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Richardson M.,University of Reading | Stolpe M.B.,ETH Zurich | Jacobs P.,George Mason University | Jokimaki A.,Skeptical Science | Cowtan K.,University of York
Quaternary International | Year: 2014

In a recent paper (Chen et al., 2013), fractional changes in temperature were correlated with fractional changes in anthropogenic emissions of carbon dioxide in order to estimate the amount of warming attributable to CO2 emissions. No justification was given for using the emissions rate rather than cumulative changes in atmospheric CO2 and the assumptions are not physically-based. This leads to counter-physical predictions, such as cases where increased heating causes the Earth to cool. Furthermore, a 10-year shift in start date alters the calculated elasticity by a factor of 2. A standard energy balance model is physically-based and outperforms the Chen et al. (2013) model, and its fitted transient climate response is consistent with changes in atmospheric CO2 causing warming equivalent to approximately 100% of the temperature change observed since 1960, consistent with formal attribution analyses. It is cautioned that purely statistical correlations are not able to demonstrate cause, and that they are particularly poor at attribution when there is no physical basis for the selection of variables and functional forms used in the correlation analysis. © 2014 Elsevier Ltd and INQUA. Source


Cawley G.C.,University of East Anglia | Cowtan K.,University of York | Way R.G.,University of Ottawa | Jacobs P.,George Mason University | Jokimaki A.,Skeptical Science
Ecological Modelling | Year: 2015

In a recent issue of this journal, Loehle (2014) presents a "minimal model" for estimating climate sensitivity, identical to that previously published by Loehle and Scafetta (2011). The novelty in the more recent paper lies in the straightforward calculation of an estimate of transient climate response based on the model and an estimate of equilibrium climate sensitivity derived therefrom, via a flawed methodology. We demonstrate that the Loehle and Scafetta model systematically underestimates the transient climate response, due to a number of unsupportable assumptions regarding the climate system. Once the flaws in Loehle and Scafetta's model are addressed, the estimates of transient climate response and equilibrium climate sensitivity derived from the model are entirely consistent with those obtained from general circulation models, and indeed exclude the possibility of low climate sensitivity, directly contradicting the principal conclusion drawn by Loehle. Further, we present an even more parsimonious model for estimating climate sensitivity. Our model is based on observed changes in radiative forcings, and is therefore constrained by physics, unlike the Loehle model, which is little more than a curve-fitting exercise. © 2014 Elsevier B.V. Source


