This is a response to Eduardo Porter's article in the New York Times on June 20, "Fisticuffs Over the Route to a Clean Energy Future."
Porter's article described a paper published in the Proceedings of the National Academy of Sciences (PNAS) by Chris Clack and coauthors on June 19, criticizing a paper colleagues and I authored in the same journal in 2015. Our original paper showed that the U.S. can transition to 100% clean, renewable energy in all energy sectors without coal, nuclear power or biofuels. Porter makes several mistakes and omissions in his article that I correct here.
First, Porter relies on his claim that "21 prominent scholars…took a fine comb to the Jacobson paper and dismantled its conclusions bit by bit." This one sentence contains two falsehoods. For starters, our conclusions were not dismantled et al. Our response, which PNAS published as the last word by not permitting a response by Clack, concludes instead, "The premise and all error claims by Clack et al. about Jacobson et al. are demonstrably false. We reaffirm Jacobson et al.'s conclusions."
Response to Forbes: Stop Inaccuracies—100% Renewable Energy Is Possible https://t.co/FX8MQlbyAh @100isNow @Howarth_Cornell @Forbes @Stanford— Mark Z. Jacobson (@Mark Z. Jacobson)1499353999.0
More important, Porter fails to point out that Clack and coauthors' own disclosure published in their paper indicates that only 3 out of 21 coauthors performed any type of research for the article. The remaining 18 did no research whatsoever, merely contributing to writing the paper with admittedly no research contribution. Of the thre authors who did perform research, one has admitted publicly, "I am not an energy expert" (see 15 minutes and 32 seconds into this UCLA debate).
Porter quotes another author, David Victor referring to our 2015 PNAS paper, as stating, "I thought 'this paper is dangerous'," despite the fact that Victor has admitted to doing no research for the article and despite the fact that he is neither a scientist nor an engineer but instead works on international policy and law. Similarly, Porter quotes another author, Varun Sivaram, as stating about the Clack paper, "Our paper is pretty devastating." But, Sivaram has also admitted in writing that he did no research for the article. Moreover, he works in foreign relations, not energy science or engineering.
In the meantime, our 100% clean, renewable energy peer-reviewed papers have collectively had more than 85 researcher-coauthors and more than 35 anonymous peer reviewers.
Porter then mimics Clack's false claim that "most of the scientific community represented on the Intergovernmental Panel on Climate Change" argues that nuclear power is necessary to help solve the climate problem.
However, Porter is wrong. As stated in our PNAS-published response to Clack, the IPCC says the exact opposite: "Without support from governments, investments in new nuclear power plants are currently generally not economically attractive within liberalized markets ..." I don't intend to be harsh. But this statement was in our response, so Porter should never have claimed about the scientific community believing nuclear is necessary in the first place.
Next, Porter claims that I "accused (my) critics of being shills for the fossil fuel and nuclear industries." No, I do not believe any of the authors are shills (someone who is paid specifically to act on someone's behalf), but I do believe most of the authors have either a research, advocacy, or financial conflict of interests in what they have written. For example, one coauthor, Sweeney, "periodically serves as a consultant or advisor to Exxon Corporation, ARCO, the American Petroleum Institute,…", all of whom profit from fossil fuels. He has also stated unequivocally, "If we were to give up on the fossil fuels, we give up on both the economy and security very quickly" (see 1 hour 29 minutes into this video).
Response to National Review: #100% renewables works https://t.co/7A6QltCEsr @MichaelEMann @Howarth_Cornell @JGKoomey @AmoryLovins @Cohan_DS— Mark Z. Jacobson (@Mark Z. Jacobson)1499451641.0
Similarly, Jane Long, another co-author, is a Senior Fellow of the Breakthrough Institute, a pro-nuclear advocacy group. It is therefore, no surprise that several authors would criticize our work because of their conflict of interest in keeping fossil fuels and nuclear power on the table.
Porter then criticizes increasing the use of underground storage in rocks, but this storage technology is inexpensive (less than 1/300th the cost per unit energy stored than batteries) and a form of district heat. Sixty percent of Denmark's heat is from district heating using water rather than rocks. Underground rocks are a less-expensive substitute for water tanks. He also somehow thinks it is impossible to build pipes to homes when virtually every new home in the United States has gas and water pipes built to it.
Porter further criticizes the use of more hydrogen, whereas hydrogen production from electricity is an advanced technology developed more than 130 years ago. Porter then unduly criticizes the cost of capital we use and the ability of industry to use demand response to shift times of energy use, when these claims are clearly addressed in our PNAS reply letter at.
Porter then falsely implies that we propose to add new hydroelectric installations equivalent to 600 Hoover dams resulting in 100 times the flow of the Mississippi River. This analogy is nonsensical, since our annual energy output is not increased at all, whereas a flow rate of 100 times that of the Mississippi would mean that we would increase annual energy output of hydropower by a factor of ten, which we don't. The mistake by Porter and co-author of the PNAS article, Ken Caldeira, who provided this claim, is that whereas we increase the ability of the hydro to discharge significantly faster for some hours, we discharge much less during other hours in order to ensure there is zero change in the annual output. Caldeira and Porter tried to make it sound as if we increase the flow rate indefinitely.
