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Thread: The Remarkable Progress of Renewable Energy

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    Administrator lpetrich's Avatar
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    Why hydrogen for high temperatures?

    Oxyhydrogen - "The maximum temperature of about 2,800 °C (5,100 °F) is achieved with an exact stoichiometric mixture, about 700 °C (1,300 °F) hotter than a hydrogen flame in air."

    Its electric competition:
    • Electric arc furnace"Industrial electric arc furnace temperatures can reach 1,800 °C (3,272 °F), while laboratory units can exceed 3,000 °C (5,432 °F)."
    • Induction furnace - using electric induction from an oscillating magnetic field.
    • Joule heating - Ohmic heating, resistance heating
    • Dielectric heating - what a microwave oven uses
    • Electric heating - "Industrial heating processes can be broadly categorized as low-temperature (to about 400 °C or 752 °F), medium-temperature (between 400 and 1,150 °C or 752 and 2,102 °F), and high-temperature (beyond 1,150 °C or 2,102 °F). "


    The (Green) Hydrogen Economy is About to Take Off - The Energy Transition Magazine

    The article then gets into hydrogen for industrial processes, described in more detail in Decarbonizing Steel and Cement - The Energy Transition Magazine
    Steel is a family of iron alloys that can sometimes be very strong. The iron in it is made by refining iron ores, and those are usually oxides and hydroxides of iron. The most common process uses coke, baked coal that is mostly carbon.
    FeOx + (x/2)C -> Fe + (x/2)CO2

    That releases CO2, along with the burning of some of the coke to make the necessary heat. An alternative is syngas, made by reforming natural gas:
    CH4 + H2O -> CO + 3H2
    The hydrogen in it reacts with the iron oxide:
    FeOx + x(H2) -> Fe + x(H2O)

    With hydrogen from electrolysis, one can do the H2-FeOx reaction there also.
    In the snowy forests of Northern Sweden, near the Gulf of Bothnia, a plant is being built to explore one of the most promising routes to decarbonizing steel: hydrogen-based DRI. “From a technical point of view, hydrogen has been proven as very good agent for iron ore reduction in the laboratory for a long time,” states Martin Pei, chairman of the board of Hybrit Development AB, a joint venture of three companies to make fossil-free steel. “It is rather easy.”

  2. Top | #772
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    Then cement for making concrete.
    But if you think steel is hard to decarbonize, consider the process of making cement. “It is even worse,” states Koch Blank. “You have carbon in the molecule of your raw material.” He is referring to limestone (CaCO3), the most common raw material for making portland cement. This limestone is ground into small bits (clinker) before being heated in kilns to a very high temperature to produce calcium oxide (CaO), releasing CO2 in the process.

    The heat used for this process is an emissions problem on its own, but more than 60 percent of the annual emissions from cement production comes from the limestone itself. This also means that, like steel, methods to improve the efficiency of the cement-making process are limited in their CO2 reduction potential.
    Alternative materials can be used, but they are often more expensive and they have different characteristics.

    High temperatures are also necessary for making brick and glass.

    An alternative way of making high temperature is concentrated solar power, and there have been some experiments with that.

    For synfuels and plastics, one can do Fischer-Tropsch with electrolysis H2 and atmospheric CO2.

    Electrolysis hydrogen is still relatively expensive, but increased production of it will produce economies of scale, driving down its cost.

  3. Top | #773
    Administrator lpetrich's Avatar
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    Can Flying Be Made Carbon Neutral? - The Energy Transition Magazine
    It is a long way from Plymouth, England, to New York; 1500 nautical miles. This summer it took the Malizia II 15 days to make the voyage, a trip that many major airlines complete in less than seven hours. But that wasn’t the point for the 60-foot racing yacht’s world-famous activist passenger, Greta Thunberg. Instead, this was the most dramatic manifestation of her commitment to avoid flying due to the carbon footprint that it imposes.
    Aviation is responsible for some 3% - 9% of humanity's CO2 emissions, comparable to shipping.

    How to avoid emitting CO2? Batteries have low energy density and hydrogen is hard to store. So electric and hydrogen airplanes won't have very long range.
    In contrast to ground transportation, most of the action in aviation to date has centered not around electric drives, but around biofuels. This is a broad term for any substance that came from a living organism, with feedstocks that include everything from corn to used cooking oil to agricultural wastes and inedible animal fat.

    Perhaps the biggest advantage is that they can be made chemically almost identical to petroleum-based jet fuel, dropped in to replace conventional fuel, or mixed in to form a blend. This means little change to manufacturing or the operational practices of airlines.

