Yes it usually is
I fell down a rabbit hole and found this link, which gives 46% for the theoretical limit for the efficiency of the internal combustion engine.
https://physics.stackexchange.com/questions/98966/maximum-th...
[1]: https://engineerine.com/meet-wartsila-31-worlds-most-efficie...
I don’t get your point on centralization however - more efficient but less robust (just like in software).
Wait, does a new prius or something like a hyundai ioniq (also 52-53 mpg) not have the internal combustion engine mechanically coupled to the transmission and drive wheels anymore?
I really like this setup, because it gives economy, but also a range and I don't need to worry about where to charge the car.
I also take issue with anyone calling a hybrid 'effectively an electric vehicle.' That is only true for PHEVs. A regular hybrid still gets exactly 100% of it's energy from gasoline.
While ICE are heat engines with a theoretical limit of 70%, they’re more specialised subsets described by the Otto (gas) and Diesel (… diesel) cycles, which have a much lower theoretical maximum.
Just plugging the temperature ranges into Carnot will give you a Carnot limit of 50%, and using Otto will yield 46% (https://physics.stackexchange.com/a/98992).
Add in that gas engines are not spherical and into a vacuum (losses and delays) and you’re in the 30s.
Once you get to cruising speed the transmission usually engages something called a "lockup" that bypass all that to get as close to the 100% number for energy transfer as possible.
Anything that doesn't require charging directly from the grid all the time, because although parts of the USA and Norway are ready for that, it's very tricky to get right globally.
Maybe hybrids like the Prius get to be so efficient that such cars will have a truly negligible impact on global warming.
Imagine you were tight on money and then think about your grocery store bill. Wouldn't you try to save in all categories, even though, say meat, was "only" 11.9% of your total bill?
Carbon reductions need to be made in every sector.
I looked at the link and to me transportation does indeed seem one of the larger sources of emissions. Everything else seems either very fragmented (lots of entries with around 2%) or similarly if not more complex - like energy use in buildings for all of the appliances.
What am I missing here, what would be easier to address than the abundance and types of cars and possibly the lack of proper public transportation?
I don't think that one can even make the argument that we should look for easy wins when change is necessary everywhere, unless we want climate catastrophe - because of people working against improvements due to their personal interests, inefficiencies in regulation and enforcement, as well as any number of other factors.
You can use a smaller battery, which means using less rare materials that are very expensive. There are a lot of indirect emissions with electric vehicles, and it's important to look at the big picture.
It's an argument pushed by fossil fuel company's because it pretends the world is static and unchanging, as though the energy mix of the electrical grid can't vary, or that changes in fuel source and process for mining operations to be cleaner wouldn't drastically effect downstream users overall emissions profile.
CO₂ -> C + O₂
2 H₂O -> 2 H₂ + O₂
C + 2 H₂ -> CH₄ (methane)
[1] https://en.wikipedia.org/wiki/Fischer%E2%80%93Tropsch_proces...
You're just going to throw that out there? You'll cite the Fischer-Tropsch process, but not "actually global temperatures are declining"?
Here[1]. The temperature hasn't gone down. The narrative hasn't changed from global warming because of this (the term was in fact dropped because people are idiots and trying to explain what global temperature is measuring in terms of energy dynamics in the climate system doesn't work...). 2022 was the 6th warmest year on record, and based on all data the overall trend is up.
[1] https://www.noaa.gov/news/2022-was-worlds-6th-warmest-year-o...
May I suggest a less belligerent/dogmatic attitude when discussing this subject? If the narrative holds it won't change the conclusion. If new data shows the narrative to be false or misleading - e.g. ice core records show the atmospheric CO₂ concentration to lag behind temperature changes, not lead them, climate sensitivity wrt. CO₂ concentration is low, feedback mechanisms are unclear, there are far too many fudge factors in the climate models to make them reliable sources - it will be much easier to adapt to the new situation. We're not talking religious dogma after all but scientific theory, that which can and should be discussed lest it turns into the former.
[1] https://www.washingtonpost.com/news/capital-weather-gang/wp/...
[2] https://www.climate.gov/news-features/climate-qa/why-did-ear...
[3] https://climate.nasa.gov/global-warming-vs-climate-change/
Running the denialist playbook as usual: slip in a insinuation that the issue has stopped without evidence, then drop a bunch of articles which don't support it while continuing to say "what if all the data supported me?" And then started alluding to a conspiracy with language choices like "dogma". Throw in some upfront tone policing because heaven forbid you have to defend your position vigorously and the recipe is complete.
Go on: hit me with "climate cycles are natural" and then lean into how the media just don't talk about the controversy.
