Mastodawn

Ketan Joshi Mar 28, 2023

Me and a few other climate folks on Twitter have noticed a very clear new prominence of climate deniers and delayers

So with some help, I gathered up some data and checked - it turns out that denial/delay, pro-fossil disinformation accounts have seen massive growth in their audience, while pro-climate-action accounts have either stagnated or shrunk.

Elon Musk is reshaping Twitter into a safe space for right-wingers, and in doing so, empowering climate change deniers, delayers and pro-fossil advocates more than ever before.

New post:

https://ketanjoshi.co/2023/03/28/musk-is-remaking-twitter-into-a-climate-denier-sanctuary/

Musk is remaking Twitter into a climate denier sanctuary

I got some data that analyses how climate deniers have changed their audience size, relative to pro-climate accounts, on Musk’s Twitter. It’s….not good.

Ketan Joshi

serklarvel Mar 29, 2023

@ketan ironically, Elon's fortune comes from a company that sells electric cars, which is supposed to reduce carbon gas emitions

Hypx Mar 29, 2023

@serklarvel @ketan Battery electric cars are just a greenwashing exercise. The real future will be #hydrogen powered cars.

serklarvel Mar 29, 2023

@Hypx @ketan agree, I don't believe electrical cars are the solution

Blake Leonard Mar 29, 2023

@serklarvel @Hypx @ketan The future is going to be (or maybe just should be) good public transportation, and "small" vehicles like bikes, skateboards, and scooters :)
As for hydrogen fuel, I feel like it's best suited for use as backup power, but not as the primary power source since it's inefficient and costly (it takes way more power to produce than it puts out).
I don't have any idea what a good primary power source for civilian vehicles like cars should be, if not batteries (which blow up).

Hypx Mar 29, 2023

@blake @serklarvel @ketan The point of hydrogen is that it neither depends on fossil fuels nor excess raw materials. If we are going to have civilian vehicles (which face it, we will), it must be something like hydrogen cars.

The counterarguments are really just FUD from battery car companies. They don't even want you to know that a fuel cell is an electrochemical cell, and that FCEVs are EVs too. There's very little downside compared to other EVs.

Grassroots Joe Mar 29, 2023

@Hypx @blake @serklarvel @ketan
Re: fossil-fuel dependence
It's true that H2 production doesn't have to depend on fossil-fuels, but it currently does.

It's important to state that H2 as a green fuel requires a very large increase in renewable electricity to use to produce green hydrogen.

Building a retail hydrogen distribution system is also needed to be the auto fuel solution. Easier or harder than charging stations?

Hypx Mar 29, 2023

@joeinwynnewood @blake @serklarvel @ketan Let's just say BEVs will never be the solution for everyone and there must be an alternative.

Grassroots Joe Mar 30, 2023

@Hypx @blake @serklarvel @ketan What is undoubtedly true is that hydrogen will/must be instrumental in the decarbonization of heavy industry, air and sea transportation.
Beyond that I think is very much up in the air depending on how much green hydrogen is available how soon.
EV adoption could go much faster than H2 availability depending on several factors.
There is also the future grid stability benefit of distributed energy storage in millions of garages to be considered.

Hypx Mar 30, 2023

@joeinwynnewood @blake @serklarvel @ketan BEV adoption does not follow green electricity FYI. In many cases, they are just being powered by fossil fuels. We should not have a double standard here.

Using car batteries as a way to stabilize the grid is an incredibly dumb idea. Those batteries are not designed for that. Meanwhile, hydrogen for grid energy storage completely solves the problem.

Blake Leonard Mar 30, 2023

@Hypx @joeinwynnewood @serklarvel @ketan Hydrogen production and storage is highly inefficient. It costs about 5 times more energy to make (and contain?) it than it produces.
Plus, the production of hydrogen, especially now, will likely use fossil fuels.

