Imagine a hot summer afternoon when you’re glad to be indoors in the cool air conditioning — and, suddenly, the power goes out. Your electric company says, “We’re sorry. We’re experiencing extremely high demand on our high-voltage lines. They’re overloaded. Things should be back to normal in five to 10 years after we’ve finished major construction to improve the lines.”
That scenario doesn’t happen because somebody works behind the scenes to plan for the high-voltage power lines needed to keep the lights – and the air conditioning – on. They have to do it years in advance of the need because it takes years to plan, design, get permits and build major transmission line improvements or new high-voltage lines.
Electric utilities have always planed transmission lines for their customers. For 10 years, PJM has planned transmission line improvements in its region. We can take an independent look at the big picture across utility territories and identify the best solutions.
To identify the need for improvements to transmission lines or for new lines, PJM’s planning group looks ahead 15 years. Planners consider:
- forecasted demand for power, which is influenced by economic factors
- generation availability
- risk of generation retiring new generating projects, which includes many renewable energy projects
- demand response
- the condition and limitations of the current infrastructure.
Though transmission lines and improvements can take many years to put in place, the economy, public policy or other factors can change very quickly. Having to base planning decisions on factors that can’t be known with certainty yet and that vary over the long term clashes with today’s culture of “just-in-time” decision-making.
For example, the economy and the use of electricity are connected. Over the last few years, the future state of the economy has been uncertain at best. When a grimmer than expected economic forecast was issued late last fall, the impact on the overall load forecast and subsequently to transmission planning led to suspending a high-voltage, long-distance line that previous forecasts had required to be built.
And, the economy is just one of the uncertainties related to transmission lines. For example, no easier to predict is the impact of policies to promote construction of more renewable generation, which would drive the need for more transmission changes to accommodate it.
Finding better ways to consider these and other varying factors in long-term planning for transmission lines is the aim of an ongoing review by PJM and its stakeholders.
In the future, we’ll explore more about what goes into transmission line planning, the evolving factors influencing planning and how we can plan for what we don’t know yet. In the mean time, rest assured that PJM will help you stay cool, calm and connected.