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Thread: The Remarkable Progress of Renewable Energy

  1. Top | #1081
    Administrator lpetrich's Avatar
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    Many present-day sailboats and sailing ships are Motorsailer ones, with both an engine and sails. One uses the engine when one is becalmed or has wrong-way wind or is in a harbor.


    I'm very skeptical of how useful sails and Magnus-effect cylinders will be for very large ships. That is because of the square-cube law. To propel the ship, one needs an area proportional to the ship's mass M, and that gives a size of M^(1/2). Since the size of the ship L is related to its mass as M ~ L^3, the necessary sail size is thus roughly L^(3/2).

    Let's look at the Ever Given, a large container ship that became (in)famous for getting stuck in the Suez Canal. Its displacement (mass) is some 267,000 metric tons.

    Scaling up from the Cutty Sark, the Ever Given would require nearly 400 thousand square meters of sail. Let's see how many masts it has space for. The CS has a mast spacing of 16 meters, and scaling to the EG's length, 400 meters, means 24 masts. Each of CS's masts had about 1000 square meters of sail, and 24 masts of that mean 24,000 square meters total. Very inadequate.

    If all that sail was in a single square kite sail, that sail would be 600 m * 600 m. For comparison, let us consider EG's deck area. Estimating it as length * beam (60 m for the EG), I find 24,000 square meters, 1/17 of the necessary sail area. The CS has 700 m^2 of deck area, 1/4 of its sail area.


    One can do similar calculations for large cruise ships. Oasis-class cruise ship has the current largest ship, the Symphony of the Seas. These ships weigh in at about 100,000 metric tons, meaning that they would need less sail than large container ships like the Ever Given. They would need 143,000 square meters of sail, nearly (400 m)^2. That's a bit longer than these ships, typically 360 m.

    With 20 masts as 16 m / mast and 1000 m^3 of sail / mast, one gets 20,000 m^2, 1/7 the necessary area.


    So I don't see how sails or spinning cylinders will work for very large ships.

  2. Top | #1082
    Fair dinkum thinkum bilby's Avatar
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    Nuclear powered ships have a long and exemplary history of traversing the world's oceans without carbon emissions.

    Sails are lovely, if you live in 1850. And don't mind being becalmed.

  3. Top | #1083
    Administrator lpetrich's Avatar
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    Quote Originally Posted by bilby View Post
    Nuclear powered ships have a long and exemplary history of traversing the world's oceans without carbon emissions.
    Nuclear marine propulsion

    Ship nuclear reactors have had only very limited use, mainly in warships and icebreakers.

    Among warships, they have been most successful in large surface ships, and also submarines.

    Nimitz-class aircraft carriers weigh in at 100K MT Nimitz-class aircraft carrier and Gerald R. Ford-class aircraft carrier, and Kirov-class battlecruisers at 25K MT Kirov-class battlecruiser. The US had some nuclear-powered cruisers that weighed in at 9K to 16K MT, but eventually gave up on nuclear reactors for them. Nuclear-powered cruisers of the United States Navy

    Icebreakers are often away from port for long stretches as part of their work. Nuclear-powered icebreaker

    So nuclear reactors could work for large tankers, container ships, and cruise ships.

    Sails are lovely, if you live in 1850. And don't mind being becalmed.
    That's why many present-day sailing ships are motor-sailers, so they will have some backup.

  4. Top | #1084
    Fair dinkum thinkum bilby's Avatar
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    Everyone needs to be like France.



    Germany has had the full focus of this alleged "remarkable progress" for over a decade now. When is it going to get average emissions from electricity generation below 100gCO2eq/kWh?

    France has been doing it for thirty years. How much longer are we supposed to wait to see this "remarkable progress"?

  5. Top | #1085
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    I think the US Navy has moved away from nuclear power to so,e degree.

    A nuclear powered Russian ice breaker can not generate in warm water, overheats.

    The Russians do not have a god record with nuclear powered ships.

  6. Top | #1086
    Elder Contributor Keith&Co.'s Avatar
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    Quote Originally Posted by steve_bank View Post
    I think the US Navy has moved away from nuclear power to some degree.
    No.
    Our Aircraft Carriers need the power.
    Our submarines are much more with the sneak using nuclear power. We can stay down as long as we want. Our book says "the ocean provides a very effective screen." The other contractor, copying off our book, says it's 'a very efficient camouflage....' dumb way to put it.
    We're currently building lots of smaller vessels, where it would not be cost effective, or tactically sound, due to the extra mass required for shielding.
    But nuke power prototype is pumping people thru...

    A nuclear powered Russian ice breaker can not generate in warm water, overheats.
    that's just lazy design or poor decisions by project leads.
    "How efficient is heat exchanging system being? Two-foot-wide pipes? Four? "
    "Idiot! It is ICE BREAKER. It is being in Arctic water! Give it hose..."

