The mains voltage is in Barcelona as in the whole of Europe 230 volts AC, plug adapters are hardly necessary.
The flat European standard fit into the Spanish sockets. In addition, the Schuko plug CEE 7/7. Most Europeans do not need to buy an adapter plug for Spain, it all fit plug and at home.
Swiss and US need an adapter.
In Spain, the share of renewable energy is 42.4% (2013) with increasing tendency. For the first time the wind was the most important energy sources for electricity generation is ascended. That there has been in any other country. The wind energy covers the electricity demand at 20.80%.
Despite radically coated subsidies, it is economical due to the good weather in Spain to operate solar power plants. At Christmas 2013 had to be throttled in Spain due to the high production of renewable energies, nuclear power plants.