View this email in your browser

Carey King Research Newsletter - Summer 2017:
Three items for this newsletter:

1: Successful crowdfunding campaign!  

A big THANK YOU to the generous donors that made my crowdfunding campaign (from April - May) a success. The bulk of the money was raised for me to hire a visiting scholar from India.  He is currently an Associate Professor of Mechanical Engineering in Kerala, India. He has expertise and experience in system dynamics modeling, energy efficiency, and macroeconomic concepts. These are just skills I need to complement my and my students' work. Further, this opens up the possibility of future international collaboration.

In addition to this Indian scholar, I will also have a visiting PhD student from the China University of Geosciences in Beijing spend one year with me as well. His advisor is also interested in the use of physics and energy principles to understand economic phenomena.

The next year is set up well to have some high quality brainpower working with me to integrate energy concepts into economic modeling!

2: Article in August 2017 edition of Earth Magazine: Why we need better macroeconomic models 

My latest lay article has come out in Earth Magazine, August 2017 edition.  The artwork is great (see image below), and I pasted an excerpt below that.

King, Carey W. Delusions of Grandeur in Building a Low-Carbon FutureEarth Magazine, August 2017, 32-37, online link.

"There is a very real trade-off between the rate at which we address climate change and the amount of economic growth we can expect during the transition to a low-carbon economy, but most economic models insufficiently address this trade-off, and thus are incapable of assessing the transition. If we ignore this trade-off, or worse, we rely on models that are built on faulty premises, then we risk politicians and citizens revolting against the energy transition midway into it when the substantial growth and prosperity they’ve been told to expect will accompany the low-carbon transition don’t materialize. It is important to note that citizens are also told that doubling-down on fossil energy also only provides growth and prosperity. But this is a major point of this article: mainstream economic models can’t tell the difference. There are foreseeable feedbacks of a fast transition to a low-carbon economy that increase the risk of major recessions. If we want to maximize our ability to achieve our future energy, climate and economic goals, we must improve macroeconomic modeling concepts."

3: Debate over 100% Renewable Energy Future: Mark Jacobson versus 21 academics 

This summer was hot with the debate over modeling a 100% renewable energy future. Not only 100% renewable electricity, but 100% of all primary energy being derived from renewable sources of wind, water, and solar in one form or another (including storage, but not from batteries!).

The issue relates to Mark Jacobson, a professor at Stanford University, that has over the last several years, produced a series of papers on modeling state, country, and world level requirements to use only renewable energy (no fossil fuels, no nuclear). In June, a journal paper with 21 co-authors critiqued one of his latest papers from 2015, essentially claiming that he has modeling errors and implausible assumptions to such a degree that it prompted an official high-profile paper highlighting the problems. 

I've provided a summary of the back-and-forth (at end of this e-mail) and highlighted one of the more contentious disagreements over what I see, as indicated by the critiquing authors, as a modeling mistake on hydropower capacity and use.  Below are links to the papers and a website (Greentech Media) that has a link to many opinions on the good or bad reasons for such a critique article.
  • Original paper:
    • Jacobson et al. (2015) PNAS paper on modeling 100% renewable energy for the U.S. by 2050: online link.  
  • Critique of original paper:
    • Clack et al. (2017) critique in PNAS of Jacobson et al. (2015): online link
  • Rebuttal to critique:
    • Jacobson et al. (2017) response in PNAS to Clack et al. (2017): online link
  • Rebuttal to the rebuttal of the critique:
    • Clack et al. (2017) response to the Jacobson response: online link
Thank you very much for your time.  As always, please contact me for more information about how you can be involved in and contribute to my research program. 


Carey W. King, Ph.D.
Research Scientist, Energy Institute and Jackson School of Geosciences
Assistant Director, Energy Institute
Lecturer, McCombs School of Business
The University of Texas at Austin, 512.471.5468,
,  @CareyWKing
Website (personal)
Website (personal)
Website (University of Texas)
Website (University of Texas)
My research takes a systems approach to describe the role of energy and energy technologies in our past and future. This approach provides the best way to both address questions about our future economy and environment as well as understand how individual technologies can and cannot affect the macro-scale and long-run trends that will frame our future options. I seek understanding of the relationships among:
  • energy resources and technologies,
  • population demographics,
  • water and food,
  • macroeconomic factors, and 
  • implications of internalizing environmental externalities.

Summary of the Debate over 100% Renewable Energy Future: Mark Jacobson versus 21 academics

Disagreement about the feasibility of using high penetrations of variable renewable electricity is not limited to arguments between fossil and renewable proponents. Even groups of renewable proponents can disagree about the feasibility of computational and analytical methods of assessing the technical or economic feasibility of transitioning to a world that uses only renewable energy.

