Reliability in PJM: Today & Tomorrow

White Paper Details the Many PJM Functions Necessary to Maintain Grid Reliability


As a broad set of trends reshapes the electric industry, a new PJM paper entitled “Reliability in PJM: Today and Tomorrow,” details the numerous functions in system planning, operations and markets that PJM oversees to maintain grid reliability. The paper lays out exactly how PJM achieves reliability every day, and how PJM is approaching the challenges of tomorrow with reliability as our core mission.

The job of ensuring grid reliability – keeping the lights on – is PJM’s most important priority. This requires constant system monitoring by the trained system operators who dispatch power in real-time coordination with operating members and industry sectors. To ensure future reliability needs, PJM undertakes extensive planning and preparation in concert with our member and stakeholder community.  Further, PJM’s markets are designed to ensure that they support PJM’s critical mission of maintaining grid reliability.

Our Evolving Grid

At the highest level, fast-emerging forces present shifts in the model in which the demand for electricity is predictable and supply is controllable, to one where this may be less so.

Reliability in PJM: Today and Tomorrow” discusses the work underway to meet future challenges through the four building blocks required for system reliability, now and in the future. They are:

  • Adequate Supply: Making sure there is sufficient generation and other resources, including demand response, available on the system to meet customer demand. This involves adequate: (1) capacity to meet peak demand on the system; (2) energy to meet the day-to-day and intraday demand; and (3) ancillary services and reliability attributes, which refer to essential grid services and resource characteristics required to maintain system balance and stability.
  • Accurate Forecasting: Forecasting plays an important role in maintaining the reliability and efficiency of the power grid. Predicting total demand, and net demand (demand minus solar and wind output), for electricity for the next hours and days, as well as many years into the future, allows for reliable system operations and planning.
  • Robust Transmission: Electricity is a real-time, on-demand commodity used virtually the moment it is created. Like any commodity, it must be delivered from the point of production – a generator – to the point of consumption – our homes and businesses. Transmission lines are the highways across which electricity is delivered. Transmission reliability is a function of thermal, voltage, stability and short-circuit power system fundamentals.
  • Reliable Operations: A system is only reliable when operated properly. A robust system may be planned and designed well, but if it isn’t operated properly, it will not be reliable. This is particularly true for the bulk electric system, as unexpected disturbances on the system can quickly escalate to cascading failures and widespread power outages if not handled properly. To keep the system reliable, grid operators work around the clock to monitor and control the system, directing how much energy should be supplied by generators to match the demand, ensuring that transmission lines and facilities stay within their operating limits, and constantly preparing for the unexpected.

Next Steps

Exploration of ongoing changes and these topic areas has already begun. In 2021, PJM set up two, four-part stakeholder workshops, one focusing on improvements to the interconnection process, and the other examining potential enhancements to the capacity market. This paper serves as a foundation to help facilitate these and other discussions that will be had as PJM, policymakers and its stakeholders advance towards an evolving and bold future.