PJM said it completed a series of renewable portfolio standards (RPS) scenario analyses as part of the 2011 Regional Transmission Expansion Plan (RTEP) process cycle to identify RPS state requirements from an RTO perspective.
PJM also noted it completed those analyses in order to develop a sourcing strategy to meet all PJM states’ RPS requirements with resources located in PJM.
Two scenarios considered two assumptions regarding offshore wind-powered generation – one at 4 GW and one at 20 GW – and both scenarios included a solar carve-out consistent with state RPS requirements.
Offshore wind energy development efforts in the PJM service territory include a project by Fishermen’s Energy in New Jersey.
PJM said a combination of reliability analysis and production cost simulations provided PJM results that drove the development of transmission overlays necessary to meet all PJM states’ RPS requirements with resources located in PJM.
Market efficiency analyses showed that congestion is driven by wind injection point locations. PJM also said that in the 4 GW offshore scenario, high levels of congestion were observed in western PJM given the level of generation modeled there. Similarly, the 20 GW offshore scenario revealed high levels of congestion in Eastern Mid-Atlantic Area Council (MAAC) the result of increased wind resource concentration off the East Coast, PJM said.
Total PJM congestion increased by about $3.7bn in the 4 GW scenario and about $2.4bn for the 20 GW scenario, compared to a base scenario.
System congestion at the levels identified in these scenario studies suggested the need for additional transmission reinforcement to support renewable resource delivery, PJM said. To that end, the transmission overlays developed by PJM mitigate constraints, improving wind energy deliverability and enabling aggregate state RPS goals to be met, the RTO added.
PJM developed a high voltage transmission overlay for each of the two wind scenarios – 4 GW offshore and 20 GW offshore. These overlays alleviated transmission constraints in the electrical areas where PJM identified NERC reliability criteria violations in peak load and light load reliability tests. The 4 GW offshore overlay required more transmission in western PJM to accommodate the higher concentration of onshore energy injection in that area. PJM also said that the 20 GW offshore overlay required more transmission in eastern PJM to support the greater penetration of offshore wind resources under that scenario.
The 4 GW offshore wind scenario included certain transmission expansion plan elements, including a 765/345-kV Cloverdale transformer replacement. Similar elements for the 20 GW offshore wind scenario included Pepco Holdings’ (NYSE:POM) Mid-Atlantic Power Pathway project, which is expected to enter in service in 2020.
PJM also said the overlays increased congestion, suggesting the need for more transmission to deliver renewable energy and reduce congestion below current levels.
However, PJM noted that the study’s objective was to develop a transmission strategy to ensure the deliverability of those resources to the aggregate of all load within PJM, not that each state’s goals would be satisfied from resources located solely within each state. Individual load-serving entities, in cooperation with state regulators, would otherwise need to seek contractual arrangements to secure the rights to renewable energy output from units in states whose RPS goals are expected to exceed individual 2026 mandated levels, PJM added. According to PJM, 2026 is the last year of the 15-year planning horizon in its 2011 RTEP process cycle.
Among other things, PJM said its scenario study showed that smaller coal units, typically also older in age, operated less often, displaced by wind-powered generating resources. Generating resources that cannot produce consistent revenue streams may become candidates for retirement, removing them from PJM’s generation fleet as a capacity resource. PJM said that as part of an ongoing, parallel scenario study of at-risk generation, it will continue to monitor and examine such system impacts.