Regardless, an alternate solution to increasing the hydropower discharge rate is to increase the discharge rate of concentrated solar power (CSP) and/or to add batteries. Both methods results in low-cost solutions as illustrated for the United States and Canada here.
The fact that the system works with either increased hydropower discharge or increased CSP and batteries contradicts Porter's quote of Clack: "The whole system falls apart because this (hydropower) is the last thing that is used. If you remove any of this, the model fails." To the contrary, the result above demonstrates that the model works without increasing hydropower peak discharge, disproving the main premise of the Clack article that our nation's energy can't run 100% on wind, water, and solar power at low cost.
In sum, I believe that a debate about our energy future can be constructive. But inaccurate statements about scientific work and amplifications of those inaccuracies help no one. Had Porter read our PNAS response carefully, he would not have made the errors he did. Nevertheless, my colleagues and I are always seeking to improve our methods and calculations. Our goals are to better the quality of life of everyone by determining the best ways to provide clean, renewable, and reliable energy while creating jobs and improving people's health and reducing costs. Hopefully others share these goals, regardless of political party affiliation.
This is a response to Robert Bryce's article in National Review on June 24, "Appalling Delusion of 100% Renewables Exposed: National Academy of Science Refutes Mark Jacobson's Dream That Our Economy Can Run Exclusively on 'Green' Energy."
Bryce's article describes a paper published in the Proceedings of the National Academy of Sciences (PNAS) by Chris Clack and coauthors on June 19, criticizing a paper colleagues and I authored in the same journal in 2015. Our original paper showed that the U.S. can transition to 100% clean, renewable energy in all energy sectors without coal, nuclear power, or biofuels. This response demonstrates that Bryce was negligent by not reporting our simultaneously published response in PNAS and by inaccurately reporting the facts.
First, PNAS did not "refute" our article as Bryce's title claims. To the contrary, PNAS published our response to Clack equally and simultaneously, giving us the last words by not allowing Clack to respond to us. Our main conclusion, which PNAS published, was "The premise and all error claims by Clack et al. about Jacobson et al. are demonstrably false. We reaffirm Jacobson et al.'s conclusions."
Response to @Forbes: Stop Inaccuracies—100% Renewable Energy Is Possible https://t.co/9SEy1r7kkC @mzjacobson @MarkRuffalo @LeoDiCaprio @350— EcoWatch (@EcoWatch)1499353031.0
Second, Bryce lauds the fact that the Clack et al. article had 21 coauthors. However, Clack and coauthors' own disclosure as published in the author contribution section of their paper indicates that only 3 out of 21 coauthors performed any type of research for the article. The remaining 18 merely contributed to writing the paper with admittedly no research contribution. Of the 3 authors who did perform research, one has admitted publicly, "I am not an energy expert" (see 15 minutes and 32 seconds into this UCLA debate. On the other hand, our 100% clean, renewable energy peer-reviewed papers have collectively had over 85 researcher-coauthors and over 35 anonymous peer reviewers.
Third, as pointed out in our published response, there were zero mathematical modeling errors in our underlying model as claimed by Clack. In one instance, Clack falsely claimed we had a model error because he believed that a number in a table of ours was a maximum value when, in fact, the text clearly indicated that the number was an annual average number that varied in time, not a maximum number. Nowhere in the text was the word "maximum" used to describe that number. Thus, Clack made up out of thin air the claim that the number was a maximum. Clack and all coauthors were informed their claim was an error through a document sent to him by us through PNAS prior to publication of their article but still refused to correct it. One must wonder what the motivation is of authors who are informed of an error before it is printed yet refuse to correct it.
In a second case, referred to by Bryce, Clack claimed we made a model error by mistakenly increasing the maximum discharge rate of hydroelectric power from reservoirs by a factor of 10. However, Clack was told in writing 16 months earlier and a second time just before publication of his article that we intentionally increased the maximum discharge rate without increasing the annual hydropower energy output (thus no change in the amount of water in any reservoir). Despite Clack being told the full truth twice and all co-authors, once, all refused to acknowledge this information, going so far as to pretend they were not aware of it by publishing in their PNAS paper, "…we hope there is another explanation…" although all were informed before publication that there was. Why would 21 authors diligently cross-checking an article do this – namely claim, "we hope there is another explanation" when all had been informed of one?
Our only mistakes were not to be clear in our original paper that we assumed an increase in the hydropower discharge rate while holding annual energy constant and to not account for the cost of the additional turbines, which we subsequently calculated as ~3% of the total energy cost. However, omissions in writing the article are not errors in the underlying model as Clack claimed. Further, the concept of adding turbines to the outside of existing hydropower dams to increase the maximum discharge rate while keeping annual hydropower energy constant was a new idea that works. The legitimate question is, what is the maximum discharge rate that is feasible by 2050 among all U.S. dams, not whether it is possible to increase the discharge rate.
