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What Drove Solar PV Price Reductions?

A new book explores the precipitous decline.

One of the most remarkable trends in energy economics over the last 50 years is the tremendous reduction in solar photovoltaic (PV) prices. The figure below charts prices on a log scale. In words, it shows that prices in 1970 were about 1,000 times higher than they are currently.

Source: Nemet (2019)

I’ve been on a quest to understand this phenomenon – I’d heard conjectures about scale economies driven by generous subsidies for rooftop installations under the German Energiewende or massive subsidies from the Chinese government, but hadn’t dug into it myself.

It turns out that Greg Nemet, a professor at the University of Wisconsin, recently published a book called, How Solar Energy Became Cheap, which provides a number of insights. And, because there are so many promising energy books to review this year (more on that to come!), I’m going to break my book reviews into pieces and devote this post to Nemet’s book.

Can We Replicate the Solar PV Price Reductions?

Understanding the decline in solar PV prices is a hugely important exercise. If we can replicate the solar experience for energy storage, carbon capture and sequestration, small nuclear reactors or other clean technologies, we’d make a lot of progress addressing climate change. Plus, I’ve had a nagging fear that the current ultra-low PV prices were unsustainable, perhaps reflecting huge subsidies that could disappear with the stroke of a pen.

So, how much of the solar experience actually can be applied to other industries? Was it pure serendipity? For example, did solar PV benefit from advances in the computer industry, which similarly use silicon’s semiconductor properties for microprocessors, that were driven by forces completely outside the energy industry? Or, are there key policies or business practices that can be replicated for other clean energy technologies?

Nemet’s book is based on 70 interviews across 18 countries and also draws on quantitative work that he and others have done for academic publications. It’s a pretty good read, especially given the format – there are footnotes, references, tables and figures, so it’s not exactly a light beach read.

The Case for Replication

At a high level, Nemet comes down on the side of replicability. In fact, the subtitle of his book is, “A Model for Low-Carbon Innovation.” I must admit that I started the book with some skepticism – I was worried that he would be so intent on drawing lessons for other industries that he would ignore the serendipitous explanations. I came away more convinced.

Nemet traces solar PV from the first Bell Lab application in 1954 through to about 2016. He argues that there were essentially four epochs when worldwide PV output was dominated by US, Japanese, then German and finally Chinese production. He devotes a chapter to each country and explores the local demand-pull policies (e.g, Japan’s first-of-a-kind net metering policy in 1998) and technology-push policies (e.g., research and development subsidies, such as the creation of the Solar Energy Research Institute, which later became the National Renewable Energy Lab (NREL)).

Nemet also points out that solar PV benefited from the fact that it was hugely scalable and could be applied across a number of niche markets. The Japan chapter explains how companies like Sharp invested in very small-scale solar cells for calculators and bigger niche applications such as lighting offshore oil platforms.

Solar PV prices really plummeted in the last 15 years, so I found the two chapters on the German and Chinese epochs most interesting. In the chapter on China, Nemet tells the fascinating story of Suntech, the first large-scale Chinese solar module manufacturer. The company was founded by Zhengrong Shi, who spent 15 years as a researcher at an electrical engineering lab at the University of New South Wales in Australia before he returned to China in 2001 with a business plan to build a plant to produce 3 MW of solar modules per year. By 2008, Suntech was producing 1,000 MW per year and had over $1 billion in sales. Suntech went bankrupt in 2013 due in part to its decision to acquire an Italian solar developer later accused of massive fraud, but current powerhouse companies such as Trina Solar, JinkoSolar and JA Solar developed closely on Suntech’s heels.

Shi’s story highlights the importance of academic R&D, as Shi was able to convince German customers that Suntech’s modules were high quality based on his relationship to the university research lab. And, Nemet emphasizes how, “Shi’s experience in the lab [gave] him a broad expertise in PV technologies that allowed him to switch technologies quickly when an opportunity for cost-reductions emerged.”

The story of Suntech and its competitors also emphasizes the doggedness of a number of Chinese entrepreneurs including Shi, who shopped his business plan around China for months before he finally found $5 million in financing. Though Nemet mentions Chinese government policies to invest in renewables to spur demand and says obliquely that, “many of these [solar] firms received substantial funding from the local governments,” I was left with the impression that Chinese solar manufacturing was really launched and developed by scrappy, capitalistic entrepreneurs.

A Series of Incremental Improvements

The scale economies in solar PV are pretty mundane – a bunch of incremental improvements in manufacturing processes, panel efficiency, supply chain optimization, and automation rather than one or two breakthroughs in someone’s R&D lab. For example, Nemet describes how early module manufacturers used second-hand manufacturing equipment repurposed from computer microprocessor plants, but as the industry expanded, suppliers for solar-specific machinery emerged.

He also describes how Shi led the switch from using poly-crystalline silicon to cheaper and more efficient mono-crystalline silicon, which is perhaps as close as we come to an ah-ha insight that drove costs down. It’s splitting hairs a bit, but this last example could be learning-by-doing rather than scale economies as the insight didn’t necessarily require huge volumes of production.

