Stem’s virtual power plants take heat off Californian grid

By John Parnell
LinkedIn
Twitter
Reddit
Facebook
Email
The CAISO control room in Folsom. Image: CAISO.

Stem’s virtual power plants (VPPs) have been utilised to provide emergency demand response services in California during a major heatwave.

The networks, installed at a number of locations throughout the state, were used to meet increasing demand from air conditioning. The anticipated weather event created a spike in day ahead wholesale prices on 19 June, and a need to reduce demand or increase supply.

The services were provided to the California System Independent System Operator (CAISO) and three utilities.

“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.”

This article requires Premium SubscriptionBasic (FREE) Subscription

Try Premium for just $1

  • Full premium access for the first month at only $1
  • Converts to an annual rate after 30 days unless cancelled
  • Cancel anytime during the trial period

Premium Benefits

  • Expert industry analysis and interviews
  • Digital access to PV Tech Power journal
  • Exclusive event discounts

Or get the full Premium subscription right away

Or continue reading this article for free

On June 20, Stem provided power to seven strained areas of the network. The aggregated assets dispatched 1.6MW of power within five minutes. During the rest of the week, there were a further 10 dispatches as the heat wave, and its impact on the grid continued.

In California, Stem uses the CAISO Proxy Demand Response (PDR) mechanism to aggregate distributed energy generators, and has been an active participant in the wholesale market over the last three years.

15 September 2026
San Diego, USA
You can expect to meet and network with all the key industry players again in 2025 from major US asset owners, operators, RTOs and ISOs, optimizers, software and analytics providers, technical consultancies, O&M technology providers and more.

Read Next

May 12, 2026
US sodium-ion (Na-ion) battery startup Alsym Energy and California-based renewables developer Juniper Energy have announced a 500MWh strategic partnership.
Premium
May 11, 2026
The US clean energy manufacturing industry is starting to undergo a wholesale restructuring and recapitalisation as companies look to reduce their exposure to numerous risks, including FEOC. 
May 11, 2026
Energy storage developer and system integrator Energy Vault has released its Q1 2026 financial results, showing expansion in its project portfolio, AI infrastructure activities, and operations in Australia and Japan.
May 11, 2026
South Korean-owned company Qcells, part of the Hanwha Group, has introduced its first domestically assembled residential battery energy storage system (BESS) to the US market.
May 8, 2026
Denmark-headquartered independent power producer (IPP) Ørsted has purchased a 150MW battery energy storage system (BESS) in Michigan, US, from developer ESA Solar Energy.