Matt Estes’s recent Explaining the Grid Substack post, “Wind and Solar will always, without exception fail us when we need electricity the most,” correctly objects to an overly broad claim about renewable generation. Existing wind and solar facilities plainly do produce useful energy and can reduce fuel use, emissions, and—at some times—system stress. But the post misses the central reliability problem facing a future grid designed around weather-dependent generation: wind and solar do not have to fail all the time to create an unacceptable reliability risk. They need only fail together, for long enough, during a severe system peak to exhaust energy storage and overwhelm the remaining dispatchable resources.
For New York, that is not an abstract issue. It is the fundamental unresolved flaw in the Climate Leadership & Community Protection Act (Climate Act) transition strategy and in plans that presume wind, solar, storage, transmission, and some undefined category of “dispatchable emissions-free resources” (DEFR) can replace the dependable capacity now provided by fossil generation.
The more accurate warning is not that wind and solar “will always, without exception fail us when we need electricity the most.” It is this:
- Wind and solar will eventually fail catastrophically during a prolonged period when electricity is needed most unless the grid has enough dependable, fuel-secure, dispatchable capacity to carry the system through the event.
That distinction matters. It explains why simply pointing out that solar and wind help during many peak-demand hours does not answer the reliability question.
I am convinced that implementation of the Climate Act net-zero mandates will do more harm than good if the future electric system relies only on wind, solar, and energy storage because of reliability and affordability risks coupled with cumulative environmental impacts of those resources. These comments are based on those concerns. The opinions expressed in this article do not reflect the position of any of my previous employers or any other organization I have been associated with, these comments are mine alone. I acknowledge the use of Perplexity AI to research and organize the material summarized in this article.
Estes responds to David Blackmon’s reference to Winter Storm Uri in Texas by noting that the 2021 Texas disaster was not exclusively a wind-and-solar failure. The University of Texas assessment found that all major types of generation experienced outages or reductions during the event. In particular, roughly 25,000 MW of natural-gas capacity went offline when Texas most needed it.
That is an important point. Fossil-fueled generation is not automatically reliable merely because it is dispatchable. Generators can fail because of inadequate winterization, fuel-supply interruptions, frozen equipment, maintenance failures, transmission constraints, or poor market incentives. Texas’s failure to require adequate cold-weather preparation was a preventable institutional and engineering failure.
But that lesson does not mean weather-dependent generation has no unique reliability limitation. A gas turbine that fails because its fuel supply froze, its equipment was not winterized, or its operator did not prepare for foreseeable weather conditions has options to be made more reliable. The remedial actions are well understood:
- Winterize equipment and gas infrastructure.
- Firm up fuel supplies and delivery arrangements.
- Test cold-weather performance.
- Establish reliability standards.
- Pay generators for availability during extreme conditions.
- Retain sufficient reserve capacity.
Those measures may be costly, but they are technically straightforward. They address a failure of equipment, fuel delivery, regulation, or market design.
The problem with wind and solar is different. Their low-output periods are not primarily a maintenance or regulatory problem. They are an inherent feature of the underlying resource.
No amount of winterization can make the sun shine at night, increase winter solar irradiance, remove snow from every panel during a regional snow event, or make the wind blow during a persistent high-pressure system. Wind and solar output can be improved at the margin by better siting, diversity, transmission, maintenance, forecasting, and geographic dispersion, but there are inherent limitations to those resources in New Yok. Moreover, none of those measures eliminates the possibility of an extended period of low wind and low solar output across a broad region.
That is why the appropriate question is not whether renewables ever provide useful electricity. Of course they do. The question is whether a system that relies on them can remain reliable during the rare but consequential weather conditions when their output is low for days or weeks.
The New York Reliability Problem
The Climate Act requires a transition to an economy increasingly dependent on electricity. Building heating, transportation, industrial processes, and other end uses are supposed to shift away from direct combustion of fossil fuels. As a result, New York’s electric system will have to serve a much larger share of total energy demand.
That transition changes the reliability stakes.
Today, New York’s most serious system challenges often occur during hot summer afternoons, when air-conditioning demand is high. Solar generation can be useful during those periods because its output tends to coincide with daytime cooling demand. Estes is correct that solar output can be particularly valuable during sunny summer conditions when electricity use is elevated.
However, the Climate Act’s all-electric end-state changes the planning problem. Widespread electrification of heating means that the most consequential peak-demand events are likely to occur during severe winter cold spells, particularly in the early morning and evening hours.
Those are precisely the periods when solar output is weakest or nonexistent.
New York’s winter solar resource is limited by several factors:
- Winter days are shorter than summer days.
- The sun is lower in the sky.
- Peak heating demand often occurs before sunrise and after sunset.
- Cloud cover can materially reduce output especially downwind of the Great Lakes in NY.
- Snow cover can reduce photovoltaic production sharply or reduce it nearly to zero until panels are cleared or conditions change.
- The coldest weather often occurs during high-pressure systems that can also suppress wind generation over broad areas.
Earlier this year I documented the impact of these factors on wind and solar availability in New York during an extended cold snap (here, here, and here).
The geography matters. New York is not Texas, California, Arizona, or Florida. General claims about solar output during hot summer days cannot be transferred automatically to an upstate New York winter reliability analysis.
Nor is it enough to say that wind output is variable but geographically diverse. There are documented weather patterns in which low wind generation extends across large areas for prolonged periods and New York wind resources are highly correlated. New York’s reliability concern is not a short-lived dip in renewable output that can be covered by a few hours of battery discharge. The concern is a multi-day—or potentially longer—period of low wind and solar generation coinciding with high electric demand.
