December 24, 2022 capacity deficiency event in New England

New England's wholesale electricity grid experienced a capacity deficiency on December 24, 2022, according to grid operator ISO New England, Inc., but the system operator says its operating procedures successfully balanced supply and demand on the regional power system during evening peak hours, when unexpected generator outages and reductions and lower-than-expected imports led to a shortfall in operating reserves.

According to ISO-NE:

ISO New England did not call for controlled power outages on Christmas Eve, but did declare a capacity deficiency, meaning the region’s supply of electricity was insufficient to meet required operating reserves in addition to satisfying consumer demand, at 4:30 p.m. This action was taken after approximately 2,150 megawatts (MW) of resources scheduled to contribute power during the evening peak became unavailable. The outages and reductions coincided with net imports being approximately 100 MW less than had been expected based on that day’s Morning Report.

While the capacity deficiency was ongoing, at 4:40 PM, ISO-NE declared a "capacity scarcity condition" under its Forward Capacity Market’s Pay-for-Performance rules. This condition remained in effect until 6:05 p.m. Under the Pay-for-Performance rules, any resource that failed to meet its capacity supply obligation is penalized at a rate of $3,500 per megawatt-hour (MWh) for failing to meet its obligation, while resources that over-performed will receive $3,500/MWh of additional revenue. In total, ISO-NE has estimated penalties for the December 24 event to be approximately $39 million. In addition, any energy resources that cleared in the Day-Ahead Energy Market but failed to provide electricity in real-time are charged the real-time price for the missing energy; Real-Time Energy Market prices averaged approximately $484/MWh over the course of the day, peaking over $2,200/MWh during the 5 p.m. hour while the capacity scarcity condition was ongoing.

On January 12, 2023, ISO-NE provided an update on the December 24, 2022, capacity deficiency, "to help correct any confusion, misinformation, and misunderstanding resulting from various news stories and social media posts." According to that update, the incident was "mainly about timing". After noting that it entered the December 24 operating day with sufficient resource commitments to meet demand and required operating reserves, with a surplus of over 950 megawatts of fast-start resources, ISO-NE explains what happened next:

As the day went on, some generators in the region experienced unanticipated issues that caused them to go offline or reduce their output. These outages were caused by cold temperatures or mechanical problems, and not due to inadequate fuel supplies. Expected imported electricity from Canada was also reduced due to transmission system issues and unexpectedly high consumer demand in Québec. Despite these issues, New England was still expected to meet demand and operating reserves over the evening peak as of 3 p.m.

Around 4 p.m., additional unanticipated outages led to a capacity deficiency in the region. This meant that the 950 MW surplus was depleted and supply was insufficient to meet both demand and required operating reserves. In response, ISO New England system operators implemented procedures for dealing with capacity deficiencies. This included calling upon any resource that could respond quickly enough to be online for the evening peak, which usually falls between 5 and 6 p.m. during the winter months. The ISO dispatched all remaining offline resources that were available to provide electricity or operating reserves during this period.

In its update, ISO-NE described pricing and customer impacts from the incident:

Prices in the Real-Time Energy Market averaged more than $2,000 per megawatt-hour (MWh) during the 2.5-hour capacity deficiency. While high, these prices are unlikely to affect most consumers given how retail rates are set in the region. Though practices vary by state and utility coverage area, the rates paid by most retail customers are set for months-long periods and not subject to volatility within the wholesale marketplace. 

Almost all of New England’s wholesale electricity is bought and sold in the Day-Ahead Energy Market, where prices were unaffected by the capacity deficiency. Average day-ahead prices during that time were roughly $285/MWh.

As ISO-NE noted in its January 4 report, other regions of North America were challenged by extreme weather around the long holiday weekend, prompting varied responses outside New England including controlled power outages.

Proposed Long Canyon energy project

Last week the Federal Energy Regulatory Commission accepted for filing an application for a preliminary permit for a pumped storage project in the Utah desert.  In January, Utah Independent Power, Inc. filed for a preliminary permit.  The Long Canyon Pumped Storage Project would entail two dams to store water drawn from the Colorado River near Moab, Utah.  (Here's a topographic map of the general location.)

