Planning for a Reliable and Resilient Electric Power Grid

In the U.S., regional transmission organizations (RTOs) and independent system operators (ISOs) are responsible for overseeing the reliable operation of the high-voltage transmission system within their respective regions. In other countries, transmission system operators (TSOs) perform similar roles. In most cases, the primary objectives of these entities are to ensure the reliable and efficient operation of the power grid, facilitate competitive electricity markets, and promote fair and non-discriminatory access to the transmission system for all market participants.

Perhaps one of the lesser-recognized responsibilities of RTOs, ISOs, and TSOs involves transmission planning. These groups are often tasked with identifying and approving new transmission projects with the aim of ensuring their respective power grids can reliably meet future electricity needs and integrate new generation sources, such as renewable energy.

A Look at PJM

PJM is the largest RTO/ISO in the U.S. It coordinates the movement of wholesale electricity in all or parts of 13 U.S. states and the District of Columbia. PJM serves more than 65 million people, manages more than 180 GW of generation capacity, and boasts a peak-demand record high in its region of more than 165.5 GW. At the end of 2023, PJM reported having 368,906 square miles of territory and 88,185 miles of transmission lines under its jurisdiction.

Paul McGlynn, vice president of Planning for PJM, spoke in May at Xcelerate Orlando 2024, an event hosted by Energy Exemplar, a global provider of energy market simulation software. “From a planning perspective, we’re always trying to make the grid more resilient,” McGlynn said. “Job number one for us is reliability.”

McGlynn said ensuring reliable operations is not an easy task. “We ensure grid reliability through our coordinated operations, as well as our long-term planning efforts, and we use our markets basically to ensure and to incent that our members are doing what we need them to do to support reliable operations,” he explained.

Every year PJM develops a comprehensive Regional Transmission Expansion Plan (RTEP). The RTEP identifies transmission system additions and improvements needed to keep electricity flowing dependably. “Last year, our board approved over $6 billion in projects to support the reliability of the system. Many of those projects are expected to be placed in service between now and 2028,” McGlynn said.

Electricity Demand and Renewable Generation Trends Continue

Transmission projects are arguably more important now than ever. Load in many parts of the U.S. had been flat for more than a decade going back to at least 2007, but that has changed since the country emerged from the COVID-19 pandemic. PJM offers a case in point. McGlynn said PJM’s load growth rate projections have been ramped up in recent years. He said comparing 2022 to 2023 and 2024, each year has seen “successively and incrementally increasing” load forecasts. This is primarily due to trends toward electrification, as well as significant increases in data center energy consumption, according to McGlynn.

PJM is forecasting an increase in its load of about 40 GW over the next 15 years, McGlynn said. Meanwhile, it expects 40 GW of generation to be retired between now and 2030. Retirements are being driven mainly by state public policy, but there are also some units being shuttered for economic reasons. McGlynn suggested these developments are raising concerns over resource adequacy.

In an effort to speed project development activity, PJM has implemented changes in how it processes interconnection queue requests. Specifically, it moved from a first in-first out approach to a first ready-first served methodology. Notably, the majority of projects coming through the queue are from the renewable sector.

“Our interconnection queue is really dominated by renewable resources—solar resources, solar and storage, and some wind,” McGlynn reported. “We expect that trend to continue moving forward.”

Planning Tools

When it comes to planning, Energy Exemplar’s PLEXOS platform is one of the tools that many RTOs, ISOs, and TSOs are using to model their systems and help make choices for the future. Energy Exemplar claims PLEXOS is “one of the world’s most powerful energy market simulation engines, providing analytics and decision-support to modelers, generators, and market analysts—offering flexible and precise simulations across electric, water, gas, and renewable energy markets.” It can analyze zonal and nodal energy models ranging from long-term investment planning to medium-term operational planning and down to short-term, hourly, and intra-hourly market simulations.

David Wilson, CEO of Energy Exemplar, offered POWER an anecdote to show how important the planning process is today. Wilson said he was in London recently meeting with a leader who has been tasked with making decisions concerning the UK’s full energy system, including electricity, natural gas, hydrogen, decarbonization efforts, and more. PLEXOS is already used quite extensively by the group, but now, detailed models of the entire country’s energy and infrastructure system are being built with the aim of laying out a 40-year plan for a full transition to net zero.

The UK leader reportedly told Wilson, “When we’re long gone, all the people in the UK are going to live with the infrastructure and the grids that we’re deciding over the next couple of years on the PLEXOS platform that you’re enabling. That’s pretty cool!” Wilson said that’s the scale his company is dealing with; entire countries are planning all the infrastructure upgrades and changes necessary to maintain a reliable and resilient grid for generations to come.

I have to agree with the UK leader—that is pretty cool! Let’s hope tools like PLEXOS help everyone making those decisions get them right.

—Aaron Larson is POWER’s executive editor.