mpweiherSeven countries now generate 100% of their electricity from renewable energy
https://www.the-independent.com/tech/renewable-energy-solar-nepal-bhutan-iceland-b2533699.html
Specifically Albania, Bhutan, Nepal, Paraguay, Iceland, Ethiopia and the Democratic Republic of Congo.
Not to downplay the positive steps that are being taken towards using renewable energy worldwide, but one must point out that all those countries except one are almost exclusively using hydroelectric power, whose availability at such scale is a geographical lottery. As for Iceland, which also relies mostly on hydroelectric power but not in such great a proportion, it makes up for it thanks to easy and abundantly available geothermal power (which, though environmentally friendly, is arguably not technically renewable).
Geothermal is powered by fission Uranium and other heavy atoms deep in the Earth.
Solar is powered by fusion of Hydrogen in the Sun.
I'd use the same classification for both.
About 20% of this is residual heat from planetary accretion; the remainder is attributed to past and current radioactive decay of naturally occurring isotopes.
Most of the radiogenic heating in the Earth results from the decay of the daughter nuclei in the decay chains of uranium-238 and thorium-232, and potassium-40.
https://en.wikipedia.org/wiki/Radiogenic_heating
Potassium is more or less distributed in the body (especially in soft tissues) following intake of foods. A 70-kg man contains about 126 g of potassium (0.18%), most of that is located in muscles. The daily consumption of potassium is approximately 2.5 grams. Hence the concentration of potassium-40 is nearly stable in all persons at a level of about 55 Bq/kg (3850 Bq in total), which corresponds to the annual effective dose of 0.2 mSv.
https://www.nuclear-power.com/nuclear-engineering/radiation-...
No, not quite. Geothermal is powered by the accumulated heat stored in rocks from fission Uranium and other heavy atoms deep in the Earth (and other phenomena).
Geothermal hotspots do not reheat by fission or otherwise at the same speed that we extract their energy (if they did we'd be in trouble if we weren't extracting it!).
As I mentioned in another comment, build a Dyson sphere of solar panels around the Sun and it will last just as long. Build an all-Earth geothermal plant and the heat will be depleted.