What efficiency from using it in a combustion device? Burning it is really inefficient unless you're just after the heat (i.e. heating a home).
In a car, burning hydrogen is horribly inefficient, you're far better off going wind turbine -> battery -> move car than wind turbine -> generate hydrogen -> burn hydrogen -> move car.
Fuel cells are far better to use with the hydrogen, and that's still not as good as a battery.
Where hydrogen really has an advantage is in energy density. Batteries are big and heavy, takes a lot of batteries to store the same amount of energy as a few kg of hydrogen.
I would be interested in hearing why you feel using hydrogen as the fuel in a car engine would be "horribly inefficient". In fact, hydrogen has the largest efficiency gains in reciprocating engines, where combustion residence times are shortest. Hydorgen has some really unique and amazing properties, such as the widest flammability limits of any fuel as well as the fastest flame speeds (nearly a full order of magnitude faster than natural gas or gasoline). One reason why recip engines are inefficient is because much of the combustion is still occurring during the power/expansion stroke, when pressures and temperatures are decreasing and reactions are being quenched as a result. Hydrogen is able to complete those reactions closer to the top of the piston stroke. Moreover, because of its wide flammability limits, the parts of the fuel/gas mixture that would be mixed inadequately in a natural gas or gasoline engine would continue to combust in a hydrogen engine.
You don't have to take my word on it. There is literally a century of research on the use of hydrogen in internal combustion engines. As long as there have been combustion devices, scientists have been studying using hydrogen as a fuel in these devices. A quick google search will bear this out.
The problem with using hydrogen in mobile/transportation applications is that hydrogen has an extremely low energy density by volume (but an extremely high energy density by mass) so we would need incredible compression pressures to provide any reasonable range. And because of its unique combustion characteristics (wide flammability range and fast flame speeds), it poses fire and explosion risks (e.g. the Hindenburg). That has limited its use in mobile applications. It's use in stationary applications is more limited, mostly because the gains in efficiencies are smaller because furnaces and boilers have longer combustion residence times.
I do believe hydrogen will find a place in a carbonless future. Lots of focus are being put into wind, solar and batteries because they are the low hanging fruit. But I think in a decade or so when the pace of innovation for these technologies slow and the growth of their implementation flattens, you will see more work going towards hydrogen. Hydrogen supply is limitless, and it can be considered renewable because water would be the feedstock and after combustion, it reverts it back to water. The problem that needs to be solved is for hydrogen to be generated with a much lower net loss in energy.
I also found a couple of videos that are pretty interesting about their efficiency gains:
The Following 2 Users Say Thank You to snootchiebootchies For This Useful Post:
I would be interested in hearing why you feel using hydrogen as the fuel in a car engine would be "horribly inefficient".
Because hydrogen is not readily available why is this something you can't grasp? It's like you think all it takes is pixie dust to produce hydrogen no conversion losses to worry about.
I would be interested in hearing why you feel using hydrogen as the fuel in a car engine would be "horribly inefficient".
Because all such engines are horribly inefficient.
You're comparing hydrogen to gasoline. That's great if you can get to 30% efficiency from 20% or something, but I'm comparing hydrogen to fuel cells or batteries, where it's more like 60%+.
Quote:
Originally Posted by snootchiebootchies
I do believe hydrogen will find a place in a carbonless future.
Maybe, but I doubt it will be to burn in most cars.
If we figure out fusion and efficiencies become largely irrelevant maybe.
__________________ Uncertainty is an uncomfortable position.
But certainty is an absurd one.
The Following User Says Thank You to photon For This Useful Post:
I'm no expert on the subject, but I can say I'll never consider an electric vehicle until it can be fully re charged in under 10 minutes. I just drive too much.
That's why hydrogen appeals to me, it's suits the world that we've built that revolves around being able to refuel your vehicle quickly and getting back to what you were doing. But obviously refining and storing it has to be improved before it's really a realistic option
Hesitant to click on this thread for sake of lowering again my outlook on the human species, but only 3% say hoax, well done CP and thank you for again restoring my faith.
I wouldn't be so sure about that. Quite a few people picked "not the main cause", which in all honesty is not that far removed from the "it's a hoax"ers.