Perhaps the best case in point is the “academic” controversy over studies led by Mark Jacobson of Stanford University and Mark Delucchi of University of California at Berkeley. Jacobson and Delucchi have published several peer-reviewed studies [1, 2, 3] on how the U.S. can transition to 100% renewable energy, not only for electricity generation, but for all primary energy needs. In particular, it was their 2015 paper published in the Proceedings of the National Academy of Sciences, or PNAS, that led to considerable discussion and controversy [3]. This paper led to critique by 21 authors that was published in PNAS in 2017 [4], and PNAS also allowed Jacobson et al. to write a response to the critique [5]. Greentech Media dedicated a webpage to the controversy

To give a feel for the expression of each group of authors, I post and discuss quotes from the Clack et al. (2017) critique as well as Jacobson et al.’s (2017) rebuttal. I then discuss one of the specific mathematical modeling points of controversy as illustrative of the challenges of projecting an energy future far-removed from ours of today.

From the Clack et al. (2017) [4] critique of Jacobson et al. (2015) [3]:
“The scenarios of [Jacobson et al. (2015)] can, at best, be described as a poorly executed exploration of an interesting hypothesis. The study’s numerous shortcomings and errors render it unreliable as a guide about the
likely cost, technical reliability, or feasibility of a 100% wind, solar, and hydroelectric power system. It is one thing to explore the potential use of technologies in a clearly caveated hypothetical analysis; it is quite another to claim that a model using these technologies at an unprecedented scale conclusively shows the feasibility and reliability of the modeled energy system implemented by midcentury.” [4]

Two quotes from the response by Jacobson et al. to the critique of their work are:

“The premise and all error claims by Clack et al. [(2017)] in PNAS, about Jacobson et al.’s [(2015)] report, are demonstrably false. We reaffirm Jacobson et al.’s conclusions.”[5]
“In sum, Clack et al.’s [(2017)] analysis is riddled with errors and has no impact on Jacobson et al.’s [(2015)] conclusions.”[5]

It is hard to be more starkly adamant and of opposite opinion than these competing statements. Clack et al. (2017) state there are errors, and Jacobson et al. (2017) response is: no there aren’t.

It is important to keep in mind that practically all authors involved, in both papers, are generally interested in understanding how to use more renewable and/or low-carbon energy! That is to say they are largely in the same camp in terms of doing engineering, science, and economic analyses that discuss how to integrate more renewable energy. Renewable energy proponents disagree on whether or not this type of scientific discussion should be out in the public. There are two general positions on this issue of openly discussing disagreements on models of future renewable energy scenarios.

Position 1 is that all open discussion of science, engineering, and economic analyses of how to transition to more use of renewable energy is a good thing. That is to say, more discussion leads to more accurate analyses in the long-run, and we want the most accurate analyses as possible. If this discussion involves a lot of both good and bad information exchange during the process, then that is OK because that is just the scientific process going through its motions.

Position 2 is that open discussion of disagreement on the technical and/or feasibility of increasing the use of renewable energy is bad thing because it gives ammunition to the fossil proponents[2]. Quite simply, fossil fuel advocates can point to peer-reviewed publications that say how going to 100% renewable energy is not possible because studies claiming that possibility are flawed.

I clearly fall into the group advocating Position 1. If I didn’t, I wouldn’t write this summary in the manner in which I have.

In the June 22, 2017 Greentech Media podcast of The Energy Gang, Jigar Shah and Katherine Hamilton argue that the paper is flawed but proposes a vision of 100% renewables[3]. They see the journal paper as benign because policy makers don’t take it seriously. Stephen Lacey disagrees and says publishing in peer-reviewed literature is serious. Lacey’s view is correct. Peer-reviewed articles are not the place for visions. They are the place for analyses with all assumptions and caveats explained for interpretations by other researchers. When writing legislation, policy makers do in fact feel more justified in basing legislation on results from peer-reviewed literature than other published formats, such as white papers or articles in lay magazines[4].

Jacobson also points how his concerns are more than greenhouse gases and current economics. His scenarios target such ideas as the improvement of local air quality, increasing jobs, and minimizing land use for energy by avoiding bioenergy. In his interview he criticizes a few of the critiquing authors by name for being pronuclear, and thus in Jacobson’s view, having a vested interest against his idea of using only wind, water, and solar (WWS) energy technologies. Others are criticized, but not by name, for being part an academic department of a university that gets money from natural gas companies that in Jacobson’s opinion influence the view of that author. He also points out that PNAS typically requires co-authors to have provided a substantial contribution, which has to be listed, to the written article. Of the 21 authors of Clack et al., only 3 are listed as having designing the research, performing the research, or analyzing the data. The other 18 co-authors are listed only as writing the paper.

