NYISO Winter Peak Analysis Implications to CLCPA

A new report prepared at the request of the New York Independent System Operator (NYISO) addresses issues associated with an electric system reliant on renewable energy sources during the winter.  This post compares these results with my previous work related to New York’s Climate Leadership and Community Protection Act (CLCPA) and discusses the implications on that law.

The Citizens Budget Commission developed an overview of the CLCPA targets in Green in Perspective: 6 Facts to Help New Yorkers Understand the Climate Leadership and Community Protection Act.  The goals of the law are truly aspirational:

Reduce greenhouse gas (GHG) emissions:

      • Reduce GHG emissions to 60 percent of 1990 emissions levels in 2030;
      • Generate zero GHG emissions from electricity production by 2040; and
      • Ensure GHG emissions are less than 15 percent of 1990 emissions levels in 2050, with offsets to reduce net emissions to zero.
      • GHG offsets means that for every ton emitted into the air one ton is removed via GHG capture of some sort. For example, a company or individual can pay a landowner to leave trees standing that would otherwise be removed or plant additional trees to offset GHG emissions.

Increase renewable electricity:

      • Increase renewable sources to 70 percent by 2030; and

Develop or support:

      • 9 gigawatts (GW) of offshore wind electric generation by 2035;
      • 6 GW of distributed photovoltaic solar generation by 2025; and
      • 3 GW of energy storage capacity by 2030.
      • Conserve 185 trillion British thermal units (TBTUs) of annual end-use energy use by 2025, of which at least 20 percent should be from energy efficiency improvements in disadvantaged communities.
      • The CLCPA also requires between 35 percent and 40 percent of spending on clean energy or efficiency programs be in disadvantaged communities and mandates an air monitoring program in at least four such communities.

I have evaluated winter peak impacts in previous posts on New York Resource Adequacy Proceeding Comments, Solar Issues in Upstate New York , CLCPA Solar and Wind Capacity Requirements and CLCPA Energy Storage Requirements.  My primary concern is the requirement to generate zero GHG emissions from electricity sector production by 2040 coupled with the increased load needed to electrify the heating and transportation sectors enough to meet the 85% reduction by 2050 target.

Fuel and Energy Security In New York State Report

NYISO  had the Analysis Group do a forward-looking assessment of the fuel and energy security of the New York electric grid during winter operations.  The November 2019 final report was titled: Fuel and Energy Security In New York State: An Assessment of Winter Operational Risks for a Power System in Transition.  The objective was to assess winter fuel and energy security risks and identify key factors that would affect risks. Specifically, the study targeted potential reliability risks and impacts under severe winter conditions and adverse circumstances regarding system resources, physical disruptions, and fuel availability.  Importantly it is a snapshot of the winter of 2023-2024 before the CLCPA renewable energy and electrification of other sectors implementation really kicks in

Previously I have analyzed the effect of winter peaks and I chose 12/29/17 to 1/12/2018, a period that is included in their analysis.  The Analysis Group defined extreme weather events including the largest increase above average daily load over a long period as 14 days from 12/25/2017 to 1/8/2018 and more extreme shorter periods where they found in the last 25 years the fourth lowest 3-day cold snap was 1/4/2018 to 1/7/2018.  Then they evaluated different scenarios that included different combinations of “(a) timeframe for the development of new renewable resources; (b) capacity imports from neighboring regions; (c) potential retirement of units affected by the peaker rule; and (d) availability of natural gas for power generation”. The evaluation determined where these scenarios might cause problems.

The analysis included the following relevant conclusions (two key points underlined by my emphasis):

    • With the continued operation and availability of most of the assets currently expected to be in place in the winter of 2023/2024, the NY grid contains sufficient diversity and depth of fuel supply to support reliable winter operations. This result is consistent with the historical operating experience in recent past winters, including during severe weather conditions.
    • Meeting the state’s renewable and clean energy goals can provide valuable reliability support, and may be particularly true with respect to offshore wind. Delayed realization of renewable resource additions (as compared to the 2017 CARIS Phase 1, System Resource Shift case levels that are assumed under initial conditions) can lead to potential LOL events that would not otherwise occur when combined with other adverse system conditions. The potential magnitude and pace of change to the resource fleet stemming from requirements under the CLCPA may be of far greater importance for evaluation than the considerations, scenarios and physical disruptions evaluated in this fuel and energy security study with respect to winter operational risks.
    • The availability and contributions of adequate levels of natural gas-fired and oil-fired (or dual fuel) generating resources is necessary to maintain power system reliability in cold winter conditions in the near-term. This is particularly true for Long Island and New York City. Simply put, avoidance of potential loss of load events in these load centers, under plausible adverse winter conditions, requires operation of natural gas and oil-fired units. Reduction in the generation available from such resources – whether through capacity retirements, low initial oil inventories, reduction in natural gas availability for power generation, or interruptions in the ability to refuel oil tanks throughout the winter represents the most challenging circumstances for reliable winter system operations in New York over the coming years.

Implications for CLCPA

The analysis notes that the “potential magnitude and pace of change to the resource fleet stemming from requirements under the CLCPA may be of far greater importance for evaluation than the considerations, scenarios and physical disruptions evaluated in this fuel and energy security study with respect to winter operational risks”.  I agree because I believe that it is absolutely necessary for the State to prove that when the energy load increases when other sectors are electrified that fuel and energy security can be maintained without using fossil fuels.

