UPDATE January 24, 2021: After posting this I prepared a comment for the New York Department of Public Service Case 20-E-0197 – Proceeding on Motion of the Commission to Implement Transmission Planning Pursuant to the Accelerated Renewable Energy Growth and Community Benefit Act addressing the Power Grid Study. I provide this update to note that there was a fourth document in the reports discussing offshore wind but that the report also did not address the problem described here.
On January 19, 2021 the New York State Department of Public Service (DPS) submitted the Initial Report on the Power Grid Study (“Power Grid Study”) prepared pursuant to the Accelerated Renewable Energy Growth and Community Benefit Act (AREGCBA). The AREGCBA legislation is intended to ensure that Climate Leadership and Community Protection Act (CLCPA) renewable generation is sited in a timely and cost-effective manner. In order for an electric energy grid powered primarily by renewable energy resources to maintain the same level of reliability as the existing system, somebody, somewhere has to provide transmission grid ancillary services. However, none of the three reports provided in the documentation address the problem apparently because it is somebody else’s problem.
I have written extensively on implementation of the CLCPA closely because its implementation affects my future as a New Yorker. I have described the law in general, evaluated its feasibility, estimated costs, described supporting regulations, listed the scoping plan strategies, summarized some of the meetings and complained that its advocates constantly confuse weather and climate. The opinions expressed in this post do not reflect the position of any of my previous employers or any other company I have been associated with, these comments are mine alone.
First let me describe transmission grid ancillary services. A reliable electric power system is very complex and must operate within narrow parameters while balancing loads and resources and supporting synchronism. New York’s conventional rotating machinery such as oil, nuclear, and gas plants as well as hydro generation provide a lot of synchronous support to the system. This includes reactive power (vars), inertia, regulation of the system frequency and the capability to ramping up and down as the load varies. Wind and solar resources are asynchronous and cannot provide these necessary grid ancillary support.
Some, but not all of the disadvantages of solar and wind energy in this regard can be mitigated through electronic and mechanical means. When these renewable resources only make up a small percentage of the generation on the system, it is not a big deal. The system is strong enough that letting a small percentage of the resources that don’t provide those services to lean on the system. But as the penetration of solar and wind energy increases the system robustness will degrade and reliability will be compromised without costly improvements. A renewable system could be coupled with extensive batteries and other storage devices, large mechanical flywheels and condensers (basically an unpowered motor/generator that can spit out or consume reactive power). These devices could approximate the behaviors of our conventional power system.
My particular concern is that the CLCPA process has only considered the energy storage ancillary services needed to keep the system operating when intermittent wind and solar resources are not available. Importantly, the other grid support requirements needed so the electric grid can transmit the power from where it is produced to where it is needed are not adequately discussed in two of the reports included in the Power Grid Study that is supposed to inform the CLCPA implementation process.
As far as I have been able to see this component of the future electric system has not been addressed by the CLCPA implementation process. I have reviewed two processes to determine if it is being considered. The Power Generation Advisory Panel that is supposed to develop recommendations for the Scoping Plan that will guide implementation of the changes to the electric system needed to meet a goal of zero emissions by 2040. In my review of their strategy recommendations, I found that they did not mention the problem.
The second process and focus of this post is the Power Grid Study. According to the Executive Summary:
“Transmission & Distribution (T&D) infrastructure will play a critical role in meeting the State’s goals by connecting new renewable resources to the grid and transmitting and delivering energy to consumers. Accordingly, the recently enacted Accelerated Renewable Energy Growth and Community Benefit Act directs the Public Service Commission (PSC) to advance the work of identifying T&D upgrades needed to reliably and cost-effectively integrate the required renewable resources, and to establish planning processes to support cost-effective and timely infrastructure development.”
“To meet these directives, the PSC, through the Department of Public Service, initiated a set of system studies, collectively referred to as the Power Grid Study, which is the subject of this Initial Report. The PGS consists of three components, each of which is included in this Report:
- A study conducted by the Joint Utilities1 on local transmission and distribution (LT&D) needs (Utility Study);
- A study of offshore and onshore bulk-power transmission infrastructure scenarios, and related environmental permitting considerations, to illustrate possible solutions to integrate the mandated 9,000 MW of offshore wind (OSW generation by 2035, sponsored by the New York State Energy Research and Development Authority (NYSERDA) and conducted by DNV-GL, PowerGem, and WSP (OSW Study)
- A state-wide scenario-based study to analyze transmission, generation, and storage options for achieving 70% renewable generation by 2030 and a zero emissions grid by 2040, sponsored by NYSERDA and conducted by Siemens (Zero Emissions Study).”
Given the importance of the transmission grid ancillary services needed to keep the lights on I assumed that they would be addressed in the Power Grid Study documents. Collectively these documents are huge so instead of reading each one to determine if these services were included, I searched them. I used search terms that I believe should be associated with this requirement. I used the following search terms: “Synchro”, “Ancillary”, “Frequency”, “Inertia”, “Reactive” and “Vars”.
