Thursday Night Links

• The Treasury Department will stop putting new pennies into circulation by early next year. Afterward, there won’t be enough pennies to use in everyday cash transactions, and businesses will need to start rounding up or down to the nearest 5 cents, the Treasury said in a statement. [WSJ]
• While the load-carrying capacity of a theoretical airship increases linearly with its length in calm air, once an airship grows to span bodies of air moving in different directions, the thickness of the airframe required to withstand discrete gusts grows at the 10/9 power. That suggests that above a certain size, the load-carrying capacity of an airship no longer increases but rather decreases with scale, since the airship structure has to be made heavier to survive the wind loads it will encounter. [Orca Sciences]
  
• In a net-zero world, we’ll lose the lowest-cost sulfuric acid we use to produce phosphate fertilizer. But other sulfur sources will pick up the slack long before other acids are used or a direct approaches to sulfur recycling become economical. [Orca Sciences]
• Given that all contrails represent ~2% of global warming, this indicates that ~1% of global warming is addressable today at under $1/tCO2eq. I don't know of any other climate intervention with such a low upfront cost and such a high probability of success. So why aren’t all airlines doing this yet? You’d think convincing airlines to avoid contrails would be easy. It’d cost them about $5 per flight to cut their climate roughly in half, vastly cheaper than any low-carbon fuel. But no airline has yet committed to it. A pessimistic take is that contrails are a ‘sincerity test’ for the world’s willingness to engage in the most cost-effective climate action, and the world is flunking so far. [Orca Sciences]
• Over a 30- to 40-year life, the energy a typical transformer dissipates as heat can cost close to five times its purchase price. Upgrading to a higher-grade core alloy—or simply right-sizing the unit—would save customers billions of dollars per year. Yet many U.S. utilities still order the cheapest devices that meet federal minimum standards, and virtually none adopt the higher-performing devices common in other countries. Why? Because ratemaking rules let them pass those losses straight through to customers and penalize them for spending that doesn’t add capacity directly. [Orca Sciences]
• Crushed rock down to a few millimeters costs $2-$3 per raw ton of rock. Course grinding down to 30 microns with ball mills costs $7-$11 per raw ton of rock. Fine grinding to ~10 microns with a stirred mill or similar technology is $12-$15/raw ton. [Orca Sciences]
• Because liquid fuels are pricey on an energy basis, synthetic fuels using dirt-cheap solar or wind could be economical. $60 per barrel of oil equates to ~$35/MWh. New solar is under $30/MWh today. Assuming a conversion efficiency of around 33%, the breakeven to make fuels would be ~$12/MWh. [Austin Vernon]
• Decentralized energy generation through solar panels paired with battery storage limits how high rates can go. Customers can defect if going off-grid or adding solar becomes cheaper. In places like California, where households pay ~$0.25/kWh, many can save money by adding a solar plus storage system. The cheaper solar and batteries get, the more competition utilities face. [Austin Vernon]
• Some processes need a lot of heat at very high temperatures (1000+ Celcius). They might be less sensitive about maintaining a specific temperature or be so large that thermal mass moderates any swings. In these cases building a furnace directly into the process makes sense. Blast furnaces in integrated steel plants and kilns in cement manufacturing are classic cases. Coal has the dominant market share in these applications. [Austin Vernon]
• Many environmental groups have already begun to protest solar and wind farms. Ground-mount solar is the industrialization of the solar PV ecosystem. Solar was OK when it was expensive because it would decrease energy usage. Technology that paves the ground and makes $10/MWh electricity attainable, driving demand up, is not what Greenpeace had in mind. [Austin Vernon]
• Modern chemical facilities usually have continuous processes, meaning each plant produces a constant amount of product rather than lumpy batches. The benefits are very similar to the Toyota Production System (they are independent discoveries of the same principles). There is no inventory accumulation within the process, equipment is optimally sized, product velocity through the equipment is high, steady-state conditions reduce variation in product quality, and there is a relentless focus on reliability because any single failure can trip the plant offline. The move to continuous processes happened naturally because many reactions will not go to completion in a batch reactor. Continuously fed reactors allow for the separation of the product and recycling of the reactant. Chemical engineering doesn't have the same dogma as Toyota because these other benefits were an accident. It is left as "continuous is better" in school. So you'll see a plant with perfect one-piece flow and incredible quality sending its product to giant tank farms or warehouses where there might be months worth of inventory! [Austin Vernon]
• Consider the light metals in the top right quadrant in the electrochemistry figure. Al and Mg both have far higher strength/weight ratios than steel; they resist corrosion much better; their production is already electrified; and their ores are arguably easier to find– Al is the most common metal in the earth’s crust, Mg is extractable directly from seawater. Both metals are more expensive than Fe today, primarily because they take much more energy to produce. But in a world with cheaper clean electricity – the world we need if we want to decarbonize steel production anyway—in the future we want, we should expect more use of Al and Mg, and much less use of steel. [Orca Sciences]
• There’s a big push out there to make steel electrically (molten oxide electrolysis, aqueous electrolysis, H2 direct reduction etc). But here Sam shows that at the renewable energy $/kWhr price that makes electro-steel work economically, the world might start switching to aluminum as a structural material. Aluminum is electrified already, comes from a more plentiful ore, has a better strength/weight ratio, and suffers from less corrosion (corrosion of steel costs us >1% of global GDP!). Currently, Al production emissions are nearly five times those of steel. But if you grant the conditions that would make electro-steel viable (i.e. near-free renewable electrons) and believe Alcoa’s claims regarding the near-term viability of carbon-free anodes, then Al prices (currently ~$2000/t, 2/3 of which is electricity for the carbon-free process) will sink towards the steel price (currently ~$1000/t, mostly ore and process cost). [Orca Sciences] 
• The same transformation has happened in almost every corner of our material lives. It has been happening for thousands of years and in every material category. Over time people have switched from mud to brick to cement, from wood to plastics to fiberglass to carbon fiber, from copper to bronze to steel to titanium, from leather to cotton to nylon, from smallholder to factory farms, from heaps of coal to thin wafers of solar PV, from vacuum tubes to specks of semiconductor, from highways to runways to Zoom. Energy intensity increases, materials get stronger and lighter, machines pack more power into smaller spaces. A signature element of modernity is how we’ve moved from materially-centered ways of doing things to energy-centered ways of doing things. Some people call this trend ‘dematerialization’. But that’s misleading. The world today may be made relatively less of stuff, but for various growth and demographic and Jevons reasons overall there’s way more stuff than ever. So I think it’s best to think of it as our world being made more and more out of energy. [Orca Sciences]