Does Demand for Power Go Up on Hot Summer Holidays and Weekends?

Occasionally we’re asked if demand for power goes up over a typically hot summer holiday such as Independence Day or a weekend.

While more people might be at home cranking up their air conditioners over a sweltering holiday or weekend, typically demand actually goes down. This is because, while you might use your air conditioner more heavily over a weekend, many offices and businesses, which use a lot of electricity to keep their entire buildings cool, close over a weekend or holiday and don’t use the amount of electricity it does throughout the work week.

You can learn more about how PJM works to keep the lights on 24/7 in the Learning Center.

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How Does PJM Make Money? What Happens When a Power Plant Retires? Two New Learning Center Pages Explain

How does PJM make money? What does PJM do to keep the grid stable when a generator plans to retire? PJM has launched two new pages on the PJM Learning Center at to help answer these questions.

Check out these new pages at

PJM redesigned the Learning Center website last year to make it a more visual and easy-to-understand online source dedicated to explaining complex PJM and power industry topics. The Learning Center project team continually works with subject matter experts across PJM departments to enhance and update the information on the website.

Learning Center

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PJM Learning Center Website Wins Award for Publication Excellence

Last September a team of PJM experts worked together to rewrite, redesign and expand the Learning Center website at to transform it into your simple, clear and visual resource for understanding the power industry and PJM.

The redesigned site has won an APEX award in the category of most improved websites. APEX stands for Awards for Publication Excellence. The award program is a competition for communications professionals.

The Learning Center touches a range of topics from how electricity is created and transported to ensure a reliable grid, to an overview of the fair and efficient electricity markets that PJM administers, to infrastructure planning as well as emerging grid technologies for the future.

PJM continues to make ongoing enhancements to the site. Stay tuned for new pages and videos launching this summer.

Apex Award

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Next Grid 20/20 Forum to Explore Gas/Electric Interoperability

PJM often holds what we call “Grid 20/20” forums that bring together PJM members, policymakers and industry experts to discuss cutting-edge ideas, visions and technologies that will transform electricity in the 21st century.

Our next forum, “PJM’s Grid 20/20: Focus on Gas/Electric Interoperability,” held on June 17, will feature Federal Energy Regulatory Commissioner Philip Moeller among the key speakers.

The forum focuses on the two industries continuing to work collaboratively to adjust to the growing use of natural gas for electric generation. PJM, regulators and gas and electric industry companies continue to assess the impact on grid operations, the markets, infrastructure planning and regulatory compliance. The trend to natural-gas-fired generation also is a factor in considering the potential impacts of the Environmental Protection Agency’s proposed Clean Power Plan.

PJM President and CEO Terry Boston will open the forum, which also will feature ISO New England CEO Gordon van Welie and three panels of industry experts.

Learn more or register on the PJM website.

Grid 20/20 2015

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PJM and Members Ready to Meet Summer Demands

PJM issued its annual summer assessment (PDF), which found that PJM will be able meet the hot weather demands the season brings. For this summer, PJM expects to serve about 155,279 megawatts at its peak (for reference, one megawatt is enough to power between 800 and 1,000 homes).

The assessment says that while summer weather conditions can test the grid, PJM should be able to meet the expected peak, with 177,650 MW of installed generating capacity to use. The extra available electricity is called a reserve, which is needed in case an extended heat wave puts an added demand on the grid or if another supply resource goes out of service unexpectedly. PJM must have a certain percentage of reserve available, called a margin, to meet federal reliability standards.

PJM expects to have about 8,500 MW of demand response and energy efficiency resources available. Demand response is a program where customers commit to reducing or interrupting their power use in the event of a system emergency.

Additionally, the recently-completed Susquehanna-Roseland transmission line that runs between Pennsylvania and New Jersey also should relieve some congestion on the grid this summer.

If you’re wondering, the highest peak use of power PJM ever served was 165,492 MW in July 2011.

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Installing Energy Storage at PJM (Video)

Energy storage can provide grid operators a reliable and flexible way to keep power supplies in balance as generation and load change throughout an operating day.