In the end, some of Nemet’s messages are encouraging: the forces of capitalism, nudged by government programs, encouraged entrepreneurs who saw a growing market for solar to invest capital and a fair amount of blood, sweat and tears into fine-tuning manufacturing processes that led to significant cost-reductions. I’m going out on a limb a bit as I’m pretty averse to making forecasts without a lot of evidence to back them up, but I don’t see an obvious reason why the price reductions have been exhausted.

As Nemet points out, though, the decline in solar prices took a long time, so even if other industries can replicate this path, they’ll have to figure out a way to do it much more quickly.

Keep up with Energy Institute blogs, research, and events on Twitter @energyathaas.

Suggested citation: Wolfram, Catherine. “What Drove Solar PV Price Reductions?”, Energy Institute Blog, UC Berkeley, September 9, 2019,


Catherine Wolfram View All

Catherine Wolfram is Associate Dean for Academic Affairs and the Cora Jane Flood Professor of Business Administration at the Haas School of Business, University of California, Berkeley. ​She is the Program Director of the National Bureau of Economic Research's Environment and Energy Economics Program, Faculty Director of The E2e Project, a research organization focused on energy efficiency and a research affiliate at the Energy Institute at Haas. She is also an affiliated faculty member of in the Agriculture and Resource Economics department and the Energy and Resources Group at Berkeley.

Wolfram has published extensively on the economics of energy markets. Her work has analyzed rural electrification programs in the developing world, energy efficiency programs in the US, the effects of environmental regulation on energy markets and the impact of privatization and restructuring in the US and UK. She is currently implementing several randomized controlled trials to evaluate energy programs in the U.S., Ghana, and Kenya.

She received a PhD in Economics from MIT in 1996 and an AB from Harvard in 1989. Before joining the faculty at UC Berkeley, she was an Assistant Professor of Economics at Harvard.

192 thoughts on “What Drove Solar PV Price Reductions? Leave a comment

  1. Richard McCann regarding your demonstrably false claim that CGNP is relying on a 2010 report. First the CAISO statistics supporting a saturation in California solar installations are current until August, 2019. The references cited are from 2016 and 2019.

    “Turns out wind and solar have a secret friend: Natural gas”, by Chris Mooney, August 11, 2016, The Washington Post, serves as an introduction to:

    “Bridging the gap: Do fast-reacting fossil technologies facilitate renewable energy diffusion?” by Elena Verdolinia, Francesco Vonab, and David Popp, Energy Policy 116 (2018) 242–256,

    • “Richard McCann regarding your demonstrably false claim that CGNP is relying on a 2010 report.”
      Your post refers to a study done in 2010 on the cost of strategies for reducing GHG emissions. That study is obsolete.

    • You’ve made two errors in reading those articles:

      1) This study is about added CAPACITY, not increased ENERGY output. It says little about whether gas generation has increased.

      2) Quote from the article: “Verdolini emphasized this merely describes the past — not necessarily the future. That’s a critical distinction, because the study also notes that if we reach a time when fast-responding energy storage is prevalent — when, say, large-scale grid batteries store solar or wind-generated energy and can discharge it instantaneously when there’s a need — then the reliance on gas may no longer be so prevalent.”

    • I still am amused that under the ‘to a hammer every problem is a nail’ metaphor – economists are stuck on the ‘economics’ issues. Very few seem to know the history of HOW and what drove the computer [especially personal] industry. The availability of low-cost CRT [displays] driven by the high volume production of TVs for consumer market. And the cost reduction of semiconductor manufacturing with volumes driven by initially military and mainframe computing demand. Semiconductors have extreme quality demands, but PV silicon can accept much lower quality. [As an example, memory prices were helped down using ‘weaker’ quality standards for consumer applications vs computing and military needs. You can accept a slightly poor audio quality in a TI Speak and Spell, but not 2+2 being 3.9999/]

      SO: a major driver in PV price drops were 1: Cost reduction from higher volumes, 2: the realization that in poly-silicon, a process manufacturing product, once a factory is established the variable cost is ‘minimal’ – so prices can be reduced to ‘near zero’, and 3: demand created by govt policies

  2. I take exception to solar power apologist Richard McCann’s false statement that zero-emission nuclear power is not dispatchable. Furthermore, baseload nuclear power serves to provide important stability services to the California power grid being subject to the destabilizing effects of large amounts of intermittent solar and intermittent wind. Both German and south Australian power grids have recently been harmed by events connected with a higher penetration of intermittent solar and intermittent wind. Those expensive harms include blackouts and damaged equipment. Grid-intervention events associated with the stops and starts inherent with both solar and wind are increasing for both of these grids.

    CGNP established during the sworn oral cross-examination phase of PG&E witness Frazier-Hampton in CPUC A.16-08-006 that all power systems require baseload power. Specifically, when asked, “Are you aware of any large electric grid, anywhere in the world that operates without a substantial continual supply of electricity from base-load sources?” PG&E witness Frazier-Hampton, who performed their needs analysis, was unable to identify such a grid anywhere. A.16-08-006 Oral Evidentiary Hearing Transcript, April 26, 2017, PG&E, Frazier-Hampton, pp. 946, line 6. Additional details are found in the Appendix, “CGNP’s Summary Responses to other Parties” Dec. 7, 2018.

