A Megawatt
In 2013, 37,007 megawatts of solar PV power were installed and world solar PV power capacity increased about 35% to 136,697 MW. One MW can power thousands of homes.
Europe, thanks to Germany, has dominated annual growth until 2013 when China topped the tables (Germany's subsidies have allowed volume uptakes that have driven pricing down globally).
Installation of solars panels in the UK is now ca. £8k. When I looked into panelling our home in 2011, it was £15K. Solar PV today accounts for 3% of electricity demand in Europe and about 6% of peak electricity demand. Trending in the right direction but will it be enough?
Evolution of global annual installation: