US schools can subscribe to an electric bus fleet at lower prices than diesel • Hacker News Board

Re: US schools can subscribe to an electric bus fleet at lower prices than diesel

#201

Post by rasz » Sat, Mar 19, 2022, 2:01 AM UTC

VBprogrammer wrote: post #169

fiftyfifty wrote: post #101

Earlier quoted context omitted.

Even in terms of primary cost, diesel buses are expensive to maintain. My FIL was a mechanic for the local school district for 15 years, so I got a little insight into that aspect of the district. Our medium sized school district, 4 big high schools and all the feeder schools for them, employs around 6 full time mechanics plus their manager with all the equipment and the facility to work on the buses year round plus…

> diesel buses breakdown regularly In comparison to what? Diesel engines in commercial vehicles are extremely reliable. It certainly could be possible for an electric bus to be more reliable, they certainly have less points of mechanical wear. However, there are a lot of power electronics going into charging their batteries and delivering the battery power to the motors.

Cummins diesels, Toyota diesels, Kubota diesels, Yanmar diesels Yes definitely.

US Detroit diesels? lol no.

Re: US schools can subscribe to an electric bus fleet at lower prices than diesel

#202

Post by olivermarks » Sat, Mar 19, 2022, 2:03 AM UTC

olivermarks wrote: post #152

lostlogin wrote: post #145

Earlier quoted context omitted.

Ever been near a car fire? They burn pretty well and you'll feel it from the other side of a multilane road. I've also seen buses burn. Is there a reason to think that more kids are going to burn in electric busses than ICE ones?

Ever been near an EV fire? They burn with the equivalent of a 220v welder across the whole battery skateboard, will literally melt aluminum wheels and body parts and require 20 tons of water to temporarily extinguish. There's a huge difference between an ICE vehicle fire, which is essentially rubber, upholstery and plastics burning sometime compounded by gasoline vapor and an EV thermal runaway trapped energy event.…

It's incredible to me that EV enthusiasts are such zealots they refuse to take into account the facts around practicality, pollution and fire risk, just choosing to downvote instead.

A demonstration of a gasoline vs battery fire https://youtu.be/tuVxwmnhqP4

Re: US schools can subscribe to an electric bus fleet at lower prices than diesel

#203

Post by skolsuper » Sat, Mar 19, 2022, 2:04 AM UTC

brg wrote: post #191

derriz wrote: post #189

Earlier quoted context omitted.

How is doing a calculation based on assuming electricity sourced 100% from coal or NG help develop an informed decision? US electricity is roughly 40% carbon free, 40% natural gas and 20% coal - wouldn’t it be more honest to use this mix in your calculation? And that’s ignoring particulates and NOx.

Coal is used to establish a lower bound.

And maybe as the type of generation used for the marginal difference in energy required. If your country generates 90% of its electricity from hydroelectric and 10% from coal, you might still use coal for the comparison because hydroelectric power would be slow to add and the extra electricity for EVs would have to provided by coal

Re: US schools can subscribe to an electric bus fleet at lower prices than diesel

#204

Post by PaulHoule » Sat, Mar 19, 2022, 2:05 AM UTC

lstodd wrote: post #125

sokoloff wrote: post #108

Earlier quoted context omitted.

https://www.youtube.com/watch?v=7nL10C7FSbE compares the flammability of several types of fuels. 2m08s for Jet-A. 3m50s for #2 diesel. 6m03s for heating oil. 7m30s for kerosene (all those are basically the same and surprising to most how not flammable they are in liquid form). 10m15s for avgas. 11m30s for auto gas.

That's some bullshit video. All you need is some tissue and a gas soldering iron or equivalent lighter. Lights up in under one second.

Back in the day we would make ‘firebowls’ with a metal bowl and burning various liquids, igniting it with a long lighter. We would burn everything from gasoline to corn oil that way.

Re: US schools can subscribe to an electric bus fleet at lower prices than diesel

#205

Post by me_me_mu_mu » Sat, Mar 19, 2022, 2:06 AM UTC

lucastheisen wrote: post #188

mike_d wrote: post #163

Earlier quoted context omitted.

I'm glad your parents were in an economic situation where you could live walking distance from school in a neighborhood safe enough to do so. Only 9% of students in the US live within a reasonable walking distance.

what is a reasonable walking distance? 9% seems like a surprisingly small number.

Just looked at CDC website it says fewer than 20%.

Suburbs have been the only place where I’ve seen lots of yellow busses because everything is so spread out. Idk where that dude got his numbers, go to any city in the USA and you'll see kids taking public transit to school aka walking.

https://www.cdc.gov/pcd/issues/2016/15_0573.htm#:~:text=Esti....

