Intern applicants have rated the interview process at Calpine with 3 out of 5 (where 5 is the highest level of difficulty) and assessed their interview experience as 100% positive. To compare, the company-average is 64.9% positive. This is according to Glassdoor user ratings.
Here are the most commonly searched roles for interview reports -
Many rounds, first with HR phone, then several with employees on the trading floor. It was an enjoyable experience as well. Offer can be expedited if necessary. Asked brainteasers, market making questions, etc.