News Article | September 2, 2016
Site: http://cleantechnica.com

Special thanks to Bob Wallace and Globi for leading this project/article. There are many questions about renewable energy and electric transport that people who haven’t been following these industries for years or decades often have, and there are also many recurring myths that many of us spend a lot of time addressing. A few commenters have proposed that what is needed is one central resource where people can find information that answers common questions about solar energy, wind energy, and electric vehicles; and that dissolves numerous cleantech myths. There are many topics to cover, and it’s probably best if they are answered by many people. Here’s how we’re thinking it might work: On this page, we’re listing many popular cleantech topics and answers to common myths (grouped under these 4 categories: 1) Solar + Wind + Other Renewables, 2) Solar Energy, 3) Wind Energy, 4) Electric Vehicles). If there are other topics you think we should add (of course there are), then list them in the comments section below. From time to time, we’ll rewrite this page and add new topics based on your proposals. For each topic, we’ll link to either 1) an existing CleanTechnica article that provides detailed answers/responses, or 2) a new document (in Google Docs) where we can crowdwrite (if others are interested) the article. Further down this page, there are all the same topics and links but also short answers for each of them. For any of the topic-specific pages, add any information you have or any suggested corrections in the comments section below this article (in the future, feedback forms will be included on each article). At some point, a new version will be created for many of these topics — a more accurate and complete version based on feedback and new information. If you’ve got other ideas/suggestions of how this system might work, let us know via the comments section below this page. Again, if you want to suggest new topics, please do so in the comments below. On to the content … and note that we don’t just allow you to copy & paste these responses when useful — we encourage you to do so! A healthy free-market democracy is built on correct and useful information being widely distributed. This first section is for one-liners linked to long articles or article drafts. For 1–2 paragraph statements on each matter (still with links to the longer pieces), scroll down further. Wind and solar electricity have become some of our least expensive ways to generate electricity (in several markets around the world). Wind is now the cheapest way to bring new electricity generation to the grid in the US as well as many other countries. Solar PV costs are rapidly dropping and solar is expected to join wind over the next few years. The levelized cost of electricity (LCOE) for solar actually beats all other sources of electricity other than wind. Furthermore, low-cost utility-scale solar is already beating out all other sources of electricity in some bidding processes, and home solar power beats the price of retail electricity (on average) in many markets. 2. Wind and solar power account for a large portion of new electricity generation capacity. In the US and elsewhere, low-priced and zero-emission solar and wind power plants are accounting for a large portion (sometimes the majority) of new power capacity additions. At the same time, coal power plants are being retired at a rapid rate. 3. Climate action is trillions of dollars cheaper than climate inaction. Investing in a clean energy economy is not cheap. It is projected to cost trillions of dollars. However, sticking with a dirty energy economy will cost society much more — many trillions of dollars more — than investing in a clean energy economy. If you actually care about costs, you should be pushing for us to make the transition quicker rather than slower. 4. We do not need baseload power, and inflexible baseload power is actually problematic. Massive renewable energy adoption and integration will rely on “load following,” not “baseload power.” In a renewable-dominated grid, inflexible baseload power gets in the way. What is actually needed is a varied system of solutions that match electricity demand with electricity supply. This includes demand response solutions, flexible electricity generation sources, a larger and more integrated transmission network, and some energy storage. It does not require an energy storage breakthrough or nuclear power. 5. Integration of renewable energy into the electricity grid is not a problem, and it’s cheaper than sticking with dirty energy sources. We can build a 24/365 reliable grid using either coal, gas, and nuclear; or with wind, solar, and other renewables. The techniques differ somewhat, but the real issue is cost. Renewables win in terms of both direct (generation) costs and external costs. Take a look at how a 100% renewable grid would operate and give us cheaper electricity. 6. There are many ways to get the majority of our electricity from renewable energy sources. According to an NREL study examining high renewable energy integration in the US, 80% of US electricity could be coming from renewables by 2050. Different regions would do best to rely on different resources. A large variety of renewable energy generation technologies combined with a good transmission network seems to be the most practical way to change to a renewable-dominated grid. 7. On the whole, comparing various electricity options based on a wide variety of factors, solar and wind are society’s best choice. Discussions of electrical generation technologies frequently fall into the trap of considering a single factor. One way this occurs is with advocates of a specific legacy technology pointing out a single downside of wind or solar generation as if it’s a gotcha. This is equally true of wind and solar advocates who point at single-factor issues with nuclear or coal, as examples, making the comparison to the more virtuous renewables. However, there is no single technology which will prevail on all grids in the future. There will be multiple generation technologies at any given time, the mix will change over time, and the specific mix will vary for specific geographies. In a multi-factorial assessment, though, solar