Regardless, an alternate solution to increasing the hydropower discharge rate is to increase the discharge rate of concentrated solar power (CSP) and/or adding batteries. Both methods results in low-cost solutions as illustrated for the United States and Canada here. These results contradict Clack's premise that our nation's energy can't run 100% on wind, water, and solar power at low cost.
Bryce further criticizes underground storage in rocks, but the storage itself is inexpensive (less than 1/300th the cost per unit energy stored than batteries) and a form of district heat. Sixty percent of Denmark's heat is from district heating using water rather than rocks. Underground rocks are a less-expensive substitute for water tanks.
Finally, Bryce continues to misstate the land requirements of wind. He quotes Clack as stating our wind turbine proposal would require 500,000 square kilometers without realizing that Clack's number relies entirely on a single number from a Department of Energy study that makes no sense because (1) the author of the study admits he includes land for future project expansion and double counts land where projects overlap and (2) it suggests only one 3-megawatt turbine every one square kilometers, which would be a waste of windy land. When data from 12 actual European and Australian wind farms with multi-megawatt turbines that have been analyzed in detail as part of an ongoing research project by Peter Enevoldsen of Aarhus University and co-workers, are used, the aggregate area required is less than one-third of what Bryce claims. Bryce further forgets that 31% of our wind turbines are offshore so use zero land.
In sum, debate about our energy future can be constructive and is certainly encouraged. But inaccurate statements about scientific work and amplifications of those inaccuracies help no one. Had Bryce read our PNAS response at all, he would not have made the errors he did. Nevertheless, my colleagues and I are always seeking to improve our methods and calculations. Our goals are to better the quality of life of everyone by determining the best ways to provide clean, renewable, and reliable energy while creating jobs and improving people's health and reducing costs. Hopefully others share these goals, regardless of political party affiliation.
Through net metering programs, homeowners who have installed solar energy systems can get utility credits for any electricity their panels generate during the day that isn't used to power home systems. These credits can be "cashed in" to offset the cost of any grid electricity used at night.
Where net metering is available, solar panels have a shorter payback period and yield a higher return on investment. Without this benefit, you only save on power bills when using solar energy directly, and surplus generation is lost unless you store it in a solar battery. However, net metering gives you the option of selling any excess electricity that is not consumed within your home.
Generally, you will see more home solar systems in places with favorable net metering laws. With this benefit, going solar becomes an attractive investment even for properties with minimal daytime consumption. Homeowners can turn their roofs into miniature power plants during the day, and that generation is subtracted from their nighttime consumption.
What Is Net Metering?
Net metering is a billing arrangement in which surplus energy production from solar panels is tracked by your electricity provider and subtracted from your monthly utility bill. When your solar power system produces more kilowatt-hours of electricity than your home is consuming, the excess generation is fed back into the grid.
For homeowners with solar panels, the benefits of net metering include higher monthly savings and a shorter payback period. Utility companies also benefit, since the excess solar electricity can be supplied to other buildings on the same electric grid.
If a power grid relies on fossil fuels, net metering also increases the environmental benefits of solar power. Even if a building does not have an adequate area for rooftop solar panels, it can reduce its emissions by using the surplus clean energy from other properties.
How Net Metering Works
There are two general ways net metering programs work:
- The surplus energy produced by your solar panels is measured by your utility company, and a credit is posted to your account that can be applied to future power bills.
- The surplus energy produced by your solar panels is measured by your home's electricity meter. Modern power meters can measure electricity flow in both directions, so they tick up when you pull from the grid at night and count down when your solar panels are producing an excess amount of electricity.
In either scenario, at the end of the billing period, you will only pay for your net consumption — the difference between total consumption and generation. This is where the term "net metering" comes from.
How Does Net Metering Affect Your Utility Bill?
Net metering makes solar power systems more valuable for homeowners, as you can "sell" any extra energy production to your utility company. However, it's important to understand how charges and credits are managed:
- You can earn credits for your surplus electricity, but utility companies will not cut you a check for the power you provide. Instead, they will subtract the credits from your power bills.
- If your net metering credit during the billing period is higher than your consumption, the difference is rolled over to the next month.
- Some power companies will roll over your credit indefinitely, but many have a yearly expiration date that resets your credit balance.
With all of this in mind, it is possible to reduce your annual electricity cost to zero. You can accumulate credit with surplus generation during the sunny summer months, and use it during winter when solar generation decreases.
You will achieve the best results when your solar power system has just the right capacity to cover your annual home consumption. Oversizing your solar array is not recommended, as you will simply accumulate a large unused credit each year. In other words, you cannot overproduce and charge your power company each month.
Some power companies will let you pick the expiration date of your annual net metering credits. If you have this option, it's wise to set the date after winter has ended. This way, you can use all the renewable energy credits you accumulated during the summer.
