 During the Queen 's tenure much has been done , not only to restore and maintain the fabric of the building , but also to transform it into a major British tourist attraction , containing a significant portion of the Royal Collection of art , which is managed from Windsor . Archaeological work has continued at the castle , following on from limited investigations in the 1970s , the work on the Round Tower from 1988 – 92 and the investigations following the 1992 fire . During 2007 , 993 @,@ 000 tourists visited the castle . This has had to be achieved in co @-@ ordination with security issues and the castle 's role as a working royal palace . In late 2011 two water turbines were installed along the River Thames to provide hydroelectric power to the castle and the surrounding estate . In April 2016 it was announced that the Royal Collection Trust is to fund a £ 27m project that will reinstate the original entrance hall of the castle to visitors , as well as a new cafe that will be housed in the 14th Century undercroft . The project will be completed at the end of 2018 , and will include a visitor centre and a dedicated learning centre . 