A water pipe buried in the desert soil in Arches National Park, near Moab, Utah.

Pumped storage projects are one way to store energy.  Electricity that is generated can be converted into potential energy stored in water by pumping it uphill.  That energy, or most of it, can be captured and converted back into electricity on command.

Utah Independent Power's application to FERC for a preliminary permit for the Long Canyon Pumped Storage Project (18-page PDF) provides some details on how the project might work.  Initially, water from the river would be pumped into the lower reservoir.  When electricity is abundant and low-priced, the project would consume electricity to pump water from the lower reservoir uphill to the upper reservoir.  When electricity is scarce or commands a high enough price, the project would release water downhill through turbines to produce up to 800 megawatts of hydroelectric energy.  In a typical pumped storage project, the same pumps used to send water uphill can be used as turbines when the water flows back down.  The owned of a pumped storage project seeks to earn profits by taking advantage of the difference between off-peak energy prices and the prices available during peak demand.

Now that the Commission has accepted the application for filing, the application is open for 60 days for public comment or a showing of interest in the site by a competing developer.  After that period, and after a technical and legal review of the application by Commission staff, the Commission may issue a preliminary permit to the applicant.  A preliminary permit does not authorize the permittee to actually construct anything; rather, it confers first priority of application for a license - what the Commission calls "guaranteed first-to-file status" - while the permittee studies the site and prepares to apply for a license, typically for a term of 3 years.

February 3, 2011 - ERCOT rolling blackouts over?

Following on yesterday's report of rolling blackouts in Texas: grid operator ERCOT has reported that the need for intermittent power cuts may have passed, although ERCOT noted that scarcity of available generation might again lead to the need for blackouts.  As the storm moves away and life gets back to normal, we're seeing some of the impacts of the blackouts.  For example, the Houston Chronicle reports that the Houston fire department responded to 30 elevator rescues yesterday - 10 to 15 times as many as on an average day.  Rolling blackouts are unpredictable; even if you know the grid operator is imposing them, you might not know exactly when they'll strike.  ERCOT and utilities tried to avoid cutting power to key elements of social infrastructure like hospitals, but anyone who got stuck in an elevator when their building lost power probably didn't enjoy the experience.

ERCOT continues to ask consumers to reduce their consumption of electricity, particularly during times of peak demand.

February 2, 2011 - weather leads ERCOT to rolling blackouts

What happens when bad weather strikes the power grid?  Depending on the storm, and the region, some customers may lose power if distribution lines are damaged.  More serious cases, like when key generators are tripped offline, may lead to more serious consequences.

Groundhog Day 2011 in Texas provides an example of the more serious consequences: power prices rising to 40 times their previous level, coupled with rolling blackouts.  The Electric Reliability Council of Texas, or ERCOT, operates the electric grid and manages the deregulated market for 75 percent of the state: about 22 million customers in areas including Houston, Dallas, Fort Worth, San Antonio, Austin, Corpus Christi, Abilene and the Rio Grande Valley.

Thanks to the weather, apparently there just isn't enough power to go around.  Reports indicate that ERCOT has imposed rolling blackouts after multiple power plants were disabled by a major ice storm.   Rolling blackouts are an extraordinary measure, seen more often in other countries than in the U.S.  When the utility cuts your power, unless you're connected to distributed generation or storage, your lights will go dark.

Beyond the rolling blackouts, the price of energy may lead to other consumer impacts.  Reuters reports that hourly energy prices in ERCOT rose from $50 per megawatt-hour to $2,000 per megawatt-hour, a forty-fold increase.  (Although individual residential ratepayers may not feel that price spike directly, it would translate into paying $2.00 per kilowatt-hour if they did - and large commercial and industrial ratepayers who buy power at wholesale in the market are exposed to these prices directly.)  Sounds like a good time for demand response!