    Furthermore, the widely-promoted “duck curve” serves to advocate for the inefficient and intermittent dispatch of natural gas fired generation required to compensate for both the intermittencies and poor alignment of the solar power production peak with the late afternoon and early evening load peak. In a previous post, I referenced “Turns out wind and solar have a secret friend: Natural gas,” by Chris Mooney, August 11, 2016, The Washington Post, serves as an introduction to: “Bridging the gap: Do fast-reacting fossil technologies facilitate renewable energy diffusion?” by Elena Verdolinia, Francesco Vonab, and David Popp, Energy Policy 116 (2018) 242–256, The environmental harms identified in those sources remain un-rebutted by McCann

    in this energy policy debate, it is “creative salesmanship” to claim that the increased emissions associated with inefficient and intermittent dispatch of natural gas fired generation yields benefits (except perhaps to natural gas wholesalers.) Furthermore, in its written testimony in CPUC proceeding R.16-02-007, CGNP establishes using CAISO data that “heat rates” for California generators are rising as more and more intermittent solar and intermittent wind are added to the California power grid. For those that are unfamiliar with the term ” heat rate,” it is a measure of efficiency in power production. Rising heat rates mean decreased efficiency.

    • My reply post seems to have disappeared.

      I posted 3 articles that showed the German and Australian power grid problems were unrelated to solar power and that the Tesla batteries has adverted an outage in Australia.

      U.S. nuclear power plants have not load followed on an hourly or even daily basis and are technologically unable to do so. I know of only one plant that cycles on a seasonal basis although there are several with operating costs above springtime power prices. (BTW, if the CAISO has negative hourly prices, why doesn’t Diablo Canyon cycle off in those hours?)

    • This got lost too:
      “Specifically, when asked, “Are you aware of any large electric grid, anywhere in the world that operates without a substantial continual supply of electricity from base-load sources?” PG&E witness Frazier-Hampton, who performed their needs analysis, was unable to identify such a grid anywhere. ”

      That the witness doesn’t know about such a situation does NOT mean that it’s not possible. That’s an incorrect logical leap.

  3. Nemet’s work is excellent.

    I’d also recommend Behind the Learning Curve and Beyond the Learning Curve.

  4. Carl Wurtz raises very important points regarding the non-dispatchability of intermittent solar and intermittent wind. Clearly, the generation resources with the greatest economic value should be dispatchable. While a homeowner may be able to run their dishwasher or clothes washer a few hours later with no economic repercussions. However, a factory, dependent on abundant and reliable power would be forced to shut down during times of no power. Furthermore, the U.S. EPA previously established a “social cost of carbon” that places a significant economic value on the harms of carbon pollution. If electricity markets were rationally-designed the combination of abundance, dispatchability, and zero-emissions would yield the greatest market rewards for nuclear power, trailed by hydropower. As a consequence of 3% fugitive methane emissions during extraction and distribution, dispatchable natural gas and coal would be tied and valued less, and non-dispatchable solar and wind would be valued the least, particularly in California which has too much of both Battery Electric Storage is simply cost-prohibitive.

    • I’ve already addressed the misinformation presented by Dr. Nelson and Carl Wurtz in many previous posts. The first point is that current conventional nuclear plants operating in the U.S. are effectively non-dispatchable. The plants that do have a “variable” output shutdown for an extended period, e.g., Columbia. (And dispatchability is not a highly valuable service based on many modeling exercises. It is certainly much less valuable than either the energy or capacity provided.)

      To say solar hasn’t provided capacity value is to ignore the fundamental reason for the “duck curve”–that solar capacity has met the midday plug load and what remains is evening loads.

      Until small modular reactors (SMR) become commercial, show that they are lower cost and fuel can be disposed of safely, that option is speculative. Nuclear advocates have made many failed promises. We’re done with the “cries of wolf”.

      • If there’s one aspect of renewable energy which can be considered consistent or predictable, it’s the limitless patience of proponents to invent excuses for renewables’ fundamental flaw of intermittency. There are only enough hours in the day to refute them because it’s necessary to refute them. Some well-meaning individuals might take them seriously.

        “To say solar hasn’t provided capacity value is to ignore the fundamental reason for the “duck curve” – that solar capacity has met the midday plug load and what remains is evening loads.”

        Richard McCann, who frequently boasts of his experience in utility regulation, is apparently unaware of the purpose of capacity markets:

        “Capacity represents the need to have adequate generating resources to ensure that the demand for electricity can be met at all times.”

        Let that sink in: “To ensure that the demand for electricity can be met at all times.” Solar and wind energy are unavailable at least two-thirds of every day; availability is unpredictable. Ergo, in terms of ensuring demand for electricity can be met at all times, solar and wind are worthless.

        • As a regulatory witness, I know that the definition of “capacity” complex and context specific. You will find many definitions here for example:

          Notably, “capacity” is defined at “Pmax” which is defined as: “The maximum normal capability of the Generating Unit.”

