Scoping Plan Reliability Feasibility – Renewable Variability

The Climate Leadership and Community Protection Act (Climate Act) establishes a “Net Zero” target by 2050 and the Draft Scoping Plan defines how to “achieve the State’s bold clean energy and climate agenda”.   However, there hasn’t been a feasibility plan that fully addresses the cost and technology necessary to provide reliable energy in the future all-electric net-zero New York energy system.  This is the second post of a series of posts describing the problem and the Scoping Plan’s failure to provide a proposal that adequately addresses the problem.  In the first post I described how the Texas blackouts of February 2021 are the inevitable outcome if the Scoping Plan does not address renewable variability correctly.  This post shows that solar variability markedly increases the resources needed.

I have written extensively on implementation of the Climate Act because I believe the ambitions for a zero-emissions economy outstrip available technology such that it will adversely affect reliability and affordability, risk safety, affect lifestyles, will have worse impacts on the environment than the purported effects of climate change in New York, and cannot measurably affect global warming when implemented.   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.

Background

The Climate Action Council is responsible for preparing the Scoping Plan that will “achieve the State’s bold clean energy and climate agenda”.  The Climate Act requires the Climate Action Council to “[e]valuate, using the best available economic models, emission estimation techniques and other scientific methods, the total potential costs and potential economic and non-economic benefits of the plan for reducing greenhouse gases, and make such evaluation publicly available” in the Scoping Plan. Starting in the fall of 2020 seven advisory panels developed recommended strategies to meet the targets that were presented to the Climate Action Council in the spring of 2021.  Those recommendations were translated into specific policy options in an integration analysis by the New York State Energy Research and Development Authority (NYSERDA) and its consultants.  The integration analysis was used to develop the Draft Scoping Plan that was released for public comment on December 30, 2021. This draft includes results from the integration analysis on the benefits and costs to achieve the Climate Act goals. The public comment period extends through at least the end of April 2022, and will also include a minimum of six public hearings. The Council will consider the feedback received as it continues to discuss and deliberate on the topics in the Draft as it works towards a final Scoping Plan for release by January 1, 2023.

The Climate Action Council claims that the integration analysis was developed to estimate the economy-wide benefits, costs, and GHG emissions reductions associated with pathways that achieve the Climate Act greenhouse gas emission limits and carbon neutrality goal. This integration analysis incorporates and builds from Advisory Panel and Working Group recommendations, as well as inputs and insights from complementary analyses, to model and assess multiple mitigation scenarios. In addition, there is historical/archived information is available through the Support Studies section of the Climate Resources webpage, and can found as part of the Pathways to Deep Decarbonization in New York State – Final Report.

Renewable Variability

I have called the renewable resource adequacy problem the ultimate problem for the Climate Act as early as September 2020.  On August 2, 2021, the New York State Energy Research and Development Authority (NYSERDA) held a Reliability Planning Speaker Session to describe New York’s reliability issues to the advisory panels and Climate Action Council.  All the speakers but one made the point that today’s renewable energy technology will not be adequate to maintain current reliability standards and that a “yet to be developed technology” will be needed.  A recent article by David Wojick at PA Pundits International titled Unreliability Makes Solar Power Impossibly Expensive does a great job describing how renewable resource availability affects reliability.

Wojick explains that meteorological variability strongly affects renewable resource availability.  In order to reliably provide electricity from an electric grid that depends on wind and solar planners have to determine the worst case.  In his article he illustrates the problem using an example for solar energy of five days of cloudy weather that reduces the energy available to essentially zero.  In the following I excerpt his description, highlight key points and provide indented and italicized comments.

Unreliability Makes Solar Power Impossibly Expensive

How many successive days of dark cloudiness to design for is a complex question of local and regional meteorology. Here we simply use 5 days but it easily could be more. Five dark days certainly happens from time to time in most states. In Virginia’s case it can happen over the whole Mid-Atlantic region, so no one has significant solar power. This rules out buying solar power from the neighbors.

