billion Euros, about 5% of GDP, in 2006. Today, the climate of Spain, historical and cultural monuments and its geographic position together with its facilities make tourism one of Spain's main national industries and a large source of stable employment and development. The Spanish hotel star rating system has requirements much more demanding than other European countries, so at a given rating Spanish accommodations worth higher.
Energy
Spain is one of the world's leading countries in the development and production of renewable energy. In 2010 Spain became the solar power world leader when it overtook the United States with a massive power station plant called La Florida, near Alvarado, Badajoz. Spain is also Europe's main producer of wind energy. In 2010 its wind turbines generated 42,976 GWh, which accounted for 16.4% of all the energy produced in Spain. On 9 November 2010, wind energy reached an instantaneous historic peak covering 53% of mainland electricity demand and generating an amount of energy that is equivalent to that of 14 nuclear reactors. Other renewable energies used in Spain are hydroelectric, biomass and marine (2 power plants under construction).
Non-renewable energy sources used in Spain are nuclear (8 operative reactors), gas, coal, and oil.
Transport
The Spanish road system is mainly centralized, with six highways connecting Madrid to the Basque Country, Catalonia, Valencia, West Andalusia, Extremadura and Galicia. Additionally, there are highways along the Atlantic (Ferrol to Vigo), Cantabrian (Oviedo to San Sebastián) and Mediterranean (Girona to Cádiz) coasts.
Spain has the most extensive high-speed rail network in Europe, and the second most extensive in the world after China. As of October 2010 Spain has a total of 3,500 km (2,174.80 mi) of high speed tracks linking Málaga, Seville, Madrid, Barcelona, Valencia and Valladolid, with the trains reaching speeds up to 300 km/h (187