Looking at the installation, I would advise the experimenter to immediately remove the hub motor from its semi-submerged state (thermal variation of the environment will pull in water through seals and bearings) and use a shaft of reasonable length to extract power.

Besides that, nice project.

Were electric ferries not a viable option?

For short routes, they are.

Here in Estonia, two ferries that sail to the island Saaremaa (route Kuivastu-Virtsu, about 4 nautical miles so really short) …they typically charge in port and travel on battery power. They have a combustion engine of course, and can use it when ice is thick (which lately hasn’t been the case, and this year is ridiculous, it’s January soon and there even no snow, not to speak of sea ice).

https://news.err.ee/1609198900/40-million-procurement-underway-for-larger-electric-vessel-to-serve-saaremaa

The power grid connection at the port was redesigned of course. Charging a ship requires more amps than an ordinary port might have access to.

But how long is the Arran sea route? Sources give me different numbers and on the map, I can’t figure out which port they actually prefer to sail from. Either way, it looks manageable on battery power.

Here is the Mauna Loa data line from 1958, matching the top figure.

https://upload.wikimedia.org/wikipedia/commons/c/c5/Mauna_Loa_CO2_monthly_mean_concentration.svg

The rest has been matched and synchronized to it using other sources. I’m not climate scientist, but I would guess the best sources are ice samples from polar regions where it accumulates from top and melts from bottom. CO2 dissolves in water and when snow falls and turns into permanent ice in such places, it captures a snapshot of that period’s atmospheric gas content, among that the CO2 level.

Geothermal makese sense on high latitudes (see Iceland for example) where heat is desirable even if electricity can’t be extracted.

Where you cannot drill deep enough (a Finnish company tried a 5 kilometer borehole and didn’t hit good enough heat) - artificial geothermal (thermal storage in large underground caverns) still makes sense, but not for electricity production. Just storing heat extracted from the environment during summer.

If drilling should get cheaper (e.g. those MIT guys declaring that they have a practical and reliable maser drilling rig), accessing good enough heat may be possible in places where it’s not worthwhile currently.

In some locations, production of geothermal energy can be combined with extracting dissolved chemicals - e.g. some borehole may produce a lot of dissolved lithium salts. No point in letting lithium back underground, better to put it aside.

It looks neat and might help in emergencies or special conditions, but if one takes a look at the wattage, sadly… 50 kW is very limited power. Probably not good for widespread use.

The helium-filled S500 blimp ascended to 500 meters above ground in the city of Jingmen, generating power at a rate of over 50 kW, according to Beijing SAWES Energy Technology Co Ltd, one of the developers of the system.

Wow, I didn’t know that seagrass has pollen, seeds and all the stuff needed for plants to sexually reproduce on land.

It might be extremely handy for the conservation effort, because you don’t need genetic engineering to spread useful traits then.

I hope they succeed. :)