One of the big problems with PV and wind power is that they don't offer any inertial load on the grid. This means that once the percentage of these sources increase the grid frequency stability decreases.
When using renewables you must still generate a majority of your supply from a big rotating generator. The inertia of the spinning generator keeps the frequency from straying from 50/60hz.
In Ireland they broke a record a few years back for having 50% of the electric generation coming from wind power. This was at the upper limit set by the grid operator (eirgrid) because above this level the frequency of the grid becomes unstable. Even though more wind power was available they didn't add it to the grid.
When using renewables you must still generate a majority of your supply from a big rotating generator. The inertia of the spinning generator keeps the frequency from straying from 50/60hz.
In Ireland they broke a record a few years back for having 50% of the electric generation coming from wind power. This was at the upper limit set by the grid operator (eirgrid) because above this level the frequency of the grid becomes unstable. Even though more wind power was available they didn't add it to the grid.