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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