          Often there are duration limits associated with firm capacity, and discounts for intermittency.

          • Your use of the term “capacity” ignores availability, and is thus entirely outside the context of capacity markets. That there may be discounts for intermittency for wind and solar does not change the fact both are incapable of ensuring demand for electricity can be met at all times. For that purpose, they’re worthless – and any attempt to assign them value constitutes a fraud at the expense of ratepayers.

          • It’s not my term for capacity, it’s the official term used by the CPUC and CAISO. If you were familiar with the calculation of effective load carrying capacity (ELCC) that goes into the NQC, you would know that the definition included availability.

  5. drgenenelson above raises several important caveats to the assumption cheap solar panels translate to lower carbon emissions.

    In a critique of the Energiewende recently, an energy analyst questioned if solar panels were free, whether the expense of land use, of mounting, of cleaning, of backup power, of transmission, of replacement every 25 years, of variability made them worth the drive to the factory to pick them up. A heated debate ensued, one devoid of any conclusive argument it would be.

    That this assumption is even debatable should force us to re-examine the value of dispatchability, of the ability to provide energy on consumers’ terms. When no one can afford to be at the mercy of weather or time of day for electricity, it seems comparing capital or per/MWh prices of dispatchable vs. intermittent energy is pointless.

  6. Dean Wolfram, thanks for the review!

    I’ve got one basic question: Did you actually enjoy reading the book and would you recommend it?

    Sounds like the author makes as good an argument as I’ve heard. Having worked for two solar manufacturing companies, but doing utility scale project development to place he panels rather than help on any aspect of manufacturing, my perspective had been that the industry was built on three pillars: progressive policy making, economies of scale and lots of investment. Policies in Germany, Ontario and California drove solar manufacturing and utility scale development to make and install as many modules as possible. Germans wanted to fight climate change and control a newly meaningful manufacturing sector. California wanted to fight climate change and employ electricians and contractors and encourage its homegrown solar economy. Of course, Chinese entrepreneurs supported by government grants (loans needing no or limited repayment) were able to swamp the Germans and everyone else just about (notable exceptions include First Solar and a few others). The Chinese government wanted to control the industry like they did with wind and employ people.

  7. While this is an interesting post, I believe it ignores classical macroeconomics,. i.e. supply and demand. California has been the state with the greatest amount of commercial photovoltaic (PV) installations of any state. However, there is a saturation in demand as solar now causes significant negative pricing and/or curtailments. Here are some CAISO annual PV commercial installation statistics (megawatts).
    2015 7,861
    2016 10,157
    2017 10,818
    2018 11,960
    2019 (Aug) 12,072

    Last year, California ratepayers paid about a billion dollars to have ratepayers in adjacent states take California’s excess solar power. Apparently, CAISO reset the payment rules to PV owners, so they are curtailing production much more in 2019 than 2018 – and receiving ratepayer curtailment payments that are likely around a billion dollars annually. (This overproduction appears to be an example of California energy policy being set by subsidy-seekers instead of being driven my rational market design.) Furthermore, neither solar nor wind are “dispatchable.” – a major shortcoming.

    California has several large pumped hydroelectric storage systems such as Helms and Castaic. However these plants appear to not be used for bulk energy storage, based on their abysmally-low capacity factors – well below 10% per the US EIA. In fact, the average daily usage of the massive Helms Pumped Storage facility was only 12 minutes per day in 2005. More details are found here: Instead, these energy storage systems appear to be used to provide “ancillary services” that maintain voltage and frequency stability. Solar and wind destabilize the grid. Finally, Battery Electric Storage Systems are hideously expensive. They are too small by about a factor of 10,000.

    Given the poor alignment between the peak production of solar power when the Sun is directly overhead and the late-afternoon to early-evening load peak, the result is that the natural-gas-fired generation that “firms” solar and wind must be dispatched in an inefficient and intermittent fashion that likely nullifies any environmental benefits of solar and wind. This problem with solar and wind has been known for some time. Some natural gas vendors are finally admitting in advertisements that they compensate for the substantial intermittencies of solar and wind.

    For all of the above reasons (and several more) California should have spent the billions of dollars expended for short-lived solar and wind installations on dispatchable, cost-effective, reliable zero-emissions nuclear power. Nuclear power plants like DCPP are designed to last a century. The eminent scientists and engineers of the California Council on Science and Technology (CCST) were requested by the California Energy Commission (CEC) in 2010 to chart a cost-effective pathway forward for California to achieve its mandated emission targets – and facilitate electrification of the highly-emitting transportation sector. Their answer was simple. Build about 30 new nuclear power reactors in addition to the four already in operation. Fossil fuel interests made sure the pair of 2010 CCST reports were ignored. You may learn more about these controversies at the Californians for Green Nuclear Power, Inc. website at CGNP is a CPUC intervenor is several relevant proceedings, including the current R1602007 Resource Adequacy proceeding. CGNP continues to advocate on the basis of science, engineering, and economics for the continued safe operation of Diablo Canyon Power Plant (DCPP) beyond 2025. If the highly-functioning DCPP is closed, power rates will climb even higher as new dirty fossil-fired generation replaces the equivalent of five Hoover Dams of zero-emissions electricity. As another Energy Institute at Hass paper by Lucas Davis established, when San Onofre Nuclear Power Station (SONGS) was closed in January, 2012, it was replaced with fossil-fired generation.