When I used those search terms in the study of offshore and onshore bulk-power transmission infrastructure scenarios, the only relevant references mentioned static synchronous series compensators and smart inverters. Those were passing references to specific kinds of equipment and did not address the scope or magnitude of the services necessary to maintain reliability. I believe this indicates that this study does not adequately address this issue
I also reviewed the Utility Study in the same way and in that report found relevant references. Eight utility companies proposed plans for local transmission and distribution systems to meet the CLCPA requirements and two included projects targeted to address these ancillary services. The Long Island Power Authority (LIPA) identified a “potentially major issue on the transmission system with the significant increase of inverter-based resources (IBR) and concurrent retirement of conventional fossil power plants is the weakness of the system and the potential for adverse IBR behavior due to this weakness, as well as voltage instability.” This is exactly the kind of issue that I believe needs to be addressed. The report does not quantify this risk but explains that it is very likely that “new synchronous resources will be required (or alternatively, existing resources not being retired and run uneconomically) to strengthen the system such that these new IBR as well as the overall power system can operate in a stable manner.” LIPA included a proxy project for at least one synchronous condenser installation on their system. Avangrid proposed Power Flow Control Devices at several locations including three (3) different technologies (Series Reactors, Phase Angle Regulators, and Static Series Synchronous Compensator devices).
In addition, the report raised the issue in a section on potential technology solutions that included “Energy storage for T&D services” that addressed ancillary services beyond energy storage:
“Energy storage is increasingly being considered for many transmission and distribution (T&D) grid applications to potentially enhance system reliability, support grid flexibility, defer capital projects, and ease the integration of variable renewable generation. Central to the State’s policies and mandates is the need to enhance power system flexibility to effectively manage renewable energy deployment and the associated increase in variability. As power systems begin to integrate higher penetrations of variable, renewable, inverter-based generation in place of conventional fossil-fuel fired synchronous generation, grid-scale energy storage could become an increasingly important device that can help maintain the load-generation balance of the system and provide the flexibility needed on the T&D system. Pumped hydro storage (PHS) and compressed air energy storage (CAES) are long-established bulk energy storage technologies.”
“Utility-scale lithium-ion battery storage has expanded dramatically, as decreasing lithium ion battery costs make this an increasingly cost-effective solution to meet T&D non-wire, reliability, and ancillary service needs. Redox flow batteries, sodium sulfur batteries, thermal energy storage (both latent and sensible heat), and adiabatic compressed air energy storage are all in various stages of demonstration. This information provides a concise overview of a wide variety of existing and emerging energy storage technologies being considered for T&D systems. It describes the main technical characteristics, application considerations, readiness of the technology, and vendor landscape. It also discusses implementation and performance of different energy storage technologies. In this Report, energy storage systems greater than 10 MW and four or more hours of duration, are considered as bulk and transmission and sub- transmission-connected energy storage.”
There were also several other general references to the ancillary services problem. However, the study did not quantify the risks of adverse inverter-based resource behavior or voltage instability in general and only LIPA included specific projects to address that problem. Kudos to the Utility Study for identifying the problem butsomeone has to quantify these risks.
I reviewed Zero Emissions Study the same way. According to the findings of the report:
“Based on the analysis carried out in the study, New York State should be able to achieve its 70 x 30 and zero-emission generation by 2040 goals under both the Initial Scenario and the High Demand Scenario using a mix of distributed energy, energy efficiency measures, energy storage, planned transmission projects, utility-scale renewables, and zero-emission resources. The most significant difference in these scenarios was the amount of renewable generation added and the scope (transmission capacity increases) of the transmission projects required to manage congestion and reduce costs.”
Note that this summary described transmission capacity increases but did not mention the ancillary support services requirements. I found no references that addressed reactive power (vars), inertia, or regulation of the system frequency, but they did mention the ramping adequacy ancillary service. Therefore, the claim that New York State should be able to achieve the targets is not based on adequate analysis.
There were three reports included in the Power Grid Study documentation. The Power Grid Study itself did not address any of the component ancillary services issues. The Utility Transmission & Distribution Investment Working Group Study broached the general problem but only two utilities offered projects to address related components of the problem. The Zero-Emissions Electric Grid in New York by 2040 confidently claimed that New York should be able to achieve its zero-emission by 2040 goal but only mentioned ramping adequacy as a potential issue. As a result, this documentation falls far short of what is necessary to guarantee the reliability of the electric system by 2040. Those unaddressed requirements will lead not only to cost shifting where the total costs of fossil fuel alternatives have to be directly or indirectly subsidized by the public, but also reliability concerns because no electric grid anywhere has resolved these transmission grid ancillary services requirements and successfully maintained a grid that is as reliant on wind and solar resources as the proposed NY grid.
Given the vital importance of transmission ancillary services to maintain a reliable grid how can anyone explain that two out of three reports on the future grid don’t even mention the problem in any detail? I could not help but notice that this situation is the same as the “Somebody Else’s Problem” phenomenon described by Douglas Adams in his novel Life, the Universe and Everything (in The Hitchhiker’s Guide to the Galaxy comedy science fiction series). Adams describes the idea of an “SEP field” as a kind of cloaking device. The character Ford Prefect says: “An SEP is something we can’t see, or don’t see, or our brain doesn’t let us see, because we think that it’s somebody else’s problem. That’s what SEP means. Somebody Else’s Problem. The brain just edits it out, it’s like a blind spot.” The text then explains: “The Somebody Else’s Problem field… relies on people’s natural predisposition not to see anything they don’t want to, weren’t expecting, or can’t explain.” I can only conclude that the authors of these reports didn’t address transmission ancillary services because it was somebody else’s problem.