When the energy market is deregulated in a given area, it is assumed that the regulated market was a monopoly, and that many customers will either stay with the provider they had in the regulated market or will not find a competitive supplier willing to serve them. The default provider is the energy provider who makes service available to these customers. This provider, also referred to as the provider of last resort, may be a disaggregated version of their original provider, or a separate entity set up by a local utility or government agency to provide service to customers which might otherwise be orphaned or have no access to competitive suppliers.

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