    And they may be better fuels, as well. Biofuel distribution leader SkyNRG estimates that the fuel it supplies is slightly more energy dense, with 90 percent less particulate pollution and none of the sulfides (SOx) that are produced from burning kerosene jet fuel. Overall, SkyNRG advertises a 1.5–3.0 percent improvement in fuel efficiency over conventional fuels.
    Then the article gets into synthetic fuels or synfuels. These can be made with H2 from electrolysis and CO2 from the air. The chemistry is well-understood but the economics still aren't good. But some experiments have been done, like Audi's "blue crude".

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    Renewable Hydrogen News: Power-to-Gas Mania Hits Maine
    Maine’s emerging position in the US power-to-gas vanguard is the subject of a new article in The Portland Press Herald last Saturday, by staff writer Tux Turkel. Support local journalism and follow the link for all the details, but for those of you go the gist of it is location, location, location.

    Turkel explains:

    “The transmission lines connecting Maine’s far-flung renewable generators to the regional electric grid sometimes are too weak to carry all their power. When that happens, grid operators order generators to reduce output or even stop running, to prevent overloading and jeopardizing reliable service.”

    By “renewable generators” Turkel means wind farms and solar arrays along with hydropower, biomass, and agricultural gas. The state is already awash in various forms of renewable energy and it hasn’t even begun to tap into its offshore wind resources yet.

    In other words, there is a major renewable energy bottleneck in Maine.
    Hydrogen made remotely can be transmitted with existing natural-gas pipelines, thus continuing the use of that infrastructure.

    Hydrogen In, Fossil Fuel Out For Leading Steelmaker, Eventually
    Fossil fuels are slowly losing their grip on the transportation and power generation sectors, and the next domino to fall is the industrial sector. In the latest development, earlier this month the leading global steelmaker voestalpine announced the startup of the largest (so far) “green” hydrogen pilot plant in the world at its site in Linz, Austria.
    Hydrogen Revolution Comes To California Railways, Eventually
    Zero emission hydrogen-powered locomotives are edging onto the tracks in Europe and Asia, and now California is getting into the act. The Golden State has just called dibs on the the first ever hydrogen train in the US. Of course, a single fuel cell train won’t knock diesel off the tracks, but it can’t hurt, either. If all goes according to plan, the new train will help spark the next generation of low carbon mass transit and railway shipping alternatives on these shores.
    Then plans on using a hydrogen train on a commuter-rail line now under construction: San Bernardino - Redlands east of Los Angeles.

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    Quote Originally Posted by bilby View Post
    Anyone who claims that hydrogen is less explosive than gasoline has insufficient knowledge to be anything other than dangerous to themselves and others.

    Hydrogen is explosive in a very wide range of blend proportions in air; It's much more of an explosion hazard than gasoline (and gasoline is the wrong comparison in the context of trucks - diesel fuel is incredibly difficult to ignite by comparison with either gasoline or hydrogen).

    Hydrogen is a great vehicle fuel in the lab. It's bloody awful in the real world, which is why it's never been seriously adopted by anyone. It's hard to contain; leaks are hugely dangerous; it is hard to carry in worthwhile quantities without very heavy containers; And it's a nightmare in any kind of crash.

    Hydrogen is a very poor substitute for gasoline - if you are going to make fuel from 'spare' electricity, you're better off making alcohols or hydrocarbons. In fact, from an engineering perspective, octane [or octane + ethanol] (gasoline) is a great fuel; And nonane thruogh hexadecane (diesel) is even better from a safety perspective.

    The only problem with these fuels is that they are currently sourced from fossil reserves, rather than being synthesized from atmospheric carbon dioxide (and water).
    bilby, I fully concede these inadequacies of hydrogen as a vehicle fuel. I also agree that liquid synfuels are the way to go. But one has to start with making hydrogen, and that's why I think it significant that there is such a buzz around it.

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    Quote Originally Posted by bilby View Post

    Anyone who claims that hydrogen is less explosive than gasoline has insufficient knowledge to be anything other than dangerous to themselves and others.

    Hydrogen is explosive in a very wide range of blend proportions in air; It's much more of an explosion hazard than gasoline (and gasoline is the wrong comparison in the context of trucks - diesel fuel is incredibly difficult to ignite by comparison with either gasoline or hydrogen).

    Hydrogen is a great vehicle fuel in the lab. It's bloody awful in the real world, which is why it's never been seriously adopted by anyone. It's hard to contain; leaks are hugely dangerous; it is hard to carry in worthwhile quantities without very heavy containers; And it's a nightmare in any kind of crash.

