26th August 2023, 16:10 | #76 | |
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| Re: The future of "Strong Hybrids" in India Quote:
Optimistically, the CO2 emissions per kwh may go down to 0.48kg/kWh by 2030. If this becomes a reality, then the typical EV (which i've assumed typically operates between 5.5-7.5km/kWh) CO2 emissions could drop to 64-87g/km. For now, as per my assumptions, it is 105-143g/km. You are right about using solar in your own society/house. Hopefully rooftop solar will catch on in a big way. As a side note, for more premium cars the story is a bit more interesting. Autocar took the Volvo XC40 Recharge for a spin and was able to get an estimated 300km from its 78kwh battery. That's just 3.84 km/kwh or 205g/km of CO2/km (only 11.2kmpl equivalent). Even with some spirited driving, I'd imagine it would have been outdone by the XC40 petrol itself ! Strange. | |
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26th August 2023, 19:13 | #77 | |||||
BHPian | Re: The future of "Strong Hybrids" in India Quote:
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Fortunately, this one working paper I dug up from ICCT does have the said references. If we consider the grid usage in charging, the 100% coal scenario (worst case), the avg grid emissions as of 2020 was 614gCO2/kWh or 0.614gCO2/Wh. (Figures taken from page 5 graph of this pdf : https://theicct.org/wp-content/uploa...apr2021-01.pdf) It pits grid at even better situation than it is acc to your linked article which doesn't seem to have any references. An EV like Nexon can get efficiency of 120Wh/km An EV like Tiago can get even better at 100Wh/km By this calculation, a 100% coal powered Nexon EV has a running emission of 74gCO2/km. For Tiago EV it’s 62gCO2/km. Quote:
Idk if 28% gain can come from strong hybrid, especially on highway where battery charge comes from engine rather than city where regen braking does the job. I could not find any source for the mileage-emission equivalence you showed either, only this one document which has emissions of some mild hybrid cars from Maruti. Pdf pg11, indexed pg6 : https://theicct.org/wp-content/uploa...s-wp-FINAL.pdf All Maruti cars except baleno SHVS are above 100gCO2/km. Baleno makes the cut barely at 99.6gCO2/km. Scross, XL6, Ciaz, all are in 120-130g/km range. Quote:
Prime which I have has consistently given me 250km in city and 240km on LKO-PRYJ highway (which is single lane for 110+ km so I can't exceed 60-70kmph on that section) I have exact trip readings, 223km on trip with 18km remaining, door to door from MNNIT Allahabad to Home. Anyway, nexon EV max can easily give 300-350km. So either fix the battery or the range. Not that it matters anyway, since the linked pdf with direct reference pits the EVs at half the emissions of what you calculated. I'm not saying mine are gospel, yours are baseless, all I'm saying is that the economictimes article you linked is using 790g/kWh without any references but the ICCT pdf is having complete footnotes for all data points, thats all. Please see if there is any error on that end Quote:
GV/Hyry may lower this figure but hycross being larger and heavier, I doubt. The aerodynamic camry seems to score 104.5g/km but Vellfire it at 145g. Last edited by Shresth_EV : 26th August 2023 at 19:17. | |||||
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26th August 2023, 19:59 | #78 | |
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| Re: The future of "Strong Hybrids" in India Quote:
1. As you will see from the report, coal power plants produce almost 1000 grams of CO2/kWh; the figure of 614grams/kWh is totally ridiculous. 2. You may use you own assumptions for EV range. I've had several folks in Mumbai and Bangalore tell me 300 km on the 40kWh battery pack is the max they see on the Nexon EV Max in the city, with spirited driving on the highway reducing range quite a bit. That's why I've taken a broad assumption of 5.5-7.5km/kWh considering different driving situations. You may take 8 if that's what you get. 3. Even if we now consider 710grams/kWh to be the baseline CO2 emission from electricity generation as the report seems to suggest, the following calculations would apply: - EV efficiency 5.5km/kWh - 130g/km (17.75kmpl petrol equivalent) - EV efficiency 7.5km/kWh - 95g/km (24.3 kmpl petrol equivalent) 4. Every liter of petrol burned emits around 2310grams of CO2 (unadjusted for E10). You will find plenty of sources for this. Thus: - 19kmpl = 121g/km - 24kmpl = 97g/km 5. Similarly, burning 1 liter of diesel emits roughly 2680 grams of CO2 6. Again - you may use other assumptions for efficiency. This is just my view based on efficiency figures I have seen reported. As batteries get heavier, efficiency decreases. So a Hyundai Ioniq 5 will never be anywhere as efficient as a Tiago, and Nexon EV will also get more km/kWh than an EV Max. Most EV taxi drivers I've asked in Mumbai get 200km from the 26.5 kw Tiago. Again, you may have had different experiences. 7. The ICCT numbers are ridiculous, using some sterile test conditions. No baleno gives 23kmpl (as assumed in this paper) real world and the camry hybrid also not give 22kmpl (as also assumed in this paper) real world. They also suggest that the BMW 7 series PHEV can achieve 40kmpl - certainly not over a 800 km highway drive where the battery can only do so much. I am trying to arrive at a more real world range. 8. As another real-world example, lets take this Kashmir to Kanyakumari trip that Evo did with the Nexon. Used approx. 600 units of electricity for 4000km, i.e. 6.66km/kWh (21.7kmpl petrol equivalent). Hope this explains where I am coming from. Good to continue drilling this down though. That's why I like this forum. Last edited by Fiero : 26th August 2023 at 20:28. | |
