The modern steam engine was invented by James Watt. The invention of the steam engine changed the world and heralded in the industrial age. What James did was take an invention and change it to make it useful by designing a condenser and making the production of steam more efficient. James also defined horsepower.
Steam for home power
Steam energy is the basis for the majority of the worlds electricity, steam from water heated by coal, nuclear or oil generated heat.
Steam for home power can be renewable if you have access to a woodlot that can be sustainably harvested. A company called Strath Steam are one of the last steam engine manufacturer left in Australia.
Steam works like this:
The water is heated in a boiler by the burning of firewood. When the boiler has generated sufficient steam this is taken to the steam engine where it converts the steam energy into a rotational force. This rotational force is then used to spin an efficient alternator to produce electricity.
When the steam leaves the engine it is directed through a condenser that takes the remaining heat from the steam and condenses the steam back into water. The water is then fed into a feed water tank where it is returned to the boiler via a feed water pump.
The byproduct of steam power is heat
When the steam leaves the steam engine it is still very hot. The easiest way to cool the steam to the point where it condenses is to feed a condensing tube through a hot water tank. Typically running at medium power the Strath Steam steam engine will produce around 200 litre's of boiling water per hour.
Obviously you need to do something with this water. Heating a house, a greenhouse, a swimming pool, a sauna, whatever, getting rid of heat is part of the steam engine experience.
In the picture below: The boiler is the brown cylinder mounted over a brick firebox. In front of the boiler is the steam engine, in this example it is driving 2 x Fisher & Paykel washing machine motors that have been converted to become DC generators producing around 900 watts (48 volt system connected). The black item forward of the steam engine is the feed water pump that circulates the re condensed water from the feed water tank below the bench. In the rear left corner is a hot water tank with a condensing coil inside it. Not shown is a pump that circulates the hot water from this tank for other uses.