and wind power come out with the highest score. It is cheaper to save fuel than to buy fuel (efficiency measures & renewables save fuel); renewables drive the development of new technologies, drive local investment, create local jobs, reduce wholesale electricity prices, reduce dependence on price-fluctuating fuels (insurance/hedge against high fuel prices), reduce trade deficits, reduce cash flow into dubious destabilizing/warmongering regimes, reduce pollution (reduce health costs), preserve nature and biodiversity (secure alimentation (more area for food production instead of fossil fuel/uranium mining), grow the tourism industry, etc.). Germany has grown its renewable power share by a factor of 5 and at the same time reached a record export surplus. Besides efficiency measures including electrification of the transportation and heat sectors, renewables are the best and fastest option to reduce CO2 emissions and thus to mitigate climate change. 10. A 70–100% renewable electricity grid is possible and even cost-competitive to build. Several studies examining the question in different ways have concluded that transforming electricity grids to 70–100% renewable energy is practical and could even save society money (without even taking externalities related to health and global warming into account). 11. It wouldn’t take a lot of land to get 40% of our electricity from solar panels. Article being drafted. (Chime in if you want to help out.) 12. Renewables are being installed not just because of subsidies. Article being drafted. (Chime in if you want to help out.) 13. Renewables are very easily and quickly scalable. (draft) Renewables can grow fast because they can be installed practically everywhere rapidly and simultaneously. Renewable capacity in the magnitude of 1 TW can in principle be added every year. Germany installed 3 GW of PV in one single month in December 2011. Germany has roughly 1% of the world’s population. So, if the entire world installs only 20% the amount of PV that Germany did 5 years ago, it would be at 720 GW per year. At a single utility-scale-PV plant, 120 MWp per month was installed. If only 10% of all cities worldwide installed utility-scale-solar at this scale at the same time, it would lead to approximately the same number just for utility-scale-solar (the world has 4,412 cities with a population of at least 150,000). In fact, if the world only installs one PV module per person per year, this already leads to 1,850 GW per year. As opposed to nuclear, which uses a scarce element even as fuel, renewables don’t depend on scarce elements. Over 90% of the PV market is silicon based, and silicon-based PV doesn’t depend on scarce elements. In fact, silicon is the second most common element in the earth’s crust. Even the cost of silver has little influence on manufacturing costs and, if necessary, silver can be replaced with more abundant metals such as copper. While some wind turbine manufacturers with direct drive turbines use permanent magnets containing rare earths, they don’t depend on it. For example, Enercon does build direct drive turbines without using any rare earths. According to the largest wind turbine manufacturer, Vestas: The contribution of rare earth elements used in the turbine generator magnets, and also in the magnets used in the tower, make a negligible contribution to total resource depletion, contributing below 0.1% of total life cycle impacts. Besides, rare earth metals are neither rare, nor earths, and permanent magnets can be made without using rare earths. 15. Renewable energy doesn’t get more in subsidies than fossil and nuclear sources have gotten, and continue to get. Fossil fuels and nuclear have received and are still receiving far more subsidies than renewables. In addition, they don’t pay for their externalized costs, which are massive forms of subsidy that society provides to fossil fuel and nuclear companies. There are so many useful articles on this topic that we didn’t choose to link just one. Here’s a list of articles to choose from: 16. The ERoEI of wind and solar is actually quite good. Article being drafted. (Chime in if you want to help out.) 17. We don’t need huge advances in energy storage to switch to renewable energy. The world already has large hydro storage and methane (power-to-gas) storage resources, and the electrification of the hot water, heating, and transportation sectors provides significant demand response flexibility. Besides, heat energy can be stored inexpensively and curtailing renewables is inexpensive and doesn’t even waste brake pads. Even if storage was entirely missing, it wouldn’t be needed until a high renewable electricity share is reached. According to VDE, Germany requires 7 TWh of storage at 80% renewable share. (And a 100% renewable share is only reasonable once the entire heating and hot water sector is electrified). For comparison: Tiny Switzerland already has 8.8 TWh of storage and Norway has even 84 TWh of storage. Germany has been trading electricity with Switzerland since 1958. 1. Solar panels aren’t free or even cheap, but they can still save you a ton of money. The question should not be about how much solar panels cost, but about how much solar power will save you. Many people think solar power is “expensive,” but that’s often only true if you look at half of the equation. In reality, solar power often saves homeowners tens of thousands of dollars. If you go solar with a straight purchase (no loan), you’re going to save the most money … but it will also be a longer period of time before you get your money back and start putting extra cash in your pocket. On the other hand, if you get a good (perhaps $0-down) solar loan, solar lease, or solar PPA, you can start saving money immediately or almost immediately. You just won’t save as much money down the road. Nonetheless, you can often still save tens of thousands of dollars (compared to buying all of your electricity from the grid and not producing any electricity yourself). Solar power prices are already low (see above) and are projected to get much lower in the coming decades simply through incremental improvements. The Bloomberg New Energy Finance solar analysis team projects that the cost of solar panels will fall from 62¢/watt at the end of 2015 to 21¢/watt in 2040 “by incremental improvements in crystalline silicon technology (thinner wafers, better-shaped busbars, better AR coating, more targeted doping, better contact technology).” No other option for electricity is projected to be competitive with solar by that time, and that is without any “breakthroughs” in solar technology. 