Comment by ssmoot | Hacker News Reader

Comment by ssmoot | Hacker News Reader

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Can you produce a car without oil? Especially one containing a large battery pack?

Last guess I read put it around 350 barrels for a family sedan. I don't know how much of that is plastics, smelting, and other materials and how much is energy requirements though (and to be fair, I have no idea how close or not that number actually is to the true cost).

But given that it takes some amount of oil at least, doesn't that invalidate the argument against increasing efficiency? Because you could call building any sort of car, even a Model S, a loosing battle then.

Another thing to think of: if you don't have access to a wall plug, and want to provide an air conditioned environment in a vehicle, there's no alternative to oil AFAIK for anything smaller than an aircraft carrier. Diesel Generators are the only option for air conditioning on Sailing Yachts for example. Nothing else has enough energy density and you can't fit enough renewable (solar, wind, hydro) power to keep up with the amps air conditioning will pull out of it.

I know that particular example is very niche. It's just an interest of mine and I'm hopeful we'll see some sort of game changer in the next decade or two.

It is possible to use very little oil for the energy of manufacturing. Most manufacturing processes require electricity, and it's possible to general electricity without oil.

In fact, in the U.S. most electricity is generated from sources other than oil. Unfortunately, a lot of it comes from coal, which is worse than oil in almost every environmental aspect. But theoretically the electricity could all come from solar, wind, hydro, and nuclear.

Cars have of lot of plastic in them, and oil is the main feedstock for the manufacture of plastic. But that's not really bad in terms of global warming, as a lot of the carbon remains locked up in the plastic (as opposed to burning oil).

The final piece of the puzzle is transportation--cars are not built all in one place, the subassemblies might be manufactured all over, and then come together for final assembly via rail, boat, truck, even airplane. Each of those burns oil, so that's a big part of the oil footprint.

Specifically on electric cars and hybrids, mining, refining, and processing the elements in the batteries is pretty nasty business, as is the recycling / disposal of them once they're flat. There are tons of EVs and hybrids out there, and I see this becoming a huge e-waste problem in the near future. Note that Tesla is/was doing something to make the part after they're discarded less bad: https://www.teslamotors.com/blog/mythbusters-part-3-recyclin...

Right, so transportation is the big issue. Last I checked it was the big tankers involved in large volumes of international logistics that generate the most green house gasses. I am unaware of any technology, so-called "clean burning" oils, electric, or whatever, that solves this problem. In fact this is probably unsolvable if I think about it free trade is going to keep these boats polluting our air until we die. I'm starting to really believe that sometimes when I'm really drunk

Your last point is the tough part. True, actual manufacturing doesn't have to use lots of oil, but there's still a hefty supply chain network that does. Years ago I read an article showing how various car parts for an "American" car came from nearly two dozen countries, in almost every continent. Even if it's a container ship with 10,000,000 car parts (which is about as efficient as transportation can get) that's still an oil footprint being left behind. Even if they're Tesla parts.

Also, electric cars still run on fossil fuels since most of our energy production relies on coal / natural gas, though renewable energy is growing.

Major energy sources and percent share of total U.S. electricity generation in 2014:

Coal = 39% Natural gas = 27% Nuclear = 19% Hydropower = 6% Other renewables = 7% Biomass = 1.7% Geothermal = 0.4% Solar = 0.4% Wind = 4.4% Petroleum = 1% Other gases < 1%

( https://www.eia.gov/tools/faqs/faq.cfm?id=427&t=3 )

I think the argument (not sure how true it is because I don't know the facts) is that we can do more to (in the future) reduce carbon emissions from power plants and that we will get benefits of scale when we move burning fossil fuels to bigger plants as opposed to doing so in every car.

That's a horrible talking point that gets repeated by the people who have never done the math. Burning that same fuel in a modern efficient (80%+) turbine and then using the resulting electricity in an electric motor (also 88%+ efficient) is way way better than burning the fuel in a combustion engine, which is like 20-30% efficient at best.

Isn't electricity's transmission efficiency less than 50%?

More like 5-6%. A quick googling yielded: https://www.eia.gov/tools/faqs/faq.cfm?id=105&t=3

Charging your battery might be less efficient.

They did the whole math in "Sustainable energy without the hot air", and over all, even burning coal and using an electric car is better than burning petrol in a comparitively small engine.

Funny enough, a similar analysis applies for heating: burning natural gas to make electricity to drive a modern heat pump is more efficient than burning the gas directly for heat at the premises.

From a physical point of view, that's possible because you only need low grade heat for your home, but burning gas produces high grade heat.

Just to clarify, the efficiency is 100% minus 5-6, or ~95%. (I know that's what you meant, just in case anyone is confused.)

Thanks for the clarification, I read it backwards first and did a double take.

Transmission losses in the US are 5%.

https://www.eia.gov/tools/faqs/faq.cfm?id=105&t=3

actually gas to electric efficiency is max 50% (60% if co-generating heat)

source: www.eurelectric.org/Download/Download.aspx?DocumentID=13549

"When waste heat is captured from these systems for heating or industrial purposes, the overall energy cycle efficiency could approach 80 percent."

http://energy.gov/fe/how-gas-turbine-power-plants-work

The trouble is that you're comparing apples and oranges, or rather efficiency of electricity generation with efficiency of heat generation. Remember that thanks to heat pumps, electric heating can often have greater than 100% efficiency, so waste heat is less useful than the same amount of electrical energy even for heating.

I think you don't understand what co-generating heat is. It's a part of generating electricity. You use that heat to heat up the next batch of water, so you end up spending less fuel turning it into steam.

https://en.wikipedia.org/wiki/Cogeneration

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