Biden administration adds exemptions into new climate rules for hydrogen energy

[nmmi]

24. 59% is losses in the power plant itself in converting the fuel's energy to electricity at the power plant and net of

station use of electricity.

From your link

It is estimated that of the 65% of primary energy lost, 59% of it is lost in the generation process. This includes:

Waste heat occurring due to inefficiencies in the process of converting primary energy to electricity. This makes up about 54% of the primary energy lost.
Electricity used internally by the power plant during operations. This makes up about 5% of the primary energy lost.

In the above, they are talking about fossil-fuel and nuclear thermal power plants that convert fuel energy (coal, oil, natgas, nuclear) to steam which spins a turbine-generator that produces the electricity

Transmission and distribution grid
Another 5 to 7% of the original primary energy is lost during the delivery of electricity through the T&D system. The energy becomes waste heat released in the air due to line losses and conversion losses in transformers and other line equipment.

To make H2,

one first needs electricity. If supplied from the grid, and if it comes from the above described fossil-fuel or nuclear thermal power plants, then one incurs that loss in primary energy (coal, oil, natgas, nuclear). And we have not yet made a mg of H2 yet.

Let's say that the hydrogen facility is at or very near the power plant so we don't have electric transmission losses described above as "Transmission and distribution grid".

So we've lost 59% of the fossil or nuclear fuel energy making electricity to feed the H2 plant. (The efficiency of the thermal power plant is 100% - 59% = 41%).

Now according to Miguelito, 50-55 kwh of that electricity goes into electrolysis that produces H2 containing 34 kwh of energy. (If we use the midpoint, that's an efficiency of 34/52.5 = 64.8%)

Then, the fuel cell converts 40-60% of that H2 energy into electricity, leaving only about 17 kwh out of the 50-55 kwh that went into the electrolyis.

If we use midpoints:

Efficiency = 41% * 64.8% * 50% = 13.3%.

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Case 2A: the ultimate power source is a solar farm or wind turbine, located near the hydrogen facility.

Leaving aside the amount of wind or sunlight that is not converted (which is kind of irrelevant, since if we didn't have the solar farm or wind turbine, it would all go to waste anyway. Yes, I know there are dollar cost and environmental costs in making solar and wind facilities).

Efficiency in converting the solar/wind facility's output electricity into H2 and then back into electricity is 64.8% * 50% = 32.4%

Case 2B. Same but we use batteries instead of hydrogen for storage. I think efficiency of converting input electricity to battery energy is about 90%. And its about 90% efficiency for converting battery energy into electricity. If that's true

Efficiency in converting the solar/wind facility's output electricity into battery energy and then back to electricity is 90% * 90% = 81%

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To me, the argument that makes me somewhat sour on H2 is that a battery system would be much more efficient than H2 (case 2B vs. 2A), as one person in the E&E group often posts and I haven't seen a response.

On the other hand, the environmental impact of making batteries is a lot higher, it seems to me (mining lithium for example), than to make H2 production facilities.

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Thanks much for your reply. I'm just trying to sort it all out

Edit in the above I had used 59% as the efficiency of the thermal power plant -- I corrected to 41%. 59% is lost, meaning 41% is left.