NorthWestern Energy Clarifies Information Related to Colstrip Unit 4

On July 1st, Colstrip Unit 4, a 740MW net generation unit in which NorthWestern Corporation d/b/a NorthWestern Energy NWE owns a 30% share (222 megawatts (MW)), tripped off-line.  Upon initial inspection, damage to the stator/rotor assembly was evident, consistent with a ground fault.  PPL Montana (PPL), the operator of Colstrip Unit 4, currently is developing a repair schedule. It is expected the unit will remain under repair for at least six months. Under the company's Reciprocal Sharing Agreement (RSA) with PPL, each party equally shares its allocation of the output, as well as the respective costs required to operate, maintain and repair each unit. Therefore the RSA effectively limits NorthWestern's share of the repair cost for this outage (and any other outage occurring at Colstrip Unit 3 or 4) to 15% of the total cost.   Also as a result of the RSA, NorthWestern will continue to receive a 15% share of the output of Colstrip Unit 3 (approximately 111MW at full capacity).  See full press release