      • Richard McCann continues to ignore the requirement that intermittent generation sources such as solar and wind REQUIRE natural gas firming. This requirement did not change since 2010. It is likely to never change Instead, solar and wind installations are promoted by fossil fuel interests to embed the substantial requirement for natural gas with the ratio of 1 MW of natural gas for each 0.88 MW of either solar or wind. . The inefficient intermittent dispatch of the natural-gas-fired generation in this scheme likely nullifies any environmental benefit of either solar or wind…….. Here’s a forthright statement from the Interstate Natural Gas Association of America (INGAA) – a natural gas trade group based in Washington, DC. To learn more, please use all three words in a Google query…… Gas Complementary Renewables On October 22, 2019 this query yielded 8.19 million results. . . . . . . Since multi-unit nuclear power plants such as Diablo Canyon Power Plant run for many years at a time, there is no fossil-fired firming requirement for nuclear power, which is a significant environmental advantage for nuclear power relative to either solar or wind.

        • I don’t ignore the need for firming–I recognize that the technologies available for firming are evolving rapidly. Storage technologies look quite promising for much of that requirement. NextEra already includes storage in half of its new solar projects:

          And as I pointed out, you misinterpreted the gas/solar firming study. Having capacity doesn’t mean that it is used much. You still haven’t answered how California’s GHG emissions could have dropped so much since 2008 if all of the gas generation occurred that you claimed is needed for firming. INGAA’s press release is far from confirming some wild conspiracy by the fossil fuel industry. They are just trying to catch up to a runaway horse. Overall gas generation in California has been greatly reduced.

          And you ignore that baseloaded nuclear plants will little ramping capability force the continued use of natural gas plants to load follow throughout the day. At least solar plants follow the general plug load (as opposed to the misrepresentative “net adjusted load” shown by CAISO that subtracts off the solar and wind generation first) which has greatly reduced the lowest efficiency midday natural gas CT generation.

          • “And you ignore that baseloaded nuclear plants will little ramping capability force the continued use of natural gas plants to load follow throughout the day. At least solar plants follow the general plug load (as opposed to the misrepresentative “net adjusted load” shown by CAISO that subtracts off the solar and wind generation first) which has greatly reduced the lowest efficiency midday natural gas CT generation.”


            Are nuclear plants forcing the use of gas-fired plants for ramping – or are the solar plants causing this? Seems rather odd that California didn’t have this fast ramping problem until all that solar capacity was installed. You need to be more honest and objective in your statements.

            Also, CAISO is justified in subtracting off solar and wind production from the gross load because the gross load is correlated with renewables production. Statistical independent does not apply.

          • The excessive size of nuclear plants has caused the need for ramping from natural gas BEFORE renewables came on the seen. Unless a resource is fully load following, it cause the need for supporting ramping generation.

          • “The excessive size of nuclear plants has caused the need for ramping from natural gas BEFORE renewables came on the seen. Unless a resource is fully load following, it cause the need for supporting ramping generation.”

            That’s true of all base load capacity. However, until solar generation became so large as to create the Duck Curve ramping was not a big problem. So where should we place the blame?

          • Based on the series of workshops that I attended hosted by SCE and PG&E over the summer, I don’t think we can conclude that ramping is such a big problem. SCE and PG&E are going to go back and conduct more studies on whether ramping creates significant added costs beyond those that are already incurred for meeting reliability targets. I haven’t seen any strong evidence supporting the claim that ramping is a significant cost addition yet.

          • Wind and solar are generation resources and they meet the metered peak load which is in fact in the late afternoon, not the early evening as the net load calculation disingenuously portrays. It is METERED or even PLUG load that is the relevant metric, not some remainder load after subtracting unfavored resources.

        • And back to my original point. The 2010 CCST’s study results were NOT based on firming requirements but cost and technology assumptions that are now obsolete. You are misrepresenting the findings from that study.

        • drgenenelson,

          I don’t understand how .88 MW of solar or wind (name plate) capacity require more than .88 MW of any kind of backup capacity. Even taking account of availability, which is around .95 percent for a gas-fired combustion turbine, that is still less than 1 MW of backup capacity.

          And I totally reject the idea that relying on natural gas-fired plants to backup renewables will negate their the reduction in CO2 that the renewables produce. Why? Because the gas plants will only run a limited number of hours per year.

          I see no problem with using gas-fired plants to backup renewables. While I haven’t run the numbers I strongly suspect that it will be cheaper to back up renewables with gas, rather than with storage – at least in the foreseeable future. Storage is just too expensive.

