NERC published its annual Long-Term Reliability Assessment (LTRA) on December 15, 2022, which covers the 10-year period between 2022 and 2032. The LTRA evaluates existing and planned generation and transmission facilities to identify emerging reliability issues, risks and uncertainties affecting the bulk power system.
As part of MRO’s responsibility to support and promote regional reliability of the bulk power system, the Reliability Advisory Council (RAC) reviews the long-term reliability assessments prepared by each of the Planning Coordinators for the four assessment areas within the region to ensure they are comprehensive and complete. The Planning Coordinators are Manitoba Hydro (MH), Midcontinent Independent System Operator (MISO), Saskatchewan Power Corporation (SPC), and Southwest Power Pool (SPP). In support of this process, MRO staff collects and reviews information about the assessment areas, which includes the Canadian provinces of Manitoba and Saskatchewan, for use in ERO Enterprise-wide assessments.
LTRA Findings
The 2022 LTRA shows reserve margins through 2027 are adequate for all of MRO’s assessment areas with the exception of MISO’s. Over the next five years, MISO’s projected reserve margin falls below its planning reference margin levels. This is primarily due to the retirement of coal, nuclear and other conventional generation resources. However, MISO expects these figures will change significantly with the implementation of future capacity plans by load-serving entities and states within MISO’s assessment area. MISO’s reserve margin also includes unconfirmed generation retirements that if postponed to later years, would improve the projected 5-year reserves. There are also additional prospective resources that could be available; however, it is not clear how many of these intermittent resources will be interconnected. Having a mechanism in place, like management of energy shortfall, to prevent or delay the retirement of generators needed to maintain system reliability could temporarily mitigate potential risks of insufficient energy supplies during peak periods until new reliable resources are available.
Over the next 10 years, the MRO region will experience significant changes to its resource mix portfolio. As shown in the table below, large amounts of solar and wind capacity additions are expected. It is important to note that not every wind and solar project in the interconnection queue will be built, as some entities may withdraw after a system impact study establishes necessary transmission upgrades may be needed before a project can connect to the bulk power system.
These projections reflect that most of the new generation is comprised of variable resources that depend on fuel that is intermittent and not available at all hours. This adds operational complexity to resource commitment and dispatch.
The two charts below show transmission development trends over the next 10 years in the MRO region. There is relatively little change in cumulative miles of bulk power system transmission under construction or in the planning phase. Most future projects are driven by grid reliability, but also help with congestion and variable generation integration. Projects under construction or in the planning phase to integrate renewables have grown since the 2021 LTRA.
MRO’s annual Regional Risk Assessment (RRA), which identifies and prioritizes risks to the reliable and secure operations of the bulk power system within MRO’s footprint, uses the LTRA as a key input. Many of the challenges identified in the 2022 LTRA are included in MRO’s RRA, which finds that extreme weather, evolving consumer demand, and changes to technology and generating resources present increasing challenges to bulk power system reliability. The top risks prioritized by the RRA become the focus of and inform the action plans developed by MRO staff and the three advisory councils. The 2023 RRA will be released in early February.
The MRO region will face a number of reliability risks in the coming decade. Of particular importance is the impact from retirements of coal, nuclear and other conventional generation. The rapid change in resource mix as new power plants rely on natural gas or intermittent resources, such as wind and solar, along with declining reserve margins and the introduction of distributed energy resources, creates uncertainties of available supply to meet demand. MRO will continue to monitor and assess these risks through participation in ERO Enterprise efforts, and will raise awareness across the region in the form of seasonal assessments the annual RRA.
– Salva Andiappan, MRO Principal Reliability Assessment Engineer and Mark Tiemeier, MRO Principal Technical Advisor