PJM has gained experience with storage technology on its campus with a two-megawatt array of lithium-ion batteries stationed at PJM’s campus. (The project is owned and operated by AES Energy Services LLC, a subsidiary of The AES Corp., a PJM member.) The array changes its output or electricity consumption in less than a second and helps PJM quickly balance short-term variations in electricity use.

Check out the below video to see how it was installed.

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The Interconnection Process: Does PJM ‘Approve’ New Generation?

Every now and then you might read that PJM has “approved” a new generator to be built within the area it serves. We don’t actually “approve” generators, however.

Here’s a simple explanation of how PJM’s generation interconnection process works:

When a generation developer begins the process to link (or “interconnect”) the unit to the grid, PJM reviews the project and lets the developer know what improvements need to be made to the transmission system as well as how much it will cost in order to connect. From there the developer decides whether or not it wants to continue with its project.

PJM doesn’t judge whether a generator should or should not be built. We just determine what needs to happen for the project to work to connect to the grid and how much that will cost the developer.

You can read more on PJM’s website.

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Total Solar Eclipse Could Challenge European Grid

According to a story published by the Guardian, a solar eclipse on Friday could cause the European power grid to suddenly lose up to 35,000 megawatts of capacity from solar generation.  One megawatt of electricity is enough to power about 800 U.S. homes.

While the sudden drop in generation certainly will challenge European grid operators, according to the story, they have prepared for more than a year for the event and are confident the system will cope. European consumers should notice nothing unusual (other than a temporarily darkened sky).

Those of us in North America will not experience any effects of the solar eclipse. It will still be night when the eclipse occurs, so it will be business as usual. Second, Europe currently relies far more heavily on solar energy for electricity generation than in North America and in PJM.

HT: The Guardian

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Ancillary Services Keep the Grid Stable

When people think of PJM’s wholesale markets, most often they’re thinking of the energy and capacity markets. PJM’s Energy Market makes sure power is available in real-time and for the upcoming day. PJM’s Capacity Market ensures supplies three years in advance. However, PJM also operates markets for “ancillary services” that keep the grid stable as electricity flows from generators to consumers. PJM operates two of these markets: the Synchronized Reserve Market and the Regulation Market.

While they’re not PJM’s largest markets, they are absolutely necessary to keep the grid reliable.

Synchronized Reserve Market

Synchronized reserve supplies electricity if the grid has an unexpected need for more power on short notice. This can happen if generators experience unexpected outages or if there is an unusual spike in energy demand, for example, because of the weather. Synchronized reserve is like a spare tire for your car – a backup in case of an emergency.

Generating units or demand response participants that supply synchronized reserve can boost their output or respond quickly to supply the needed power.

Regulation Market

Regulation service stabilizes the grid during the constant, short-term changes in energy use. Fluctuations in energy use happen in seconds, so regulation works instantaneously to balance supply and demand. If supply and demand are not balanced, power equipment can be damaged or blackouts could occur.

Energy storage devices such as water heaters and plug-in electric vehicles can provide regulation service because they can react to PJM’s signals quickly and only need to provide power for short periods of time. (This is compared to a traditional generator, which can provide power for long intervals, but also takes far longer to change its output.)

You can learn more about how water heaters and plug-in electric vehicles can sell power into PJM as well as more about PJM’s ancillary services on the Learning Center.

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Get the Inside Scoop from PJM Inside Lines

Each week, PJM facilitates multiple meetings, tracks about 30 issues through the stakeholder process, regularly files with the Federal Energy Regulatory Commission and meets with dozens of governmental and regulatory authorities, industry groups, members and peer organizations. As a result, news happens often at PJM.

To better share this news, PJM launched a new company news site that provides current, important PJM news largely geared to stakeholders. PJM Inside Lines is the company’s official new site.

The site will be updated as news occurs. It replaces the monthly Inside Lines newsletter, which was sent directly to subscribers. This site is unique from and Plugged In because it focuses on news with broader appeal to members and others who are impacted by the stakeholder process as well as regulatory decisions.

Plugged In continues to provide brief and unique insights into PJM and the energy industry and is geared to a general audience.

PJM Inside Lines has added new features. The “Tips and Tools” feature highlights resources on and “City Spotlight” highlights a city within the PJM footprint. The executive column will continue to provide a perspective on key issues impacting PJM and its stakeholders.

Inside Lines Screenshot

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