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Comment by mg | Hacker News Reader

This reminds me of the discussions some years ago whether one should invest in an SSD when buying a new laptop or stay with a spinning disk.

Nowadays, barely any new laptops are released without an SSD.

When it comes to electric versus petrol, I often think about the fact that the sun sends more energy to earth in an hour than all of mankind uses in a year.

I guess that in theory, all that energy could be captured with parts that need no service at all and do not degrade? Of course, we will not practically reach that efficiency. But we will continue to improve towards this limit. When I think of what it takes to dig for oil and all the steps needed to turn that into a moving car, the way we are heading seems clear.

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SSD only became mainstream after 3D TLC was invented, bringing costs down. Planar MLC was okay but was still somewhat expensive, tech enthusiast thingy.

So for petrol, sure, if we just had as energy dense batterry as fossile fuels.

No, current tech is not there yet. The big range vechiles are stupidly expensive, and the inexpensive ones are daily commuters only, mostly. They also charge slowly. Most people don't own multiple vechiles for different purposes, the primary purpose of personal vechile is utility and mobility. People get stuck in their personal bubbles and forget that for most people cars are actually a tool.

For batteries, big range drops in winter, no solution for people living in apartments with no capability to "charge at home", high electricity prices at not "charge at home" places.

Please don't bring in hydrogen here :) it's Toyota's pipe dream, not reallity. We really need 3D NAND flash of SSD moment for batteries, that would revolutionize a lot of industries, not just personal vechiles.

Even with SSDs, it's only laptops specifically that made a wholesale shift to SSDs. Why? Because laptops get jostled around, and SSDs are impervious to rough handling.

Over in the land of desktops, servers, and other stationary computing installations, HDDs are still superior if you do not explicitly require (or want) the fast access speeds and latencies of SSDs which are oftentimes overkill for most use cases.

SSDs also had an inflection point when floods hit Thailand knocking out plants where a good chunk of spinning rust HD motors were made. Spinning drives exploded in price pushing people to accept a smaller but faster SSD and deal with it.

> We observed the first uptick at the end of October, reaching its peak in the first week of November with price increases in the 80-190% range for desktop drives and 80-150% for mobile units. Although we're beginning to see price reductions across the board, on average drives are still about 60-90% more expensive than they were before the flooding.

https://www.techspot.com/guides/494-hard-drive-pricewatch-th...

It doesn't help that greed means that even though electricity is everywhere and is the most fungible form of energy, we're putting arbitrary limitations to buying it, way more than gas/petrol despite the latter actually requiring significantly more infrastructure.

With a gas car I am confident I can drive up to any gas station and get fuel with my credit card. I'm not confident I can do the same with electric cars - even if I do find a charge point, I'm worried it's not going to let me pay & charge until I download a stupid app, provide a ton of data to hundreds of data brokers and still remain stranded when all this mess of moving parts breaks down somewhere and doesn't let me proceed.

The amount of digging and extremely polluting chemical processing required to manufacture an electric car is massive. After that, you need to power it, which means expanding the electric grid and power facilities (which means even more destruction of environment). And, at the end of the day, the power used to charge these cars is still more likely than not gonna come from fossil fuels.

I feel we’re pushing the electric cars too early on people. The grid is far from being green yet, and the batteries are not that great in terms of efficiency, safety (spontaneous combustion anyone?) and the toll on natural environment. And yet governments are not doing any deeper analysis, and are just ramming those things down people’s throats.

Does that mean mankind has to grow its energy usage 24 times to match the energy absorbed by the Earth?

More like 24 * 365 times.

Assuming the quoted figures are correct ...

it'd be more like 24 x 365 (and a bit) to match the per hour input to per year usage.

24 * 365 times

Thinking about energy usage always puzzles me.

I'm not even sure if driving a car from one city to another really uses energy.

For example, let's look at it this way: The energy from the sun is heating earth. When we use some of it to drive a solar-powered electric car from one city to another, does that lower the temperature of planet earth? I would think it does not. So why did we get the energy to drive the car for free? I would think that the surprising answer is: Moving something from A to B does not use energy at all. But I'm not sure.

Um.

There’s this little detail of efficiency. Much less than 100% of energy used for acceleration and overcoming friction is actually spent on those. Most ends up heating up random stuff like engines, brakes, roads and tires.

I’m confused why do you think anything could be moved from A to B for free? You have to charge the car, or fuel it up, after all?

It can be more instructive to consider entropy rather than energy usage.

The energy coming from the sun has low entropy and that makes it easy to capture and convert into electricity/plants etc. When you use some of that energy to move a car, you're converting the useful low entropy of the electricity/fuel into high entropy "waste" heat that can no longer be easily captured and used.

Isn't that "waste" heat still warming the planet? Isn't turning a cold planet into a warm planet a good thing and therefore the "waste" heat is still "used" for something useful?

No not really. There's a known problem with the atmosphere starting to retain too much heat (as opposed to radiating it out into space) due to the amount of CO2 (and other gasses) that people are dumping into the atmosphere. Far from being useful, it's likely to collapse our current civilisation.

