are on the platform (MinnPost).
- Its distinction is meters to markets. One platform handles program enrollment, event dispatch, baseline settlement, and virtual power plant (VPP) offers into day-ahead and real-time markets (OATI).
- It is mostly software, not an aggregator. The utility usually runs the program and decides dispatch; in Hawaii, OATI held the grid services contract itself, with Sunrun supplying about 1,000 home batteries for 4.3 MW (Utility Dive).
Where OATI fits
Highlighted boxes are the roles this company plays; the green bar shows where its programs sit from demand response to an orchestrated VPP.
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A mix of businesses, one data backbone
OATI is better known to grid operators than to the public. Its oldest products handle the plumbing of wholesale power: the Open Access Same-Time Information System (OASIS) that transmission owners use to sell transmission service, and electronic tags (e-Tags) that document each interchange transaction (OATI). NERC and WECC contract with OATI for the data services that reliability coordinators use to curtail transactions when lines overload (FERC). OATI also supplied scheduling and tagging systems for CAISO’s energy imbalance market and SPP’s western expansion (OATI).
It launched what it calls the industry’s first DERMS in 2009, with Kansas Power & Light, now Evergy (PR Newswire). It also builds microgrid controls under the GridMind name, which can island a site and make it schedulable through a DERMS (OATI). VPP Economics classifies OATI as a DERMS provider because that is how utilities buy it for grid flexibility programs; the market and transmission software is what lets the same platform reach wholesale markets.
What the DERMS does
OATI’s DERMS lets a utility define program rules, enroll customers and aggregators, validate eligibility, forecast load up to seven days ahead, call events, and settle performance with a configurable baseline engine (OATI). On the market side it takes day-ahead and real-time prices, builds VPP portfolios, forecasts their capability and submits offers (OATI).
Deployments span demand response at large investor-owned utilities and small cooperatives. San Diego Gas & Electric runs a demand response management system from OATI integrated with the CAISO market, including an aggregator portal (OATI). Turlock Irrigation District in California chose it for commercial load control and smart thermostats (APPA). Landis+Gyr resells it as Landis+Gyr DERMS, Powered by OATI, paired with its meters (Landis+Gyr).
Two OATI-run programs by device count
Enrolled or planned devices, as reported
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Cooperatives: one platform, many utilities
OATI’s strongest market is cooperatives, where a G&T buys power for many small distribution co-ops. Its multi-company design gives the G&T a system view while each co-op sees its own devices. Hoosier Energy administers its thermostat programs this way for 17 members (OATI). North Carolina Electric Membership Corporation uses OATI DERMS and GridMind across 26 co-ops to manage solar, batteries, demand response and islandable microgrids, and in February 2026 announced a move to real-time orchestration (PR Newswire).
In Hawaii, OATI won Hawaiian Electric’s first grid services purchase agreement, delivering capacity and fast frequency response from Sunrun home batteries (Utility Dive) and water heater controls from Resource Innovations’ Shifted Energy, about 2.5 MW (Resource Innovations).
What it means for program design
Count dependable kW, not devices
Company totals such as 10,000 MW of controllable load are capacity under command, not what a program delivers at an event.
Multi-company setups suit co-ops
A G&T can run one DERMS for many members, keeping each co-op’s view separate while settling centrally.
Integrate rather than replace
Device platforms and aggregators connect to the utility’s DERMS as sub-aggregators, as Sunrun and Shifted Energy did in Hawaii.
Method and caveats
Figures are company-reported, checked October 19, 2026. OATI’s own utility counts vary by page (225+ in its February 2026 release; 250+ on its DERMS page); this profile uses the lower figure. VPP Economics has no affiliation with OATI or any company mentioned.