Jacobson also points out that the Clack et al. (2017) paper is very uncommon because while it presents a critique of original research rather than original research itself, it is published as a regular “research report”. Usually, disagreements over the methodology or results of a research article are discussed via back-and-forth letters to the editor of the journal. For some reason, the PNAS editors found it worthwhile to publish the Clack et al. (2017) critique in the more formal full length manner.[5]

To give you a feel for how researchers try to translate assumptions in models into insightful outcomes, I highlight one of the modeling points of contention within the Jacobson et al. (2015) study. This centers on the assumptions for how hydropower generation would operate within the presented 100% WWS scenario. It is necessary to go through the numbers in the paper to explain the disagreement.

Table 2 of Jacobson et al. (2015) shows the amount of hydropower electricity generated over six years (2050–2055) as 2,413 TWh. The hydropower footnote of Table 2 states “The capacity factor for hydropower from the simulation is 52.5%, which also equals that from ref. 22.” where reference 22 is another paper by Jacobson [6]. Knowing total energy generation and capacity factor enables the calculation of installed hydro capacity as 87.5 GW, and this is the same stated “installed capacity” for 2050 in Table S2 of [3]. Clack et al. (2017) call this a modeling error because Figure 4B of Jacobson’s paper [3] indicates the need (on the simulated days indicated) for approximately 1,300 GW of instantaneous power output from hydropower. To produce 1,300 GW at any instant, the installed capacity must exist and be accounted for. This is a very large difference between 1,300 GW and 87.5 GW of hydropower capacity as the 1,300 GW of hydropower capacity is “... approximately 9 times the theoretical maximum instantaneous output of all [presently U.S.] installed conventional hydropower and pumped storage combined.”[4]. Quantities adding up to 1,300 GW of hydropower capacity do not appear in Jacobson et al. (2015), even when including 57.7 GW of pumped hydropower storage capacity listed in Table S1.

Thus, Clack et al. (2017) call this a modeling error because “The hydroelectric production profiles depicted throughout the dispatch figures reported in both the paper [Jacobson et al. (2015)] and its supplemental information routinely show hydroelectric output far exceeding the maximum installed capacity ...”. In short, the model results contradict the stated quantities and thus the capabilities used within the model.

Jacobson et al. (2015) do not agree that the 1,300 GW of hydropower capacity represents a modeling error. They state “... The value of 1,300 GW is correct, because turbines were assumed added to existing reservoirs to increase their peak instantaneous discharge rate without increasing their annual energy consumption ...” as stated in footnote 4 of the original paper [5][6]. However, footnote 4 of Table S2 of [3] only references that hydropower is limited by “... its annual power supply ...” and is used for ”... peaking ...”[7] Jacobson’s papers make no mention of a quantity relating to 1,300 GW of installed capacity[8]. In addition, since Jacobson et al.’s rebuttal agrees that 1,300 GW is a correct number for installed hydropower, then they indeed have made a couple of errors. First, the capacity factor of hydropower capacity is really 3.5%, and not the stated 52.5%[9] To state a generation of 2,413 TWh you can use 87.5 GW at 52.5% capacity factor, 1,300 GW at 3.5% capacity factor, but not 1,300 GW at 52.5% capacity factor. Second, since Jacobson et al. do not ever explicitly state a quantity of hydro capacity near 1,300 GW, they neglect the additional cost of approximately 3.4 trillion dollars[10].

In a Clack et al. rebuttal to Jacobson et al.’s rebuttal, they state that Jacobson et al. are “Purposefully refusing to acknowledge clear mistakes. This is most clearly seen in this exchange from the discussion of installed capacity of hydropower in the Jacobson et al. models.”[7]. In addition they conclude that Jacobson et al.’s response “... confirms that the [hydropower capacity modeling] error is actually more severe than this.” This last statement sums up the argument on the hydropower modeling question. Jacobson et al.’s explanations of their models hydropower capacity were sufficiently answered in their journal papers or the responses to Clack et al.’s critiques.


