"I fail to see the argument for photvolataic panels on houses. The system can not store the energy for later use"
not entirely true. A major component of electricity generation is transmission loss. PhotoVoltaic panels feed electricity into the grid locally . It is generated and consumed locally, reducing transmission loss, P.V. cell generation also mean F.F. power stations can reduce or turn off their output.
Electricity can be generated on demand by hydro systems. Hyrdro can also store energy - by pumping the water back uphill.