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27th August 2023, 13:03 | #79 | |||||||
BHPian | Re: The future of "Strong Hybrids" in India Quote:
The sources of all the data points are given in the footnotes of the ICCT doc, please refer to the doc linked by me. Quote:
In that sense, ARAI (even with the optimistic mileage figures), or EPA/WLTP, who are using actual tailpipe emissions while driving, for the regulatory green light, are using "overestimated" figures? Because if this was the universally acceptable thing, we won't have cars running around with emission test kits, they'd just whip out their Casio calcs and be done with it. In that sense, should we not then do the same for coal? The numbers should surely hold up, no? Quote: Again, let me clarify, I'm not saying this 297 number is true, I'm just trying to see if the analogy works when applied to coal, but clearly it isn't working. It defies logic why should emission testing need so much R&D when it could be as easy as taking standard values of carbon content in fuel and doing stoichiometry on it. Quote:
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The XpressT uses 72V DC architecture which has more losses compared to a higher voltage architecture like the 300-400V industry standard which still has more losses than 800V upcoming architectures (used in Ioniq5, EV6, taycan) Quote:
That should be a relevation to the govt that the cars are polluting more than ARAI said they would, even if its under the cutoff figure for compliance. Quote:
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Last edited by Shresth_EV : 27th August 2023 at 13:10. | |||||||
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27th August 2023, 21:54 | #80 | ||||||||
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| Re: The future of "Strong Hybrids" in India Quote:
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So yes, CO2 emissions are a factor of distance driven for every liter. But ARAI and EPA are not testing only for CO2. For NOx, SOx and other things, it is probably not a finite, which is where DPF and other tech probably come in, but leaving that discussion aside. Quote:
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28th August 2023, 13:06 | #81 |
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| Re: The future of "Strong Hybrids" in India Having read all the point of views. I can conclude the following 1. One can safely say that with today's grid composition. Electric vehicles and Hybrid vehicles do almost similar CO2 emission. Just that one does it where we live and other does it in remote areas where major population doesn't live 2. More we add renewable sources of energy, cleaner the electric car will be to drive. People with roof top solar setup are already doing that. Now coming to the fact that future for strong hybrids is very robust. 1. Why do Toyota/Maruti have two premium models on the hybrid technology? Why is the technology not being implemented in mass market cars. Example - Baleno/Glanza, XL6/Rumion, Brezza should get it. There is no roadmap to add hybrid to these cars. 2. Why are manufacturers like Hyundai/Kia second in sales numbers in India not investing in hybrid technology in India? They have hybrid technology outside India on sale. 3. Why didn't Toyota bring PHEVs to India which are much more relevant for the Indian car scene? |
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28th August 2023, 15:49 | #82 | |
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| Re: The future of "Strong Hybrids" in India Quote:
The Indian government also never did anything to promote hybrids. Hybrids get no incentive for fairly noticeable emissions reduction. Perhaps strong hybrid tech in smaller cars (sub 4m) isn't as feasible as EVs. Imagine a top end hybrid Venue costing 18-19 lacs Mumbai? Would the efficiency gains be worth it? On the other hand, you could go about your business quite well in the city with a 15-25kwh battery in a small car which in the long run may be more cost efficient. If you go to the other end of the spectrum though, things are more interesting. Larger vehicles like the Ioniq 5, C40 Recharge, BMW ix have relatively large and expensive batteries. Imagine a battery powered Innova trying to get 400+km real world range, the battery and added cost would also be mammoth; perhaps hybrids just work better here from a cost perspective, for the manufacturer and the consumer. | |
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28th August 2023, 21:53 | #83 | |
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I did not go over the numbers carefully but something does not add up. Here is my reason. I am assuming by hybrid you mean plug in hybrid. Now the plugin part is the same as EV so what ever emission is present in EV should be the same. And the rest is petrol any way. Also if the charging happens during running, there should be an overall loss in the K.E - Regen system any way which i think gives at the best 0.7 precent. So I do not see how hybrids can be better than EV (or even close to EV). there might be some unrealistic assumption that has come up some where or there is an assumption. The other possibility is that Coal Plants are significantly bad compared to Petrol engine which I am not really sure about. All said and done Coal plants should have the economy of scale Last edited by Chetan_Rao : 28th August 2023 at 23:57. Reason: Merged consecutive posts. | |
