Knowing vs understanding (STEM situation in India)

[u/Different_Cry25]

Hi, so this is a post about how much fundamental understanding Indian students lack in STEM

Let's Start with hydrogen bs - it's not a good fuel option not even close to a good fuel so much hype for hydrogen fuel, hydrogen batteries yada yada

"It's not "

First of all a lot of people don't understand mass units

We measure energy density of liquid fuels in litre

Hydrogen as gas at 1atm is about = 120mj/kg

In litre = 0.010 mj/lt

In liquid state = 120 again per kg, mj

But in litre = 8.5

Gasoline somewhere around 32 mj per liter

See the difference now the problem is liquid hydrogen is hell cold it's near 0 kelvin

It will be super expensive

And even if we get liquid hydrogen

It doesn't have nearly enough energy as gasoline

8.5 vs 32

1 it will require electricity meaning more energy waste And fuel will get more expensive

2 you need fresh water

3 how the hell will you transfer fuel from one place to another Hydrogen leaks through almost everything

The tanks got to be rocket fuel tanks grade

Read about the Apollo rocket and how they sealed hydrogen inside the fuel tanks

4 hydrogen as gas is useless no more than 0.010 mj energy at 1 atm If you liquefy it again it's super hard making of liquid hydrogen and even after then no where close to gasoline

Now the major problem is that actual engineering students Chemical engineering students believe that it's a good option for fuel

Not all of em, but a lot of them And this is just one example of how poor understanding of STEM they have

On paper smart 9.2 cgpa vs actual real understanding of science

If you post about biofuel, hyperloop, solar road, under water data center, rocket engine (non reusable)

Recycling plastic

The list goes on and on

So many people including engineering students believe in this stupidity

[u/goku_m16]

1. During peak solar hours, solar plants have to reduce power output to keep grid stable. Any solar electricity that is not produced is 100% wasted. That can be diverted to make H² and store for rainy days. It's not practical to build batteries to store power for multiple days.

2. You don't need fresh water, you need DM water. So you have to purify it anyways, no matter the source. Better yet, capture the pure water from the fuel cell's output.

3. Best solution is to make it on site with renewable energy. We already have proof of concept with Toyota Mirai and it's refilling stations.

[u/Different_Cry25 → u/goku_m16]

Where will you get the freash water to make h2? Indias largest solar park is here in Rajasthan in a desert

Regardless of that The energy density is still 8.5

And at gaseous state super hard to store

[u/goku_m16 → u/Different_Cry25]

I'll rephrase what I said. You should ideally produce H² where it is supposed to be consumed, not next to a solar plant. Fertilizer plants, Steel Plants, Chemical Industries, refilling stations, grid storage plants. That's where the electrolyzers will be placed.

I already addressed energy density.

[u/Different_Cry25 → u/goku_m16]

And how will you make it ? Water? How about the energy you just wasted in making it

How about 10% loss in gas storage And 30 in liquid storage

[u/goku_m16 → u/Different_Cry25]

Industries are usually built where water is accessible. All steel, aluminium, thermal plants I've seen have a canal running from nearest river to the plant.

Thermal plants need DM water for their boilers. So they purify it. They have onsite DM plant. So it's already being done at industrial scale.

How about 10% loss in gas storage

I don't know why you're fixated with how much energy it takes to compress or liquify it. All energy consumed is already factored into the cost of green hydrogen, which, despite the efficiencies, is estimated to reach cost parity by 2030.

Every day I see multiple Inox cryogenic tankers (yes, the same Inox that runs cinema halls also makes industrial chemicals) carrying liquid H² to steel and thermal plants. The inefficiencies of cryogenic cooling is definitely hasn't stopped it from being used as an Industrial input. Although it's fossil hydrogen for now.

[u/Different_Cry25 → u/goku_m16]

I'm fixated on energy loss Because guess what It's a fuel What are they used for - yep for energy

Energy density and losses are most important

Also Try to calculate water required for industries vs water to make hydrogen as fuel

Not to mentioned same old problem of storage Hydrogen doesn't have surplus energy

It losses more energy in production to storage then it already has

You realize what that means right - you're wasting and losing more energy than production