AnS purchased in the free AnS day-ahead market or through tender can be divided into the following categories:

• primary frequency control (PC) 
• secondary power control (SC)
• tertiary power control (TC)
• quick-start reserve available within 10 minutes (QS10)
• quick-start reserve available within 15 minutes (QS15)
• operating reserve (OR)
• rapid unloading (RU30) 

The following AnS can be purchased via a direct contract with an AnS provider:

• Vltava river (VRC) 
• load change (LC30)
• secondary voltage and reactive power control (SUQC) 
• island operation capability (IO) 
• black start capability (BS) 

Assistance from interconnected power systems:

• emergency assistance;
• real-time electricity supply from/to neighbouring countries.

A full overview of AnS categories and the technical definitions regarding AnS can be found in the Grid Code.