New York ISO outlines grid needs to support 50% renewable energy target

The New York Independent System Operator filed July 8 comments with the New York State Public Service Commission supporting Gov. Andrew Cuomo’s goal of getting 50% of the state’s energy from renewable resources by the year 2030 (called the “50% by 30”) plan, adding that a lot of grid projects will be needed to get this renewable energy into the New York City load center.

This goal, covered under the Clean Energy Standard (CES), will play a significant role in shaping the bulk power system in New York State over the next 15 years. NYISO said it has concerns over how the New York PSC is developing and planning to implement the CES to achieve the 50% by 30 objectives.

For the CES initiative to be successful, new renewable resources must be reliably and efficiently integrated into the bulk power system and NYISO’s wholesale electric market structure. The NYISO said it believes that the commission’s record would be incomplete without a fuller discussion of the CES impacts on the state’s bulk power system and wholesale electricity markets.

The July 8 comments focus on bulk power system needs, particularly new transmission, and certain wholesale market ramifications associated with the CES initiative as described in the Department of Public Service (DPS) Staff White Paper on the Clean Energy Standard.

The NYISO’s comments address three principal issues related to system reliability:

  • additional transmission capability necessary to reliably transport energy from renewable resources developed in remote areas, mainly western and northern New York, to New York’s southeast load centers;
  • additional energy and ancillary service requirements necessary to maintain system reliability with the level of intermittent resource penetration required by the CES; and 
  • the state’s resource adequacy requirements resulting from the significant additional intermittent resource penetration required by the CES.

The DPS Staff White Paper states that “the CES program will be required to add an additional 33,700 GWh of renewable energy to meet the 50% by 2030 mandate.” The CES Draft Supplemental Environmental Impact Statement prepared for the DPS Staff (“DPS SEIS”) reiterated that approximately 34,000 GWh of new renewable energy supply in 2030 will be required to achieve 50% by 30.

The DPS SEIS further assumed that approximately 5,000 GWh of that new supply will be met with “behind-the-meter” generation (such as customer-sited solar photovoltaic). Therefore, approximately 29,000 GWh/year of additional energy will have to come from new wholesale renewable generators.

The DPS SEIS projects that a mix of approximately 12,000 MW of renewable resources will be developed in response to the CES, bringing New York’s total renewable generation capability to over 19,000 MW (including generators in New York State and imports from Ontario and Quebec). The DPS SEIS’s projected resource mix for the Base Case Fixed-REC category includes additional resources of approximately 6,800 MW of utility-scale solar, 3,500 MW of land-based wind, 600 MW of conventional hydroelectric, 450 MW of renewable imports, 360 MW of biomass and anaerobic digestion, 200 MW of off-shore wind and 3,000 MW of behind-the-meter solar.

Approximately 90%, or 17,000 MW, of New York’s total renewable generation is anticipated to be located in Upstate New York (NYISO Zones A-F). The NYISO in the July 8 comments used the DPS’s projected renewable resource build-out and associated energy production figures (e.g., capacity factors) to facilitate analysis and discussion without endorsing the assumptions of the DPS SEIS.

"The DPS SEIS correctly assumes that a large percentage of the new renewable resources will be intermittent, located away from the State’s load centers, and distributed over a large geographic area," NYISO wrote. "Such a significant build-out of renewable resources will require new or upgraded transmission facilities on both the bulk power system and the sub-transmission systems to deliver the output of these new resources to the southern and eastern portions of New York State, where demand for electricity is greatest.

"Significant additional transmission system investment will be required to deliver energy from anticipated new renewable resources beyond the AC Transmission and Western New York public policy initiatives now underway, which are important steps to improving operation of the bulk power system that were not included in the DPS SEIS.

"Much of New York’s renewable energy capability is located in upstate New York, with additional potential in the Canadian provinces of Ontario and Quebec, requiring upgrades to the bulk power transmission system to deliver the renewable energy to load. The resource mix and geographic distribution of the new renewable resources will dramatically change power flows across the New York State bulk transmission system. Significant additional volumes of renewable energy will have to move east and south across the State to serve load. In order to achieve 50% by 30, the bulk power transmission system must have the capability to deliver all renewable resources’ energy production simultaneously.

"The bulk power transmission system’s transfer capability is limited by engineering principles based on the physical capability of the system designed to maintain safe, reliable operations and protect equipment. If the system is undersized at any point between the renewable generator locations and the load centers, renewable generation may likely be curtailed, jeopardizing achievement of 50% by 30 based on the projected build-out in the DPS SEIS.

"In order to maximize the yearly average load served by renewable generation, cross-state energy transfers will actually increase as load decreases due to the fact that more renewable generation is available to serve the downstate load. As renewable penetration in the upstate regions outweighs the load in those same regions, additional energy transfers from upstate renewable resources to downstate load centers are necessary, subject to the transmission system capability.

"A lower total system load allows a higher percentage of load to be served by renewable resources. Curtailment of renewable generation to maintain transmission system reliability, consistent with the NYISO’s 2010 Wind Study finding, would quickly jeopardize achievement of 50% by 30 because energy will not be deliverable from renewable resources to downstate load centers.

"The anticipated renewable generation development and cross-state energy transfer increases are significant compared to the existing system flows. Transmission system constraints already materialize at a number of interfaces in the west to east and north to south directions across the State during certain system conditions. Additional renewable resources built in the western and northern portions of the State will exacerbate the transmission constraints that limit energy transfers across the State.

"The NYISO has begun analyzing potential new transmission facilities to help accommodate additional renewable resource build-out throughout western and northern New York. Based on the volume of new renewable generation resources and the locations for build-out projected in the DPS SEIS, the NYISO estimates that one likely transmission development scenario could require nearly 1,000 miles of new bulk power transmission, in addition to the AC Transmission and Western New York public policy initiatives now underway, to avoid frequent west to east transmission constraints in the future.

"Sub-transmission systems (i.e., 69 to 138 kV transmission facilities) will also require significant investment to bring the renewable energy from renewable resource sites to the bulk power transmission system. The sub-transmission system must have the capability to transfer intermittent renewable resources’ full energy output to the bulk power system in order to fully utilize qualifying energy production from these resources. Undersized sub-transmission systems may result in renewable energy generation being curtailed to maintain local electric system reliability.

"As the CES progresses, and the asset mix and locations become clearer, the NYISO will conduct further analyses of both the bulk and sub-transmission upgrades necessary for the CES to be accomplished."

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.