The airport of Madrid is connected to the Metro system, providing service to the center of Madrid within 30 minutes for the price of 4,50 €. Find more information under: http://www.metromadrid.es/en/index.html
Depending on traffic, a taxi from the airport to the centre of Madrid takes about the same time or longer and costs 30 € fixed price. The legal frame of taxi rides to/from the airport can be consulted under: http://www.aeropuertomadrid-barajas.com/transportation/madrid-airport-bytaxi.htm. Please, note that a taxi from ESAC to Madrid (Barajas) airport takes about 50 min in normal traffic conditions.
Information for tourists
In the official tourism webpage of Madrid you can find additional information, maps and guides.