Saying "not the main cause" is their way of having their cake and eating it too. They get to claim that they are "not climate deniers", while at the same time fight tooth and nail against any policy which would actually move us toward dealing with the issue in an impactful way.
If you don't believe in what the vast majority of the world's climate scientists are saying, then you are claiming to either understand the issue better than they do, or you think that there's a vast conspiracy to deceive the public.
Last edited by Mathgod; 04-12-2019 at 09:30 PM.
The Following 4 Users Say Thank You to Mathgod For This Useful Post:
If you don't believe in what the vast majority of the world's climate scientists are saying, then you are claiming to either understand the issue better than they do, or you think that there's a vast conspiracy to deceive the public.
Do the vast majority of the world’s climate scientists believe that the science is settled on this issue?
We are well aware that those who support the mainstream position that anthropogenic climate change represents a grave threat to the future of humanity will deplore our decision to represent both side of the debate (or even to characterize the ongoing discussion as a “debate” at all). They have convinced themselves that only cranks and paid stooges could possibly disagree with them. We see things differently.
Simply stated, we maintain that appeals to authority and scurrilous ad hominem attacks are no substitute for rational argument...
...This means, among other things, that mainstream climate scientists who roundly condemn climate skeptics for seeking support from private industry ought to be a bit more circumspect, seeing that they themselves receive millions in financial backing from government agencies.
Quote:
Bengtsson was born in Trollhättan, Sweden, in 1935. He holds a PhD (1964) in meteorology from the University of Stockholm. His long and productive career included positions as Head of Research and later Director at the European Centre for Medium-Range Weather Forecasts in Reading in the UK (1976 — 1990), and as Director of the Max Planck Institute for Meteorology in Hamburg (1991 — 2000). Bengtsson is currently Senior Research Fellow with the Environmental Systems Science Centre at the University of Reading, as well as Director Emeritus of the Max Planck Institute for Meteorology.
Bengtsson’s scientific work has been wide-ranging, including everything from climate modelling and numerical weather prediction to climate data and data assimilation studies...
...Bengtsson is best known to the general public due to a dispute which arose in 2014 over a paper he and his colleagues had submitted to Environmental Research Letters, but which was rejected for publication for what Bengtsson believed to be “activist” reasons. The paper disputed the uncertainties surrounding climate sensitivity to increased greenhouse gas concentrations contained in the Intergovernmental Panel on Climate Change (IPCC) Fourth and Fifth Assessment Reports. Bengtsson and his co-authors maintained that the uncertainties are greater than the IPCC Assessment Reports claim.
Quote:
Christy was born in Fresno, California, in 1951. He holds a PhD (1987) in atmospheric science from the University of Illinois. He is currently Distinguished Professor of Atmospheric Science and Director of the Earth System Science Center at the University of Alabama in Huntsville...
...Christy has long been heavily involved in the climate change/global warming discussion, having been a Contributor or Lead Author to five Intergovernmental Panel on Climate Change (IPCC) reports relating to satellite temperature records. He was a signatory of the 2003 American Geophysical Union’s (AGU) statement on climate change, although he has stated that he was “very upset” by the AGU’s more extreme 2007 statement.[15]
Christy began voicing doubts about the growing climate-change consensus in the 2000s. In an interview with the BBC from 2007, he accused the IPCC process of gross politicization and scientists of succumbing to “group-think” and “herd instinct.”[16]
Quote:
Curry was born in 1953. She holds a PhD (1982) in geophysical sciences from the University of Chicago. She has taught at the University of Wisconsin, Purdue University, Pennsylvania State University, the University of Colorado at Boulder, and Georgia Institute of Technology (Georgia Tech). In 2017, under a torrent of criticism from her colleagues and negative stories in the media, she was forced to take early retirement from her position as Professor in the School of Earth and Atmospheric Sciences at Georgia Tech, a position she had held for 15 years (during 11 of those years, she had been Chair of the School). Curry is currently Professor Emerita at Georgia Tech, as well as President of Climate Forecast Applications Network, or CFAN (see below), an organization she founded in 2006.
Curry is an atmospheric scientist and climatologist with broad research interests, including atmospheric modeling, the polar regions, atmosphere-ocean interactions, remote sensing, the use of unmanned aerial vehicles for atmospheric research, and hurricanes, especially their relationship to tornadoes. Before retiring, she was actively researching the evidence for a link between global warming and hurricane frequency and severity.