The Scoping Plan projects 2050 solar capacity between 60,604 and 65,210 MW for three mitigation scenarios.  Given the latitude of New York which translates into short days in the winter, the effect of the Great Lakes on Upstate cloudiness in the winter, and potential for significant snowfall over the entire state, it is reasonable to expect that none of this capacity will be available for at least five days.

Reliability requires designing for these relatively extreme events. With conventional generation you design for maximum need for power but with wind and solar you also have to design for minimum supply. That minimum case is what I am looking at here.

The required battery capacity is simple. Five days at 24 hours a day is 120 hours. To supply a steady 1,000 MW that is a whopping 120,000 MWh of storage. We already have the overnight storage capacity for 16 hours so we now need an additional 104 hours, which means 104,000 MWh of additional storage.

Keep in mind that today the available Li ion batteries only provide 4 hours of energy.

However, the required additional generating capacity to charge these dark days batteries is far from simple. It all depends on how long we have to do the charging. The more time we have the smaller the required generating capacity.

It is vital to get the dark days batteries charged before the next dark days arrive, which in some cases might be very soon. This too is a matter of meteorology. To be conservative we here first assume that we have two bright sunny days to do the job.

Two days gives us 16 hours of charging time for the needed 120,000 MWh, which requires a large 7,500 MW of generating capacity. We already have 3,000 MW of generating capacity but that is in use providing round the clock sunny day power. It is not available to help recharge the dark days batteries. Turns out we need a whopping 10,500 MW of solar generating capacity.

This 10,500 MW is a lot considering we only want to reliably generate 1,000 MW around the clock. Moreover, some of this additional generating capacity will seldom be used. But reliability is like that due to the great variability of weather. In conventional fossil fueled generation the extreme event that drives design is peak need (also called peak demand). Special generators called “peakers” are used for this case. In the solar case the special equipment is batteries or other forms of storage.

This is an important point.  In order to provide electricity when it is needed a significant fraction of generating capacity will seldom be used.  If it is not used much it will be difficult to pay for it.  Inevitably, it will mean very high electricity prices during those peak periods.

Note that if we have 5 days to recharge the dark days batteries then the amount of required generation is a lot less. Five days gives us 40 hours to charge the 120,000 MWh so one only needs 3,000 MW of additional generating capacity, added to the 3,000 MW we need to produce daily power on sunny days.

I cannot over emphasize the importance to determine the frequency, duration, and intensity of low wind and solar resource availability.  If it is found that New York can only expect 2 full days will be available to recharge the batteries, then the Scoping Plan projected 2050 solar capacity between 60,604 and 65,210 MW only produces between 5,772 and 6,211 MW of reliable solar energy.  On the other hand, if New York can expect 5 full days will be available to recharge the batteries that same capacity produces between 10,101 and 10,868 MW of reliable solar energy.

At this point we need 120,000 MWh of battery storage and from 6,000 to 10,500 MW of generating capacity, in order to reliable supply 1,000 MW of round the clock power.

If it is found that New York can only expect 2 full days will be available to recharge the batteries, then the Scoping Plan projected 2050 solar capacity between 60,604 and 65,210 MW will require between 692,619 MWh and 745,260 MWh of energy storage to produce the 5,772 and 6,211 MW of reliable solar energy.

These large numbers occur because following a period of dark cloudy days we are doing three things simultaneously during the daylight generating hours. We are (1) generating 1,000 MW of immediately used electricity, while recharging both the (2) nighttime batteries and the (3) dark days batteries.

Note too that the numbers should actually be bigger. Batteries are not charged 100% and then drained to zero. The standard practice is to operate between 80% and 20%. In that case the available storage is just 60% of the nameplate capacity. This turns the dark days 120,000 MWh into a requirement for 200,000 MWh.