          • @RobertBorlick: To understand why any environmental benefits of solar and wind are nullified by the inefficient and intermittent dispatch of fossil fuel generation that firms solar and wind, think about your fossil-fired vehicle…. The miles per gallon (efficiency) diminishes in stop-and-go driving relative to operating the same vehicle on the open road (even with higher air resistance in the latter case). . . . Generators are massive machines. Making them stop and start – or even as practiced in California, converting them to ‘spinning reserve” when the Sun is shining or the wind is blowing yields increased emissions. The California Independent System Operator (CAISO) as an advocate for this fossil-fired inefficiency has aggressively promoted the “Duck Curve” – a public relations technique in which a liability is promoted widely so that the public becomes convinced it is a benefit. The Duck Curve is actually a sales aid for natural-gas-fired generation. The CAISO boasts about their high ramp rates in their public relations documents. The maximum 3-hour ramp recorded by CAISO to date was on January 1, 2019. The value was 15,617 MW. To put this figure in perspective, 15,617 MW is about 7.5 Hoover Dams (each at 2,079 MW) This huge ramp was mostly met by aggressively dispatching dirty fossil-fired generation. A word picture for this inefficiency is to think about a dragster “burning rubber” as it starts up to compete in a quarter-mile run. . . . . . Now think about what you learned about efficiently operating a vehicle.. Efficiency is maximized by gentle starts and stops. Wear and tear are minimized in the latter case. The dramatically reduced fossil-fired ramp of only about 6,000 MW for 3 hours for all of California is found on Monday, January 14, 2019. The low ramp was a consequence of clouds apparently covering most of California, yielding negligible solar output This increased efficiency of steady-state operation of fossil-fired is what California should be striving for. Baseload nuclear power is the best foundation for California increased fossil-fired generation efficiency.

          • Yes, the average heat rate has risen for gas fired units over the last decade, but the reduction in overall generation has far exceeded that efficiency loss so that on net gas fired generation has fallen substantially. The empirical evidence is overwhelming.

          • Well, that makes sense. But I have never seen those increased emissions quantified. Can you cite the analysis that backs up your assertion? I would like to read it.

          • @RobertBorlick The silence from Richard McCann when asked by you to provide documentation more than four months ago for his assertion is significant. A confounding factor is “wet years” in which abundant hydropower is more available. Watch the in-state and out-of-state fossil fuel use climb in dry years with a lower hydropower contribution. As CGNP’s CPUC filings have established, the heat rate, or number of MMBTus per MWh, have been increasing for individual generators over time as a consequence of the increasingly inefficient dispatch of the fossil generation required to compensate for the huge (about 80% in California) intermittency for both California solar and California wind.

            Thus, the number of hours these gas plants run is significant. An argument can be made that this intermittency compensation is a significant revenue stream for fossil fuel providers as about 20,000 MW (ten Hoover Dams) of fossil generation is now required to compensate for the intermittency of the nominal 12,000 MW of California large-scale solar and 6,000 MW of California wind No wonder big fossil suppliers such as BP America and Total SA of France are running advertisements about the fact they provide fossil energy to compensate for the intermittency of solar and wind.

            If California had spent the same amount on nuclear power as the state has spent over the last decade on short-lived solar and wind – following the recommendations of the CCST in a pair of reports in 2011, we would not be seeing the growing fossil-fired ramp rates. CAISO provides ample documentation of the year-to-year increases in ramp rates. California power sector emissions would be decreasing as dispatchable, high capacity-factor zero-emissions nuclear power displaced fossil-fired generation.

            There’s a unique additional problem in California associated with the fact that California solar generates considerable power when it is not needed. As a result, California ratepayers paid an extra billion dollars in 2018 for the residents of Oregon, Nevada, and Arizona to TAKE California’s excess solar generation. The new CAISO process of “self curtailment” is much more opaque, but likely imposes comparable annual costs on California ratepayers.

          • I had not come back to this site for a while, which was the reason for the silence. There’s not a “single” report that comes to this conclusion. It requires working with data to make the calculations (which I did a couple years ago for a client and not willing to share unless you want to pay me–otherwise you have the sources to do the calculations.)

            Here’s CARB’s GHG inventory. The figure on p.5 shows the downward trend from 2008 to 2017 with a single blip in 2012 for the SONGS closure:

            Here’s the CAISO Market Monitor Reports for 2001-2018 that show the average implied heat rates (which generally are dropping):

            Here’s the CEC Energy Almanacs that go back into 2001 that show annual generation by natural gas sources:

            The CEC doesn’t publish annual gas demand for electricity anymore, but the EIA has that data here:

            As to flexible generation capacity that’s needed, studies by PG&E and SCE for use in their GRCs shows about 17,000 MW, but I think the incremental amount for renewables is less than 10,000 MW. But most importantly, its just a change in type of capacity. California already has enough capacity for its peak reliability needs, and there appears to be no additional need for new flexible capacity to meet that flex need. It’s only additional start up/commitment and minor incremental heat rate costs that are incurred. Flex capacity costs appear to be pretty small, much smaller than initial estimates. There’s no way that this has incurred the equivalent of $8,000/kW which is what nuclear would have cost based on our analyses prepping for the 2009 Cost of Generation Report.

