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March 2017  •  Issue 8
The ISO is a nonprofit public benefit corporation that manages the bulk electric market, and the flow of electricity over the high-voltage, long-distance power lines for California and a small part of Nevada.

California’s energy grid continued to evolve in 2016. Besides successfully integrating more than 2,600 megawatts of new solar resources last year, the ISO completed a ground-breaking study that may eventually lead to better integration of these renewable resources and reduce the need to build new natural gas resources.

In 2016, the ISO experienced summer days of nearly constant solar peaks, with the highest output from solar power of 8,545 megawatts occurring on Sept. 14. We also saw a moment in May when renewable energy served 56 percent of our total demand.

Also last year, the ISO solidified the western Energy Imbalance Market (EIM) with new participants Arizona Public Service and Puget Sound Energy Electric, which you can read more about in this edition of Energy Matters. The EIM participants are experiencing significant benefits to costs and operating efficiencies and reliability. As of the end of 2016, participating utilities in the EIM realized a total of more than $142 million since its launch in November 2014. In addition, the ISO welcomed the news that more utilities are exploring participation or started the process to join the real-time energy market.

A significant highlight was completing a process to track and quantify greenhouse gas emissions from generation used to serve California’s consumers. This marks the first GHG tracking report from energy resources within ISO service territory. Our story below has more on this subject.

We also continued our commitment to ensure all interested stakeholders and members of the public have multiple ways to stay informed on the issues and news from the ISO — including by website, social media, mobile applications and individual stakeholder attention.

One last note, the ISO is continuing to assist the state leaders on creating a multi-state regional energy market that promises to provide significant cost savings while better using renewable resources. For more on efforts to create an expanded grid, see our July 2016 Energy Matters found here.

The stories below and this newsletter will help you keep track of how the ISO is shaping the energy grid to meet our renewable goals and to keep energy costs as low as possible. Thank you for reading.



Steve Berberich, President and CEO

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ISO study shows flexible renewables can balance grid


The ISO in collaboration with the National Renewable Energy Laboratory (NREL) and power plant owner First Solar has completed an extensive test of a solar photovoltaic generation facility that shows solar resources can provide essential grid services, including voltage support, just like traditional resources. The testing was conducted in August 2016 on a 300 megawatt First Solar plant to understand how fast it could react to real-world conditions, such as immediately supplying energy to manage the voltage and frequency of energy already on the system. This critical service is now supplied by traditional resources but with the buildout of solar under California’s ambitious energy policy, it is essential renewable resources can be relied upon to support grid reliability. The testing found that First Solar’s solar plant, equipped with enhanced inverters, performed with enough agility to provide grid support.

“These findings mean renewable energy in the ISO footprint — and beyond — could be integrated into power grids at a much higher and faster pace than once believed, giving a glimpse at the future green and sustainable electric networks,” Mr. Loutan said. “With these results, the electric industry can expect one day to realize ambitious goals of using primarily renewable sources to power our economy.”

The ISO published the report, “Using Renewables to Operate a Low-Carbon Grid” in January. The ISO Board of Governors noted the findings as groundbreaking for advancing renewable integration in California, where a dramatic rise in solar power in recent years puts the state at the forefront of operating a low-carbon system.

For more on this significant discovery, visit the "Integrating renewables reliably" section of the webpage here.

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EIM cost benefits top $28 million in Q4 2016


The western Energy Imbalance Market 2016 fourth quarter report shows participating utilities realized benefits totaling more than $28 million during the last three months of 2016. The total benefits the market has generated since its inception in November 2014 reached more than $142 million. The EIM, a real-time wholesale energy market, is serving consumers in eight states and is the place utilities turn to buy low-cost power and schedule it for delivery five minutes before it is needed. The EIM is also grid operators to move surplus renewable energy resources to where it’s needed rather than having that resource go to waste at certain periods of the day. During the last quarter of 2016, surplus solar resources from California were used to offset 10,011 metric tons of CO2 emissions from less clean resources.

In October 2016, two new utilities entered the market, Arizona Public Service and Puget Sound Energy of Washington state. Portland General Electric and Idaho Power have agreed to enter the market in 2017 and 2018, respectively, while Seattle City Light and the Balancing Authority of Northern California and its member Sacramento Municipal Utility District will enter in 2019. Meanwhile, more utilities have announced there are actively exploring participation including Mexican grid operator El Centro Nacional de Control de Energía (CENACE), Salt River Project (Phoenix, AZ) and the Los Angeles Department of Water and Power. Read the Q4 2016 EIM benefits report here.

Meanwhile, the ISO Board of Governors at its December meeting adopted a formal process outlining the way the EIM Governing Body will address issues related to the real-time market. The "Guidance for Handling Policy Initiatives within the Decisional Authority or Advisory Role of the EIM Governing Body" details steps the EIM Governing Body must take in considering policy issues, making decisions or providing advice to the Board.

To view the ISO Board meeting documents, click here. For more information on the western Energy Imbalance Market Governing Body, click here.

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Greenhouse gas emissions for ISO load falls in 2016


The ISO is now tracking greenhouse gas emissions from power dispatches in its service territory. The “Greenhouse Gas Emission Tracking Report” is a monthly report that began in December. The most recent report released on February 28 shows GHG emissions in 2016 were below the previous two years. About 57.40 million metric tons of CO2 were produced last year in generating power. That's down from 66.24 million metric tons in 2015 and 68.78 million metric tons in 2014. The report evaluates generation within California and imported power used to serve ISO territory, which is about 80 percent of California and a small section of Nevada. See the graph below for the monthly tracking.

Figure 1: GHG Emission Tracking Report February 2017

Click here for more information on this report.

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Follow ISO news in a variety of convenient ways


The ISO is committed to being transparent and communicating about all the different issues and challenges we are working on. We have developed several ways you can keep up with us:

  •  Daily Briefing, a summary for market notices
  •  ISO Today app, making web features available at your touch
  •  RSS feeds for topics of interest
  •  Social media channels Twitter, YouTube and Facebook
  •  Flex Alert mechanisms alerting you when and how to conserve electricity
  •  Energy Matters newsletter, keeping you apprised of ISO news and activities

Visit our notifications webpage here to sign up to receive the notices and news releases that best suits your needs. And we always welcome feedback; contact us at with your comments and suggestions.

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Renewables growing in ISO’s energy mix


Renewables now make up significant amount of the generation connected to the ISO grid. Here is the most recent tally of resources connected to the grid (amounts as of 12/19/2016). This table only contains power plants that are fully commercial.

See the graphic below for resources by type and percentage of total capacity. To see these resources at work, download the ISO Today app from your Apple or android store, or visit Today’s Outlook on the web at this link.


Resource TypeAmount
(in megawatts; values have been rounded)
Solar (utility scale only)9792
Small Hydro (30 megawatts & smaller)1296
Biofuels (biomass, biogas, etc.)1316
Energy storage (all types)40*
Total Renewables20,410
Natural Gas38,912
Large Hydro8527
Various ***805

* An additional 60 megawatts of battery storage was connected at the end of December for a total now of about 100 megawatts.
** These coal units are only used for onsite generation at large industrial users, such as refineries, but are not used for retail sale to consumers.
*** These are small units bundled together and participate in the market as one unit; the fuels used could be a mix of natural gas, hydro, renewables, biogas, etc.

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