3. Solar panels definitely don’t take more energy to manufacturer than they produce. Article being drafted. (Chime in if you want to help out.) 4. Solar works well far beyond deserts and sunny climates. Article being drafted. (Chime in if you want to help out.) Article being drafted. (Chime in if you want to help out.) 6. How practical/likely are cars that incorporate solar panels into the vehicle body? Article being drafted. (Chime in if you want to help out.) While wind turbines can’t produce electricity if the wind isn’t blowing, the electricity they produce is worth exactly as much as the electricity produced by any other type of power plant. When a wind turbine produces a kilowatt-hour of electricity, it’s fundamentally worth as much as a kilowatt-hour of electricity from nuclear power, coal power, solar power, or anything else. There is a slight externality from the variability of wind energy and its “integration costs,” but those are determined to be just 4 tenths of a cent per kWh (not even half a cent per kWh). For sure, this extra cost isn’t even worth mentioning compared to the health and environmental externalities that come from coal and natural gas power plants, or the economic risk that comes with nuclear power plants. Even at very high percentages of wind power (such as seen in Denmark, northern Germany, Scotland, Portugal, and Iowa), wind energy can be integrated into the grid without extra backup energy or costly investments. 2. Wind works well in many, many locations. Article being drafted. (Chime in if you want to help out.) Article being drafted. (Chime in if you want to help out.) In the meantime, here are some of the articles that will feed into the in-depth piece: Electric cars produce zero emissions themselves, but even if you don’t have solar panels and you get your electricity from the grid, driving an electric car results in fewer emissions than driving a gasmobile or conventional hybrid in almost every case. Electric cars themselves produce zero emissions when driven, but even if you factor in the emissions from electricity produced in your region that is utilized to power your electric car, it’s extremely likely your electric car is cleaner than a Toyota Prius. Furthermore, these emissions are not “local” — they’re likely not occurring in your neighborhood, in your town, or in your city. Of course, if you have solar panels on your roof that produce as much electricity as you use, you are essentially driving on sunshine and producing no emissions from any source when you drive. It’s also important to remember that the grid is getting cleaner every day, so electric cars charged from the grid will just keep getting cleaner and cleaner. 2. How much land would it take to produce enough electricity to power EVs (powering all of them with wind energy)? In actuality, not a lot of land area is needed for the extra electricity generation that would be required if all of our cars were EVs. And that doesn’t even account for the land you would regain from oil/gas-related activities. Norway is a Scandinavian country with more than its fair share of cold weather, yet it is far ahead of any other nation in electric car adoption. 24% of new car registrations were electric car registrations in the first half of 2016 in Norway, while no other country has reached 3% market share. Norway’s electric car market share has been steadily growing for years. Of course, electric cars work fine in Norway’s cold climate and in other cold climates as well. Few grids are dominated by coal electricity at this point, and coal is on the downtrend in markets around the world. Coal has seen a monumental collapse in the USA, and now accounts for only 28% of electricity production. 0% of new electricity capacity in the USA in the first half of 2016 came from coal, while electricity production from the polluting energy source dropped by 15 GWh. In 2015 as well, 0% of new US electricity capacity came from coal. Aside from grid electricity, many electric car drivers decide to go solar. 6. Even with current electric cars, 87% of vehicles on the road today could be replaced by a low-cost electric car even if there is no possibility of recharging it during the day. A study by MIT and the Santa Fe Institute published in the journal Nature Energy on August 15 found that electric car range anxiety is overstated in most cases. The study analyzed the driving habits of drivers on a second-by-second basis. It concluded that 87% of vehicles on the road today could be replaced by a low-cost electric car even if there is no possibility of recharging it during the day. 7. Electric cars often actually save owners a great deal of time. Among current EV drivers, the vast majority of charging is done at home or work. In such places, it takes a few seconds to plug in the car and a few seconds to unplug it. In actuality, it is often easy to leave with a “full tank” (full battery) most of the time. Drivers no longer have to find gas stations on or near their travel routes, don’t have to spend time getting off the road and into the gas station, don’t have to get out and pump gas, don’t have to go inside or pull out their credit card and pay for gasoline, and don’t have to take their cars in for oil changes & smog checks. In the end, this saves them a lot of time, even if you take into account the times when they have to charge in public (during which they can often eat, play, or engage in other useful activities). For climate topics, we highly recommend this Skeptical Science page. However, we are dealing with some of the common claims repeatedly as well and may also create a list for these topics.   Drive an electric car? Complete one of our short surveys for our next electric car report.   Keep up to date with all the hottest cleantech news by subscribing to our (free) cleantech newsletter, or keep an eye on sector-specific news by getting our (also free) solar energy newsletter, electric vehicle newsletter, or wind energy newsletter.  


