Ocean Thermal Energy is an interesting technology. This post on The Energy Collective covers many of the details. However I think it unlikely that it will be pursued aggressively. The infrastructure that would need to be put in place would address most of the issues hindering 100 % adoption of solar and wind. But hey are already mature and so could be pursued with lower risk. The author also points out some additional environmental benefits to OTEC that are worth considering.
Some thoughts I have in response to the Ocean Thermal concept are as follows:
I think there are a few fundamental weaknesses to the overall concept in comparison to others, wind and solar in particular.
1) Once it is decided to build a hydrogen energy economy, intermittency and CF are no longer at issue and $ / MWhr becomes the primary evaluative figure of merit. With a hydrogen based energy economy, solar and wind are no longer constrained by intermittency since the energy is stored as hydrogen and easily dispatched in a highly responsive as needed basis.
2) Your cost figures appear to be based upon projections for OTEC at scale where solar and wind are based upon (almost) up to date numbers. Lazards puts utility scale solar at $72 / MWhr with projections only 3 years out at $60. Your proposal assumes both hydrogen and HVDC. Under the assumption of that infrastructure wind power can be land based and land based wind is currently at $37 / MWhr at favorable sites. PPAs are already beating this even when adjusted for PTC. The experience curve for wind is about $14% per cumulative doubling of deployment.