Global warming is not caused by waste heat. It is not caused by energy use per-se (indeed, energy is never used, but always conserved). It is caused by a shift in the equilibrium temperature, at which the amount of energy radiated by the Earth equals the amount of incident sunlight. The surface of the Earth gets hotter to radiate the same amount of energy (picture an incandescent light bulb), because greenhouse gasses form an insulative barrier. Burning fossil fuels releases CO2, which increases the amount of insulation. It does also release heat, but that hardly matters; if that were all it did, the heat would ultimately be radiated into space as infrared. The problem isn't "energy use". Nuclear, for example, wouldn't appreciably increase planetary temperatures (I say this not to be a booster for nuclear power, but just because it adds heat that does not come from the sun without creating greenhouse gasses, so it works as an example.). The problem is greenhouse gasses.

Toy ODE model:

dx/dt = -k x + a + b.

Here, x is temperature, a is solar heat input, and b is heat input from human sources. I'm dropping some coefficients that would make the units strictly work. We have a >>> b. The coefficient k says how easily the Earth radiates heat. Adding greenhouse gasses makes k closer to zero.

At equilibrium, dx/dt = 0. Solving,

x = (a + b) / k ~= a / k

Again, b is tiny relative to a. So almost the only thing that matters is k.

Venus would be a pretty unpleasant place to live for many reasons, one of which is how balmy it is due to its atmosphere being quite effective at trapping heat from the sun.

We actually spend quite a bit of energy doing the work of moving heat from colder to hotter areas because humans don't like to be too hot.

Energy is, in fact, conserved, as you point out. When we colloqually talk about 'using energy', we are generally referring to converting low-entropy energy (like electricity, sunlight, chemical energy from fuel) into high-entropy energy (ultimately dissipated as heat in the air), hopefully doing useful work along the way. High-entropy energy cannot generally be harnessed to do useful work anywhere nearly as easily as low-entropy energy.

Let me try to wrap my head around this:

Say there is a completely static, black planet. All sunlight that hits it is turned into heat which is dissipated into the universe. Nothing moves on that planet.

The static black inhabitants of the planet are very thankful for the sun that it makes their planet nicely warm and cozy.

Now one day, one of them is allowed to travel to planet earth and read Hacker News. He reads this very thread.

Are you telling him that they are wasting half of the benefits they could get from the sun? They could have a nice warm planet AND drive around in electric cars all day? For free? Everything else would stay the same?

If so, doesn't that make driving a car "free" in that it not even increased the amount of entropy? Since the sunlight would have turned into high entropy heat anyhow?

I'm not sure if you're asking actual or rhetorical questions. Assuming they're genuine:

> Are you telling him that they are wasting half of the benefits they could get from the sun? They could have a nice warm planet AND drive around in electric cars all day? For free? Everything else would stay the same?

Strictly speaking, yeah, they're not using all the energy they could. "Wasting" seems like a weird way to say it though, because it feels like that implies they want to be doing something with it.

> If so, doesn't that make driving a car "free" in that it not even increased the amount of entropy? Since the sunlight would have turned into high entropy heat anyhow?

On a long enough timescale nothing matters from the point of view of entropy. Net entropy will always increase. This is a pretty useless observation if you're trying to make a value judgement on the much smaller timescale of a civilization or the much smaller physical system of a planet, where having easily harnessable energy is important.

Yes, if you are replacing a process which basically just converts low entropy energy into high entropy heat directly with something that does more interesting along the way, the end result is basically the same from an entropy point of view. Generally we as a species are not limited by the entropy available at the moment, but by our ability to harness it and the consequences of doing so in terms of the balances of the systems that it flows through.

You're missing many many factors that are part of the total footprint of a vehicle: making & maintenance of the vehicle, of roads, infrastructure, maintenance buildings, energy, resources, parkings, ... all indirect environmental costs basically

Fuel being petrol or electric is only a small part of it

Other answers correctly talk about entropy. Here’s an analogy that might help with intuition.

A kilogram bar of solid gold is worth about $70K.

Take every atom of that gold and sprinkle them separately into the ocean. You haven’t used any gold: it’s all still there. The difference in value of the bar and the seawater containing the exact same gold is in the arrangement and availability of the gold, not its mere existence.

Same with energy stored in a battery vs stored in slightly warmer atmosphere.

I wasn't comparing energy in a battery to energy in the atmosphere.

I was comparing a car in city A with a car moved to city B. Both in warm atmosphere. You can heat the atmosphere AND move the car, without creating more entropy than by just heating the atmosphere. So it looks like moving the car does not create entropy / does not use energy.

With the gold, you cannot buy an apartment with it if you sprinkle it in the ocean. You have to decide: Buy an apartment OR sprinkle it in the ocean. You can't get the apartment AND an ocean with gold sprinkles. So you can't get the apartment for free.

No, about 100,000 times.

> what it takes to dig for oil and all the steps needed to turn that into a moving car

Indeed. Petrochemicals form a fundamental physical part of all cars. And everything else. I look forward to the innovations that need to replace them.

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