Benestad R.E.,Norwegian Meteorological Institute | Nuccitelli D.,Skeptical Science | Lewandowsky S.,University of Bristol | Lewandowsky S.,University of Western Australia | And 6 more authors.
Theoretical and Applied Climatology | Year: 2015

Among papers stating a position on anthropogenic global warming (AGW), 97 % endorse AGW. What is happening with the 2 % of papers that reject AGW? We examine a selection of papers rejecting AGW. An analytical tool has been developed to replicate and test the results and methods used in these studies; our replication reveals a number of methodological flaws, and a pattern of common mistakes emerges that is not visible when looking at single isolated cases. Thus, real-life scientific disputes in some cases can be resolved, and we can learn from mistakes. A common denominator seems to be missing contextual information or ignoring information that does not fit the conclusions, be it other relevant work or related geophysical data. In many cases, shortcomings are due to insufficient model evaluation, leading to results that are not universally valid but rather are an artifact of a particular experimental setup. Other typical weaknesses include false dichotomies, inappropriate statistical methods, or basing conclusions on misconceived or incomplete physics. We also argue that science is never settled and that both mainstream and contrarian papers must be subject to sustained scrutiny. The merit of replication is highlighted and we discuss how the quality of the scientific literature may benefit from replication. © 2015 The Author(s) Source


Nuccitelli D.,Skeptical Science | Cowtan K.,University of York | Jacobs P.,George Mason University | Richardson M.,University of Reading | And 5 more authors.
International Journal of Modern Physics B | Year: 2014

Lu (2013) (L13) argued that solar effects and anthropogenic halogenated gases can explain most of the observed warming of global mean surface air temperatures since 1850, with virtually no contribution from atmospheric carbon dioxide (CO2) concentrations. Here we show that this conclusion is based on assumptions about the saturation of the CO2-induced greenhouse effect that have been experimentally falsified. L13 also confuses equilibrium and transient response, and relies on data sources that have been superseeded due to known inaccuracies. Furthermore, the statistical approach of sequential linear regression artificially shifts variance onto the first predictor. L13's artificial choice of regression order and neglect of other relevant data is the fundamental cause of the incorrect main conclusion. Consideration of more modern data and a more parsimonious multiple regression model leads to contradiction with L13's statistical results. Finally, the correlation arguments in L13 are falsified by considering either the more appropriate metric of global heat accumulation, or data on longer timescales. © 2014 World Scientific Publishing Company. Source

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