The Unmetered Supply (UMS) Certificate is issued by the UMSO to a customer taking an unmetered electricity supply. It confirms the agreement to offer an unmetered supply and provides key information that is used by the electricity supplier to bill the customer. For example, it will identify whether the UMS supply is to be settled on a Non-Half Hourly or Half Hourly basis.
Where the UMS is settled Non-Half Hourly and the UMS Certificate is issued for the first time, it will give the MPAN(s) and the Estimated Annual Consumption (EAC). The UMS Certificate is updated when something changes, such as the inventory of equipment.
The customers’ chosen electricity supplier will require the information on the UMS Certificate to offer commercial terms and, once accepted, to register the MPAN.
If the customers’ connected equipment changes, they should provide an updated inventory which will usually change the EAC so a new UMS Certificate will be issued with a copy passed to the registered electricity supplier to amend the billing details. The customer must confirm once a year to the UMSO that the inventory has not changed.
There are currently two methods to trade electricity. The UMSO activities differ for each trading arrangement. Customers with small equipment inventories will be operating on a non-half hourly basis whereas the larger highway authorities trade on a half-hourly basis. However, from 2024 all new connections will only by provided on a half hourly basis and all remaining non-half hourly will be migrated to half hourly.