Designing equipment that will operate reliably at the conditions of this depth is arguably an order of magnitude harder than designing reliable systems that operate in orbit. The expense of lift out of earth's gravity well aside, the actual operating environment is space is clean, with low pressure differentials, lacking corrosion and bio-fouling.
An example of how difficult and complex this is can be readily observed in a 40 year long research grade power plant at NELHA near Kona, HI. The OTEC process uses warm surface seawater to evaporate a working fluid ( ammonia water mixture) using the vapor to drive an electric turbine, and then uses cold deep seawater from 2200ft (~671m) to drive the condenser loop and recirculate the working fluid. The significant difficulties are the massive heat exchangers required to make it work and all of the seawater facing systems face continual bio-fouling and corrosion problems.
They achieve a minimal efficiency and struggle to compete on cost with solar and wind. This is the state of the technology, when mechanical operations are just above sea level and the only real problems at depth are pipeline collapse due to over-accelerated flow and the aforementioned bio-fouling.
Moving those operations to a greater depth significantly changes the pressure. OTEC's pipe only has to deal with 2200 feet / 66.7 atmospheres (~980ppsi) while the wiring and enclosures of the 'lava thermal' rig only survived a few minutes of operation at 5000 feet / 151.5 atmospheres (~2227ppsi). It is illogical to expect for any durable, low cost, renewable power to be reliably operated under those conditions.
This also risks destabilizing poorly understood ecosystems with organisms whose lifespans typically exceed the span of time we have been studying them.
Where these activities occur in international waters the UN International Seafloor Authority requires multi-year environmental baseline studies. Prior to any non-research installation, requirements include biodiversity monitoring, chemical outputs and impacts. before any structural installations are authorized. Contractors are required to continually map biodiversity (microbes, unique gastropods, and specialized crabs) and to monitor chemical outputs in order to avoid permanently impacting the ecosystem's natural dynamics.
So, moving into 'Exclusive Economic Zone' water of a kingdom without rigorous international oversight is an indicator of how this company views the potential regulatory market.
The image of 'saving Tonga from diesel' is a nice greenwash, but if this was economically motivated and truly viable, then locations much closer to megawatt scale underserved growing markets with investment potential and scalar consumer demand, such as the Azores, New Zealand, or Izu Japan would be where this happens first.
So, nice toy research and fancy press publicity with the opportunity to get "It works" headlines and unlock the next Series A tranche is all I can see from here. Hard pass, full stop.
An example of how difficult and complex this is can be readily observed in a 40 year long research grade power plant at NELHA near Kona, HI. The OTEC process uses warm surface seawater to evaporate a working fluid ( ammonia water mixture) using the vapor to drive an electric turbine, and then uses cold deep seawater from 2200ft (~671m) to drive the condenser loop and recirculate the working fluid. The significant difficulties are the massive heat exchangers required to make it work and all of the seawater facing systems face continual bio-fouling and corrosion problems.
They achieve a minimal efficiency and struggle to compete on cost with solar and wind. This is the state of the technology, when mechanical operations are just above sea level and the only real problems at depth are pipeline collapse due to over-accelerated flow and the aforementioned bio-fouling.
Moving those operations to a greater depth significantly changes the pressure. OTEC's pipe only has to deal with 2200 feet / 66.7 atmospheres (~980ppsi) while the wiring and enclosures of the 'lava thermal' rig only survived a few minutes of operation at 5000 feet / 151.5 atmospheres (~2227ppsi). It is illogical to expect for any durable, low cost, renewable power to be reliably operated under those conditions.
This also risks destabilizing poorly understood ecosystems with organisms whose lifespans typically exceed the span of time we have been studying them.
Where these activities occur in international waters the UN International Seafloor Authority requires multi-year environmental baseline studies. Prior to any non-research installation, requirements include biodiversity monitoring, chemical outputs and impacts. before any structural installations are authorized. Contractors are required to continually map biodiversity (microbes, unique gastropods, and specialized crabs) and to monitor chemical outputs in order to avoid permanently impacting the ecosystem's natural dynamics.
So, moving into 'Exclusive Economic Zone' water of a kingdom without rigorous international oversight is an indicator of how this company views the potential regulatory market.
The image of 'saving Tonga from diesel' is a nice greenwash, but if this was economically motivated and truly viable, then locations much closer to megawatt scale underserved growing markets with investment potential and scalar consumer demand, such as the Azores, New Zealand, or Izu Japan would be where this happens first.
So, nice toy research and fancy press publicity with the opportunity to get "It works" headlines and unlock the next Series A tranche is all I can see from here. Hard pass, full stop.