    Hydrogen is a very poor substitute for gasoline - if you are going to make fuel from 'spare' electricity, you're better off making alcohols or hydrocarbons. In fact, from an engineering perspective, octane [or octane + ethanol] (gasoline) is a great fuel; And nonane thruogh hexadecane (diesel) is even better from a safety perspective.

    The only problem with these fuels is that they are currently sourced from fossil reserves, rather than being synthesized from atmospheric carbon dioxide (and water).
    That picture of the Hindenburg blowing up is most striking.
    NOTE: No trees were killed in the sending of this message, but a large number of electrons were terribly inconvenienced.

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    New 'anti-solar' panel generates electricity in the dark | TheHill
    noting
    Anti-Solar Cells: A Photovoltaic Cell That Works at Night | UC Davis
    What if solar cells worked at night? That’s no joke, according to Jeremy Munday, professor in the Department of Electrical and Computer Engineering at UC Davis. In fact, a specially designed photovoltaic cell could generate up to 50 watts of power per square meter under ideal conditions at night, about a quarter of what a conventional solar panel can generate in daytime, according to a concept paper by Munday and graduate student Tristan Deppe. The article was published in, and featured on the cover of, the January 2020 issue of ACS Photonics.
    noting
    Nighttime Photovoltaic Cells: Electrical Power Generation by Optically Coupling with Deep Space | ACS Photonics

    It would work by tapping thermal energy that powers infrared-light emission.


    Circular economy can improve the profitability of wind power -- and vice versa | EurekAlert! Science News
    In Åland, the circular economy processes selected for research were biodiesel production utilising waste from the fish industry and the further processing of biogas into synthetic methane. In addition to methane, biogas produced from biowaste contains carbon dioxide, which must be separated from the methane to produce valuable fuel equal to natural gas. However, carbon dioxide can be used to manufacture synthetic methane with hydrogen, but hydrogen production requires a lot of electrical energy. Consequently, the cost and origin of electricity largely determine the profitability and ecological sustainability of the process.
    Thus getting around intermittency by making synfuels when the wind is blowing.

    Plummeting costs spur Oregon floating wind activity | New Energy Update
    The U.S. Pacific coast is seen as a major future market for emerging floating wind technology, as water depths are too large to accommodate fixed-bottom wind farms. Several projects have been proposed in California and activity is now spreading north. Demand for renewables in Oregon is set to soar as utilities race to meet stringent state targets.
    Fossil Fuels Aren’t Even a Very Good Investment | The New Republic
    Jim Cramer is done with fossil fuel stocks. It’s not that the fundamentals are bad, the irascible investment guru and Mad Money host told CNBC anchor Becky Quick last week. The dividends are great. But “nobody cares,” he explains. “The world has changed. There’s new managers [trying to] appease younger people who believe that you can’t ever make a fossil fuel company sustainable. In the end they make fossil fuels. We’re in the death knell phase.”

    Quick rushed to clarify. “The death knell phase for the stocks, but not the death knell phase for us using fossil fuels, right?” Cramer didn’t offer much comfort, comparing multinational oil and gas companies—historically, some of the world’s most profitable—to the comparatively meager and maligned tobacco industry. “You can tell that the world’s turned on them.”
    Nice to see rejection of blood money.

  8. Top | #778
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    Synthetic gas could be as cheap as fossil fuels by 2022–report - "But better infrastructure will be needed."

    noting CO2-to-Fuels Renewable Gasoline and Jet Fuel Can Soon Be Price Competitive with Fossil Fuels: Joule
    Whenever we fill up at the pump or take our seat on an airplane, we add to the carbon emissions cycle created by the transportation industry. Despite knowing its negative effects, the cost and access to alternatives can be prohibitive (Teslas aren't cheap). But with recent innovation in renewable fuel technology, a new report predicts that synthetic gas will become as cheap as fossil fuel by 2022.

    The report, published last week in the energy-focused academic journal Joule, focuses on one type of renewable energy creation in particular called direct air capture (DAC), and highlights how this alternative could fit into already existing fuel infrastructure.

    ...
    "Recent breakthroughs in separations and catalysis, along with long-trend reductions in solar and wind electricity costs, have significantly increased the potential for cost-competitive renewable fuels from direct air capture (DAC) of CO2," writes McGinnis. "This is an important development because there is little time available to reduce CO2 emissions sufficiently to avoid the worst effects of climate change."
    Report author Rob McGinnis claims that catalysts are now good enough to enable the necessary reactions to occur at room temperature and atmospheric pressure, with the CO2 being dissolved in water. Thus doing Fischer-Tropsch without a lot of heat and pressure.

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