State Corporation Commission; cost allocation proceedings for certain electric utilities. Directs the State Corporation Commission to conduct proceedings to review cost allocation among different customer classifications for certain electric utilities. For Dominion Energy and Appalachian Power, the Commission is directed to determine if the cost allocation of transmission costs require customers that are not high-load customers, as defined in the bill, to unreasonably subsidize the transmission costs attributable to serving high-load customers by January 1, 2027. For Dominion Energy, the Commission is directed to determine if the current allocation of generation and distribution costs require customers that are not high-load customers to unreasonably subsidize the generation and distribution costs attributable to serving high-load customers by January 1, 2028.