Curry was drummed out of academia for expressing in public her reservations about some of the more extreme claims being made by mainstream climate scientists.
Quote:
Lindzen was born in Webster, Massachusetts, in 1940. He holds a PhD (1964) in applied mathematics from Harvard University. He is currently Professor Emeritus in the Department of Earth, Atmospheric and Planetary Sciences at MIT.
Already in his PhD dissertation, Lindzen made his first significant contribution to science, laying the groundwork for our understanding of the physics of the ozone layer of the atmosphere.[22] After that, he solved a problem that had been discussed for over 100 years by some of the best minds in physics, including Lord Kelvin, namely, the physics of atmospheric tides (daily variations in global air pressure).[23] Next, he discovered the quasi-biennial oscillation (QBO), a cyclical reversal in the prevailing winds in the stratosphere above the tropical zone...
...Lindzen was a Contributor to Chapter 4 of the 1995 Intergovernmental Panel on Climate Change (IPCC) Second Assessment, and to Chapter 7 of the 2001 IPCC Working Group 1 (WG1). Nevertheless, in the 1990s, Lindzen began to express his concern about the reliability of the computer models upon which official IPCC and other extreme climate projections are based. He has been especially critical of the notion that the “science is settled.” In a 2009 Wall Street Journal op-ed, he maintained that the science is far from settled and that “[c]onfident predictions of catastrophe are unwarranted.”[27] For his trouble, Lindzen has suffered the usual brutal, ad hominem attacks from the climate-change establishment.
Quote:
Shaviv was born in Ithaca, New York, in 1972, but was raised in Israel. He holds a doctorate (1996) in physics from the Israel Institute of Technology in Haifa. He spent a year as an IBM Einstein Fellow at the highly prestigious Institute for Advanced Study in Princeton, New Jersey (2014 — 2015). He is currently Professor and Chair of the Racah Institute of Physics at the Hebrew University of Jerusalem.
Shaviv first made a name for himself (see his 1998 and 2001 papers, below) with his research on the relationship between inhomogeneities in stellar atmospheres and the Eddington limit (the equilibrium point at which the centrifugal force of stellar radiation production equals the centripetal force of gravitation). This theoretical work led to a concrete prediction that was later confirmed telescopically (see the 2013 Nature paper listed below).
Of more direct relevance to the climate-change debate was a series of papers Shaviv wrote, beginning in 2002 (see below), detailing a bold theory linking earth’s ice ages with successive passages of the planet through the various spiral arms of the Milky Way galaxy, and with cosmic radiation more generally. He has also expressed his conviction that variations in solar radiation have played an equal, if not greater, role in the observed rise in mean global temperature over the course of the twentieth century than has human activity (see his 2012 paper, below). He maintains, not only that anthropogenic greenhouse gases have played a smaller role in global warming than is usually believed, but also that the earth’s climate system is not nearly so sensitive as is usually assumed.
In recent years, Shaviv has become an active critic of the results and predictions of the Intergovernmental Panel on Climate Change (IPCC) and other organizations supporting the consensus view. In particular, he rejects the often-heard claim that “97% of climate scientists” agree that anthropogenic climate change is certain and highly dangerous. Shaviv emphasizes (see the video clip, below) that “science is not a democracy” and all that matters is the evidence for these claims — which he finds deficient.
Some of the world’s most brilliant minds are skeptical of the belief that human’s and CO2 are the primary driver behind climate change. Are they science deniers? Flat earthers?
How many more climate scientists are skeptics, but are not speaking out for fear of the mob outrage, and for fear of having their lives turned upside down like the group listed above?
The Following 3 Users Say Thank You to The Fonz For This Useful Post:
Because all such engines are horribly inefficient.
You're comparing hydrogen to gasoline. That's great if you can get to 30% efficiency from 20% or something, but I'm comparing hydrogen to fuel cells or batteries, where it's more like 60%+.
Yes, converting chemical energy to mechanical energy in an internal combustion engine is indeed inefficient. My point is that using hydrogen in internal combustion engines to partially or wholly displace fossil fuels can result in efficiency gains that offsets the net energy loss from the production of hydrogen. This is easily proven, as per the videos I embedded earlier.
