With a wind turbine or PV system, the storage of the energy is the expensive part of the system.
Using a water heater element to convert the energy into heat allows you to easily heat the liquid
used in your heating system and transferring the energy to your concrete floor which ends up being
the storage mass system for the energy produced. A well insulated concrete floor and building will
stay warm for a number of days after coming up to temperature. A bank of batteries can get expensive
and requires some maintenance for reliable service. You could also utilize a large insulated water tank
to hold hot water as your energy storage system. I have seen various system employed to provide heat
on hydronic systems. It really comes down to what your property will allow and what you can afford.
You could also use a passive hydronic solar panel system that converts the sun light into heat and heats the
liquid in the system and then circulates the liquid through the concrete floor. This type of system usually requires a small circulating pump and expansion tank to move the fluid through the system.