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28th August 2023, 22:10 | #84 |
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29th August 2023, 21:46 | #85 | |
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| Re: The future of "Strong Hybrids" in India Quote:
2. I was talking about strong self-charging hybrids with small 1-3kw battery packs which spend a lot of their running time in the city with the ICE acting like a generator and not powering the wheels, like the Honda City HEV. Seem to comfortably manage mileage in the early 20s in the city. I think what you speak of are plug-in hybrids which can do 50-70 km in EV mode when fully charged. There aren't any mainstream examples of this in the Indian market. | |
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30th August 2023, 12:50 | #86 | |
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| Re: The future of "Strong Hybrids" in India Quote:
of than ICEs (the hybrid part of it does not matter really). 1. Almost 100% of the electricity is generated from thermal plants. 2. The thermal plants has the same efficacy (measured in CO₂ emission per kWh (1 unit) of electric energy generated. In this scenario a BEV is like an ICE for charging the batteries and then using the battery+motor system to drive the car. Let η by the efficiency of the BEV charging system + electric motor. So 1 unit of electricty will translate into η unit of motive energy through the EV drive train + battery which means that 1 unit of motive force will need roughly 1/η units of electricity and its equivalent CO₂. Now this calculations would make it appear as if BEVs are worse than ICE's because the ICE does not incur a loss of (1 - η) due to the round tripping of energy through the electrical drive train, but this is a flawed analysis. What is interesting however is that even this unfavorable (to BEV) calculation can reveal something very interesting. If we move on to a scenario when β fraction of our electricity source is from thermal plants and the rest (1 - β) is from renewables then the total emissions for producing 1 unit of motive force in BEV = (1/η * β) because that is the faction that is produces by thermal plants. So even if we transition to (1 - η) renewables, we will break even against this very lopsided calculation. Let us now analyse with actual values of η. The electric motor is very efficient (unlike the ICE) and it is not unfair to believe that it gives an efficiency of 0.9 (i.e. 1 unit of stored electricity = 0.9 unit of motive energy). I think (not sure of this point) it can also be assumed that the charging system has an efficacy of 0.9. So an overall efficiency of 0.9 * 0.9 = 0.8. Therefore we can assume η = 0.8 which I think is realistic. So if we even transition to 0.2 fraction renewables, we would be doing good. Now let us discuss the hybrid scenario. As mentioned if 100% of electricity is through coal then ICEs look better than BEV but this is not correct because ICEs have notorious efficiency when not run under the right RPM range. A hybrid can salvage the situation and thus give better mileage by using two strategy: 1. It can charge the battery and then use it for driving the car. This means it can keep the ICE running at the best RPM. 2. It can use regen braking. But then hybrids are just like BEVs + ICE charging and regen braking is also available to the BEV. So for me hybrids are like BEV + 100% thermal power generation. It can never catch up with BEVs. There is no point in investing in hybrid (may be it made sense in the early Prius time) form the emission point of view. Can hybrid technology improve ?If we look at the hybrid technology as a whole it is ultimately a heat engine and the best efficiency that an engine can achieve is limited by the efficiency of the Carnot cycle (about 0.4 would be the best case scenario). So there are theoretical limits to what we can achieve from a heat engine based solution. This is also the reason why Hydrogen based ICE is a really really bad idea not even worth prototyping. | |
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24th December 2023, 11:56 | #87 | |
Distinguished - BHPian | Re: The future of "Strong Hybrids" in India Hybrid vehicles have overtaken pure-play electric cars in India. Quote:
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24th December 2023, 15:09 | #88 | |
BHPian | Re: The future of "Strong Hybrids" in India Quote:
Since jap trio sell non hybrid/SHVS models of same cars, it’s downright dishonest to count them as same. Brownie points for SHVS don’t count at a point when Maruti have gotten themselves tax notice for embezzlement of hybrid subsidies on SHVS TBHP discussion thread on the same (Maruti gets notice for the second time for 'dubious' hybrid tech (SHVS)) Is the author using sources which includes these start stop systems? Because then even splendor has start stop nowadays. And that would put majority of bike sales being hybrid as well | |
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