If the world can get rid of all internal combustion engines and replace them with electric motors and replace all furnaces and boilers with electric heaters, I would understand better why you feel there is no place at all for hydrogen combustion. But I don't see that happening at all.
Surveys of the peer-reviewed scientific literature and the opinions of experts consistently show a 97–98% consensus that humans are causing global warming.
Authors of seven climate consensus studies — including Naomi Oreskes, Peter Doran, William Anderegg, Bart Verheggen, Ed Maibach, J. Stuart Carlton, and John Cook — co-authored a paper that should settle this question once and for all. The two key conclusions from the paper are:
1) Depending on exactly how you measure the expert consensus, it’s somewhere between 90% and 100% that agree humans are responsible for climate change, with most of our studies finding 97% consensus among publishing climate scientists.
2) The greater the climate expertise among those surveyed, the higher the consensus on human-caused global warming.
^ I found this and interesting commentary on the infamous "97%" comment. Note that Skeptical Science is run by the people who did one of the 97% studies(the Australian team reference below) so they have a pretty big interested to say what Troutman quoted.
Quote:
Astoundingly, the 97% number comes from a handful of methodologically feeble studies beginning with historian of science Naomi Oreskes in 2004 claiming she’d looked at 928 articles about climate change in scientific journals and 75 percent of them endorsed the “consensus view” that “Earth’s climate is being affected by human activities” while none directly disputed it. Which you’ll notice says nothing about it being dangerous or manmade. Nor did it claim 97% agreement. (And even her 75% didn’t withstand subsequent scrutiny.)
Five years later, two University of Illinois researchers sent an online survey to over 10,000 Earth scientists asking two simple questions: Did they agreed that global temperatures had risen in the last couple of centuries and did they think human activity was a significant contributing factor. They got 3,146 responses, so at best about 30% even of that sample. Of those 90 percent said yes to the first question and 82 percent yes to the second. Again no manmade, no dangerous, and where’s the 97%?
Well, the researchers discarded all but 77 responses from people who self-described as climate experts, of whom 75 said yes to the second question. And 75 out of 77 is 97%. But there’s still no mention of danger and even this very skewed sample only said our influence was significant. Not overwhelming. Not even dominant.
Another survey by Australian researchers in 2013 claimed to have looked at 12,000 scientific papers on climate change and found 97% agreement… that greenhouse gases had some impact on global warming. Again not dangerous and not manmade. Also, it turned out, not true. Nearly two-thirds of the papers said nothing on the consensus. Of the 34% that did, 33% endorsed it. Which again is 97% but only that we’ve had some impact. Which could mean as little as accepting the “urban heat island” effect. A far better question would be how many of the studies said we caused most of it.
Amazingly, we know. Buried deep in the paper is the figure: 64. Not 64%. 64 papers. Out of nearly 12,000. Half a percent, rather short of 97%. And it gets worse. Climatologist David Legates actually read those 64 papers and found that 23 didn’t say what the Australian team claimed. The only danger here is to scientific integrity
Worth reading the whole thing, it isn't all that long. I have seen other analysis like this before, so now I'm skeptical of the 97% claim. No that I'm suggesting that most climate scientists don't have a consensus, but that this 97% thing is probably a little extreme.
The Following User Says Thank You to Fuzz For This Useful Post:
Some of the world’s most brilliant minds are skeptical of the belief that human’s and CO2 are the primary driver behind climate change. Are they science deniers? Flat earthers?
How many more climate scientists are skeptics, but are not speaking out for fear of the mob outrage, and for fear of having their lives turned upside down like the group listed above?
I understand your point. You’re saying that because there are still scientists out there that disagree, the science in not yet in, or conclusive. This is missing out on the most important facet of the communal belief on climate change and global warming (pick your favorite euphemism) - the unified theory.
There has always been disagreement in some of the specifics in the over-arching discussion, but what the vast majority of scientists who study our environment, climate, eco-systems, and so on, agree upon is the unified theory. The unified theory brings together all fields of research and defines a common element in studies and research affecting these very different fields. This unified theory is what brings meaning to the chaos. This is what brings those 97% of experts together and have them agreeing on the premise of what is happening to our planet.
