The result isn't exactly surprising: sure, this kind of “battery” has an enormous energy density but you need thousands of years to actually harvest the energy. Even assuming that no energy is converted to heat (rather unlikely), the output of a 1 kg battery will be below 3 watt.
That should be barely enough to power a smartphone. So the use cases mentioned in the articles are complete bullshit: even an electric bike would need at least 100 kg in battery. Electric cars? Just forget it…
This approach is only something for low-power scenarios where you cannot change the battery. And in fact, similar power sources have been used for space probes.
Never mind that the cost calculation is also bogus: nuclear waste will only be free as long as it is useless.
Ouch, typo in the image – 1.81 * 10^19, not 1.81 * 10^20. Also, it's 2.9 J/s, not 29. The end result is correct, I forgot to correct a mistake for intermediate steps. ☹️
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