Citizens Budget Commission Getting Greener – Energy Storage Estimate

Update: I have prepared three technical posts on this report: Once I completed these three posts, I realized that they were too wonky for a general audience.  The first post discussed their findings, the second post addressed their renewable energy forecast to meet the CLCPA, and the third post calculates the energy storage requirement for a winter peak period.  Because the CBC study is so important, I have prepared a less-technical summary that hits the highlights of all three posts.

On December 9, 2019 the Citizens Budget Commission (CBC) released a report entitled Getting Greener: Cost-Effective Options for Achieving New York’s Greenhouse Gas Goals  that addresses the impacts of the Climate Leadership and Community Protection Act (CLCPA).   There is much to like about the report but I disagree with a few of their recommendations and have concerns about some of the methodology.  In order to do this report justice, I have prepared three posts.  If you have an interest in New York energy policy I recommend that you read the entire document.  It is well written, comprehensively covers many of the issues associated with the CLCPA, and makes estimates of the resources needed to implement the CLCPA.  The first post discussed their findings and the second post addressed their renewable energy forecast to meet the CLCPA.  This post calculates the energy storage requirement for a winter peak period.


The CBC is a nonpartisan, nonprofit civic organization whose mission is “to achieve constructive change in the finances and services of New York City and New York State government”.  They claim to serve the public rather than narrow special interests try to preserve public resources, whether financial or human; and focus on the well-being of future New Yorkers which they say are “the most underrepresented group in city and state government”.

The CBC Energy Policy Committee managed the development of the report.  It was prepared for CBC by Seth Hulkower, President of Strategic Energy Advisory Services.  Apparently, this project has been in the works for a long time because the “initial findings of this report were presented at a CBC research conference held in New York City in December 2018”. The report was not completed until December 2019 because of New York’s changing policies over the past year.  In particular, the Climate Leadership and Community Protection Act was promulgated in July 2019. They made revisions based on feedback from external reviewers and staff at the Public Service Commission and the New York League of Conservation Voters but noted that their willingness to assist in the research does not “imply any endorsement of the report’s findings and recommendations”.

Future Energy Storage Requirements

One of my primary concerns with the CLCPA is how much energy storage would be needed.  In order to determine how much is needed we need to know the difference between expected generation and expected load at the time of the greatest difference.   I applaud the CBC for developing an estimate of the renewable energy requirements of this legislation.  The MW capacity I derived from the CBC work can be used to estimate how much energy storage would have been required to meet an example winter peak period in January 2018 for a scenario that includes the added load due to heating and transportation and the 2040 renewable energy resources.  I previously made an estimate of the energy storage requirements for a summer peak period but I only considered existing load.

The first step is to determine the renewable capacity in MW expected to be necessary to meet the future load.  The CBC Forecast of 2040 Capacity (MW) Resources to Meet CLCPA Goals table lists those resources.  In the previous post I described how I used a combination of historical and meteorological data to estimate future output for the two-day winter peak period.  Results are shown in the January 3-4 2018 Winter Peak With CBC Forecasted 2040 Capacity Resources to Meet CLCPA Goals table. This table shows that there was a fifteen-hour period from January 3, 2018 at 1600 until January 4, 2018 at 0600 with hourly storage deficits totaling 134,545 MWh.  That period will be used to calculate the amount of storage needed.  In the earlier analysis I looked at five-minute data but this one will only look at hourly values.

In the absence of some sophisticated methodology to determine how best to provide the necessary energy storage, I arbitrarily limited the battery resource duration to eight hours and then picked different battery capacities until I had a positive margin (generation plus storage minus load).  I assumed that the least cost energy storage approach would maximize energy storage duration based on lower costs per MWh in a recently released report from the National Renewable Energy Lab (NREL): “2018 U.S. Utility-Scale Photovoltaics-Plus-Energy Storage System Cost Benchmark”.

In the Estimated Energy Storage Required and Potential Price Necessary to Prevent Deficit on January 3-4 2018 table I summarize the energy storage needs and my projection for the amount of different duration energy storage systems needed.  I chose three 8-hour duration battery systems of 1,200, 7,600 and 7,700 as the primary systems and four other battery systems to erase the remaining deficits.  Note that when I did this kind of analysis using 5-minute data that there were higher peaks amongst the hourly values.  If that is the case for this scenario, then it would require even larger batteries.

Future Energy Storage Costs

The aforementioned NREL battery benchmark report estimated costs for a limited number of battery durations.  I calculated costs for different duration energy storage costs in a post at What’s Up With That.  The Calculated Cost Breakdown $ per kWh Parameters for a US Li-ion Standalone Storage System for Different Durations table shows the methodology used to calculate the battery costs for this estimate.  The estimated cost for the energy storage necessary to meet this winter peak period is a staggering $47 billion.

But that’s not all.  NREL reported on an analysis of the life expectancy of lithium-ion energy storage systems in 2017 in Life Prediction Model for Grid-Connected Li-ion Battery Energy Storage System.  The study tested batteries to simulate how long they would last in real-world conditions by reaching a certain depth of discharge rates and testing battery degradation over time.  Under NREL’s scenarios, an energy storage system is expected to last between seven and 10 years. “Without active thermal management, 7 years lifetime is possible provided the battery is cycled within a restricted 47% DOD operating range. With active thermal management, 10 years lifetime is possible provided the battery is cycled within a restricted 54% operating range,” NREL said.

My estimate of the batteries needed assumed 100% discharge and the NREL results indicate that smaller battery discharge is necessary in order to prolong the life expectancy up to ten years.  In other words if by magic we could install all the renewable resources and all the necessary battery energy storage today, then by the time 2040 rolled around most of the renewable resources would be reaching the end of their life expectancy and we would have to start installing the third round of a significantly larger number of batteries than I projected.


As documented in my previous post, energy storage will be required to keep the lights on, homes heated and cars charged on calm nights.  No amount of over-building solar and wind will remove that constraint.  The cost of the energy storage using LI ion batteries needed to meet an example winter peak period is estimated to be $47 billion dollars.  That value is probably conservative because of limitations on the operating range to extend life expectancy out to ten years.

I can only conclude that the State of New York must do a feasibility study to refine the CBC analysis of future renewable resources needed.  The analysis has to be detailed enough that the energy storage requirements can be projected so that a full cost estimate of compliance with the CLCPA can be estimated.

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 ( reflects that outlook. The second blog addresses the New York State Reforming the Energy Vision initiative ( 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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