Is Net Metering Available Near You?
Net metering offers a valuable incentive for homeowners to switch to solar power, but these types of programs are not available everywhere. Net metering laws can change depending on where you live.
In the U.S., there are mandatory net metering laws in 38 states and Washington, D.C. Most states without a mandate have power companies that voluntarily offer the benefit in their service areas. South Dakota and Tennessee are the only two states with no version of net metering or similar programs.
If net metering is available in your area, you will be credited for your surplus energy in one of two ways:
- Net metering at retail price: You get full credit for each kilowatt-hour sent to the grid. For example, if you're charged 16 cents per kWh consumed, you'll get a credit of 16 cents per kWh exported. This type of net metering is required by law in 29 states.
- Net metering at a reduced feed-in tariff: Surplus electricity sent to the grid is credited at a lower rate. For example, you may be charged 16 cents per kWh for consumption but paid 10 cents per kWh exported. Feed-in tariffs and other alternative programs are used in 17 of the states where retail-rate net metering is not mandatory.
Note: This is just a simplified example — the exact kWh retail price and solar feed-in tariff will depend on your electricity plan.
The Database of State Incentives for Renewables & Efficiency (DSIRE) is an excellent resource if you want to learn more about net metering and other solar power incentives in your state. You can also look for information about solar incentives by visiting the official websites of your state government and utility company.
Other Financial Incentives for Going Solar
Net metering policies are one of the most effective incentives for solar power. However, there are other financial incentives that can be combined with net metering to improve your ROI:
- The federal solar tax credit lets you claim 26% of your solar installation costs as a tax deduction. For example, if your solar installation had a cost of $10,000, you can claim $2,600 on your next tax declaration. This benefit is available everywhere in the U.S.
- State tax credits may also be available depending on where you live, and they can be claimed in addition to the federal incentive.
- Solar rebates are offered by some state governments and utility companies. These are upfront cash incentives subtracted directly from the cost of your solar PV system.
In addition to seeking out solar incentives available to you, you should compare quotes from multiple installers before signing a solar contract. This will ensure you're getting the best deal available and help you avoid overpriced offers and underpriced, low-quality installations. You can start getting quotes from top solar companies near you by filling out the 30-second form below.
Frequently Asked Questions: Solar Net Metering
Why is net metering bad?
When managed correctly, net metering is beneficial for electricity consumers and power companies. There have been cases in which power grids lack the capacity to handle large amounts of power coming from homes and businesses. However, this is an infrastructure issue, not a negative aspect of net metering itself.
In places with a high percentage of homes and businesses using solar panels, surplus generation on sunny days can saturate the grid. This can be managed by modernizing the grid to handle distributed solar power more effectively with load management and energy storage systems.
How does net metering work?
With net metering, any electricity your solar panels produce that isn't used to power your home is fed into your local power grid. Your utility company will pay you for this power production through credits that can be applied to your monthly energy bills.
Can you make money net metering?
You can reduce your power bills with net metering, using surplus solar generation to compensate for your consumption when you can't generate solar power at night and on cloudy days. However, most power companies will not pay you for surplus production once your power bill has dropped to $0. Normally, that credit will be rolled over, to be used in months where your solar panels are less productive.
On very rare occasions, you may be paid for the accumulated balance over a year. However, this benefit is offered by very few electric companies and is subject to limitations.
This is a response to James Conca's article in Forbes on June 26, "Debunking the Unscientific Fantasy of 100% Renewables."
Conca's article describes a paper published in the Proceedings of the National Academy of Sciences (PNAS) by Chris Clack and coauthors on June 19, criticizing a paper colleagues and I authored in the same journal in 2015. Our original paper showed that the U.S. can transition to 100% clean, renewable energy in all energy sectors without coal, nuclear power or biofuels. In this response, I show that Conca was negligent by not reporting on our response in PNAS and by seriously misrepresenting facts.
Conca's article starts with two misrepresentations. First, Conca points to the Clack critique in PNAS but nowhere does he mention that PNAS published our response to Clack equally and simultaneously. In fact, PNAS gave us the last words by not allowing Clack to respond to us. Our main conclusion, which PNAS published, was "The premise and all error claims by Clack et al. about Jacobson et al. are demonstrably false. We reaffirm Jacobson et al.'s conclusions." Conca did not report this.
Second, Conca states in the first sentence that "twenty-one prominent scientists issued a sharp critique," but fails to point out that Clack and coauthors' own disclosure published in their paper indicates that only three out of 21 coauthors performed any type of research for the article. The remaining 18 did no research whatsoever, merely contributing to writing the paper. Of the three authors who did perform research, one has admitted publicly, "I am not an energy expert" (see 15 minutes and 32 seconds into this UCLA debate. In the meantime, our 100% clean, renewable energy peer-reviewed papers have collectively had more than 85 researcher-coauthors and more than 35 anonymous peer reviewers.
