>he last one was 750k years ago. I'm in the northern hemisphere. We have no winter. I

The magnetic north and south pole do not affect the seasons. The earths tilt affects seasons. This does not swap.

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And because it happens every 200k years on average and we are beyond that does not mean it will happen in the next 75 years. What about 100 years ago by the same argument?

No, it's possible to boil the water to make steam

It is impossible to recover nearly as much energy from that that steam as it would take to boil it.

It's not a 'today's technology' thing it's a law of thermodynamics thing.

Water is not a source of energy, it is a medium of energy transfer.

Every kg of water at boiling point being converted to steam takes say 2133 kJ of energy.

You cannot then power a generator with that steam and get more than 2133 kJ of energy out of it. Your actual efficiency of a steam generator is 10-40%

So now you have 2133 x 0.4 = 853 kJ of electric energy.

So you take 20% to the boiler and you have 170 kJ of energy. Which is not enough to boil a kg of water.

Even if you had an impossible 100% efficiency boiler, steam system, turbine and battery system you'd never be able to pull even 1 kJ out without decreasing your steam volume.

No, you cannot power a generator with steam then take part of that energy to make as much steam as powered the generator.

You require more energy to make the steam than you can recover from the steam max.

Cut out the electric generator and just imagine boiling water with steam to make steam.

You're trying to do that and get more steam out than went in plus enough to overcome the turbine and battery efficiency and have usable power left over for the ship