Gas storage facilities are required to be run efficiently, with an optimised operational and investment model, to maximise the return on capitol for the shareholders. The asset operation will often be automated and run remotely, where possible.  Hydrocarbon Accounting (HCA) & Third Party Access Systems manage the commercial process for the gas storage facility.  The HCA system needs to accurately interpret the rules of the storage agreement between the operator and the storage users to ensure a fair and non-discriminatory use of the facility.The business critical nature of HCA demands a high availability business system that is robust, scalable and flexible to account for both change and expansion.  The lean operation models necessitate a HCA system that is capable of reliably automating the key business processes in a secure, and by nature, web based environment.HCA systems will be considered mission critical and expected to have an extended operational life consistent with the asset investment.