Please refrain from using terms like denialist, it does nothing to help the discourse. Also, that 'bunch of articles' I sent does support what I said, this being a break in the rising temperature trend. You seem to want to hear much more in what was said, why is that?
As to the 'conspiracy with language choices' I think you realise that this is no conspiracy but a simple fact - what used to be called 'global warming' is now called 'climate change'.
As to 'tone policing' I'd suggest reading your posts I replied to.
[1] https://en.wikipedia.org/wiki/Holocene#/media/File:Holocene_...
When one party wins by default, they benefit from stalemate-seeking tactics. "Just Asking Questions" unfortunately works very well for this purpose. Dogma poisons the discourse, yes, but so does accidentally extending good faith to a bottomless well of bad faith questions, which has been the conservative playbook on climate change since forever. I learned this the hard way, over and over again. The counter-strategy is dogma.
In order to have a scientific discussion rather than a political discussion, we need to know your intentions, and that's extremely difficult on a pseudoanonymous internet forum. It sucks, but this is probably how it has to be.
The truth, freed from ideology. This will be hard to achieve given the enormous amounts of money involved on all sides - from "green new deals" via trillions of € in subsidies to even larger amounts of money on the fossil-fuel-status-quo side. With politicians who have made their careers on either portraying themselves as apostles of Gaia or ensuring the continuous flow of oil, gas and coal - and thus the continuation of an industry which more or less defined whole US states and several countries.
Just because it is hard - and probably impossible - to get the actual truth does not mean I want or need to cave and just follow one of the narratives. Given enough people looking for the actual truth it may become possible to reach it and act upon it but it better be sooner rather than later.
What is your purpose in asking such leading questions by the way? Do you agree that an actual scientific discussion - as opposed to one directed by The Science™ - is the better course? Also, who are the we who would like to know? I speak for myself, not for others. Who do you speak for?
The IPCC reports are one google away.
When you're done reading at least the abstracts in the IPCC reports - but it is worth the time to read the actual reports themselves - you can also read a few other sources, e.g. Schellenberger's Apocalypse Never: Why Environmental Alarmism Hurts Us All, Björn Lomborg's False Alarm: How Climate Change Panic Costs Us Trillions, Hurts the Poor, and Fails to Fix the Planet and Steve Koonin's Unsettled: What Climate Science Tells Us, What It Doesn't, and Why It Matters. These give a far better view over what climate change entails and how it can be dealt with than the breathless fear-mongering as seen in the media and as spouted by politicians.
It's a much longer trend than 2012-2016. I remember 2011, the last time conservatives were playing the "global warming has paused" game, but then oops! It returned to trend. No Ls were acknowledged, of course.
What do the radiative flux measurements say this time around? They measure the derivative directly and are upstream of the most chaotic mixing process. Last time they said "sorry, heat is still piling up, globe's still warming." They were correct. What do they say this time?
2012-2016 is not the period of warming, it is the period from which the warming trend changed into a cooling trend. Seen over the last century the warming trend is far longer, the most recent one starting somewhere in the beginning of the 70's until the mentioned 2012-2016 frame. After that a slight cooling period followed, taking down the temperature by 0.06°C/yr until 2022. 2022 was another warm year so if 2023 will be warm as well the cooling trend is most likely broken. These sort-time variations are not significant when discussing 'climate' - roughly defined as 'the weather trends over at least a 30 yr stretch' - but they do control what makes the news.
One question: why do you state is is ´conservatives' who claim that the warming trend was broken? You don't know whether those people were conservatives nor do I. It does not make sense - and is extremely counterproductive - to equate a person's stance on single issues like 'climate change' with their political affiliation since these issues should not in any way be connected to political ideology. If they are connected they are by definition suspect since ideology trumps objective reasoning. Either the climate changes - and it does, no question there - or it does not, independent on whether you or I vote for whatever party we choose. Allowing ideology to taint the discussion just turns off a large part of the populace no matter which ideology it happens to be. It is just plain stupid for climate change to be a 'progressive' cause, crime reduction to be a 'conservative' cause, etc. These issues should be pulled out of the ideological realm so that they can be discussed by everyone without accusations of -isms by 'either' side.
<compose> + _ + [0-9]
superscript: ^ + [0-9]
O⁰… O⁹
The long-winded way is to use your OS's character map tool: find the glyph you want there and copy+paste. Under Windows 10+ there is the emoji keyboard (hit [win]+;) which also gives access to much more including super-/sub- script characters, which is a little more convenient than character map. Presumably other OSs have similar available too.
Better is to have support for a compose key sequence. Usually build in to Linux & similar, you just might have to find the setting to turn it on and configure what your compose key is. Under Windows I use http://wincompose.info/ and there are a couple of similar tools out there. In any case it is useful for more than super- and sub-scripts: accented characters & similar (áàäæçffñ), some fractions (¼,½,¾), other symbols (°∞™®↑↓←→‽¡¿⸘♥⋘»‱), and configurable too so you can make what you use most easiest to access (and if you are really sad like me you can do something https://xkcd.com/2583/ to type hallelujah too!).
On mobile devices a fair few “special” characters are usually available (though it depends what keyboard you have installed) via long-press on the right keys of the virtual keyboard.
The second reason is that hydrogen is 1/10th the density of diesel even when liquid (which is as dense as it gets). Maintaining hydrogen in its liquid form is energy intensive. Hydrogen tends to leak through the smallest cracks and also because the atoms are so small tends to leak even through solid metal. To sustain the high pressures and degradation by hydrogen you need a very expensive tanks. You also need to handle the case, when the car crashes/ catches fire releasing all of the hydrogen somewhat safely. This tends to be a 6 MW flame upward of the car. Too bad if it crashed under a bridge or garage. This is much worse than a burning ICE/ BEV car.
Hydrogen gas stations have all of the problems with the tanks as well. That makes them very expensive. Battery charging stations are somewhat easier - everywhere you have higher voltage you can build a decent charging station. Big parking lots can have solar roofs fulfilling a part of the charging demand and keeping the cars colder in the summer.
At the same time you don't have any of the advantages of batteries - such as that you can charge them almost everywhere or when breaking. Hydrogen cars would need to be hybrids basically to improve on these, in this regard they are more similar to classical ICE cars.
Finally, making hydrogen ecologically and economically is not that easy in big quantities. In the end, you realize it is means to a longer operation of the infrastructure of classical fossil fuel companies. Unrelated to cars, you can put some hydrogen (up to about 8% it seems) into natural gas without noticeable change in properties when used for heating. But you can probably slap a green or at least "blue" stamp on the solution. In the end, all of this is just as damaging as the production/ burning of bio diesel/ gasoline spiked with ethanol. Putting hydrogen into cars would just make support this fossil fuel agenda without actually helping the environment much and quite possibly enable decades of even more damage to the environment and public health with profits mostly for just a few already filthy rich people.
[0] https://www.quora.com/Can-I-create-a-Hydrogen-fuel-cell-with...
It is surprisingly difficult to get numbers on how much oil is used to extract, refine and transport oil.
The best I found was this:
https://www.speakev.com/threads/energy-required-to-refine-oi...
Does anyone have better numbers?
https://sustainability.equinor.com/climate-tables
The headline figure is maybe to compare 11.4 mill. tonnes CO2e emissions from "Scope 1 + Scope 2" (direct emissions from the company plus indirect emissions because they buy electricity and stuff), versus 243 mill. tonnes CO2e from Scope 3 (emissions from people burning the hydrocarbons sold).
If that figure is correct, you can add 1.6 percent to the car tailpipe emissions figures to account for production and refining etc.
But this is an oil & gas company that tries very hard and is among the best in the world for minimising emissions from production and refining. I would not be surprised if gasoline from US shale oil is more than an order of magnitude worse.
https://www.sciencedirect.com/science/article/pii/S030142151...
Whereas if you compare CO2 emissions, you can do these things and in theory get down to zero emissions from production and refining of gasoline.
Damn, I've never thought about that before. In hindsight that feels like an obvious thing to consider but this is the first time I'm aware of that thought entering my brain. Thank you for provoking the thought.
What would be the equivalent consideration on the other side? Would it be something like inquiring into the energy requirements of creating and maintaining the electrical grid, especially given the increased load of wide-scale vehicle electrification, instead of assuming we get that for free?
Anyway maintaining a more robust grid should be much cheaper than maintaining thousands of gas stations and the trucking routes used to keep them filled up.
ChatGPT summary:
In 2019, the world seaborne trade volume reached about 11.08 billion tons. Out of this, crude oil, oil products, and gas accounted for approximately 32.5% (3.6 billion tons) of the total volume. Coal made up another 8.4% (935 million tons). In total, energy products represented around 40.9% of the global seaborne trade volume.
It's important to note that these figures are from 2019, and the percentages may have changed since then due to various factors, including evolving global energy markets, fluctuations in demand, and the transition to renewable energy sources. The percentage may also vary depending on how you define "energy products."
Sources: https://unctad.org/webflyer/review-maritime-transport-2020
But yeah, no one then goes on to give equivalent numbers for petroleum.
Not to mention the socialized costs of all the wars, military spending and human lives spent to secure stable sources of fossil fuels. If you actually break down the numbers and applied some basic ethics, I doubt fossil fuels have been cost competitive for decades.
<snark, i'm totally against military aggression>
It's almost as if they want an excuse for running a massive military.
