The basic steam point of water is when it is heated to a temperature of 212 degrees Fahrenheit, 100 degrees Celsius or 373 degrees Kelvin.

However, thanks to a great many technological advances since the days of the Industrial Revolution and the first iterations of steam engines, much of the world's power plants now rely on a much higher controlled steam pressure point known as supercritical steam.  The term supercritical refers to a thermodynamic state in which a substance's liquid and gaseous states are essentially blurred, turning the substance into a single, homogenous fluid. Water reaches its supercritical point when it is  subjected to 22.1 megapascals of pressure. At highly sophisticated clean coal power plants, this process requires advanced metal alloy containment and translates to a temperature level of 720 degrees Fahrenheit or more.

Smaller scale steam applications are separately being embraced by both those seeking to live a more environmentally friendly green lifestyle and by self-professed members of the survivalist crowd, who see the simple transformation of water into vapor as a reliable and easily accessible mode of self-reliance. Reliable home steam power machines have yet to be fully harnessed, but it is an area of residential power growth poised to explode.

Originator of the Modern Water-Steam Applications 

Prior to the advent of the steam engine, the true originator of modern applications of the water-steam temperature point was Thomas Savery. He invented and patented in 1698 the Savery Pump, a process whereby steam was used to pump water out of mines rather than the previously antiquated method of buckets and bailing.