Thank you for this Jeff. OTEC operates pretty much the same as Enbridge's Turboexpander. Excpept that ocean surface heat that is and will be doing the damage of global waming boils a working to fluid to produce the vapor that drives the turbine that produces electricity. This in turn electrolyzes water to produce H2 rather than getting it from natural gas where you get 1 CO2 molecule for every 4 H2. When you electrolyze water at a depth of 1000 meters, hydrogen arrives at the surface at a pressure of 100 atmospheres or about one third the 350 needed to compress the gas sufficiently to get a reasonable volume for most transportation applications. In moving the surface heat to deep water to produce the necessary power you starve tropical storms of their power and limit sea level rise. You also rein in atmospheric warming as witnessed by the hiatus of the past 15 years that has been brought about by mixing due to stronger than normal trade winds. When you produce hydrogen with OTEC you start with water and end with water, whereas with natural gas you start with a greenhouse gas and endup with another. Other than that Enbridge gets the benefit of hydrogen pretty much right on in their video.
It would be nice if they could be convinced to produce it in the most environmental beneficial way possible. And of course if they want to market energy to the Asian market, hydrogen can be produced on their doorstep.
Severin Borenstein points out in his article It’s Time to Refocus California's Climate Strategy, "The primary goal of California climate policy should be to invent and develop the technologies that can replace fossil fuels, allowing the poorer nations of the world – where most of the world’s population lives – to achieve low-carbon economic growth. If we can do that, we can avert the fundamental risk of climate change. If we don’t do that, reducing California’s carbon footprint won’t matter."
I think OTEC presents greater opportunities for California than your examples.