Transforming the Twentieth Century: Technical Innovations and Their Consequences

industrial processes.

In contrast, electricity intensity continued to increase even after 1950: electricity

the gas turbine. In less than two decades after its introduction, this machine transformed many facets of modern societies: without it there would be neither affordable long-distance flights nor inexpensive long-distance deliveries of natural gas.

oxygenation of aquacultural ponds (now the fastest expanding method of producing animal protein)

One of the greatest engineering challenges that had to be overcome in order to bring such machines to market included the development of single-crystal nickel-based superalloys for turbine

Comparisons for the Western world show that during the 20th century life expectancies rose from the mid-40s to the late 70s; cost of food as the share of disposable income fell by anywhere between 60% and 80%; virtually all households had electricity supply and were saturated with telephones, radios, TVs, refrigerators, clothes washers, and microwa

There are only three major classes of fossil fuels (coals, crude oils, and natural gases) and five major renewable energy flows (direct solar, wind, water, tides, biomass), and only a handful of prime movers (steam, water, wind, and gas turbines and internal combustion engines) are used to convert these energies into electricity, heat, and motion.

Finally, CO2 (in steam reforming of natural gas: 7.05 kg of this gas is produced per kilogram of hydrogen)

Cost advantages drove this innovation: minimills, dispensing with blast furnaces, needed much lower capital investment (only 15–20% of the total needed for new BFs), and their operating costs were also considerably lower as continuous casting eliminated the equipment and energy needed for reheating and shaping the ingots