Hypx Mar 30, 2023

@blake @joeinwynnewood @serklarvel @ketan It helps to not swallow BEV propaganda on this subject. The efficiency between hydrogen and lithium is not significant, and both are vastly more efficiency than conventional internal combustion engines. This becomes more obvious once you realize the need for grid energy storage and the cost and raw material problems of li-ion batteries.

ckfinite Apr 22, 2023

@Hypx @blake @joeinwynnewood @serklarvel @ketan Lithium batteries are extremely efficient on a columbic basis (you get in about 99% of the energy out what you put in https://www.nature.com/articles/s41560-020-0648-z). The main loss of energy is in the charger itself, and modern SMPS design can get that to around 90% efficiency. Hydrogen is considerably worse than this.

Understanding and applying coulombic efficiency in lithium metal batteries - Nature Energy

Coulombic efficiency (CE) has been frequently used to assess the cyclability of newly developed materials for lithium metal batteries. The authors argue that caution must be exercised during the assessment of CE, and propose a CE testing protocol for the development of lithium metal batteries.

Nature

ckfinite Apr 22, 2023

@Hypx @blake @joeinwynnewood @serklarvel @ketan

Hydrogen production is at best about 80% efficient (https://www.sciencedirect.com/science/article/pii/S2589299119300035), the fuel cell is about 60% efficient (https://www.sciencedirect.com/science/article/abs/pii/S1364032111004709) and then you have another voltage conversion (another 90%ish efficient step). This doesn't include compression or liquefaction for transport.

All-in, then, hydrogen is only around 40% efficient (https://www.sciencedirect.com/science/article/abs/pii/S0360319908015061) at delivering electric energy to a motor vs. the 80-90% offered by BEVs.

ckfinite Apr 22, 2023

@Hypx @blake @joeinwynnewood @serklarvel @ketan
Compressing or liquefying H2 for transportation requires another step of between 80% and 60% efficiency to be added on top (https://www.hydrogen.energy.gov/pdfs/9013_energy_requirements_for_hydrogen_gas_compression.pdf).

Thus, on a kWh-for-kWh basis, the hydrogen car is considerably less efficient (by about a factor of 2 to 3) compared to a BEV. The main advantage would be if you can make hydrogen without needing electricity.

Hypx Apr 22, 2023

@ckfinite @blake @joeinwynnewood @serklarvel @ketan This is mostly just propaganda. A fuel cell is an electrochemical system. It has more or less same rules governing it. Theoretical efficiency is 100% at every step. Real world analysis will also find that batteries have huge efficiency issues of their own (weight, production, parasitic losses, cold weather, etc.), and in practice there is little to no difference in efficiency.

ckfinite Apr 22, 2023

@Hypx @blake @joeinwynnewood @serklarvel @ketan When you say 100% efficiency, what's that in relation to? Is it realized efficiency of the process compared to maximum theoretical performance or in terms of overall thermodynamic efficiency?

ckfinite Apr 22, 2023

@Hypx @blake @joeinwynnewood @serklarvel @ketan I'm also sort of generally interested in why these papers that I've cited are propaganda.

Hypx Apr 22, 2023

@ckfinite @blake @joeinwynnewood @serklarvel @ketan Your citations are not supporting your claims. They are just pointing out current levels of technology. Future technology progress will eliminate the efficiency problem. Even today, it is already mostly irrelevant. Batteries are heavy and expensive, and fuel cells are already efficient enough to justify replacing the former with the latter.

ckfinite Apr 22, 2023

@Hypx @blake @joeinwynnewood @serklarvel @ketan You specifically claimed that they were propaganda - I'm still interested in why. These papers clearly lay out why there is a current 2-3x efficiency gap between FCEV and BEV. To cite a modern paper, take for example Aminudin et al (https://www.sciencedirect.com/science/article/pii/S0360319922048534) who identifies electrical efficiency of the fuel cell itself (not including electrolysis) of 72%. Are you saying that 72% thermodynamic efficiency is ~100% of theoretical?

