Pattern Energy and Talen Energy Corporation (TEC) will invest up to $1bn to develop the 600MW Silverthorn wind project in southeastern Montana that will hook up for grid interconnection at the nearby Colstrip coal-fired plant's substation.

When commercially operational in 2026, Silverthorn will reduce the carbon intensity of Talen’s electric generation in Montana, help ensure grid resiliency, and provide reliable power for the state’s fast-growing economy, said the partners.

Silverthorn, which will become the state’s largest wind farm, is part of a joint venture between Pattern and Cumulus Renewables, an affiliate of Talen Energy Supply, the competitive energy business of parent TEC.