The Icarus Portent
- Nov 12, 2021 2:38 pm GMT
Richard E. Smalley, 1996 Nobel Prize in Chemistry, in a series of lectures given in 2005 shortly before his passing from leukemia, found that the consensus of his audiences was energy is the most critical problem mankind will face this century and that it is the solution to its next nine greatest challenges. “To give all 10 billion people on the planet the level of energy prosperity we in the developed world are used to, a couple of kilowatt-hours per person, we would need to generate 60 terawatts around the planet—the equivalent of 900 million barrels of oil per day”, he said.
Unfortunately, the goal of generating 60 TW of power runs up against the thermodynamic limit identified by Physicist Tom Murphy in his blog post Galactic-Scale Energy, whereby the historical U.S. growth rate of 2.3% for global power since 1650 leads to a requirement for as much power as the sun will be generating in less than 1000 years.
Engineers equate thermal efficiency with capital efficiency, which is why fusion, which requires temperatures of about 100 million degrees Kelvin, is considered energy’s holy grail. But the waste heat of nuclear power and fission, if and when it comes commercially available, is higher than coal or other fossil fuel fired plants.
Waste heat can be used to heat homes and industry during the winter, but summer heat waves in 2003, 2006, 2015, and 2018 forced shutdowns or curtailment of the output of some nuclear plants and the problem of waste heat from fission or fusion, to say nothing of other thermal plants, will grow exponentially and as assuredly as does the COVID virus.
Waste heat from the thermal processes that produce energy, and the low thermodynamic efficiency of these processes is unsustainable.
Icarus defied the laws of both nature and man, including his father, and rose higher and higher to look down, like a god, on those below with fatal consequences. And in many respect we too will be burned producing energy from fission and fusion. And instead, we should be producing our energy as remotely as possible from the Sun that brought about Icarus’ downfall.
In their paper Increasing ocean stratification over the past half-century two of the planet’s top climate scientists, Michael Mann and Kevin Trenberth point out that increasing ocean stratification inhibits the vertical mixing of heat, carbon, dissolved oxygen, and nutrients. With implications for tropical storm formation and strength, a decline in ocean oxygen concentration, reduced nutrient flux and alteration of marine productivity and biodiversity. All of which are mitigated by reducing ocean stratification by converting a portion of the surface heat to work and relocating the bulk of the heat into deep water from where it returns and can be recycled to produce more work.
The conventional wisdom is the low thermal efficiency of Thermodynamic Geoengineering (TG) and high volumes of seawater that must pass through the large heat exchangers would render the capital cost per MW of power capacity too high for economic feasibility.
A TG system is an arrangement, in order of cost, of a platform and hull, heat exchangers, turbines, electrolyzers (if hydrogen is to be produced), pumps, a heat pipe, and an interface between the platform, the pipe and the condensers and/or the electrolyzers situated in deep water.
The paper Preliminary design of a 100 MW-net ocean thermal energy conversion (OTEC) power plant study case: Mentawai island, Indonesia estimates heat exchangers account for about 21% of the total cost of a system like TG and the next biggest cost is the turbine.
The physicist James Lau, in his 2016 MIT Climate CoLab presentation Cost effective OTEC (ocean thermal energy conversion) electrical power plant calculated the total mass of the heat exchangers for a 50 MW plant at 1700 metric tonnes, which equates to 34,000 tonnes for 1 GW.
At USD $5000/tonne for marine grade aluminum this totals $170,000,000 and labor typically doubles the cost of materials in marine construction so, the heat exchangers would cost $340,000,000.
But the heat exchangers for the TG plant of the same capacity are both evaporators and condensers so the cost of each function would be $170 million each. Cheaper than the Chinese coal fired plant’s cooling system.
The following DOE schematic shows the relationship between a 20-meter Steam Turbine and a 1-meter supercritical CO2 turbine
Whose Brayton Cycle’s Economic and environmental benefits they itemize as:
- Broad applicability to variety of heat sources
- Higher plant efficiency
- Reduced fuel consumption and emissions
- Low cooling water consumption
- Compact design/footprint lowers capital cost
Public policy benefits including:
- U.S. leadership in a transformative technology
- Enhanced U.S. global competitiveness
- Progress towards DOE Strategic Goals and President’s Climate Action Plan
All of which are enhanced and advanced by a TG system using a CO2 working fluid that becomes supercritical at the bottom of a 1000-meter-long column of the gas that gains about 5oC under the influence of gravity. And which is as remote from the wax melting influence of the Sun as is possible and is the best possible use of CO2.
Thirty-one thousand TG platforms flying the Stars and Stripes to produce 12 times the current US consumption of primary energy while mitigating every consequence of global warming, costing about a fifth the $.10/kWh US citizens for their electricity provide the jobs, taxes and political stability that every politician could ever ask for.
Daedalus challenged human limitations that had so far kept mortals separate from gods, until finally, he broke right through. With fission and fusion, we also are needlessly tempting the gods.
They have provided us with more energy than we can use, are not using the best of it, are instead glutinously consuming fossil fuels and playing with the fire of fission and soon of fusion.
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