  7. Top | #1087
    Administrator lpetrich's Avatar
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    List of largest ships by gross tonnage - be careful, "tonnage" is a measure of internal volume: Gross tonnage

    Look for "displacement" as a measure of a ship's mass, because it's the amount of water the ship pushes aside.

    The largest ships include supertankers, container ships, ore carriers, and cruise ships.

    Bloom Energy Unveils Electrolyzer to Supercharge the Path to Low-Cost, Net-Zero Hydrogen - Hydrogen Central
    Low-cost electrolysis has been difficult to achieve due to electricity costs, which can account for nearly 80 percent of the cost of hydrogen production through electrolysis. An opportunity has emerged, as renewable energy costs have declined precipitously over the last decade. Any reduction in electricity requirements makes hydrogen production more economical and scalable.

    Because it operates at high temperatures, the Bloom Electrolyzer requires less energy to break up water molecules and produce hydrogen. As a result, Bloom Energy’s electrolyzer consumes 15 percent less electricity than other electrolyzer technologies to make hydrogen when electricity is the sole input source.

    Unlike low-temperature PEM and alkaline electrolyzers that predominantly require electricity to make hydrogen, the Bloom Electrolyzer can leverage both electricity and heat to produce hydrogen. Bloom Energy’s high-temperature electrolyzer technology has the potential to use up to 45 percent less electricity when integrated with external heat sources than low-temperature PEM and alkaline electrolyzers.
    Where will it be used?
    First announced electrolyzer pilot: In November 2020, Bloom Energy announced it will supply its electrolyzers to an industrial complex in Changwon, Korea in collaboration with its Korean partner, SK EcoPlant. Supporting the Changwon RE100 initiative to create renewable ecosystems, the new project paves the way for South Korea to reach carbon neutrality by 2050. The units will ship to Changwon in mid-2022.
    More news at Hydrogen Central - News & Market Intelligence to stay ahead - it's "green" hydrogen that one should keep an eye on, hydrogen generated by electrolysis. The electricity can then be supplied by renewable-energy or nuclear-energy generation.

  8. Top | #1088
    Administrator lpetrich's Avatar
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    High-temperature solid-oxide electrolysis seems most practical on a large scale, because of the square-cube law. But industrial-scale elecrolysis is what we need, with megawatt and gigawatt equivalent output.

    Has the Carbontech Revolution Begun? - The New York Times - "Science can now pull carbon out of the air. For that to make a difference, though, businesses need to find profitable places to put it."

    This is not a new technology, but I'm sure that it will get more prominence in synfuel and chemical-feedstock technologies.
    Yet in their very composition, they were something new. This carpeting was a result of four years of intensive research and development, according to Interface. It incorporated a material made from recycled vinyl and processed vegetation; it was infused with a latex created from smokestack exhaust. It was topped and tufted with salvaged nylon. And it had been manufactured in the least environmentally demanding way possible. By Interface’s reckoning, the carpeting had a carbon footprint of negative 300 grams per square meter. “It’s not a magic material,” Erin Meezan, chief sustainability officer at Interface, told me recently. But the math does have a magical quality to it: In part because of how the carbon is sourced, carpeting a 10-feet-by-20-feet conference room, say, with these tiles can be seen as the equivalent of pulling roughly 12 pounds of carbon dioxide out of the atmosphere.
    "By some estimates, nearly 40 percent of global CO2 emissions comes from buildings and construction, a level that Meezan notes is unsustainable. “That’s why we’re doing this,” she said." -- Erin Meezan, chief sustainability officer at Interface

    Volker Sick, a professor of mechanical engineering at the University of Michigan who runs the school’s Global CO2 Initiative — its mission is to make carbon utilization a mainstream pursuit for U.S. industry — believes that carbontech offers a counterpoint to the prevailing thinking about CO2. It assigns a value to the gas and allows us to imagine it as not only a problem but also a resource. “Think back maybe 200 years, when this whole Industrial Revolution began, when we moved away from what was largely a circular economy to one that’s extractive,” Sick says. “We began to take from the earth, use and then dispose. So, I think we need to use things in a circular way again. And the way it works is not that we go back to before — build a log house and hunt and collect berries. There are too many of us around. We have to have industrial processes.” An essential aspect of a circular carbon economy, Sick notes, would involve using renewable, emissions-free energy to put CO2 into products. “That’s the real linchpin for this whole thing,” he says.
    Reversion to a preindustrial lifestyle -- the thought of it makes me gag. With renewable energy, it will be possible to sustain a full-scale industrial economy.