Third, as pointed out in our published response, there were zero mathematical modeling errors in our underlying model as claimed by Clack. This clarifies an inaccurate quote Conca attributes to me, "…there is not a single error in our paper." Not only did Conca never interview me to obtain such a quote, but the misquote is wrong on its face, since we acknowledge in our PNAS response (which Conca does not cite) our failure to be clear in our paper about one particular assumption and our neglect of one cost. However, while we were not clear in our original paper, there was no underlying model error, contradicting Clack's major contention in his paper.
Specifically, in one instance, Clack falsely claimed we had a model error because he believed that a number in a table of ours was a maximum value when, in fact, the text clearly indicated that the number was an annual average number that varied in time, not a maximum number. Nowhere in the text was the word "maximum" used to describe that number. Thus, Clack made up out of thin air the claim that the number was a maximum. Clack and all coauthors were informed their claim was an error through a document sent to him by us through PNAS prior to publication of their article but still refused to correct it. One must wonder what the motivation is of authors who are informed of an error yet refuse to correct it.
Conca's article repeats another one of Clack's false claims. Namely, the claim that our goal of using 100% clean, renewable energy will increase costs if we exclude nuclear power and coal with carbon capture, stating that our doing so is "at complete odds with serious analyses and assessments, including those performed by the Intergovernmental Panel on Climate Change, the National Oceanic and Atmospheric Administration, the National Renewable Energy Laboratory, the International Energy Agency and most of academia."
However, as stated in our PNAS-published response to Clack that Conca negligently fails to cite, the IPCC says the exact opposite: "Without support from governments, investments in new nuclear power plants are currently generally not economically attractive within liberalized markets, ..." Further, unlike in our studies, neither the IPCC, NOAA, NREL, nor the IEA has ever performed or reviewed a cost analysis of grid stability with near 100% clean, renewable energy so could not possibly have come to the conclusion claimed by Conca.
Conca, then makes a misleading and irrelevant statement. He says that we "assume a nuclear war every 30 years or so." The PNAS study he is criticizing says nothing of the sort. He fails to tell readers he is referring to a completely different paper that I wrote from 2009 that estimated the upper-limit risk of nuclear war from nuclear weapons proliferation. However, just like he negligently failed to report our response published in PNAS, Conca failed to report the lower-limit risk of nuclear war as stated in the 2009 paper, zero nuclear wars. Why would he report only the upper-limit of a risk rather than both the upper and lower-limit risks?
Conca then claims we assumed 15 million acres covered by wind and solar, which is wrong, but even if it were correct, he doesn't realize this is only 0.66% of U.S. land area to replace all fossil fuels. He forgets that the 1.7 million active and 2.3 million inactive oil and gas wells alone in the U.S. plus the 20,000 new ones each year occupy more than 1% of U.S. land area for the roads, well pads, and storage facilities.
Conca then falsely claims we proposed to add new hydroelectric installations equivalent to 600 Hoover dams when our paper clearly calls for zero new dams. We propose only to increase the hydropower maximum discharge rate by adding turbines without increasing the annual hydropower energy output (thus no change in the annual amount of water in any reservoir). The concept of adding turbines to the outside of existing hydropower dams to increase the maximum discharge rate while keeping annual hydropower energy constant was a new idea that works. The legitimate question is, what is the maximum discharge rate that is practical relative to other options by 2050, not whether it is possible to increase the discharge rate.
Regardless, an alternate solution to increasing the hydropower discharge rate is to increase the discharge rate of concentrated solar power (CSP) and/or adding batteries. Both methods results in low-cost solutions as illustrated for the United States and Canada here. These results contradict Clack's premise that our nation's energy can't run 100% on wind, water and solar power alone at low cost.
Conca further criticizes underground storage in rocks, but it is inexpensive (less than 1/300th the cost per unit energy stored than batteries) and a form of district heat. Sixty percent of Denmark's heat is from district heating.
In sum, debate about our energy future can be constructive and is certainly encouraged. But inaccurate statements about scientific work and amplifications of those inaccuracies help no one. Had Conca read our PNAS response at all, he would not have made the errors he did. However, my colleagues and I are always seeking to improve our methods and calculations. Our goals are to better the quality of life of everyone by determining the best ways to provide clean, renewable, and reliable energy while creating jobs and improving people's health and reducing costs. Hopefully others share these goals, regardless of political party affiliation.
PNAS published a paper today by nuclear and fossil fuel supporters, which is replete with false information for the sole purpose of criticizing a 2015 paper colleagues and I published in the same journal on the potential for the U.S. grid to stay stable at low cost with 100 percent renewable wind, water and solar power. The journal also published our response to the paper.
The main arguments made by the authors, most of whom have a history of advocacy, employment, research or consulting in nuclear power, fossil fuels or carbon capture, are that:
1. we should have included nuclear power, fossil fuels with carbon capture (CCS) and biofuels as part of our mix because those technologies would lower costs;
2. it will be too hard to scale up several of the technologies we propose; and
3. our modeling contained errors.