The relevant reliability question is therefore:
- Can New York supply demand throughout the worst plausible extended wind-and-solar drought? If the answer depends on unspecified future resources, then the Climate Act transition plan has not yet demonstrated that it can meet its statutory reliability obligation.
Storage Does Not Eliminate the Problem
Battery storage is valuable. It can shift solar output from midday to evening, provide frequency support, reduce ramping requirements, respond quickly to contingencies, and help cover short-duration capacity needs.
But batteries are energy-limited resources. They can discharge only until their stored energy is exhausted.
A 1,000 MW battery with four hours of duration can provide approximately 4,000 MWh of energy. That may be highly useful for managing a four-hour evening peak. It cannot, by itself, supply 1,000 MW for several days of low renewable output.
The distinction between power and energy is critical:
- Power capacity determines how much electricity can be delivered at one time, measured in MW.
- Energy capacity determines how long that delivery can continue, measured in MWh or GWh.
New York’s future resource planning must address both.
Short-duration batteries may help meet a resource adequacy metric based on a few peak hours. They do not necessarily solve the problem of surviving an extended period when wind and solar output remain low, demand remains elevated, and batteries cannot be fully recharged.
A grid reliant on wind, solar, and batteries has a circular vulnerability during a renewable drought:
- Wind and solar output falls.
- Storage discharges to meet demand.
- Low renewable output prevents storage from recharging adequately.
- The renewable lull continues.
- Storage is depleted.
- The system must depend on dispatchable generation, imports, demand reductions, or outages.
The Unanswered DEFR Question
New York energy-planning documents frequently refer to “dispatchable emissions-free resources,” but that label is not a resource plan. It is a placeholder. A credible reliability strategy must specify:
- What the DEFR technologies are.
- How much capacity will be needed.
- How much energy they can provide.
- How long they can operate continuously.
- What fuel or energy source they will use.
- Whether that fuel can be stored on site or delivered reliably during extreme weather.
- Whether the technology can be deployed at scale in New York.
- What it will cost to build, maintain, and use.
- Who will pay for capacity that may run very infrequently.
- Whether the resource remains available during the same weather conditions that reduce wind and solar output.
The last point is especially important.
If New York’s DEFR solution is hydrogen manufactured with surplus wind and solar power, then the state still must demonstrate that it can produce, store, transport, and retain enough hydrogen to carry the system through the worst relevant wind-and-solar drought. Calling hydrogen “dispatchable” does not make the upstream energy problem disappear.
The system must have enough renewable energy and electrolyzer capacity to make hydrogen during favorable conditions, enough storage to preserve it until an extreme event occurs, enough generating capacity to convert the hydrogen back into electricity, and enough infrastructure to ensure that the fuel is available when needed.
That could mean maintaining a very large and very costly resource that operates only during rare events.
There is also a difficult economic problem. Suppose the weather event that establishes the planning requirement has a return period longer than the useful economic life of the DEFR facility. A resource built specifically to protect against an event expected only once every several decades may reach the end of its life before it is ever called upon to perform its defining function. The resource still must be financed, maintained, inspected, fueled, staffed, and tested.
That raises the unavoidable affordability question:
- How can New York finance dependable capacity that may be essential for reliability but is used so rarely that it cannot recover its costs from energy sales?
The answer is capacity payments, regulated cost recovery, or some comparable reliability obligation. But that means the costs of a wind-solar-storage-DEFR system cannot be evaluated only by comparing the energy cost of wind and solar with the energy cost of conventional generation. The full cost must include the dependable backup system, long-duration energy storage, new transmission, distribution-system upgrades, fuel infrastructure, reserve margins, and the cost of maintaining resources for rare but severe weather events.
Nuclear Is the Obvious DEFR
Nuclear power is a proven dispatchable emissions-free resource. It can provide dependable electricity through New York’s winter peaks without relying on wind or sunlight, and its fuel can be stored on site. However, new plants face substantial costs, long construction timelines, and financing risks, but those challenges are better understood than the performance and cost of the still-undefined resources the Climate Act Scoping Plan expects to replace fossil generation.
If New York builds nuclear capacity, it should use it as a primary source of reliable zero-emission electricity—not merely as rarely used backup for a wind, solar, battery, and hydrogen system that still needs dependable generation during prolonged renewable shortfalls.
Conclusion
Estes’ issues with Blackmon’s statement is overly absolute. Wind and solar do not always fail when electricity is needed most. At many times they provide useful, and sometimes very valuable, electricity. But Estes’s response does not address the more consequential problem for New York’s Climate Act transition.
Wind and solar are weather-dependent resources. There will eventually be extended periods when both are insufficient, particularly during winter conditions when an electrified New York may face its greatest demand. Batteries can help for hours and, with enough investment, perhaps longer. They cannot solve the problem indefinitely unless there is enough energy available to recharge them. That means New York must have sufficient dependable, fuel-secure, dispatchable capacity to supply electricity through the worst credible periods of low wind and solar production. Failure to provide that resource in an electric system overly reliant on wind and solar will create an unacceptable reliability risk.
The state calls that resource category DEFR. Yet it has not demonstrated what technology will provide it, how much will be required, how it will be fueled, whether it can operate for the full duration of the worst case renewable drought, or how ratepayers can afford a resource that may be used only rarely. Until those questions are answered, claims that wind, solar, and storage can provide an affordable and reliable all-electric energy system are premature. I do not think that Este’s Substack post adequately addressed DEFR and its necessity for reliability.
New York should stop treating DEFR as an undefined future technology and recognize that nuclear generation is the proven scalable zero-emission resource capable of providing the dependable electricity the state will need when wind and solar cannot. New York must address this issue as soon as possible.
