401–410 of 919 posts
I swear I've been reading this headline for last 15 years.
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The big reason for this is thermodynamics. A conventional internal combustion engine car has to convert chemical energy to kinetic energy - the absolute best theoretical efficiency of this might be 70%, but in practice it's more like 30%. Electric cars have to pay the same thermodynamic penalty, but they pay it at the power station (In practice, thanks to renewables, not all the electricity used to charge a car will…
It is a sign of the success of the oil industry that this analysis always takes the cost of electricity generation back to the source, but assumes that fuel stations pump from a perfect source of naturally refined/distilled hydrocarbons. 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-t…
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?
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As to whether those hybrids have a 'huge effect' on 'global warming' depends on many factors but assuming the narrative around climate change - the term 'global warming' has been swapped for the latter since the average global temperature has gone down for a number of years after an earlier steady rise - in relation to the CO₂ hypothesis holds truth the main factor of importance is the source of the carbon used in th…
by the way, how did you do all those subscript formatting tricks?? It would be great to know how to post more advanced things in the comments here.
+ _ + [0-9]
superscript: ^ + [0-9]
O⁰… O⁹
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I know Equinor publishes quite detailed numbers from their operations: 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 t…
>EROI values for our most important fuels, liquid and gaseous petroleum, tend to be relatively high. World oil and gas has a mean EROI of about 20:1 (n of 36 from 4 publications) (Fig. 2) (see Lambert et al., 2012 and Dale, 2010 for references). The EROI for the production of oil and gas globally by publicly traded companies has declined from 30:1 in 1995 to about 18:1 in 2006 (Gagnon et al., 2009). The EROI for disc…
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.
I just realized how much energy efficiency is being squeezed out of a Tesla. It's incredible. A normal diesel fueled sedan such as the Chevy Cruze diesel runs at about 31mpg, which is 13.2 km/l or 15.3 km/kg. Diesel has a mind-boggling 12700 Wh/kg energy density[1], which translates to an efficiency of ~827 Wh/km for the Chevy. By contrast, the Tesla Model S, has a ~540 kg battery[2]. At 272 Wh/kg (from the posted ar…
All that extra energy ICE cars carry isn't actually being put to use very well. They don't have more powerful engines. They don't have more torque. They don't have more acceleration. And even their range isn't that much better. You can of course get models that take something like 100+ liters of petrol. But the per liter performance only gets worse if you do that (heavier cars are less efficient).
The reality is that yes, fuel is very energy dense but sadly most of that isn't transformed into motion when you use it. You are instead making lots of noise (vibrations) and heat. Both are actually bad for your car. So, you use most of the energy to wear out your car faster. The more powerful the car, the less efficient they are. And the faster they break down.
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The big reason for this is thermodynamics. A conventional internal combustion engine car has to convert chemical energy to kinetic energy - the absolute best theoretical efficiency of this might be 70%, but in practice it's more like 30%. Electric cars have to pay the same thermodynamic penalty, but they pay it at the power station (In practice, thanks to renewables, not all the electricity used to charge a car will…
Though that makes me think that hybrids have a real future. Or hydrogen fuel cells. 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.
Wow 2 day iPhone battery life. Let’s go!
No, it would definitely be an iPhone that is twice as thin and still lasts a single day.
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Not that confusing, only the US measures fuel in gallons, isn't it? Everyone else just uses liters.
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The entire world uses metric units apart from America, Libya and Myanmar. https://worldpopulationreview.com/country-rankings/countries...
What I absolutely love about this fact is that America is still using British Imperial units. After literally having a war over whether or not the US should be independent of British rule, you're still holding on to our measuring system despite the rest of the world moving on.
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> the absolute best theoretical efficiency of this might be 70% 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...
It's a different metric but it is generally accepted that F1 cars have reached an overall thermal efficiency of 50%, which is cool. This is taking into account energy recovery from kinetic (regenerative braking) and thermal sources (from the turbo).