This is where your scientists fall on their face. They have no unified theory. They propose varying theories, then spend time tearing down those posited by others. They believe they are the only ones with the correct explanation, and that it is unique in its understanding of the issue. This is why they hold no credibility in the big picture.
This is no different than if you discovered a lump and go to your doctor. Your doctor decides to send you to 100 of the best oncologists in the world, and they each do an examination of you and take a small biopsy of your lump. 97 of these doctors agree that it is a form of melanoma and a treatment regime including excision, radiation, and some chemotherapy is required. There is some disagreement in the exact prescriptive approach, but the diagnosis and treatment regime is pretty much agreed upon. The other three disagree completely. One guy says it’s related to your dandruff, and a little Selsun Blue will fix you right up. Another suggests it’s juast athlete’s foot, and a little Absorbine Junior will cure you. Another suggests that your near sightedness is causing you to bump into the same table, and it’s just scar tissue. Who do you listen to? I mean, the science is clearly not in on what this lump is? Are you headed to Shoppers looking for a bottle of dandruff shampoo, some Absorbine, and some new readers? Sounds that is what you would do.
The problem we are really facing is that the media has done such a ghastly job in presenting this issue to the public and informing them. The media thrives on conflict, and they are the ones who continue to forward this ridiculous notion that the science is not yet in. When the6 discuss the issue they bring on a climate scientist to represent the theory, and then a denier to counter. The denier is usually a trainer speaker and better at countering the expert than the expert is countering the talking head. This makes the expert look weak, even though they are the expert and the talking head is just that, a talking head whose job it is to obfuscate and mislead. If the media really wanted to show the public what this issue was about, they would bring 100 scientists into the room and seat 97 of them on one side of the table (those who agree in the unified theory) and then bring in the three who have counter theory. They would then let the 97 make them unified statement, and then allow the other three to argue amongst themselves about which of their counter-theories was more correct.
This is the current state of the issue. The science is in, and it is irrefutable. Climate change is happening, it is happening at an alarming pace, and human activity is responsible. The only question is, are we too late to take action?
Bengtsson's submitted paper had made the case that the Earth's climate sensitivity to the increased greenhouse effect is relatively low by comparing the results of several previous studies, but had not made the case well. The journal in question, Environmental Research Letters published the full comments from the reviewer in question, showing that the recommendation to reject the paper was because,
"The overall innovation of the manuscript is very low ... The paper does not make any significant attempt at explaining or understanding the differences, it rather puts out a very simplistic negative message giving at least the implicit impression of "errors" being made within and between these assessments,"
Comments from a second reviewer were even more brutal. This is precisely the purpose of peer-review – to filter out papers that aren't sufficiently accurate or don't add anything significant to our scientific understanding. In fact, Environmental Research Letters is a high-quality scientific journal with a 65% rejection rate. For examples of innovative research in this area, see our discussions of recent papers by NASA's Drew Shindell and Texas A&M's Kummer & Dessler.
In fact, Bengtsson himself seemed taken aback by the conservative media distortions of the journal's rejection of his research (although one wonders why he leaked the reviewer comments to The Times to begin with), telling the Science Media Centre,
"I do not believe there is any systematic “cover up” of scientific evidence on climate change or that academics’ work is being “deliberately suppressed”, as The Times front page suggests. I am worried by a wider trend that science is being gradually being influenced by political views. Policy decisions need to be based on solid fact."
Statement on climate change from 18 scientific associations
"Observations throughout the world make it clear that climate change is occurring, and rigorous scientific research demonstrates that the greenhouse gases emitted by human activities are the primary driver." (2009)2
International academies: Joint statement
"Climate change is real. There will always be uncertainty in understanding a system as complex as the world’s climate. However there is now strong evidence that significant global warming is occurring. The evidence comes from direct measurements of rising surface air temperatures and subsurface ocean temperatures and from phenomena such as increases in average global sea levels, retreating glaciers, and changes to many physical and biological systems. It is likely that most of the warming in recent decades can be attributed to human activities (IPCC 2001)." (2005, 11 international science academies)10
Intergovernmental Panel on Climate Change
“Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, and sea level has risen.”13
“Human influence on the climate system is clear, and recent anthropogenic emissions of greenhouse gases are the highest in history. Recent climate changes have had widespread impacts on human and natural systems.”14
Dr. John Christy is a Professor of Atmospheric Science and Director of the Earth System Science Center at the University of Alabama in Huntsville (UAH). He has also been Alabama's State Climatologist since November 2000. He is mostly known for his work with the satellite-based temperature monitoring for which he and Dr. Roy Spencer received NASA’s Exceptional Scientific Achievement Medal. Christy helped draft and signed the 2003 American Geophysical Union statement on climate change [Source: Wikipedia].
