By Michael Kuser

Preliminary results from a biennial NYISO study show high congestion in three areas of the New York bulk power system, mainly in the eastern part of the state, ISO officials said Tuesday.

The 2017 Congestion Assessment and Resource Integration Study (CARIS) found congestion on the Central East interface, through the line eastward to Albany, and from the capital down the Hudson River Valley toward New York City.

“These are not necessarily surprising, being consistent with what we’ve seen in past studies,” said Timothy Duffy, the ISO’s manager of economic planning. “We also did find one interesting piece, which was a small line, referred to as Edic-Marcy, which we have found in the past year or so to have some significant contribution to congestion on the system.”

The Edic-Marcy line is located in the central part of the state.

The CARIS process requires planners to identify the top congestion elements on the system. “That’s obviously a key indicator of where developers ought to be thinking in terms of building additional transmission to provide value in terms of reduced congestion,” Duffy said.

The ISO’s Tariff calls for the CARIS to identify four solutions for each case study. Planners start with a generic solution such as transmission, demand response, energy efficiency and generation, then model those solutions and develop specific costs associated with them, calculating high-level cost-effectiveness tests and benefit-to-cost ratios.

The only benefit the CARIS process factors into its benefit-to-cost calculation is a reduction in statewide system production costs. While the study reports other benefits such as reductions in emissions, capacity market payments and consumer energy payments, it does not reflect them in the benefit-to-cost ratios.

“In terms of Phase I, there’s a whole host of data that’s presented,” Duffy said. “We look at historic, we look at its projected congestion on the system, we identify what the key drivers are, and we look at a number of different scenarios in terms of gas prices; for example, other load forecasts, other big macro changes on the system and how they affect system congestion.”

Six Studies

The ISO studied the three congested areas under six scenarios:

• Study 1: Central East-Edic-Marcy
• Study 2: Central East
• Study 3: Central East- New Scotland- Pleasant Valley
• Study 4: Study 3 with Edic- Marcy relaxed
• Study 5: Study 3 under the System Resource Shift Case
• Study 6: Study 5 with Edic-Marcy relaxed

Planners began with a “business as usual” (BAU) case consistent with past practices. In most such cases, the ISO is very constrained in terms of what it can model and assume, so the BAU results are of limited value, Duffy said.

A second set of results is more forward-looking, the product of the ISO “taking a step further, beyond the confines of the Tariff, in terms of the minimal amount of work required by the tariff,” Duffy said. “We created this system resource shift case, which essentially allowed us to use our judgment to identify a set of assumptions so that the results of the study would provide additional meaning.”

In including the system resource shift case, Studies 5 and 6 differed from the first four by modeling the Indian Point nuclear plant and all New York coal units as retired by 2020/21. In addition, the studies forecast that the state would meet its Clean Energy Standard 2030 goal of 50% renewable resources by 2026.

The study’s model included 4.6 GW of onshore wind, 10.8 GW of utility-scale solar and 250 MW of offshore wind in service by 2026, annually producing 28.5 TWh of renewable energy. ISO planners supplemented this with annual energy reductions of 10.5 TWh from energy efficiency.

Phase II of the CARIS process invites developers to propose specific transmission projects to address congestion on the system. The ISO will perform a benefit-to-cost analysis for each proposed transmission project to assess eligibility for regulated cost recovery.

While estimates of production cost savings will still dictate project eligibility, Phase 2 will examine zonal locational-based marginal pricing (LBMP) load savings to identify beneficiaries and determine cost allocation. The LBMP value used is net of transmission congestion contract (TCC) revenues and bilateral contracts.

To qualify for cost recovery under the ISO’s Tariff, a transmission project must have a capital cost of at least $25 million, benefits that outweigh costs over the first 10 years of operation and received approval to proceed from 80% or more of the actual votes cast by beneficiaries on a weighted basis.

Having met these conditions, the developer must also file with FERC for approval of the project costs and rate treatment.

Public Policy Tx

Switching gears from discussion about the CARIS process, Zach Smith, NYISO vice president for system and resource planning, said the ISO’s planning process has three core pieces: reliability, economic and public policy.

Among the steps taken so far on the public policy front, the ISO “last year selected the Western New York Public Policy Transmission project, and we’re currently going through stakeholder discussions on the AC transmission public policy, and we anticipate a selection of those projects in July this year,” Smith said. (See MC Approves Western New York Tx Proposal; NYISO Management Committee Briefs: Sept. 27, 2017.)

The proposed AC projects include the $1 billion Edic-Pleasant Valley 345-kV line and the $246 million Oakdale-Fraser 345-kV line, which are intended to relieve downstate congestion by upgrading the AC transmission systems north and west of New York City. (See Downstate NY to Pay 90% of AC Tx Projects.)

Smith highlighted one change in the ISO’s planning process, noting that under FERC Order 1000, “an interregional transmission project can be proposed under any of our planning processes.”

An interregional project is one physically located in two regions, such as transmission that ties PJM to New York.

“That project could then get a joint cost allocation, where customers within the PJM system might bear some costs, and New York might bear some cost,” Smith said. “To date we have not had an interregional project, but there is that potential there.”