A Michelin Star Dish and A Reliable Power Grid — What Are The Similarities?
I sat in a Michelin star restaurant, admiring my dream dish just served while listening to the waiter’s introduction. This delicacy in front of me is a result of top-quality ingredients, professional food preparation, unique cooking techniques, and finally, the chef and the staff’s seamless coordination and great passion for cooking. “It is beautiful,” I commended, “the process of making a Michelin star dish is just like how we keep our power grid reliable…” “Oh really!? That’s cool!” the waiter replied politely, though I could read a gleam of puzzlement in his smile.
OK, I confess. The story above is completely made-up. I realized that I needed a “story” (like many MBA programs teach 🙂) to justify the presumably obscure title that compares a Michelin dish with power systems reliability — two seemingly unrelated items, and I was enlightened after watching several episodes of Chopped on the Food Network. But, but, despite the (clumsy) story, the analogy, in my opinion, is 100% legit. To prove it, let’s walk through the roadmap to grid reliability.
The Roadmap to Grid Reliability
Reliability is more than just having enough generation capacity to serve the load. Instead, it is a multifaceted process that involves coordination and collaboration among multiple business units at various time frames.
Just like a tasty dish starts with top-quality ingredients, good reliability starts with a thoughtful resource plan. The resource portfolio should be carefully planned to serve the load growth and reflect the expected energy futures. Typically, this process looks at least ten years ahead and will capture the big picture of the energy policies and the projected economic growth in the area. Subsequently, transmission infrastructure should be assessed for the proposed resource plan. Transmission upgrades, non-wires alternatives such as DER, and other load-offsetting techniques should be carefully compared for their reliability and economic value addition. Locational factors should be considered because all resources may not have the same effectiveness in addressing localized reliability concerns. Based on the transmission assessment’s findings, the original resource plan may need to be revisited and modified to balance the capacity requirements and the deliverability constraints. It is crucial to start the planning process early and review it regularly because as new information arises, so does the plan. In addition, the resource and transmission plans should be tested against various scenarios to ensure their robustness to withstand a set of pre-defined disturbances. It is also crucial to reserve sufficient lead time for transmission upgrades because building transmission lines can easily take 5–10 years, and once they are built, changes are difficult and costly. Because the long-term planning process is based on numerous assumptions, with many not being realized in hindsight, moderately overplanning the system is usually not considered bad practice.
Ingredients are to cooking what a resource and transmission plan to power system operations. Without high-quality ingredients, even the best chef will fall short of expectations. Similarly, a robust resource and transmission plan is the foundation for system operations to develop flexible operating plans and deliver uncompromised reliability against various real-time conditions.
After the resource and transmission plan is finalized, operations will take over the “show.” From several months earlier to real-time, the operations engineering team performs multiple rounds of engineering studies, including Power Flow, Contingency Analysis, and Stability Analysis, to understand and evaluate the potential impact of outages, planned or forced. From there, they develop operating plans and tools to mitigate the risk and assist reliable power operations. A typical study cycle and the associated timelines for U.S. utilities and ISOs today are described in the chart below.
The seasonal studies primarily identify the critical reliability concerns for the coming peak load season, which historically define the worst operating condition. Since the studies must be done before most outage planning timeframes, an all-line-in-service condition is usually assumed unless there is solid evidence that some equipment will be taken out for an extended period. The system is then tested under different load levels to determine the maximum load serving and the import capabilities. In recent years, with the increasing generation of renewables during the day, the grid has started to witness issues driven by excess generation, which typically are not observed during peak load season. Recognizing this risk, today’s responsible operations (and planning) teams have started examining reliability concerns for the shoulder seasons in addition to their long-time peak-only analysis.
From two weeks ahead to one day ahead is what we typically refer to as the “operations planning” time frame, during which outages are modeled and studied in detail. Operations planning studies aim to evaluate the reliability risk for a specific day with the expected operating conditions. Historically, utilities and ISOs perform one set of studies for each day to cover the expected operating condition at the daily peak. With more moving parts in the grid today, however, two rounds of studies may be required, with the first round focusing on the daily peak, and the second round augmented to hourly or key hours analysis during the day-ahead time frames.
When it comes to real-time, things should look pretty good if everything goes as planned, assuming the operations planning studies were done right. However, this is rarely the case. Changes in system conditions appear regularly due to various reasons, from forecast deviation and equipment trouble to crew availability. Operations engineers will be in standby mode to answer any questions from system operators and restudy the system condition as needed.
In summary, the definition of reliability is further augmented in the operations time frame:
- Despite specific lines and generators may not be available due to maintenance, the system must have sufficient transmission capacities to withstand all credible contingencies and show satisfying frequency and voltage profiles.
- The resources should have enough ramping ability to handle sudden changes in operating conditions driven by solar and wind availability and extreme weather conditions such as heatwaves and wildfires.
- Software tools and communication paths must be healthy functioning as they are extensions of the system operator’s eyes and hands and will provide the situational awareness critical to supporting the real-time reliability of the power grid.
The following chart summarizes critical definitions and components that lead to a reliable power grid.
From A Michelin Star Dish to A Reliable Grid
Top-quality ingredients alone do not make a solid Michelin star dish. Similarly, a good resource and transmission plan itself also doesn’t automatically ensure a reliable grid. Failing any of the requirements above could lead to compromised reliability in real-time, which may limit or interrupt the load-serving capability. From ingredient sourcing to cooking execution, from food preparation to the art of plating, every step is indispensable in delivering the best possible Michelin dish. Likewise, a highly reliable power grid is only plausible with proactive collaboration and coordination among key stakeholders such as resource planning, transmission planning, energy procurement, and operations at all time frames. While playing different roles at different times in the process, all these stakeholders are critical players in achieving world-class reliability.
Conclusions
A reliable power grid in real-time goes a long way! While reliability is materialized only in the operations time frame, it is not an “operation only” concept. World-class reliability originates from a thoughtful resource and transmission plan based on a thorough analysis of the system and realistic expectations of possible energy futures, which, as an analogy, provides the essential ingredients for operations. Once the plan is initiated, the implementation progress must be carefully tracked, and the plan should be regularly reviewed and revised to account for the evolvement of critical inputs, which, if not correctly modeled, could constrain the later operations due to the “path dependence.” When it enters the operations planning stage, reliability comes from strategically scheduled maintenance plans and prudently conducted studies against the forecasted system condition. Eventually, all the hard work and collaboration will pay off in real-time operations. The capable resource portfolio and robust transmission network, together with the well-defined operating and contingency plans, will allow engineers, operators, and energy traders to efficiently utilize the resources and transmission facilities to deliver the promised reliability under various operation conditions.
