Tag Archives: coal

China keeps building coal-fired plants so we can close ours.

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Part of the mandate to the 2020 election was to join with Europe and the rest of the western world in agreeing to stop the use of coal. It’s a low cost way to generate energy. Of course we still like to buy things, and we’ve largely turned to China, a country that still burns coal, and thus makes things cheap. The net result of this shift to Chinese goods is that China keeps building coal-fired plants while we shut ours. As it happens, China is worse than the US in terms of CO2 per output, but at least when China pollutes, we don’t see the smoke directly, and we don’t see their new coal plants at all. So we feel better buying things from China than from the US. Besides, slave labor is cheap.

From th eEconomist, December 2020.

Buying Chinese goods is good for the importers, and for the non-manufacturing consumer, at least in the short term. It has the effect of exporting jobs though, and eventually we have to support the displaced workers. It also means we don’t keep up our manufacturing technology. Long term, that affects innovation, and that starts to displace other industries. Antibiotic production has already left the US and along with it semiconductors. Still, we feel good about it since the Chinese don’t let us see the slave labor camps. We do get to see the haze of the pollution.

The Chinese expect this pattern to continue. China is building new coal-fired plants at a furious rate. Presently China has most of the world’s coal-fired power plants. Mostly these are only 4 to 12 years old, far younger than our forty year old plants China plans to build more, and keeps encouraging us to shut down ours. Even 10 years ago, China lead the world in CO2 output. And their fraction of the CO2 keeps climbing.

China is popular with the press. In part, I expect, that’s because they pay the international experts. lAlso, writers and editors are consumers industrial products, but not manufacturers. Consumers benefit from slave labor, or maybe not, but displaced American workers certainly suffer. Also, of course, the news requires pictures and personal stories to keep viewer interest. If you can’t get pictures of young protesters, like Grey Thunberg, you can get an interesting story. Our Chinese pollution is out of sight, and not in the press.

Robert Buxbaum, January 6, 2021. BTW, if we wanted preserve jobs and stop CO2 pollution, we’d go nuclear.

The future of steamships: steam

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Most large ships and virtually all locomotives currently run on diesel power. But the diesel  engine does not drive the wheels or propeller directly; the transmission would be too big and complex. Instead, the diesel engine is used to generate electric power, and the electric power drives the ship or train via an electric motor, generally with a battery bank to provide a buffer. Current diesel generators operate at 75-300 rpm and about 40-50% efficiency (not bad), but diesel fuel is expensive. It strikes me, therefore that the next step is to switch to a cheaper fuel like coal or compressed natural gas, and convert these fuels to electricity by a partial or full steam cycle as used in land-based electric power plants. 

Ship-board diesel engine, 100 MW for a large container ship

Diesel engine, 100 MW for a large container ship

Steam powers all nuclear ships, and conventionally boiled steam provided the power for thousands of Liberty ships and hundreds of aircraft carriers during World War 2. Advanced steam turbine cycles are somewhat more efficient, pushing 60% efficiency for high pressure, condensed-turbine cycles that consume vaporized fuel in a gas turbine and recover the waste heat with a steam boiler exhausting to vacuum. The higher efficiency of these gas/steam turbine engines means that, even for ships that burn ship-diesel fuel (so-called bunker oil) or natural gas, there can be a cost advantage to having a degree of steam power. There are a dozen or so steam-powered ships operating on the great lakes currently. These are mostly 700-800 feet long, and operate with 1950s era steam turbines, burning bunker oil or asphalt. US Steel runs the “Arthur M Anderson”, Carson J Callaway” , “John G Munson” and “Philip R Clarke”, all built-in 1951/2. The “Upper Lakes Group” runs the “Canadian Leader”, “Canadian Provider”, “Quebecois”, and “Montrealais.” And then there is the coal-fired “Badger”. Built in 1952, the Badger is powered by two, “Skinner UniFlow” double-acting, piston engines operating at 450 psi. The Badger is cost-effective, with the low-cost of the fuel making up for the low efficiency of the 50’s technology. With larger ships, more modern boilers and turbines, and with higher pressure boilers and turbines, the economics of steam power would be far better, even for ships with modern pollution abatement.

Nuclear steam boilers can be very compact

Nuclear steam boilers can be very compact

Steam powered ships can burn fuels that diesel engines can’t: coal, asphalts, or even dry wood because fuel combustion can be external to the high pressure region. Steam engines can cost more than diesel engines do, but lower fuel cost can make up for that, and the cost differences get smaller as the outputs get larger. Currently, coal costs 1/10 as much as bunker oil on a per-energy basis, and natural gas costs about 1/5 as much as bunker oil. One can burn coal cleanly and safely if the coal is dried before being loaded on the ship. Before burning, the coal would be powdered and gassified to town-gas (CO + H2O) before being burnt. The drying process removes much of the toxic impact of the coal by removing much of the mercury and toxic oxides. Gasification before combustion further reduces these problems, and reduces the tendency to form adhesions on boiler pipes — a bane of old-fashioned steam power. Natural gas requires no pretreatment, but costs twice as much as coal and requires a gas-turbine, boiler system for efficient energy use.

Todays ships and locomotives are far bigger than in the 1950s. The current standard is an engine output about 50 MW, or 170 MM Btu/hr of motive energy. Assuming a 50% efficient engine, the fuel use for a 50 MW ship or locomotive is 340 MM Btu/hr; locomotives only use this much when going up hill with a heavy load. Illinois coal costs, currently, about $60/ton, or $2.31/MM Btu. A 50 MW engine would consume about 13 tons of dry coal per hour costing $785/hr. By comparison, bunker oil costs about $3 /gallon, or $21/MM Btu. This is nearly ten times more than coal, or $ 7,140/hr for the same 50 MW output. Over 30 years of operation, the difference in fuel cost adds up to 1.5 billion dollars — about the cost of a modern container ship.

Robert E. Buxbaum, May 16, 2014. I possess a long-term interest in economics, thermodynamics, history, and the technology of the 1800s. See my steam-pump, and this page dedicated to Peter Cooper: Engineer, citizen of New York. Wood power isn’t all that bad, by the way, but as with coal, you must dry the wood, or (ideally) convert it to charcoal. You can improve the power and efficiency of diesel and automobile engines and reduce the pollution by adding hydrogen. Normal cars do not use steam because there is more start-stop, and because it takes too long to fire up the engine before one can drive. For cars, and drone airplanes, I suggest hydrogen/ fuel cells.