The beauty of steam is that any heat source makes it. Once made it becomes power. Historically heat came from wood, then coal, then hydrocarbons, and then nuclear fusion, or is it fission, and now it is going back to wood, a carbohydrate made of glucose molecules, and solar energy. For some people it appears that making steam with heat is either too simple or too complex because they want to do it some other way.
I am going to list the other methods with the comment that they are uniformly bad ideas. Most of the time I attempt to be polite and diplomatic. It is a struggle. We do not have the time, space, or psychic energy to be polite today.
The first bad idea is cavitation. Someone figured out that a metal cylinder with gouges milled into it with an end mill and when submerged in a tank of water and rotated at high speeds so that cavitation–the forming and collapsing of steam bubbles–happens a lot will turn mechanical power into steam with over 90% efficiency. Therefore they want to make steam that way forgetting that the rotating power is usually an electric motor and the main reason to make steam is to generate electricty and thus this exercise in the conservation of energy and thermodynamics will barely and with good luck end up with 20% of the electricity started with. It is an idea, just not a good one.
The next bad idea is microwaves. Someone read that microwaves heat water at a high degree of efficiency and thus we need to make steam that way. Similar comments can be made about conservation of energy as the above paragraph. What one concludes is that steam has a magical attraction to many people. It would be more convenient if those people excited about steam had taken physics in high school.
Another method of confusing energy is to use electricity to make steam. We are blessed with two ways: the most obvious is a resistance wire and if one does not like that then there is a way to take alternating current and bounce it back and forth between two plates immersed in water, heating it by some means of internal friction. The efficiencies of turning electricity into heat into steam do not need to be addressed because the overall efficiency is bad. If a person gained some advantage in torque or power transmission or drive train and drive cycle efficiency over using electricity directly then one might make an argument for this long way around the barn. Electricity, no friend of mine, appears to be a reliable method of generating large amounts of torque; at least good enough to operate heavy freight trains.
The latest way I heard of recently is ultrasound. There is little that I can say at this point in the discussion because of the mental exhaustion induced by the above interesting ideas.