Renewable Energy has many parts, and some of them can do jobs that others cannot do. It is important to work together to bring the best renewable Energy to the world that we can hope to achieve.
This diagram represents a short overview over different elements of a renewable energy network, and what the different parts can do, and what not.
For example, Hydropower can be both an energy source (flowing water through a turbine) but also a means of energy storage (by keeping the water behind the dam). Renewable Biomass can be stored well, but can also be turned into a renewable source of energy. Batteries can store energy well, but cannot produce energy.
Thoughts, comments, likes :-)
Well, Wikipedia claims
In that sense, it's the only renewable energy source we have that's not indirectly powered by the sun. It's most similar to (proper) nuclear power, but the latter isn't "renewable" because it requires digging up fuel from the crust.