The paper is dangerous because virtually every sentence in it is inaccurate, but most people don't have time to check the facts. To that end, we include an additional line-by-line response to the paper.
Here are summaries of our main responses to the "Clack" paper:
1. To Clack's claim that nuclear, fossils with carbon capture and biofuels reduce costs of decarbonization, the Intergovernmental Panel on Climate Change (IPCC) concludes the exact opposite (Section 7.8.2):
"Without support from governments, investments in new nuclear power plants are currently generally not economically attractive within liberalized markets, ..."
Similarly, even strong nuclear advocates disagree:
" ... there is virtually no history of nuclear construction under the economic and institutional circumstances that prevail throughout much of Europe and the United States."
Next, an independent assessment of our 100 percent wind, water and solar plans versus nuclear and CCS options concludes:
"Neither fossil fuels with CCS or nuclear power enters the least-cost, low-carbon portfolio."
Even Christopher Clack, CEO of Vibrant Clean Energy, doesn't believe his own abstract. He tweeted: "Completely agree that CCS are too expensive currently ..."
Completely agree that #CCS are too expensive currently and we need new technologies to assist with decarbonization.… https://t.co/Kdw89YrZMe— Christopher Clack (@Christopher Clack)1494030332.0
Clack claiming nuclear and carbon capture are inexpensive is based on outdated, minority studies that (a) underestimate their high costs; (b) ignore the 10-19 year lag time between planning and operation of a nuclear plant versus 2-5 years for a typical wind or solar farm; (c) ignore the cost of the 25 percent higher air pollution due to the 25 percent additional energy thus 25 percent more fossil fuel mining, transport and combustion needed to run carbon capture equipment; (d) ignore the climate cost of the 50 times higher carbon emissions of fossil fuels with carbon capture relative to wind per unit energy; and (e) ignore the "robust evidence" and "high agreement" by the IPCC of weapons proliferation, meltdown, mining and waste risks associated with nuclear power. They also ignore the air pollution, carbon emissions and land use issues associated with large-scale biofuels.
As part of their argument Clack further ignores more than a dozen other published studies that have examined high penetrations of renewables in the electric power sector without nuclear or carbon capture, as referenced here, falsely implying that ours is the only one.
2. To Clack's claim that we propose technologies that can't be scaled up, we disagree. Underground thermal energy storage in rocks is a well tested (in multiple locations) and established low-cost seasonal heat-storage technology that costs less than 1/300th that of batteries per unit energy stored. It is a form of district heating, which is already used worldwide (e.g., 60 percent of Denmark). Moreover, hot water storage or electric heat pumps can substitute for underground thermal energy storage.
Clack also criticizes our proposal to use some hydrogen, but hydrogen fuel cells already exist and the process of producing hydrogen from electricity was discovered in 1838. Its scale-up is much easier than for nuclear or CCS. With respect to aircraft, the space shuttle was propelled to space on hydrogen combustion, a 1,500-km-range, 4-seat hydrogen fuel cell plane already exists, several companies are now designing electric-only planes for up to 1,500 km, and we propose aircraft conversion only by 2035-2040.
Clack further questions whether industrial demand is subject to demand response, yet the National Academies of Sciences review states: "Demand response can be a lucrative enterprise for industrial customers."
3. To Clack's claim that we made modeling errors, this is absolutely false, as indicated in each specific published response. Most notably, Clack claims that we erred because our peak instantaneous hydropower load discharge rate exceeded our maximum possible annual-average discharge rate. But Clack is wrong because averages mathematically include values higher and lower than the average. Clack made other similar mathematical errors.
More importantly, it was made clear to Clack by email on Feb. 29, 2016, that turbines were assumed added to existing hydropower reservoirs to increase their peak instantaneous discharge rate without increasing their annual energy consumption or the number of dams, a solution not previously considered. It was also made clear that it was alternatively possible to increase the discharge rate of CSP, or concentrating solar power, rather than hydropower. Increasing hydropower's peak instantaneous discharge rate was not a "modeling mistake" but an assumption.
Despite having full knowledge in writing, not only in 2016 but also weeks prior to the publication of their article, that this was an assumption, Clack and coauthors made the intentionally false claim in their paper that it was an error. The fact that Clack (twice) and all his coauthors (once) were informed in writing about a factual assumption, but intentionally mischaracterized it as a mistake, then further falsely pretended the numbers resulted in mathematical errors when they knew there were none, speaks to the integrity and motivation of the Clack et al. authors.
4. Clack falsely claims that the 3-D climate model, GATOR-GCMOM, that we used "has never been adequately evaluated," despite it taking part in 11 published multi-model inter-comparisons and 20 published evaluations against wind, solar and other data. And, despite Zhang's 2008 Atmospheric Physics and Chemistry Journal comprehensive review that concluded GATOR-GCMOM is "the first fully-coupled online model in the history that accounts for all major feedbacks among major atmospheric processes based on first principles" and hundreds of processes in it still not in any other model.
