Madrid offers a wide range of hotel options across different price ranges.
For convenience during the conference at CIEMAT, participants may especially wish to consider accommodations in the Moncloa area, which is located nearby.
One example is the following one:
Hotel Exe Moncloa (4*): https://www.eurostarshotels.com/exe-moncloa.html
If you prefer a more central location, hotels around Plaza España, Gran Vía, or Plaza Mayor are at a distance in public transport from CIEMAT of around 30 minutes for Plaza España or 40 minutes for Gran Vía or Plaza Mayor. Some examples from the Catalonia hotel chains are:
Hotel Catalonia Plaza España: https://www.cataloniahotels.com/es/hotel/catalonia-plaza-espa%C3%B1a
Hotel Catalonia Gran Vía: https://www.cataloniahotels.com/es/hotel/catalonia-gran-via-madrid
Hotel Catalonia Plaza Mayor: https://www.cataloniahotels.com/es/hotel/catalonia-plaza-mayor