            Please provide a citation from the CAISO, CPUC, LBNL or DOE that excess renewables in 2018 cost California $1B. If it’s another source, please provide the full data used for the calculation.

          • Richard: Your use of aggregated heat rate data hides many problems. CGNP’s 2019 filings in R1602007 examine heat rates for large and small generators over time as the penetration of California solar and wind increased .
            Here’s data for Southern California Edison’s biggest Combined Cycle Gas Turbine generation plant:
            The increasing heat rate for Mountainview from 2013 to 2017 corresponds to increasing solar penetration in southern California. The data shows decreasing fossil fuel consumption for this “workhorse” plant, as you claim. However, what is happening is that more and more of the generation to meet peak demand is being shifted to “peakers” that have heat rates about *twice* that of this baseload plant. The increasing use of these peakers also raises social justice issues. CGNP attended hearings in Oxnard, California regarding the proposed Puenta Power Project, which would add another peaker to the generators in Oxnard. Already, the economically disadvantaged community in the neighborhood of the existing Oxnard peakers shows increased respiratory illness such as asthma among the very young and very old. These were additional reasons why CGNP opposed the Puenta Power Project.
            Company Name: Southern California Edison
            Generator Number: G0795
            Generator Name: Mountainview Generating Station
            Mountainview Power Plant in Redlands, CA has a nameplate capacity of 1,058 MW.

            Year Net MWh Main MMBTU Heat Rate
            2017 4,053,420 30,176,400 7.445
            2016 4,900,360 35,658,400 7.277
            2015 5,753,490 41,751,600 7.257
            2014 6,183,070 44,188,900 7.147
            2013 5,516,840 39,149,900 7.096
            2012 6,609,470 47,120,500 7.129
            2011 4,626,580 33,354,200 7.209
            2010 6,051,140 43,228,100 7.144
            2009 5,754,370 41,503,900 7.213
            2008 6,691,300 47,781,900 7.141
            2007 6,308,450 44,557,400 7.063
            2006 4,888,070 35,447,200 7.252
            2005 148,559 1,081,100 7.277

            For this table, the heat rate is expressed in MMBtu per MWh.
            Efficiency decreases as the heat rate increases.
            MMBTU = Millions of BTUs. 1 MWH = 1,000 kWH.
            Data Sources: USEIA Mountainview Monthly Natural Gas Consumption and Monthly Generation
            At 100% Capacity factor, Mountainview would generate 9,274,428 MWh per year.

          • While Mountainview’s efficiency fell by 4.3%, its gas consumption decreased by 37%. That’s not surprising since lower amount of generation is associated with longer periods of running at inefficient minimum loads. That’s an expected result from increased renewable generation until Mountainview is completely pushed off the grid.

          • Here’s some CEC aggregated data showing the general increase in the use of peakers.
            The annual values are affected by the relative supply of hydropower. In “wet” years, there is less demand for fossil-fired generation. However, note the increasing use of peaking generators from 2011-on.
            Table 6: Annual Values Natural Gas Usage, MMBtu
            Year “Combined Cycle” Peaking
            2001 19,036,000 19,862,000
            2002 92,581,000 14,307,000
            2003 189,850,000 12,386,000
            2004 269,908,000 14,090,000
            2005 307,828,000 13,021,000
            2006 415,525,000 13,067,000
            2007 513,084,000 15,977,000
            2008 542,740,000 19,473,000
            2009 544,781,000 19,453,000
            2010 521,691,000 15,816,000
            2011 398,968,000 18,869,000
            2012 615,296,000 28,393,000
            2013 629,434,000 36,726,000
            2014 650,038,000 45,231,000
            2015 636,741,000 45,442,000
            2016 522,255,000 40,027,000
            2017 460,969,000 42,558,000
            Data Source:Table 6: Natural Gas Usage for California’s Power Plants, 2001-2017 (MMBtu)
            URL: Archived 03 31 19 by Gene A. Nelson, Ph.D.
            Nyberg, Michael. 2018. Thermal Efficiency of Natural Gas-Fired Generation in California: 2018 Update

          • Two points:

            – As you pointed out, hydropower generation dropped substantially from 2012-2016, so little can be garnered from trend data over that period.

            – Note also that during that period most of California’s inefficient steam generation fleet was retired and replaced with efficient combined cycle plants. Focusing solely on CCGT output ignores the vast reduction in output form the rest of the gas fleet.

            – The output for a single CT increased an average of 25 GWH per year. SCE has 6 of those in its fleet, which means that gas generation increased an average of 150 GWH. In a system with an average annual load of 200,000+ GWH, that’s 0.075% of total generation. That’s truly trivial compared to large overall reductions shown in the CARB inventory.