  1. Mark Z. Jacobson and Mark A. Delucchi. Providing all global energy with wind, water, and solar power, Part I: Technologies, energy resources, quantities and areas of infrastructure, and materials. ENERGY POLICY, 39(3):1154–1169, MAR 2011.
  2. Mark A. Delucchi and Mark Z. Jacobson. Providing all global energy with wind, water, and solar power, Part II: Reliability, system and transmission costs, and policies. ENERGY POLICY, 39(3):1170–1190, MAR 2011.
  3. Mark Z. Jacobson, Mark A. Delucchi, Mary A. Cameron, and Bethany A. Frew. Low-cost solution to the grid reliability problem with 100% penetration of intermittent wind, water, and solar for all purposes. Proceedings of the National Academy of Sciences, 112(49):15060– 15065, 2015.
  4. Christopher T. M. Clack, Staffan A. Qvist, Jay Apt, Morgan Bazilian, Adam R. Brandt, KenCaldeira, Steven J. Davis, Victor Diakov, Mark A. Handschy, Paul D. H. Hines, Paulina Jaramillo, Daniel M. Kammen, Jane C. S. Long, M. Granger Morgan, Adam Reed, Varun Sivaram, James Sweeney, George R. Tynan, David G. Victor, John P. Weyant, and Jay F. Whitacre. Evaluation of a proposal for reliable low-cost grid power with 100% wind, water, and solar. Proceedings of the National Academy of Sciences, 114(26):6722–6727, 2017.
  5. Mark Z. Jacobson, Mark A. Delucchi, Mary A. Cameron, and Bethany A. Frew. The United States can keep the grid stable at low cost with 100% clean, renewable energy in all sectors despite inaccurate claims. Proceedings of the National Academy of Sciences, 114(26):E5021– E5023, 2017.
  6. Mark Z. Jacobson, Mark A. Delucchi, Guillaume Bazouin, Zack A. F. Bauer, Christa C. Heavey, Emma Fisher, Sean B. Morris, Diniana J. Y. Piekutowski, Taylor A. Vencill, and Tim W. Yeskoo. 100% clean and renewable wind, water, and sunlight (WWS) all-sector energy roadmaps for the 50 united states. Energy Environ. Sci., 8:2093–2117, 2015.
  7. Staffan A. Qvist. Response to Jacobson et al. (June 2017), available at


[1] Your Guide to the Bitter Debate Over 100% Renewable Energy: https://www.
[2] Joe         Romm,     Dear         scientists: Stop         bickering about       a                100%       renewable power      grid          and          start                making    it              happen:
a-carbon-free-grid-is-unstoppable-so-why-did-a-nasty-debate-about-it-just-erupt-fa2bf7a6827a/ accessed June 21, 2017.
[3] June       22,           2017: 100-renewable-energy-debate.
[4] In discussing my and my colleagues’ research with persons at the Council on Environmental Quality as well as staff members of House and Senate committees, these policy makers have confirmed with me on multiple occasions that they prefer peer-reviewed literature to inform energy and environmentally-related legislation.
[5] From PNAS website,, accessed August 13, 2017
“Submissions must be:
  • original scientific research of exceptional importance,
  • work that appears to an NAS member to be of particular importance, and
intelligible to a broad scientific audience.”
[6] “Clack et al. (1) [(2017)] then claim incorrectly that the 1,300 GW drawn in figure 4B of Jacobson et al. (2) [(2015)] is wrong because it exceeds 87.48 GW, not recognizing that 1,300 GW is instantaneous and 87.48 GW, a maximum possible annual average [table S2, footnote 4 in Jacobson et al. (2) [(2015)] and the available LOADMATCH code]. The value of 1,300 GW is correct, because turbines wereassumed added to existing reservoirs to increase their peak instantaneous discharge rate without increasing their annual energy consumption, a solution not previously considered. Increasing peak instantaneous discharge rate was not a “modeling mistake” but an assumption consistent with Jacobson et al.’s (2) table S2, footnote 4, and LOADMATCH, and written to Clack on February 29, 2016.”[5]
[7] Footnote 4 of Table S2 of [3]: “Hydropower use varies during the year but is limited by its annual power supply. When hydropower storage increases beyond a limit due to non-use, hydropower is then used for peaking before other storage is used.”
[8] Jacobson’s 50 state roadmap for 100 % WWS states 91.7 GW of total hydropower capacity being needed in Table 2 [6].
[9] capacity factor of 1,300 GW of hydropower capacity = (2,413 TWh × 1,000 GW/TW)/(1,300 GW × 8,760 hr/yr × 6 years) = 3.5%.
[10] Clack et al. (2017) calculate this 3.4 $trillion using Jacobson et al.’s (2015) stated cost to add hydro capacity of 2.82 $million/MW: (1,300 GW total future capacity - 8.74 GW of existing capacity) × (2,820 $million/GW) = 3,400,000 $million = 3.4 $trillion.
To learn more about Carey's research, visit his website or contact him using this information:
e:      |  web:    |     ph: +1 512-471-5468    |    t: @CareyWKing
The University of Texas at Austin, 2304 Whitis Ave, C2400, Austin, TX 78712-1718

unsubscribe from this list  update subscription preferences 
Copyright © 2017 Carey W. King.
You are receiving this email because you are a friend or colleague with whom I have exchanged business cards, or you have requested to be added to this newsletter.

This email was sent to <<Email Address>>
why did I get this?    unsubscribe from this list    update subscription preferences
University of Texas at Austin · 2304 Whitis Ave · Stop C2400 · Austin, TX 78712 · USA

Email Marketing Powered by Mailchimp