Solar Water Heating
Statistics in this 2004 assessment show that whilst many forms of alternative energy technologies have been receiving lots of press in Europe and the US, this does necessarily paint a picture of activities elsewhere. China and Japan (No 1 and 2 in capacity) can count Solar Water Heating systems as very much the norm as they have embraced this easy to install technology. The total power being saved by using solar thermal to heat water by traditional rooftop modules is estimated at 70GW (70 Nuclear installations are not needed) where China and Japan account for half of this amount.
Since these figures are a bit dated and by looking at the low figures for Wind Energy in the graphs, you could estimate that a more up to date figure for installed global Solar Water Heating capacity is nearer to 80GW. Growth in Europe averages out at about 20% and with the increase in public awareness, higher power bills and uncertainty in energy supplies, no real barriers seem to exist for the expansion of Solar Water heating.
All the details can be viewed in www.estif.org/143.0.html