The steam synth runs on coal, Esbit Tablets (hexamine), Ethanol or Propane.
It requires a pretty constant, hot fire to keep the synth going continuously. The boiler can build up to 40-50psi before the safety valve opens.
The pressure delivered to the engine is controlled by a ball valve seen between the boiler and the engine. The dynamo is much like a brushless, permanent magnet motor which is spun by a belt attached to the flywheel. This creates an alternating magnetic field which is turned into electricity by an inductive pickup.
The steam synthesizer does not use any electricity — only steam power. In fact it generates electricity! It generates about 6 watts of AC at high pressure and speed.
The steam synthesizer runs for about 20 minutes on one tank of water.