It's not like renewable energy doesn't take resources/energy to produce as well. It's just borderline impossible to get real numbers because you'd pretty much need perfect information on the supply chains.
Not saying that renewables don't still win in such a comparison.
There must be small impact of that as well to the CO2 calculations.
If your car gets 30 mpg, has a 16 gallon tank (that you refill at 1/4 tank, so you're buying 12 gallons), and you drive an extra 5 miles to pay $3.93/gallon instead of $4.00/gallon, how much did you really save?
I'll give you a hint: It's less than a nickel.
Meanwhile, you've probably driven at least 10 minutes that you didn't need to drive. 10 minutes to save a few pennies.
The math only gets worse as the gas prices go up and your fuel economy goes down. You need a greater delta to make the drive worth it.
Siting a gasoline station is highly strategic. They know exactly where to put them and how much to charge on the real estate and vendor sides.
On the way to the charging station, we probably pass a dozen gas stations.
I love my EV but let's not pretend it's always more convenient. If you have the opportunity to charge at home/work then yes it's great, but you're still reliant on public charging infrastructure if you decide to drive outside your normal range, and it takes a lot longer to charge than it takes to fill up a tank of gas, even considering the speed of Tesla Superchargers.
(1) Alberta tar sands production, which relies on imports of natural gas to melt and process the tar sand into a crude oil equivalent, called syncrude. If the syncrude is shipped to San Francisco Bay for refining at Chevron's Richmond Refinery, then you have to tag on the shipping fuel used, the gas used in the refinery, and finally the tanker fuel used to move the fuel to a gas station in San Francisco. Finding all these numbers is not easy, it's often proprietary, but you can find that a lot of natural gas is used at refineries (bulk numbers):
https://www.eia.gov/dnav/pet/pet_pnp_capfuel_dcu_nus_a.htm
(2) Sweet light crude from a pressurized reservoir that's refined a few miles away from the oil field and used in a nearby city.
The end-product, refined gasoline, has the same state property (energy density) regardless of how it was manufactured, but that's irrelevant for getting the energy that it cost to make it. I imagine the spread can be pretty wide indeed, as the above examples show.
Generation can be from clean sources and is already happening in some jurisdictions.
Even if a clean source is not available, the pollution can best be controlled at the source. In this period of history, hundreds of millions of people make billions of polluting trips every day in their communities.
Although owning any car is the poorest choice of all for the environment, there are two ecological benefits to driving a BEV or a PHEV.
* better efficiency than ICE
* zero emissions in the case of BEV, zero emissions *for most trips* in the case of PHEVYou mean thermal energy?
Both cars are converting chemical energy to kinetic. The theoretical maximum for this is 100%. But one uses a thermal intermediate step, that reduces that maximum.
How close/far would you say we are as a society on "having significant renewable generation"?
https://www.eia.gov/todayinenergy/detail.php?id=55960
They're still pretty close to each other right now. Renewables are at 21%, coal 20%, nuclear 19%. However, nuclear is flat and coal is declining. Renewables are still growing rapidly and will widen their lead significantly in a few more years. See the first embedded chart in the article, showing output trends since 2010. Also see the short term forecast at the end of the article:
"In our March Short-Term Energy Outlook, we forecast the wind share of the U.S. generation mix will increase from 11% last year to 12% this year. We forecast that the solar share will grow to 5% in 2023, up from 4% last year. The natural gas share of generation is forecast to remain unchanged from last year (39%); the coal share of generation is forecast to decline from 20% last year to 17% in 2023."
[0] https://en.m.wikipedia.org/wiki/List_of_coal-fired_power_sta...
Just to expound on this. Power stations turn fuel to heat, and heat to electricity via steam turbines.
In ICE cars, that heat is the main loss of power. Whole systems in cars are built to get rid of that excess heat in the engine.
ICEs are most efficient under medium-low RPMs and high load. The electric motors can sustain low speed cruising, letting the engine shut off entirely if it wouldn't be well utilized, and also fill in for high torque demand to keep engine power output lower.
So when you look at the headline "efficiency" of an electric car, you need to take that thermodynamic penalty into account first.
A modern series hybrid like a Toyota Prius is effectively an electric vehicle and a gas generator (which means it has the same efficiency gains due to regenerative braking). That gets 52 mpg, which is about 493 Wh/km. If you generated the 225 Wh the Tesla needs in even the most efficient combined cycle gas turbine powerplant you'd need 375 Wh. Less - but not nearly as drastic as it first seems.
Renewables change the picture though - once you have significant renewable generation the carbon intensity of electricity starts dropping, which means that remote powerplant vs local powerplant argument falls apart. That is when the real power of electric vehicles kicks in - they can take their energy from anywhere.