PIERRE, S.D.(WNAX)- The South Dakota Public Utilities Commission is dealing with a request from Black Hills Energy to add extra charges to customers that have their own power generation facilities.

Chairman Chris Nelson says its part of the changing mix of electricity production.

Nelson says there are fixed costs to maintain the electric grid for all customers.

Nelson says this case could be the first of a rising wave.

The Commission has allowed more parties to intervene in the hearing, which will be held later.