Should utilities (electricity) be defined as overhead or a seperate resource in OPM?

we are using actual costing and create a single batch for the whole period.

Since actual costs of utilities is available at period end we can simply update the usage and/or rate of electricity consumed and capture the actual cost.

Given this scenario can electricity be created as a single separate resource in OPM or is it necessary/helpful to create it as overhead and attach it to multiple resources (machines) ?