  9. Top | #1089
    Administrator lpetrich's Avatar
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    A carbontech future does not mean a high-tech makeover for everything we use. A growing movement to construct large commercial buildings out of timber, for instance — recently, a 280-foot-high wood office tower went up in Norway — follows a time-tested way to take CO2 from the atmosphere while avoiding the emissions generated by steelmaking and the production of concrete. Big wooden structures can embed more than a thousand metric tons of carbon that have been naturally absorbed by trees; just as crucially, they can sequester it from the air for many decades or perhaps centuries. Timber skyscrapers may prove more straightforward in their engineering than other carbontech products, though. For most of the things we buy and use, defossilization may depend on novel manufacturing techniques and innovations. It also requires pushing hard against historical convention — the circumvention of several hundred years of industrial evolution and dependencies on oil and coal.
    Noting As Concerns Over Climate Change Rise, More Developers Turn to Wood - The New York Times

    A biological version of synfuels technology:
    In Skokie, Ill., a company called LanzaTech has spent more than a decade designing bacteria that digest carbon gases and produce fuels like ethanol. The air in the company’s labs, where small so-called bioreactors are fed carbon monoxide and other gases in order to test different bacterial recipes, is pungent with fermentation. Jennifer Holmgren, LanzaTech’s chief executive, told me there that its immediate strategy is to place its technology next to industrial plants around the world, where it can capture carbon emissions at the source. “They have carbon, and they have energy for the organism,” Holmgren said. “I can pump that into a bioreactor and make ethanol.” Or, she said, she could employ other LanzaTech bacteria that would digest the same ingredients and yield a different product, like acetone for nail-polish remover or chemicals to make industrial foams or gels. In April, the company’s ethanol was used to produce a chemical ingredient for a Unilever laundry detergent sold in China, where LanzaTech now has two working plants.
    A nnon
    In Berkeley, Calif., I visited a company until recently known as Opus 12 but now called Twelve. It is refining a process, first discovered by Japanese scientists in the 1970s and further developed by Kendra Kuhl and Etosha Cave, two of the company’s founders, that uses metal catalysts to transform CO2 by bubbling it through water. This yields the building blocks for polymers, chemicals and fuels. The firm is seeking to become the world’s first fossil-fuel-free chemical company and to brand consumer items, like sneakers or sunglasses, with “Twelve,” much the way waterproof shoes or jackets carry a Gore-Tex badge. Last year, Twelve collaborated with Mercedes-Benz to demonstrate that a structural pillar for a car’s interior could be made through its CO2 utilization process. At first view, this wouldn’t seem to offer much of an environmental impact. But one of the firm’s founders, Nicholas Flanders, told me that the payoff for making car parts from recycled carbon could be substantial. “There are currently about 300 kilograms of polymers in every new car,” Flanders said, “and that’s going to be the case even for electric cars, too.”
    Opus 12 (company) - Carbon Transformation | Twelve

    The company is rather vague about its technology: "Our technology combines a new class of CO2-reducing catalysts with a novel device that splits CO2 with just water and renewable electricity as inputs."

    From Wikipedia, "Opus 12 utilizes polymer electrolyte membrane electrolysis, which splits apart water molecules into its component pieces (O2, electrons, and hydrogen ions) via the application of electricity. By adding a catalyst to the cathode, they are able to split up CO2 into CO and O2."

    Electrolysis of water - oxygen is made at the anode (positive electrode) and hydrogen at the cathode (negative electrode).

    From the description, it seems that Twelve has an electrolytic-cell technology which adds CO2 to the cathode to make small oxyhydrocarbons:

    Carbon dioxide + hydrogen:
    CO2 + H2 -> CO + H2O -- carbon monoxide
    CO + H2 -> HCOOH -- formic acid
    HCOOH + H2 -> CH2O + H2O -- formaldehyde
    CH2O + H2 -> CH3OH -- methanol
    CH3OH + H2 -> CH4 -- methane

    These OHC's can then be used as feedstocks for further chemical syntheses.

    This is much like direct synthesis of ammonia with electrolysis, like this:

    Hybrid electrolysis produces record-high ammonia yields
    noting
    Catalyst-free, highly selective synthesis of ammonia from nitrogen and water by a plasma electrolytic system | Science Advances

  10. Top | #1090
    Administrator lpetrich's Avatar
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    As a rule of thumb, it is always easier to reduce CO2 emissions by avoiding fossil-fuel burning rather than finding ways to bury (or use) the gas emissions after the fact.

    Nevertheless, carbontech products might help during what is sure to be a difficult energy transition. This is especially true in economic sectors that, for technological reasons, are hard to electrify, like jet planes, or for industrial processes that are hard to decarbonize, like making cement, steel or fertilizer.

    ...
    A thriving CO2 market might likewise spur demand, and drive down prices, for a fledgling technology known as direct air capture, which uses machines to remove CO2 straight from ambient air, rather than from factory smokestacks
    Direct air capture: The Tiny Swiss Company That Thinks It Can Help Stop Climate Change - The New York Times

    A nice thing about direct air capture is that it can be done wherever one wants to use the captured CO2. For instance, many plastic factories could have carbon-capture systems to supply their feedstocks.

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