1982 National Energy Laboratory Report on OTEC
The xerox scan of the old scientific report is dark and stained, with primitive printing and poor font and layout. But the columns and official investor report style belie the real science presented, without preamble or typical science summary.
The 1-mile long cold water pipe was deployed successfully in 1981, thanks to "Calm weather and much hard work." The pipe extends from the surface to 2,000 feet deep. It can pump 500 GPM of deep cold 9-10 C) water. The warm water pipe pumps 2,000 GPM of surface seawater (24-28C). When allowed to foul freely, it showed immediate increase in resistance to heat transfer, which biofouling countermeasures ameliorated.
The article presents a glowing portrait of research advancing at a fast pace, but is offset with somber photos of cloud-mottled skies and the inclusion of disturbing headings like "biofouling countermeasures". (Biofouling is when nimals get sucked in, and the system can become clogged by marine animals and plants. This could also be used positively to grow algae) Funding is flowing in from multiple sources like the cold and warm water siphoned from the rich offshore resources...
The project is strategically located with nearby availability of cold, deep ocean water and a warm ocean surface layer that is not subject to strong seasonal cooling. The warm water intake only 15 feet offshore may explain the much more rapid initiation of biofouling than previous experiments. A 300 foot extension has been designed and was to be installed in 1983. They plan to add 2 new 500 GPM pumps to replace the original coldwater pump that only pumped from Feb to June at 340 GPM before failing. They propose reconfiguring the OTEC-1 coldwater pipe to provide a capacity of 22,000 GPM, which would "satisfy their coldwater needs for the foreseeable future."
What ever became of all of this? The Makai Engineering website presents research from the 2010s that seems directly related to work done in the early 1980's, as if a 30 year gap is missing from the story, a lull in research perhaps while people's careers stagnated, limited by something mundane like the size or strength of piping availability or funding. Maybe the ocean was still there but the money stopped coming from Washington. Reagon took the solar panels off the white house, and the country went back to sleep for 30 years while a couple of billion people were born and the climate inched toward the 2 degree warming threshold.
This dark paper seems to hold secrets of the past, arcane mad science experimentation. All that is not said, like the sea creatures sucked up. So that today when ocean researchers wonder about the effects of cold water outfalls they have to design and bring their own small pipes and pumps.
2008 Reserach: Artifically Induced Upwelling
Used to understand how marine microbial ecosystems respond to large-scale perturbations. Diatoms will consume nitrogen, leaving some amount of phosphorus in the water, which will stimulate a second-stage bloom of nitrogen-fixing cyanobacteria. These blooms are often observed during summer months in open ocean waters when there are almost no nutrients at the surface and the winds generally are calm. What triggers the blooms and where are the nutrients coming from? We need to know.
Vast, seemingly barren regions comprise more than two-thirds of our oceans and nearly 40 percent of the entire Earth. Need to replace about 10 percent of the surface waters with upwelled water to fuel a bloom. Some scientists have looked at iron fertilization as a way to trigger biological growth in nutrient-poor areas of the ocean, but “everything responds to iron,” Letelier said. “You can’t control what grows.”
The researchers believe they can control plankton growth by determining which species respond to specific nutrients, and then adjusting the rate of nutrient feeding by the frequency and duration of water pumping.
Where the ocean is about 4,500 meters deep, the bottom layers of water have too much CO2 because of the decaying organisms that have sunk to the floor. Their studies have shown, however, that water at a depth of 300 to 700 meters has the proper ratio of nitrogen and phosphorus to trigger a two-stage phytoplankton bloom.
Currently, they are able to pump about 50 cubic meters of water per hour (=4 GPM) using wave energy. "If we want to generate a bloom in an area of one-square kilometer, we would need to replace about 10 percent of the surface waters with upwelled water, which would take about a month at the rate we pumped.”
The scientists used undersea gliders in their Hawaii study to monitor the water from the pump so they have an idea how widely and quickly it disperses, and how much of an impact it can have on surface waters.
Resources
List of OTEC plants around the world: https://en.wikipedia.org/wiki/Ocean_thermal_energy_conversion
1982 report about OTEC work at NEL Hawaii: https://nelha.hawaii.gov/wp-content/uploads/2014/01/NELH_AnnRpt_1982.pdf
Upwelling Press Release: https://today.oregonstate.edu/archives/2008/sep/scientists-test-%E2%80%9Cartificial-upwelling%E2%80%9D-learn-more-about-complex-ocean-ecosystem-be
More NEL reports: https://nelha.hawaii.gov/resources/library/
Makai Engineering: https://www.makai.com/ocean-thermal-energy-conversion/
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