The analysis also states that “Simply put, avoidance of potential loss of load events in these load centers, under plausible adverse winter conditions, requires operation of natural gas and oil-fired units”.  The CLCPA requirement that all electric energy must come from non-fossil fired sources in 2040 is an extraordinarily difficult goal to meet.  The political calculus to include this in legislation was not backed up by any analysis.  The state has to show how this can be done as soon as possible lest New York resources be squandered on an impossible quest.  As I show below, the actual renewable resource may not support this target because of logistical issues and even if it does there may be immense costs.

Need for Renewable Energy Resource Analysis

In my back of the envelope analysis of the summer peak energy storage requirements I used actual wind speed data to estimate the New York off-shore wind resource.  New York State awarded the first two contracts for off-shore wind projects in July 2019.  The Equinor 816 MW winning project press release said “The project is expected to be developed with 60-80 wind turbines, with an installed capacity of more than 10 MW each”.  Among the many details redacted in the public version of their proposal was specific information on the proposed wind turbines.  The public version included a diagram of the proposed wind turbine size as compared to the Chrysler building and showed that top tip of the blade at 250 m.  I estimated the hub height to be 173 m by scaling the drawing.  In this analysis I characterized wind energy output as a function of observed wind as follows.   I found a wind turbine power output variation curve that had a cut-in speed of 3.5 m/s and a cut-out wind speed of 25 m/s. Using that wind variation curve, I estimated that output of each 10.2 MW wind turbine will equal 0.971 times the wind speed minus 3.4.

For the input meteorological data, I found a National Oceanic and Atmospheric Administration buoy located 30 nautical miles south of Islip, NY (40°15’3″ N 73°9’52” W) that I used to represent NY offshore wind resource availability. The observed wind speed at the hub height is proportional to the logarithm of the height above ground.  For that calculation I assumed a hub height of 173 m and a surface roughness of 0.0003 using the buoy anemometer height of 4.9 m. I downloaded hourly NDBC data for 2018 and 2017 and calculated the wind energy output for every hour in the period 12/25/2017 to 1/8/2018 using that relationship and the wind turbine output variation equation I derived.

The key finding is that there were two no wind energy output periods on 3-4 January 2018 during an intense cold snap when electric load is high as shown in the New York Off-Shore Wind Generation Estimate for 9000 MW CLCPA Off-Shore Target table.  I was surprised to see that the wind resource went to zero during a high load period not only when the winds were light on January 3 but also when a deep low pressure developed and the wind speeds exceeded 25 m/s on the very next day.  The wind generation estimate table lists the output from a single 10.2 MW wind turbine, 80 turbines in the Equinor proposed wind facility and for all 9,000 MW of Cuomo’s CLCPA target of 9,000 MW of off-shore wind.  It is important to note that adding even more wind turbines still does not preclude the need for substantial energy storage.  While all the New York off-shore wind resource may not go to zero simultaneously that resource is going to be highly correlated across the available area so they all will track closely.


Every time I look at the meteorological data relative to the winter peak I get a surprise.  I expected that the winter observed peak load would occur during very cold weather associated with a slowly moving high pressure system that originated in the cold northern plains large enough to cover the entire northeastern US.  The resulting multi-day period of clear skies, light winds, and inherent cold temperatures would result in very high energy demand for heating.  The early January 2018 high load period was very different.  Weather maps for this period show (January 2018 Weather Maps) a relatively small high pressure system in the central US on January 2 that moved east ahead of a storm system on January 3.  The high pressure was strong enough over the New York offshore wind region that winds were less than 3.5 m/s for five hours on January 3.  However, the storm system moved eastward and re-developed into a strong storm just off the coast on January 4 with an eleven-hour period of greater than 25 m/s wind speed 13 hours after the light wind period ended.  By January 5 the storm had raced northeast to the Canadian Maritimes but was pumping cold air back across New York State.

This period must be analyzed in more detail by New York State to determine whether the CLCPA requirements endanger fuel and energy security.  If the assumptions I used for no wind power due to light winds and strong winds are correct then there will be 16 hours of no wind power in a 29-hour period during the coldest extended duration cold weather event that the Analysis Group identified after analyzing 25 years of data.  Furthermore, it also overlaps fourth worst 3-day cold snap.  The State needs to estimate what the future load will be when the home heating and transportation sectors are electrified to meet the CLCPA emission reduction goal and then assess whether renewable resources will be adequate during the entire extended duration period using the proprietary energy output information in the renewable energy proposals submitted to the State not only in the NYSERDA off-shore wind program but also the Article Ten applications.  This analysis has to be done for the entire state and obviously will lead to an estimate of the amount of energy storage necessary in 2040 when no electric energy from fossil-fired facilities is allowed.  It is not clear to me if there is enough space available where it is needed to site all the renewable and energy storage necessary.  Even if there is enough space, this analysis will provide the information needed to estimate how much all this will cost.

Frankly, it is laughable that the New York State legislature and Governor Cuomo enacted a law mandating specific energy and emission reduction goals without doing such an analysis first.  I believe it is time for the energy professionals in the State to step up and demand such an analysis before the State squanders money on a system design that can only be implemented with massive wind, solar and energy storage development.  Even if this system could be developed it will surely be expensive.  Just how much is anyone’s guess until such a study is completed.

Author: rogercaiazza

I am a meteorologist (BS and MS degrees), was certified as a consulting meteorologist and have worked in the air quality industry for over 40 years. I author two blogs. Environmental staff in any industry have to be pragmatic balancing risks and benefits and (https://pragmaticenvironmentalistofnewyork.blog/) reflects that outlook. The second blog addresses the New York State Reforming the Energy Vision initiative (https://reformingtheenergyvisioninconvenienttruths.wordpress.com). Any of my comments on the web or posts on my blogs are my opinion only. In no way do they reflect the position of any of my past employers or any company I was associated with.

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