          • Here’s example data for a SCE peaker plant. Note with increasing solar and wind penetration, these less-efficient plants are being used more. Regrettably, the CEC does not appear to classify natural-gas-fired plants as “peaker” versus “baseload” plants. CGNP needed to research SCE’s regulatory filings to learn the identity of some of their peaker plants.
            Net generation 45 MW Barre peaker (56474) all fuels all primemovers annual
            Source: U.S. Energy Information Administration

            Year MWh CF MMBTU “MMBTU/MWh”
            2017 33,132 8.40% 336,913 10.169
            2016 28,750 7.29% 295,224 10.269
            2015 33,129 8.40% 336,110 10.145
            2014 29,409 7.46% 307,394 10.452
            2013 16,282 4.13% 175,024 10.750
            2012 25,507 6.47% 270,245 10.595
            2011 6,191 1.57% 71,151 11.493
            2010 6,446 1.63% 74,873 11.615
            2009 2,715 0.69% 35,852 13.205
            2008 4,727 1.20% 56,982 12.055
            2007 9,165 2.32% 107,634 11.744

            100% CF = 394,470 MWh

            It would require more than 23.5 Barre peaker plants to equal the nameplate capacity of Mountainview.

            The general California trend favored by increased solar and wind penetration since 2010 is to shift more of the fossil-fired generation on less-efficient (10+ MMBTu/MWh) peakers instead of larger, more efficient CCGT plants such as Mountainview with heat rates around 7 MMBTu/MWh. As noted previously, this substitution yields significantly higher ratepayer burdens to integrate the intermittent solar and wind into the grid.

            Prior to the introduction of large amounts of intermittent solar and wind onto the California, the fossil-fired peak in the late afternoon and early evening had a much more modest height. High ramp rates imply lower efficiency.

            Here is the quote regarding the cost of sending California’s 2018 solar generation when it is not needed to consumers in Oregon, Nevada, and Arizona.

            Here’s a transcript of California Assemblymember Brian Dahle (R – Redding) speaking at a 28 August 2018 floor session regarding the passage of SB 100 (De Leon.) The video is available at CGNP’s website for your review.

            ….”I want to share with you what we are doing in the State of California right now. We have this thing called the ‘Duck Curve.’ Have you seen that Duck Curve? (Gestures) Where we’re producing too much energy during the day and not enough when the Sun isn’t shining and wind is not blowing. The ratepayers in California are paying a billion dollars a year right now to offset the cost going to other states. Because when you put one electron in, one comes out, and when you have too many, you have to send it somewhere. And we’re sending our electricity to Arizona, to Nevada, to Oregon, and we’re paying to do that. And it’s driving the cost up. Let’s talk about this in the future where we can lay out a plan where we’re not paying other states to take our electricity. We’re not doing it for the environment here. (Assemblyman Jordan Cunningham [R- San Luis Obispo] starts at 48 seconds regarding the importance of Diablo Canyon Power Plant’s zero-carbon power.)….

            Los Angeles Times Energy Reporter Sammy Roth also criticized the high cost of sending California’s excess solar power to adjoining states in 2018.

          • I also recall reading a draft CAISO proposed rule where the natural gas consumption of California generators would only be totaled during the periods a generator was producing electricity – not during periods the generator is consuming fossil fuel in “back down” or “back off” mode. Current CAISO market rules are quite opaque to “outsiders” that are not informed of where important data is hidden. Thus, CAISO performance data is suspect.

            US EIA net energy consumption and net generation statistics for generators are more reliable. Unsurprisingly, CAISO favored the controversial 2018 AB813 plan for regional grid integration that has been repeatedly proposed by Berkshire-Hathaway’s PacifiCorp since 2003. Most Californians don’t know that PacifiCorp has 6,000 + MW of dirty coal-fired pants, mostly in Wyoming and 3,000 + MW of natural – gas fired generation. PacifiCorp wants to sell their fossil-fired power in the California market. PacifiCorp’s annual fossil-fired generation dwarfs their annual solar and wind generation. PacifiCorp currently has no nuclear power generation, despite the fact that Diablo Canyon Power Plant’s cost of production at about $28.00 per MWh substantially undercuts the production cost at PG&E’s large CCGT Colusa Generating Plant at about $38.00 per MWh, per PG&E’s 2018 FERC Form 1.

          • The CARB AB32 inventory reports that I’ve posted here innumerable times are based on direct reports from generators that emit more than 25,000 tonnes of GHG per year (most moderate sized plants). None of these inventory numbers come from CAISO data, so that’s irrelevant.

            SB1305 requirements substantially limits imports from PacifiCorp’s coal fleet to California.

  8. [unless i missed it as I speed read the post on my phone before getting off at BART Downtown]

    A point not mentioned is the classic semiconductor [and others] experience curve. The key is in rising volumes. I will leave out the many jokes about selling at a loss and then ‘making it up in volume’ etc. So for every doubling of cumulative volume costs [not prices] drop x %, where the x varies by industry.

    Another expression of the experience curve is Moore’s Law – chip performance doubling every 18 or so months.

    For panels, initially the silicon was a major part of cost. But as volume increased that share dropped, and the cost of ‘assembly’ of the physical panel took over. With automation of assembly that dropped too. Now the installation on-site ‘labor’ cost is probably largest factor. There are moves to integrate/ automate parts of that too. The last will be regulatory/ permitting costs.

    My concern re solar/PV is about mitigating end-of-life disposal of the toxic materials.

    [by the way it is Sharp not Sharpe – i think{

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