If it is found that New York can only expect 2 full days will be available to recharge the batteries, then with this constraint the Scoping Plan projected 2050 solar capacity between 60,604 and 65,210 MW will require between 1,154,364 MWh and 1,242,100 MWh of energy storage to produce the 5,772 and 6,211 MW of reliable solar energy.

The cost of the dark days case

Wojick also calculates costs in his article.

A standard figure from EIA for the cost of grid scale battery arrays is $250 per kWh, which gives $250,000 per MWh. At this cost the required 200,000 MWh of storage for around the clock 1,000 MW is $50 billion.

In order to provide adequate energy storage for the Scoping Plan solar capacity costs range between $288.6 billion and $310.5 billion for the three mitigation scenarios.

A standard EIA figure for PV solar capacity is $1300 per kW or $1,300,000 per MW. This makes the 6,000 to 10,500 MW cost $7.8 to 13.7 billion.

The Scoping Plan solar capacity costs range between $78.8 billion and $84.8 billion.

This makes $60 billion for just 1,000 MW a good rough estimate for stand-alone solar capacity to meet the 5 dark cloudy days case. (Adding wind power does not reduce this number because the 5 dark days may also see zero wind output.)

The total Scoping Plan solar capacity costs range $367.4 billion and $395.3 billion!

 There is a major disconnect between Wojick’s cost estimate and the values presented in the Scoping Plan.  According to Figure 51 from Appendix G, Section I, the Scenario 2, “Strategic use of low-carbon fuels” net present value of costs relative to the reference case (2020-2050) are $310 billion; Scenario 3, “Accelerated transition away from combustion”, costs are $290 billion; and Scenario 5, “Beyond 85%” costs are $305 billion.  If just the cost for the solar resources necessary are over $367 billion, then something has to be reconciled. 

Scoping Plan Appendix G, Section I states that “The integration analysis includes calculations for three different cost metrics: Net Present Value (NPV) of net direct costs, annual net direct costs, and system expenditure” and notes that “the NPV of levelized costs in each scenario incremental to the Reference Case from 2020-2050”.  Depending on the Reference Case costs that could account for some of the difference.  However, the Scoping Plan does not include any tables that list costs for the Reference Case and Scenarios.  The only data available are in figures.  At the time of this writing, January 23, 2022, the spreadsheet resources that provide numbers used in most figures are not available for any of the figures with cost numbers.  As a result, I cannot reconcile the cost numbers shown here and the Scoping Plan costs.

Conclusion

Wojick’s analysis provides a simple, easily replicated description of the effect of day length on solar resource availability.  He demonstrates that accurately determining the expected solar resource availability is critically important for reliability planning.  It is also obvious from his work that someone says solar generation is cheaper than fossil-fired generation, that person is not considering all the reliability requirements.

There are implications to the Scoping Plan.  Scenario 2, “Strategic use of low-carbon fuels” projects 2050 solar capacity of 64,621 MW; Scenario 3, “Accelerated transition away from combustion”, projects 60,604 MW; and Scenario 5, “Beyond 85%” projects 65,210 MW.  Wojick shows that if it is found that New York can only expect 2 full days will be available to recharge the batteries needed to provide power when the sun isn’t shining, then the Scoping Plan projected 2050 solar capacity range of 60,604 to 65,210 MW only produces between 5,772 and 6,211 MW of reliable solar energy.  On the other hand, if New York can expect 5 full days will be available to recharge the batteries the Scoping Plan capacity produces between 10,101 and 10,868 MW of reliable solar energy. 

I have been unable to determine how the Scoping Plan addresses the issues raised.  I don’t think the integration analysis that forms the basis of the Scoping Plan adequately determined the worst-case meteorological conditions for wind and solar availability.  I don’t know how the integration analysis addressed the reliability issues associated with wind and solar resource availability but I am sure that the New York Independent System Operator and New York State Reliability Council have not reconciled their reliability responsibilities with the Scoping Plan.  Clearly the Climate Action Council must address this problem.