Dr. Christy believes that the climate system is quite insensitive to humanity’s greenhouse gas emissions and doubts that human activity is to blame for most of the observed recent warming.
Other professional affiliations: Dr. Christy is listed as a "Roundtable Speaker" for the George C. Marshall Institute, a right-wing conservative think tank on scientific issues and public policy. He is also listed as an expert for the Heartland Institute, a libertarian American public policy think tank [Source: DeSmogBlog]
Favourite climate myths by John Christy
Below are many of the climate myths used by John Christy plus how often each myth has been used . . .
My point is that using hydrogen in internal combustion engines to partially or wholly displace fossil fuels can result in efficiency gains that offsets the net energy loss from the production of hydrogen. This is easily proven, as per the videos I embedded earlier.
A little more detail with basic percentages, sources, etc would aid greatly in understanding what you mean when you say "can result in efficiency gains that offsets the net energy loss from the production of hydrogen".
You lose 20-30% right off the top, and hydrogen IC engines are not that much more efficient than gasoline ones to offset that.
Quote:
Originally Posted by snootchiebootchies
If the world can get rid of all internal combustion engines and replace them with electric motors and replace all furnaces and boilers with electric heaters, I would understand better why you feel there is no place at all for hydrogen combustion. But I don't see that happening at all.
Who said anything about "all"? As I've said in cases where efficiency doesn't matter (i.e. heating) it may find use. I never said there's no place at all for hydrogen combustion.
Just that it makes no sense in cars.
__________________ Uncertainty is an uncomfortable position.
But certainty is an absurd one.
A little more detail with basic percentages, sources, etc would aid greatly in understanding what you mean when you say "can result in efficiency gains that offsets the net energy loss from the production of hydrogen".
You lose 20-30% right off the top, and hydrogen IC engines are not that much more efficient than gasoline ones to offset that.
Let's say a semi-trailer truck running on diesel has a fuel consumption rate of 40 L of diesel per 100 km of travel, based on a thermal efficiency of 28%.
LHV of diesel = 36 MJ/L
So mileage in terms of fuel energy input = 36 x 40 = 1440 MJ per 100 km
Let's say we want to displace 10% of that diesel fuel input with hydrogen:
1296 MJ of the chemical energy comes from diesel fuel, and 144 MJ comes from hydrogen.
Let's say for every 1 MJ of energy from the alternator used to generate the hydrogen, only 0.7 MJ of hydrogen is actually produced.
Energy used to produce 144 MJ of H2 = 144 MJ / 0.7 = 206 MJ
So about 60 MJ of fuel energy has to be consumed just to produce the hydrogen. This means 1440 - 60 MJ = 1380 MJ of fuel energy is used for mechanical energy: 1236 MJ is from diesel fuel and 144 MJ from hydrogen.
Hydrogen addition to a diesel engine is shown to improve the thermal efficiency of the engine from about 20% to as much as 50% as per figure below. But let's be conservative and say the thermal efficiency of the diesel engine increases 20%, or from from 28% thermal efficiency to 34% thermal efficiency.
The total km of travel now possible with that engine would be:
0.40 / 0.28 x 1380 / 1440 x 100 km = 116 km
The fuel consumption of the truck using the same amount of fuel energy has improved by (116 km - 100 km)/100 km x 100 = 16%.
This is a similar guarantee from this company, although they don't provide any details of how much hydrogen is used. Their 20% cost reduction likely also includes savings from having to perform less oil changes and particulate filter replacements so our calculation of a 16% fuel efficiency savings on 10% hydrogen addition is probably pretty close to how they come up with their numbers.