In sum, Clack's analysis is riddled with intentional misinformation and has no impact on the conclusions of our 2015 grid integration study, namely that the U.S. grid can remain stable at low cost upon electrification of all energy sectors and provision of the electricity by 100 percent wind, water and solar power combined with low-cost electricity, heat, cold and hydrogen storage and demand response.
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[Editor's note: On Dec. 29, former NASA scientist Dr. James Hansen wrote a piece on advancing nuclear energy to help address climate change and air pollution. The article below, by Stanford professor Mark Jacobson, provides a response to Hansen's comments.]
Comment 1 by Dr. James Hansen:
The urgency of expanding clean energy implies that nuclear power, presently the largest source of carbon-free energy and historically the clean-energy source of fastest scale-up, likely must play an important role in meeting needs for dispatchable electric power, carbon-neutral fuels and fresh water.
Nuclear is an opportunity cost relative to clean, renewable wind, water and solar energy because of
a. the significant lag time between planning and operation of a nuclear plant relative to a wind, solar, or geothermal plant;
b. higher carbon emissions of nuclear per unit energy; and
c. nuclear weapons proliferation risks, meltdown risks, waste disposal risks, and uranium mining risks. As such, the only basis for nuclear growth is if 100% wind, water and solar is not possible. However, because the technical feasibility of 100% wind, water and solar across 139 countries and 50 states has been shown to be possible, evidence suggests at this time that a solution can be obtained without nuclear.
The scale-up time for existing nuclear (10-19 years between planning and operation compared with 2-5 years for wind or solar) is too slow to help solve climate problems. Nuclear power requires 10-19 years between planning, permitting, financing and operating in all countries of the world.
This time includes 3.5-6 years to find a site, obtain a permit for the site, and obtain financing for the reactor, 2-3 years for the review and approval of the construction permit, 0.5-1 years between permit approval and issue, and 4-9 years for construction. (Jacobson, Energy and Environmental Science, 2, 148-173, 2009).
On the other hand, onshore wind and solar require an average of 2-5 years. A wind farm takes an average of 1-3 years for siting, purchasing or leasing land, monitoring winds, negotiating a power-purchase agreement and permitting. The construction period for a large wind farm is 1-2 years. A solar photovoltaic or concentrated solar power plant is also 2-5 years. Geothermal requires 3-6 years. (See citations in Jacobson, Energy and Environmental Science, 2, 148-173, 2009).
Nuclear is not carbon free and emits 6-24 times more carbon-dioxide equivalent emissions than wind per unit energy produced over the same 100-year period. Such emissions include those during (a) planning, permitting, constructing, operating, refurbishing and decommissioning a nuclear plant versus a wind turbine and (b) the emissions associated with reducing carbon sequestration in soil by covering the soil with impermeable material or by mining.
Whereas, the emissions associated with constructing, operating and decommissioning a plant are accounted for in the standard lifecycle assessment (LCA), those associated with the timelag between planning and operation and downtime due to refurbishment (OC, opportunity cost emissions) and emissions associated with the loss of carbon from soil, are not.
IPCC (2014) Section 7.8.1 (P. 540) suggests that the range in lifecycle carbon emissions from nuclear is 4-110 g-CO2-eq/kWh: The ranges of harmonized lifecycle greenhouse gas emissions reported in the literature are ... 4-110 gCO2eq/kWh for nuclear power.
The high-end of IPCC (2014) is 40 g-CO2-eq/kWh, higher than the high end of 9-70 g-CO2- eq/kWh provide in Jacobson (Energy and Environmental Science, 2, 148-173, 2009), suggesting the LCA results of Jacobson (2009) are well within the range of accepted norms.
However, when comparing different energy technologies for mitigating climate change, it is essential to account for the full emissions associated with the choice of one technology over the other over a similar period. This necessitates including emissions from the background grid associated with the difference in time-lag between planning and operating one technology versus another, the difference in emissions from the grid during downtime of each plant due to refurbishment, and the emissions associated with covering the soil with impermeable materials in each case.
Table 3 of Jacobson (Energy and Environmental Science, 2, 148-173, 2009) summarizes the opportunity cost emissions of nuclear power (59-106 g-CO2-eq/kWh) relative to wind and solar (0 g-CO2-eq/kWh), since the opportunity cost is taken relative to the generators with the shortest time-lag).
The figures in this document further summarize the comparison of all emissions from nuclear (LCA, OC, soil emissions and others) relative to all wind, water and solar technologies.
The net result of the data in the figures is that nuclear carbon-equivalent emissions per unit energy range from 6-24 times those of wind power, thus they are not zero.
