The PJM Interconnection's transmission needs are shifting away from large-scale, cross-system backbone projects toward smaller expansions and projects needed to maintain reliability when generators retire, according to a new report.
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"The $3.2 billion of baseline transmission investment approved during 2017 continues to reflect a shift in the dynamics driving transmission expansion needed through study year 2022," according to the 2017 Regional Transmission Expansion Plan Report, issued Thursday. The annual report summarizes transmission enhancements undertaken to maintain or strengthen reliability.
The drivers behind PJM's changing transmission requirements include flat load growth, energy efficiency, generation shifts, and aging infrastructure, among others. The factors are resulting in fewer large-scale projects at 345 kV, 500 kV, and 765 kV voltage levels and higher levels of transmission investment below 345 kV, according to the report.
The grid operator's 2017 PJM Load Forecast Report shows a 10-year RTO summer normalized peak growth rate of 0.2%, with average 10-year annualized summer growth rates for individual PJM zones that ranged from -0.3% to 0.4%. These trends are being driven by evolving customer behavior that includes the use of more efficient manufacturing equipment and home appliances and the growth of distributed energy resources such as behind-the-meter rooftop solar installations.
PJM says it is managing "an unprecedented capacity shift" being led by federal and state public policy and broader fuel economics. Some of the more pronounced changes PJM's markets include:
**New generating plants powered by Marcellus and Utica shale natural gas
**New wind and solar units driven by federal and state renewable incentives
**Generating plant deactivations
**Market impacts introduced by demand resources and energy efficiency programs
Natural gas plants totaling over 57,700 MW account for 80% of the generation seeking capacity interconnection rights. PJM notes that "favorable fuel economics" have emerged with the development of the Marcellus and Utica shale formations located in the middle of its territory.
Based on generation deactivation plans submitted to date, more than 27,000 MW of coal-fired generation will have left PJM between 2011 and 2020. The economic impacts of emissions regulation and other public policy initiatives coupled with plant age many over 40 years old make ongoing operation "prohibitively expensive," the report says.
PJM estimates natural gas as a percentage of its generation capacity mix will continue to grow, while plants powered by coal will decrease, with coal making up less than 30% of PJM's capacity by 2023.
TRANSMISSION PROJECTS DRIVEN BY DEACTIVATIONS
Deactivation studies conducted during 2017 identified thermal and voltage reliability criteria violations requiring system reinforcements in several areas across PJM. In its western sub region, the grid operator received deactivation notification that coal-fired Stuart Units No. 1-4, Stuart Diesels, Killen Unit No. 2 and Killen Combustion Turbine - totaling over 2,900 MW - would retire on June 1, 2018. These deactivations drove the need for nine RTEP projects across several PJM western zones totaling $58.3 million.
PJM had 21 storage devices connected to its system totaling 524 MW of nameplate capacity as of December 31, 2017. These mainly consist of battery and flywheel technology and several of them are part of hybrid plants paired with wind-powered generation.
The devices are mainly "energy-only" that participate in PJM's ancillary service markets, often supplying frequency regulation. There are also prototype projects that are exploring the benefits of electric vehicle-to-grid technology and thermal storage which uses large electric water heaters that can respond to grid needs, according to the report.
Energy storage can also serve as a transmission asset that can relieve congestion. As part of the 2016/2017 Long-Term Regional Transmission Expansion Plan Proposal Window, PJM received two proposals that included battery energy storage systems. One involves constructing a new 230 kV line coupled with a 20 MW/40 MWh battery to relieve congestion on the Conastone-Graceton and Graceton-Bagley 230 kV lines located in the BGE zone.