“Scientists have long suspected that extra ocean heat uptake has slowed the rise of global average temperatures,"
Just as climate change is anthropogenic, ocean heat uptake can be induced by human enterprise, using heat pipes that utilize the phase changes of a working fluids to move trapped surface heat into the abyss in accordance with the 2nd law of thermodynamics that dictates also that such movements, through a heat engine, produce work. Researchers from the University of Hawaii have estimated the oceans have the potential to produce 14 terawatts of energy with ocean thermal energy conversion and due to the low thermodynamic efficiency of the process approximately 20 times more heat is moved from the surface to the deep in that process therefore virtually all of the heat the oceans have been accumulating as a result of global warming – estimated by NOAA in 2010 to be about 330 terawatts/year – can safely be sequester or converted to useful energy.
Not only does this approach slow the rise of global average temperatures, it is demonstrably the cheapest way to produce carbon-free energy.
The following table from the MIT masters thesis of Shylesh Muralidharan shows the high capacity factor of OTEC as well as its competitive levelized capital cost with respect to other technologies. (Although not shown in this table the paper points to a study that shows a deep water condenser architecture - the design that moves heat the deepest - can bring down the installed capital cost of a 100 MW plant ship from 4000 $/kw to 2650 $/kw.)
The thesis also shows that doubling plant size leads to a cost/kW reduction of OTEC plants by approximately 22%.
Using CO2 as a working fluid for the deep water condenser design allows for plants of gigawatt capacity.
Extrapolating for a 1 GW plant of the deep water condenser design, it would cost $86*2650/4000*78/100*(1-(.22*(200/800))) or 42 $/MWh for the lowest levelized capital cost for all energy sources but for combined cycle natural gas and would be the cheapest of all renewables.
It is this capacity to scale to low cost combined with the environmental dividends inherent in the production of energy from this source that makes it transformational as well as vital to the sustainability of the planet.