Stem Energy Storage Network Delivers Emergency Grid Relief in California Heat

June 28, 2017

Stem Energy Storage Network Delivers Emergency Grid Relief in California Heat

Stem repeatedly over-delivers committed demand reductions for the state grid during heat wave

MILLBRAE, California. — June 26, 2017Stem Inc. activated several of its virtual power plants, networks of energy storage systems located at business and institutions throughout the state, multiple times during an unprecedented heat wave last week, automatically dispatching stored energy to provide emergency Demand Response services to the California System Independent System Operator (CAISO) and three major utilities.

As a major heat wave approached California on June 19, 2017, energy prices in the day-ahead wholesale market rose significantly, signaling a need for resources that could act quickly to increase energy supply or reduce demand in order to prevent widespread blackouts. Having regularly offered stored energy from its network into the CAISO markets since 2015, Stem’s latest bids started to clear.

Stem first committed to reduce energy demand for Pacific Gas & Electric (PG&E) and Southern California Edison at 5 pm PT on June 20 through the Day-Ahead settlement process the night before. Then at 5:15 pm on June 20, while already dispatching in four areas within the PG&E and SCE service territories, additional Stem offers to provide energy with less than five minutes notice were accepted further south in three parts of San Diego Gas & Electric’s (SDG&E) service territory. Stem stepped up, dispatching energy storage systems at customer locations across seven utility zones to deliver on-time and more than promised.

In this one hour, Stem delivered stored energy from its customer network to seven strained areas of the CA grid simultaneously at the height of an unprecedented heat wave. Acting as virtual power plants, aggregations within the Stem network automatically responded to rising wholesale prices in as little as five minutes to dispatch 1.6 MW of targeted relief, 21% more than committed. Stem’s network similarly dispatched fast, on-demand power 10 more times across the three utilities’ service territories in the remainder of the week as the heat continued.

“Stem proves again and again that we can step up immediately and deliver, right when the state or utility needs help,” said John Carrington, CEO of Stem. “When we are called, our network responds in minutes or less.”

In California, Stem uses the CAISO Proxy Demand Response (PDR) mechanism to aggregate DERs, and has been a very active participant in their wholesale market over the last three years. CAISO prices have cleared higher than the bids of storage-based demand response providers more frequently than expected in 2017. For example, Stem’s network responded to 150 “real-time,” or five-minute dispatch events for SDG&E from January to May of 2017. Stem is the leader in bidding aggregated distributed energy resources (DERs) into wholesale markets in California and across the U.S.

Stem Inc., the global leader in commercial-scale intelligent energy storage services, provides storage-as-a-service to commercial and institutional customers and is backed by the industry’s largest project finance pool at $350 million. Stem delivers predictive analytics software to get real-time and future usage and cost data for customers to improve overall efficiency. Customers pay a monthly subscription fee and on average save two to three times what they pay for the service. Reducing commercial peak demand helps improve local grid stability and distribution energy planning.

About Stem, Inc.
Stem creates innovative technology services that transform the way energy is distributed and consumed. The company’s mission is to build and operate the largest digitally connected energy storage network for our customers. Our world class analytics optimize the value of customer’s energy assets and facilitate their participation in energy markets, yielding economic and societal benefits while decarbonizing the grid. Headquartered in Millbrae, California, Stem is funded by a consortium of leading investors including Angeleno Group, Iberdrola (Inversiones Financieras Perseo) GE Ventures, Constellation Technology Ventures, Total Energy Ventures, Mitsui & Co. LTD., RWE Supply & Trading, and Mithril Capital Management. Visit for more information.


Media Contacts
Josh Garrett
Antenna Group for Stem, Inc.