From Faraday's Coil to the Turbine Hall

The 29 August 1831 demonstration at the Royal Institution: moving a magnet through a coil of wire produces a current. Electromagnetic induction is the working principle of the generator and the transformer, nearly all electricity generated since.

The machine built on Faraday's own principle, and developed by Faraday himself in 1832: steam, water and gas turbines exist to spin it, which is why most of the world's electricity arrives through one.

Charles Parsons's 1884 heat engine, the single most widely used electricity-generating machine ever built; every operating nuclear power plant generates through one, and coal was its first century's fuel.

James Francis's 1849 reaction turbine, associated with sites like the Aswan High Dam; a mixed-flow design that takes the middle range of head and flow, leaving the very high heads to Pelton wheels and the low ones to adjustable Kaplan turbines.

Viktor Kaplan's 1913 refinement: adjustable blades combined with adjustable wicket gates to hold efficiency across a wide range of flow, suited to the low-head, high-flow rivers where a Pelton wheel would be the wrong tool.

Lester Allan Pelton's impulse design, patented 26 October 1880, for the opposite end of the hydropower range from Kaplan's: very high heads and low flows.