Sorry for being confusing, the planned cuts I wrote of are in Italy.

there are at least 100,000 solar PV installations in Spain. Which using information from the national system operator suggests an average solar pv installation size of less than 50 watts.

You confuse mean and median... The typical size of rooftop installations is 10kW. 100,000 of those is 1GW -- much less than half of the Spanish total.

I brought some numbers on this here: DoDo:

the 2008 Spanish PV boom (see stats upthread) was overwhelmingly in large greenfield farms (and large industrial rooftops), not on private home rooftops. While I don't have actual stats for it, one can add up the 2008 Spanish plants in the World's largest photovoltaic power plants ranking: just the farms 2MW or above add up to 2096 MW, out of the 2700MW total. (Out of the 3400MW added in Germany this year, the same number is just 517 MW.)