Re: US schools can subscribe to an electric bus fleet at lower prices than diesel

#206

Post by buggythebug » Sat, Mar 19, 2022, 2:24 AM UTC

Have met the owner. Stand up guy

Re: US schools can subscribe to an electric bus fleet at lower prices than diesel

#207

Post by bluGill » Sat, Mar 19, 2022, 2:26 AM UTC

VBprogrammer wrote: post #169

fiftyfifty wrote: post #101

Earlier quoted context omitted.

Even in terms of primary cost, diesel buses are expensive to maintain. My FIL was a mechanic for the local school district for 15 years, so I got a little insight into that aspect of the district. Our medium sized school district, 4 big high schools and all the feeder schools for them, employs around 6 full time mechanics plus their manager with all the equipment and the facility to work on the buses year round plus…

> diesel buses breakdown regularly In comparison to what? Diesel engines in commercial vehicles are extremely reliable. It certainly could be possible for an electric bus to be more reliable, they certainly have less points of mechanical wear. However, there are a lot of power electronics going into charging their batteries and delivering the battery power to the motors.

Most parts that break on a car are common to electric or engines. Suspension, brake fluid (the brakes might last longer but the fluid should be replaced every few years), tires, doors, seats.

Re: US schools can subscribe to an electric bus fleet at lower prices than diesel

#208

Post by bluGill » Sat, Mar 19, 2022, 2:28 AM UTC

asdff wrote: post #144

MengerSponge wrote: post #77

The secondary costs of running a diesel fleet are also huge! Diesel motors generate a substantial amount of fine particulate that is unhealthy for anybody, and particularly unhealthy for children. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC121970/ Even if an electric fleet is the same cost, changing over would save tons of money and alleviate tons of suffering. It's the right thing to do for any ethical reason you…

Do school districts still use diesel? CNG seems pretty popular these days.

For city buses. Schools are mostly diesel from what I've seen. You need special infrastructure to fill CNG, which limits trips.

Re: US schools can subscribe to an electric bus fleet at lower prices than diesel

#209

Post by BurningFrog » Sat, Mar 19, 2022, 2:51 AM UTC

mtgx wrote: post #130

MengerSponge wrote: post #77

The secondary costs of running a diesel fleet are also huge! Diesel motors generate a substantial amount of fine particulate that is unhealthy for anybody, and particularly unhealthy for children. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC121970/ Even if an electric fleet is the same cost, changing over would save tons of money and alleviate tons of suffering. It's the right thing to do for any ethical reason you…

> Diesel motors generate a substantial amount of fine particulate that is unhealthy for anybody, and particularly unhealthy for children. This is one of the biggest issues with US' private healthcare system. The U.S. government just doesn't feel that direct "cost" in the same way countries that have to pay to fix the health of their citizens do. This is why you see a lot of other countries put higher taxes on sugar,…

I really doubt this causation, for a few reasons.

1. Everyone gets sick and dies. Dying a bit earlier from diesel probably doesn't cost more than whatever you would have died from later.

2. These other countries also have government funded pension system. If people live longer that's an added expense! If you do the cynical math, government finances are best if people die of something cheap soon after they retire.

Re: US schools can subscribe to an electric bus fleet at lower prices than diesel

#210

Post by hedora » Sat, Mar 19, 2022, 3:01 AM UTC

bsdetector wrote: post #179

kemiller wrote: post #119

Earlier quoted context omitted.

Engineering Explained did the math: https://www.youtube.com/watch?v=6RhtiPefVzM Spoiler: Well-to-wheels, BEV cars are better than the best gas cars (top end prius) even if the source electricity is 100% coal. The best is still not driving, but it's a step in the right direction.

This video is actually a great example of how smart people can fool themselves. The sources he uses for breakeven time (DOE) assumes 24.3 mpg [1] for the average regular car, but people don't drive average cars they drive specific cars. If you take the DOE assumptions and approach this from the other end, CO2 pollution by mpg, then you find an ICE car getting approx 30 mpg or more is less polluting per mile driven th…

There are many, many assumptions to such calculations. Here's PG&E's best guess at g CO2 / kWh based on time of day/year in California (page 2):

https://ww2.arb.ca.gov/sites/default/files/classic/fuels/lcf...

If you only charge from noon to two in Q1, then use have zero marginal emissions per mile driven (this is the best case). If you only charge from 7-8pm you emit 142.06 gCO2e/MJ.

1 megajoule = 0.2777777778 kilowatt-hour

Converting gives us ~512 g CO2e per kWh.

Car efficiency is measured in miles per kWh. 4 miles per kWh is doable (some cars are better, some worse). So, that's 128g CO2e per mile.

50 miles per gallon would be great. A gallon of gas emits 20 lbs CO2, or 0.4lbs per mile, which is 181 grams per mile.

So, if you only charge at the worst possible time in California (basically forcing PG&E to use natural gas plants to charge your car), then a 50 mpg car is still 50% worse than a slightly larger EV.

In practice, you charge during off peak hours. At night, emissions are about half worst case. During the day, they're 10% of worst case.