The MPX is being developed along two development paths 1) Rate-Based and 2) Merchant. The primary opportunity for the MPX is the Rate-Based path offered through the upcoming Massachusetts legislation, expected by the end of July. Meanwhile, in order to maintain the Merchant option, MPX applied to FERC for Negotiated Rate Authority in May, 2016.
On July 1, 2016, FERC Issued: "ORDER GRANTING APPLICATION FOR AUTHORIZATION TO CHARGE NEGOTIATED RATES, SUBJECT TO CONDITION, AND GRANTING WAIVERS" - Docket ER16-1619-000. You can read the Order here. This will allow the MPX to eventually issue an Open Solicitation to generators seeking access to Boston and the New England energy Market.
Merchant transmission projects are not new. Currently, MPX sister project, the New England Clean Power Link is conducting an Open Solicitation to serve ISO-NE. This Order will maintain the Merchant Option for the MPX while pursuing the Rate-Based option in the Mass RFP.