Hypx Apr 22, 2023

@ckfinite @blake @joeinwynnewood @serklarvel @ketan I cannot access the whole paper, but he is factually wrong if he is making that claim. The theoretical limit is 100% efficiency, as in 100% conversion of chemical to electrical energy.

https://www.dynamictidalpower.eu/resources/Documenten/Maximum_conversion_efficiency_of_hydroge.pdf

ckfinite Apr 22, 2023

@Hypx The 72% thermodynamic efficiency is of a *realized* PEM fuel cell; the theoretical 100% efficiency is a lot like carnot-ideal efficiency: you don't get particularly close to that.

In that paper they note that even the idealized efficiency with real gases is not 100%:
> The lowest value of the maximum efficiency is 82.1%, 75.7%,
and 79.3%, respectively, for CH4-air fuel cell, H2eO2 fuel cell,
and H2-air fuel cell and the corresponding highest maximum
efficiency is 92.7%, 82.7% and 82.7%.

ckfinite Apr 22, 2023

@Hypx A real fuel cell is going to have losses that aren't included in this idealized process model; achieving 87% (72% vs. 82.7%) of the maximum theoretical performance is actually pretty good for a thermodynamic process!

Hypx Apr 22, 2023

@ckfinite You are reading it wrong. It is clearly saying 100% is the maximum.

@Hypx Yes - the *theoretical* maximum. They do not claim you can attain this with any real-life fuel cell. Again, it's like carnot ideal heat engines: the theory says that you should be able to make them much more efficiently than you actually can because there's losses that exist in the real world that don't on paper.

Hypx Apr 22, 2023

@ckfinite Again, once you are hitting something like 90% efficiency, what is the point of criticizing fuel cells then? There is no reason to choose li-ion batteries over them. Which BTW, are only about 80-90% efficient in real world operation anyways.

ckfinite Apr 22, 2023

@Hypx Because every little bit adds up, as is evidenced in li-ion cells. That 80-90% number is not in the *battery* (https://iopscience.iop.org/article/10.1149/1.3268129/pdf; realized li-ion battery efficiency is in excess of 99.6%) so much as it is in the *charger*. This is what I'm talking about when I'm constantly referring to SMPS losses.

You claimed earlier that each step has "100% efficiency" so I'm just going through step by step challenging that. I'll then go back and multiply all of these little subidealities.

Hypx Apr 22, 2023

@ckfinite You do realize that refers to COULOMBIC efficiency? Charging/discharging efficiency is around 90%, with more losses from other sources. Also, efficiency drops dramatic at higher C levels. Li-ion batteries are not magic.

ckfinite Apr 22, 2023

@Hypx Yes. Coulombic efficiency is the primary measurement of energy efficiency of charging the *battery itself*; it's dividing the ampere-hours taken out of the battery by the amp-hours originally put into the battery e.g. equation 8 from https://animation.fer.hr/images/50036152/EUROCON%202021_Determining_Lithium-ion_Battery_One-way_Energy_Efficiencies_Influence_of_C-rate_and_Coulombic_Losses.pdf. The numbers you're citing here *include charger losses* which vastly dominate over the losses inherent to the battery.

ckfinite Apr 22, 2023

@Hypx In realized li-ion battery systems most of the energy is not lost to internal resistance of the battery (which is what causes coulombic efficiency < 1 - the charge is lost to heat; the extremely low resistance of li-ion batteries is also why they explode when they get shorted out) but instead to the losses intrinsic to the AC-DC/voltage conversion in the SMPS used to charge the battery.

ckfinite Apr 22, 2023

@Hypx I agree that high efficiency, high speed fueling is a major advantage of hydrogen. That is not my contention here.

Hypx Apr 22, 2023

@ckfinite You're just spamming nonsense here. A significant amount of energy is also lost as heat. Voltage is also being lost. You are simply confusing yourself.