Dr. Hansen argues that nuclear power “must" play an important role in the future. However, there is no scientific basis for this statement and his claim does not address the problems with nuclear power identified by the international community. First, whereas IPCC (2014) suggests that nuclear could play a role, they also imply that a solution can be obtained without nuclear. Specifically, they state that some proposed mitigation options may not be necessary:
IPCC (2014) FAQ 7.2. P. 569. The main mitigation options in the energy supply sector are energy efficiency improvements … use of renewable energy, use of nuclear energy, and carbon dioxide capture and storage (CCS) … A combination of some, but not necessarily all, of the options is needed.
Second, in the executive summary, IPCC (2014) clearly summarizes significant issues regarding nuclear power that Dr. Hansen does not discuss and that have not been resolved to date. IPCC (2014) states there is “robust evidence and high agreement" regarding these issues:
IPCC (2014) Executive Summary. P. 517. Barriers to and risks associated with an increasing use of nuclear energy include operational risks and the associated safety concerns, uranium mining risks, financial and regulatory risks, unresolved waste management issues, nuclear weapons proliferation concerns, and adverse public opinion (robust evidence, high agreement).
Finally, IPCC (2014) points to several studies that show that large penetrations of clean, renewable energy could do the job pending more grid integration studies:
IPCC (2014) Section 7.6. P. 533. Studies of high variable RE penetration (8 citations, including Delucchi and Jacobson, 2011) and the broader literature (2 citations) suggest that integrating significant RE generation technology is technically feasible, though economic and institutional barriers may hinder uptake … The determination of least-cost portfolios of those options that facilitate the integration of fluctuating power sources is a field of active and ongoing research (citations).
Since the publication of IPCC (2014), Jacobson et al. (Proc. Natl. Acad. Sci., 112, doi: 10.1073/pnas.1510028112, 2015), found multiple low-cost solutions to the grid integration problem across the 48 contiguous United States when 100% wind, water and solar (WWS) generation for all energy sectors (electricity, transportation, heating/cooling, industry) was combined with low-cost storage, demand-response and hydrogen production. Roadmaps were subsequently developed for 139 countries. In sum, if 100% wind, water, solar works for each state and country as suggested in these studies, there appears to be no need for the growth in nuclear power. Because of the significant lead time, lesser carbon benefit, weapons proliferation risk, meltdown risk, waste risk and uranium mining risk, nuclear appears to be an opportunity cost relative to clean, renewable energy.
Comment 2 by Hansen:
Nuclear power will need to complement renewable energies, providing sufficient baseload electric power to help address the challenge of replacing energy presently obtained from fossil fuels.
At high penetrations of intermittent renewables, baseload power becomes more expensive and more difficult to complement renewables. This effect is summarized in IPCC (2014), Section 220.127.116.11, P. 534, which states, …high shares of variable RE power, for example, may not be ideally complemented by nuclear, CCS, and CHP plants (without heat storage).
Comment 3 by Hansen:
Several blatant falsehoods about nuclear power were repeated in that session (AGU, December 2015), including that (1) nuclear power has a large carbon footprint (it is actually as low as that of renewables, and it is even lower with advanced generation nuclear power), (2) nuclear power is a slow way to decarbonize (in fact all of the fastest decarbonizations in history occurred via nuclear power, (3) nuclear power gets inordinate subsidies (in fact renewable subsidies dwarf nuclear subsidies).
Response 3a: Regarding (1) carbon footprint, see Response 1b.
Response 3b: Regarding (2) slow decarbonization by nuclear, see Response 1a.
Response 3c: Regarding (3) subsidies, IPCC (2014) states the following about nuclear: IPCC (2014) Section 7.12.4. P. 567. Nuclear has received significant support in many countries … IPCC (2014) Section 7.8.2. P. 542. Without support from governments, investments in new nuclear power plants are currently generally not economically attractive within liberalized markets …
Comment 4 by Hansen:
Referring to Jacobson et al. (Energy and Environmental Sciences, 8, 2093-2117, 2015). Not included in this chart is the “water" portion of this proposed renewable power installation: it is equivalent to 50 Hoover dams, one for each state; although the proposition is to do this with a larger number of smaller dams, it is not clear that these dams would be welcomed by all environmentalists.
Response: This statement is incorrect. Table 2 of Jacobson et al. (2015), shows that the 50-state roadmaps call for only 3 new conventional hydroelectric plants (thus dams), not 50, and they are all proposed for Alaska (thus none in the 48 contiguous states). The ones in Alaska can also be substituted for wind. The 48-contiguous-state grid integration study, (Jacobson et al., Proc. Natl. Acad. Sci., 112, doi: 10.1073/pnas.1510028112, 2015), similarly calls for zero new hydroelectric dams in these states. It does allow for pumped hydroelectric storage facilities that are existing plus those with pending licenses and preliminary and pending preliminary permits, but many of these exist already and they are nothing like Hoover Dam.
Similarly, the 139 country 100% wind, water, solar roadmaps, propose zero new conventional hydroelectric dams for any country. The efficiency of existing hydroelectric plants is proposed to increase, and existing plus planned pumped hydroelectric will also be used.
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